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2024 Volume 39 Issue 1
2024, 39(1): 1-6
doi: 10.3866/PKU.DXHX202311076
Abstract:
With the advancement of the field of chemistry, the synthesis of an increasingly diverse range of compounds has become feasible. The study of substances now encompasses various scales:from macroscopic to microscopic, often extending into the mesoscopic domain, typically at the nanoscale. At the nanometer scale, many materials manifest size-dependent effects, with quantum dots standing out as the most prominent representative. Quantum dots denote a class of semiconductors that exhibit size-dependent quantum effects when their dimensions closely approach the exciton Bohr radius. Through meticulous size control while preserving a consistent chemical composition, it is plausible to modulate the bandgap along with the accompanying absorption and emission spectra. This characteristic brings new opportunities for the research and application of semiconductor nanomaterials. The 2023 Nobel Prize in Chemistry was awarded to quantum dots and claimed that they light up nanoscience. Combining the three Nobel laureates' work, this article embarks upon the historical trajectory of the discovery and synthesis of quantum dots, offering a concise overview of the pertinent scientific achievements.
With the advancement of the field of chemistry, the synthesis of an increasingly diverse range of compounds has become feasible. The study of substances now encompasses various scales:from macroscopic to microscopic, often extending into the mesoscopic domain, typically at the nanoscale. At the nanometer scale, many materials manifest size-dependent effects, with quantum dots standing out as the most prominent representative. Quantum dots denote a class of semiconductors that exhibit size-dependent quantum effects when their dimensions closely approach the exciton Bohr radius. Through meticulous size control while preserving a consistent chemical composition, it is plausible to modulate the bandgap along with the accompanying absorption and emission spectra. This characteristic brings new opportunities for the research and application of semiconductor nanomaterials. The 2023 Nobel Prize in Chemistry was awarded to quantum dots and claimed that they light up nanoscience. Combining the three Nobel laureates' work, this article embarks upon the historical trajectory of the discovery and synthesis of quantum dots, offering a concise overview of the pertinent scientific achievements.
2024, 39(1): 7-14
doi: 10.3866/PKU.DXHX202305078
Abstract:
Instrumental analysis experiment is one of the core curriculums due to its practicality and applicability. In the context of the construction of "Double First-Class" universities, in response to the existing problems in the teaching of instrumental analysis experiments, reforms have been made in terms of teaching mode, teaching content, and teaching methods. This has resulted in the creation of a multi-modal blended teaching course system that combines online and offline learning, conventional experiments, virtual simulation experiments, and autonomous innovative design experiments, as well as flipped classrooms and problem-based learning. Teaching practice has shown that this new teaching course system is conducive to stimulating students' interest and initiative in learning, guiding students to internalize knowledge, cultivating higher-order thinking and comprehensive problem-solving abilities, improving teaching efficiency, and optimizing teaching effectiveness.
Instrumental analysis experiment is one of the core curriculums due to its practicality and applicability. In the context of the construction of "Double First-Class" universities, in response to the existing problems in the teaching of instrumental analysis experiments, reforms have been made in terms of teaching mode, teaching content, and teaching methods. This has resulted in the creation of a multi-modal blended teaching course system that combines online and offline learning, conventional experiments, virtual simulation experiments, and autonomous innovative design experiments, as well as flipped classrooms and problem-based learning. Teaching practice has shown that this new teaching course system is conducive to stimulating students' interest and initiative in learning, guiding students to internalize knowledge, cultivating higher-order thinking and comprehensive problem-solving abilities, improving teaching efficiency, and optimizing teaching effectiveness.
2024, 39(1): 15-21
doi: 10.3866/PKU.DXHX202305091
Abstract:
Examining the construction of professional ideology and politics from a systemic perspective is of both theoretical and practical significance. Currently, there are several issues in the ideological and political education of chemical normal speciality, including dispersed ideological elements, generalized educational objectives, discrete course objectives, and a singular educational subject. To address these issues, the article proposes several measures:using holistic thinking to clarify the systemic nature of professional ideology and politics, using hierarchical thinking to enhance advanced cultivation goals, using collaborative thinking to enhance the coupling of various courses, using open thinking to enhance the aggregation of educational outcomes, and thus promoting the construction of professional ideology and politics in chemical education teacher training.
Examining the construction of professional ideology and politics from a systemic perspective is of both theoretical and practical significance. Currently, there are several issues in the ideological and political education of chemical normal speciality, including dispersed ideological elements, generalized educational objectives, discrete course objectives, and a singular educational subject. To address these issues, the article proposes several measures:using holistic thinking to clarify the systemic nature of professional ideology and politics, using hierarchical thinking to enhance advanced cultivation goals, using collaborative thinking to enhance the coupling of various courses, using open thinking to enhance the aggregation of educational outcomes, and thus promoting the construction of professional ideology and politics in chemical education teacher training.
2024, 39(1): 22-28
doi: 10.3866/PKU.DXHX202305081
Abstract:
The newly published "Organic Chemistry Experiment (6th Edition)" from Dalian University of Technology combines both printed textbook and online digital resources. The online resources integrate the content from the teaching CD and website resources in 5th edition, alongside newly developed digital resources for 6th edition, to enhance and expand the printed version. The textbook newly presents 14 fundamental experiments in topics about reaction mechanism verification, visualized synthesis, Huang Minglong's reduction, and olefin interchange etc. Additionally, it includes 3 comprehensive experiments:natural cinnamaldehyde extraction and hydroxyaldehyde condensation, proline-catalyzed asymmetric synthesis and LED photocatalytic luminescent material preparation. All new experiments draw from domestic and international experimental teaching papers. Moreover, A design-oriented experiment on industrial flavor esters using the Fischer esterification synthesis, as well as a research-oriented experiment which optimizing the reaction condition for the microwave-assisted Williamson synthesis of 4-nitrophenethyl ether, are also dicussed. The 6th edition textbook establishes a personalized learning platform fostering students' experimental abilities and cultivating a rigorous and innovative style of study.
The newly published "Organic Chemistry Experiment (6th Edition)" from Dalian University of Technology combines both printed textbook and online digital resources. The online resources integrate the content from the teaching CD and website resources in 5th edition, alongside newly developed digital resources for 6th edition, to enhance and expand the printed version. The textbook newly presents 14 fundamental experiments in topics about reaction mechanism verification, visualized synthesis, Huang Minglong's reduction, and olefin interchange etc. Additionally, it includes 3 comprehensive experiments:natural cinnamaldehyde extraction and hydroxyaldehyde condensation, proline-catalyzed asymmetric synthesis and LED photocatalytic luminescent material preparation. All new experiments draw from domestic and international experimental teaching papers. Moreover, A design-oriented experiment on industrial flavor esters using the Fischer esterification synthesis, as well as a research-oriented experiment which optimizing the reaction condition for the microwave-assisted Williamson synthesis of 4-nitrophenethyl ether, are also dicussed. The 6th edition textbook establishes a personalized learning platform fostering students' experimental abilities and cultivating a rigorous and innovative style of study.
2024, 39(1): 29-37
doi: 10.3866/PKU.DXHX202306036
Abstract:
Embracing the modern "student-centered" educational philosophy, this approach aims to reinvent the analytical chemistry curriculum by incorporating modern media, innovative teaching techniques, and ideological and political education. Aligning with professional training objectives, the curriculum content has been restructured. With the aid of tools like the Chinese University MOOC, virtual simulation training platforms, and Xuexi Tong, modern media is employed to deliver teaching content. By choosing novel teaching methodologies, we aim to spark students' passion for learning and enhance their ability to apply theoretical knowledge to analyze and address complex issues. The consistent integration of ideological and political elements throughout the teaching process accentuates the courses' value-oriented role. In line with the instructional methods, a diverse assessment system is established to evaluate both teaching outcomes and student learning achievements.
Embracing the modern "student-centered" educational philosophy, this approach aims to reinvent the analytical chemistry curriculum by incorporating modern media, innovative teaching techniques, and ideological and political education. Aligning with professional training objectives, the curriculum content has been restructured. With the aid of tools like the Chinese University MOOC, virtual simulation training platforms, and Xuexi Tong, modern media is employed to deliver teaching content. By choosing novel teaching methodologies, we aim to spark students' passion for learning and enhance their ability to apply theoretical knowledge to analyze and address complex issues. The consistent integration of ideological and political elements throughout the teaching process accentuates the courses' value-oriented role. In line with the instructional methods, a diverse assessment system is established to evaluate both teaching outcomes and student learning achievements.
2024, 39(1): 38-43
doi: 10.3866/PKU.DXHX202307005
Abstract:
According to the goal of cultivating innovative talents, aiming at the drawbacks of traditional instrumental analysis teaching, relying on the competition, the frontier of scientific research is introduced into the classroom, and the reform of "teaching, research and competition " integrated teaching mode is carried out with online teaching as a link. This teaching mode focuses on cultivating students' innovative consciousness, innovative thinking, innovative ability, as well as the ability to comprehensively analyze and solve problems. Meanwhile, the teaching mode also promotes the connection between theory and experiment teaching, forming a teaching system of "vitality and reality combining, theory-practice integration".
According to the goal of cultivating innovative talents, aiming at the drawbacks of traditional instrumental analysis teaching, relying on the competition, the frontier of scientific research is introduced into the classroom, and the reform of "teaching, research and competition " integrated teaching mode is carried out with online teaching as a link. This teaching mode focuses on cultivating students' innovative consciousness, innovative thinking, innovative ability, as well as the ability to comprehensively analyze and solve problems. Meanwhile, the teaching mode also promotes the connection between theory and experiment teaching, forming a teaching system of "vitality and reality combining, theory-practice integration".
2024, 39(1): 44-48
doi: 10.3866/PKU.DXHX202306066
Abstract:
Integrating ideological and political education into professional curriculum has become a challenge faced by educational reforms. Instrumental analysis, an indispensable component of modern chemical education, must also be intertwined with ideological and political education. This ensures that students, while mastering knowledge and skills, also possess high moral integrity and professional ethics, fostering comprehensive modern talents. This article presents a brief history of the development of instrumental analysis and the evolution of two common instrumental analysis methods, exploring the elements of ideological and political education within. It also discusses diverse approaches to incorporate these elements into modern teaching. The goal is to seamlessly integrate ideological and political elements into instructional language, teaching environments, and platforms, emphasizing role models, enabling students to experience the joy and sense of accomplishment in learning, and fostering a psychological identification with the discipline of chemistry.
Integrating ideological and political education into professional curriculum has become a challenge faced by educational reforms. Instrumental analysis, an indispensable component of modern chemical education, must also be intertwined with ideological and political education. This ensures that students, while mastering knowledge and skills, also possess high moral integrity and professional ethics, fostering comprehensive modern talents. This article presents a brief history of the development of instrumental analysis and the evolution of two common instrumental analysis methods, exploring the elements of ideological and political education within. It also discusses diverse approaches to incorporate these elements into modern teaching. The goal is to seamlessly integrate ideological and political elements into instructional language, teaching environments, and platforms, emphasizing role models, enabling students to experience the joy and sense of accomplishment in learning, and fostering a psychological identification with the discipline of chemistry.
2024, 39(1): 49-56
doi: 10.3866/PKU.DXHX202306080
Abstract:
Cultivating outstanding professionals in energy chemistry can not only promote the development of the energy industry, but also constitute an essential component of the construction of applied science and engineering disciplines. Based on the internationally advanced outcome-based education (OBE) philosophy, this article uses the "Introduction to Energy Chemistry" course as an example, and puts forward a series of suggestions for exploring interdisciplinary professional course teaching reforms. With the aim of enhancing students' abilities and learning outcomes, we focus on students' understanding and application of knowledge, emphasize their active participation and collaboration, as well as impart learning skills and analytical thinking. In teaching, a student-centered approach is adopted to reform the objectives, competency standards, teaching assessment, learning resources, and methods of the introductory course in energy chemistry. By incorporating the OBE educational philosophy, the energy chemistry curriculum is made more targeted and practical. This enables students to better grasp the subject matter and apply their knowledge to real-life situations and work scenarios. The reformed curriculum integrates practical experiences and emphasizes the application of learned concepts, thereby enhancing the relevance and usefulness of the energy chemistry course for students. Ultimately, this leads to improved teaching quality and comprehensive enhancement of students' overall abilities, providing new ideas for the reform of new interdisciplinary professional course teaching.
Cultivating outstanding professionals in energy chemistry can not only promote the development of the energy industry, but also constitute an essential component of the construction of applied science and engineering disciplines. Based on the internationally advanced outcome-based education (OBE) philosophy, this article uses the "Introduction to Energy Chemistry" course as an example, and puts forward a series of suggestions for exploring interdisciplinary professional course teaching reforms. With the aim of enhancing students' abilities and learning outcomes, we focus on students' understanding and application of knowledge, emphasize their active participation and collaboration, as well as impart learning skills and analytical thinking. In teaching, a student-centered approach is adopted to reform the objectives, competency standards, teaching assessment, learning resources, and methods of the introductory course in energy chemistry. By incorporating the OBE educational philosophy, the energy chemistry curriculum is made more targeted and practical. This enables students to better grasp the subject matter and apply their knowledge to real-life situations and work scenarios. The reformed curriculum integrates practical experiences and emphasizes the application of learned concepts, thereby enhancing the relevance and usefulness of the energy chemistry course for students. Ultimately, this leads to improved teaching quality and comprehensive enhancement of students' overall abilities, providing new ideas for the reform of new interdisciplinary professional course teaching.
2024, 39(1): 57-62
doi: 10.3866/PKU.DXHX202307078
Abstract:
Guided by the idea of an organic integration of knowledge, ability, and quality in quality-oriented education, the acid-base dissociation content in Inorganic Chemistry teaching is reorganized to construct a new curriculum design module. The restructured content expands into 5 modules, including electrolyte solution fundamentals, acid-base theory, acid-base strength, dissociation equilibrium of weak acids and weak bases, and fundamental concepts of acid-base titration and error. The reconstruction of the teaching content is progressive while ensuring a comprehensive foundation of knowledge, aiming to facilitate students' development in terms of professional abilities.
Guided by the idea of an organic integration of knowledge, ability, and quality in quality-oriented education, the acid-base dissociation content in Inorganic Chemistry teaching is reorganized to construct a new curriculum design module. The restructured content expands into 5 modules, including electrolyte solution fundamentals, acid-base theory, acid-base strength, dissociation equilibrium of weak acids and weak bases, and fundamental concepts of acid-base titration and error. The reconstruction of the teaching content is progressive while ensuring a comprehensive foundation of knowledge, aiming to facilitate students' development in terms of professional abilities.
2024, 39(1): 63-68
doi: 10.3866/PKU.DXHX202308043
Abstract:
With the advent of ChatGPT-4, the development and application of artificial intelligence (AI) technology have entered a new era, inevitably exerting a profound impact on the cultivation of modern scientific and technological talents. This paper begins by offering an overview of AI technology and its application in chemical research. It then discusses the updated criteria essential for fostering innovation ability of chemistry students in this new age of AI. Finally, the exploration and practice undertaken in the teaching reform for cheminformatics are presented.
With the advent of ChatGPT-4, the development and application of artificial intelligence (AI) technology have entered a new era, inevitably exerting a profound impact on the cultivation of modern scientific and technological talents. This paper begins by offering an overview of AI technology and its application in chemical research. It then discusses the updated criteria essential for fostering innovation ability of chemistry students in this new age of AI. Finally, the exploration and practice undertaken in the teaching reform for cheminformatics are presented.
2024, 39(1): 69-72
doi: 10.3866/PKU.DXHX202307062
Abstract:
“Medical Organic Chemistry” is a compulsory course for first-year students in various majors of the medical school. The course is challenging, and its core content is less relevant to clinic practice, which easily creates a sense of difficulty for students. In our teaching practice, we introduce real clinical cases to uncover the linkage between organic chemistry knowledge and clinical practice, thereby stimulating the enthusiasm of medical students for learning the course.
“Medical Organic Chemistry” is a compulsory course for first-year students in various majors of the medical school. The course is challenging, and its core content is less relevant to clinic practice, which easily creates a sense of difficulty for students. In our teaching practice, we introduce real clinical cases to uncover the linkage between organic chemistry knowledge and clinical practice, thereby stimulating the enthusiasm of medical students for learning the course.
2024, 39(1): 73-79
doi: 10.3866/PKU.DXHX202307080
Abstract:
In response to teaching painful points, team teachers guided by ideological and political education and utilized modern information technology as the medium, optimize course objectives, reconstruct teaching content, and reshape teaching process. Meanwhile, team teachers strengthen interactive debates, improve evaluation mechanisms and explore a teaching innovation path of "three convergences, four prominences ". It comprehensively addresses the "pain points" of the course, strives to create an outstanding course with "two genders and one degree", and promotes the enhancement of students' innovation ability and comprehensive qualities.
In response to teaching painful points, team teachers guided by ideological and political education and utilized modern information technology as the medium, optimize course objectives, reconstruct teaching content, and reshape teaching process. Meanwhile, team teachers strengthen interactive debates, improve evaluation mechanisms and explore a teaching innovation path of "three convergences, four prominences ". It comprehensively addresses the "pain points" of the course, strives to create an outstanding course with "two genders and one degree", and promotes the enhancement of students' innovation ability and comprehensive qualities.
2024, 39(1): 80-86
doi: 10.3866/PKU.DXHX202306008
Abstract:
Incorporating cutting-edge scientific examples into course instruction can not only illustrate the practical significance of the fundamental principles, but also provide examples for the flexible application of these principles, inspiring students' independent thinking abilities. Interface chemistry is an important subject in physical chemistry courses, but students often overlook this part of the knowledge due to the lack of significant interface phenomena in conventional-scale multiphase systems. In recent years, nanomaterials have become a hot topic of scientific research. Nanomaterials exhibit more significant interface phenomena due to their high interface-to-volume ratio. Applying the basic principles of interface chemistry to the study of nanomaterials has led to a series of remarkable achievements. This article first reviews the related basic principles of interface phenomena such as Laplace pressure and contact angle, and then introduces four technological breakthroughs:molecular motors, photo-controlled microfluidic devices, liquid gating techniques, and superhydrophobic surfaces, developed based on these principles.
Incorporating cutting-edge scientific examples into course instruction can not only illustrate the practical significance of the fundamental principles, but also provide examples for the flexible application of these principles, inspiring students' independent thinking abilities. Interface chemistry is an important subject in physical chemistry courses, but students often overlook this part of the knowledge due to the lack of significant interface phenomena in conventional-scale multiphase systems. In recent years, nanomaterials have become a hot topic of scientific research. Nanomaterials exhibit more significant interface phenomena due to their high interface-to-volume ratio. Applying the basic principles of interface chemistry to the study of nanomaterials has led to a series of remarkable achievements. This article first reviews the related basic principles of interface phenomena such as Laplace pressure and contact angle, and then introduces four technological breakthroughs:molecular motors, photo-controlled microfluidic devices, liquid gating techniques, and superhydrophobic surfaces, developed based on these principles.
2024, 39(1): 87-94
doi: 10.3866/PKU.DXHX202306052
Abstract:
Olefins are a very important class of compounds, which can be transformed to various complex organic molecules through a series of transformations. In this paper, C-C cross coupling reaction based on olefinic C-H bond activation is described in detail. Based on the activation of C-H bonds, C-C bonds are constructed through C-C cross coupling reaction by transition metal catalysts such as Rh, Pd and Co. This introduction of olefinic C-H bond activation can enrich and expand the knowledge of olefins in organic chemistry courses, and it is also helpful for students to understand the forefront of organic chemistry development, stimulate their learning enthusiasm and initiative, and cultivate their scientific research literacy.
Olefins are a very important class of compounds, which can be transformed to various complex organic molecules through a series of transformations. In this paper, C-C cross coupling reaction based on olefinic C-H bond activation is described in detail. Based on the activation of C-H bonds, C-C bonds are constructed through C-C cross coupling reaction by transition metal catalysts such as Rh, Pd and Co. This introduction of olefinic C-H bond activation can enrich and expand the knowledge of olefins in organic chemistry courses, and it is also helpful for students to understand the forefront of organic chemistry development, stimulate their learning enthusiasm and initiative, and cultivate their scientific research literacy.
2024, 39(1): 95-104
doi: 10.3866/PKU.DXHX202306015
Abstract:
Chirality research holds paramount theoretical significance and practical prospects in the field of organic chemistry. With the advancement of science and technology and the deepening of our understanding, a plethora of new concepts and techniques continue to emerge. Inherent chirality arises from the introduction of a curvature in an ideal planar structure that is devoid of perpendicular symmetry planes in its bidimensional representation, distinguished from conventional central, axial, planar, and helical chirality. It possesses unique stereochemistry and offers extensive application prospects. This review focuses on the structural characteristics, synthesis, and separation of naturally occurring inherent chiral compounds, synthetically derived chiral calixarenes, pillararenes, cyclotriveratrylenes, tribenzotriquinacenes, saddle-shaped octatomic rings, sumanenes, and cage compounds. Furthermore, it sheds light on future developmental directions and new opportunities in this domain.
Chirality research holds paramount theoretical significance and practical prospects in the field of organic chemistry. With the advancement of science and technology and the deepening of our understanding, a plethora of new concepts and techniques continue to emerge. Inherent chirality arises from the introduction of a curvature in an ideal planar structure that is devoid of perpendicular symmetry planes in its bidimensional representation, distinguished from conventional central, axial, planar, and helical chirality. It possesses unique stereochemistry and offers extensive application prospects. This review focuses on the structural characteristics, synthesis, and separation of naturally occurring inherent chiral compounds, synthetically derived chiral calixarenes, pillararenes, cyclotriveratrylenes, tribenzotriquinacenes, saddle-shaped octatomic rings, sumanenes, and cage compounds. Furthermore, it sheds light on future developmental directions and new opportunities in this domain.
2024, 39(1): 105-110
doi: 10.3866/PKU.DXHX202306022
Abstract:
Stereoselectively pure oximes play a pivotal role in organic synthesis, pharmaceuticals, and as food additives. Traditional synthesis methods rely heavily on the steric hindrance of substrate substituents to achieve oxime stereoselectivity, presenting a significant challenge in organic synthesis. This article offers a concise overview of the latest advancements in techniques and methods for stereoselective oxime synthesis. The insights presented herein are rooted in fundamental organic chemistry. Introducing these concepts into academic curriculum can broaden student perspectives and ignite their enthusiasm for problem discovery and resolution.
Stereoselectively pure oximes play a pivotal role in organic synthesis, pharmaceuticals, and as food additives. Traditional synthesis methods rely heavily on the steric hindrance of substrate substituents to achieve oxime stereoselectivity, presenting a significant challenge in organic synthesis. This article offers a concise overview of the latest advancements in techniques and methods for stereoselective oxime synthesis. The insights presented herein are rooted in fundamental organic chemistry. Introducing these concepts into academic curriculum can broaden student perspectives and ignite their enthusiasm for problem discovery and resolution.
2024, 39(1): 111-118
doi: 10.3866/PKU.DXHX202306039
Abstract:
Amides, as nitrogen-containing compounds with unique physicochemical properties and biological activities, have demonstrated broad application prospects in fields such as medicine and materials. Particularly, compared with the vast majority of traditional amides in which the intramolecular p-π conjugation effects lead to a planar structure, the twisted amides, however, present distortions of the amide bond from planarity, thus resulting conformational and electronic modifications such as amide bond twist and nitrogen pyramidalization. The bond distortion of twisted amide is typically defined by the Winkler-Dunitz distortion parameters twist angle (τ) and pyramidalization parameters (χN). The former describes the magnitude of rotation around the N-C(O) bond while the later describes pyramidalization at nitrogen and pyramidalization at carbon. The values of τ=40° and χN=40° are considered as threshold values that allow for unique reactivity of the twist amide bond. This article introduces the unique structure and reactivity of these compounds, focusing on cyclic twisted amides and acyclic twisted amides, based on the range of τ > 40° and χN > 40°.
Amides, as nitrogen-containing compounds with unique physicochemical properties and biological activities, have demonstrated broad application prospects in fields such as medicine and materials. Particularly, compared with the vast majority of traditional amides in which the intramolecular p-π conjugation effects lead to a planar structure, the twisted amides, however, present distortions of the amide bond from planarity, thus resulting conformational and electronic modifications such as amide bond twist and nitrogen pyramidalization. The bond distortion of twisted amide is typically defined by the Winkler-Dunitz distortion parameters twist angle (τ) and pyramidalization parameters (χN). The former describes the magnitude of rotation around the N-C(O) bond while the later describes pyramidalization at nitrogen and pyramidalization at carbon. The values of τ=40° and χN=40° are considered as threshold values that allow for unique reactivity of the twist amide bond. This article introduces the unique structure and reactivity of these compounds, focusing on cyclic twisted amides and acyclic twisted amides, based on the range of τ > 40° and χN > 40°.
2024, 39(1): 119-125
doi: 10.3866/PKU.DXHX202305068
Abstract:
A comprehensive instrumental analysis experiment was designed based on persistent organochlorine pollutant detection. The quantitative and qualitative analysis of the organochlorine pollutants in red wine samples was carried out through infrared spectroscopy characterization, synchronous thermal analysis characterization, optimization of solid-phase microextraction conditions, and gas chromatography. The designed experiment allows students to participate in the entire instrumental analysis process and cultivates their ability to solve practical problems.
A comprehensive instrumental analysis experiment was designed based on persistent organochlorine pollutant detection. The quantitative and qualitative analysis of the organochlorine pollutants in red wine samples was carried out through infrared spectroscopy characterization, synchronous thermal analysis characterization, optimization of solid-phase microextraction conditions, and gas chromatography. The designed experiment allows students to participate in the entire instrumental analysis process and cultivates their ability to solve practical problems.
2024, 39(1): 126-133
doi: 10.3866/PKU.DXHX202305057
Abstract:
In order to enable undergraduate students majoring in chemistry and related fields to understand the basic characteristics of hydrogel materials and their applications in macroscopic non-equilibrium supramolecular self-assembly, we have introduced a comprehensive research-oriented experiment titled "Macroscopic Non-equilibrium Supramolecular Self-Assembly Experiment". This experiment mainly includes the preparation method of polyelectrolyte hydrogels based on homogeneous free radical polymerization, the construction method of macroscopic non-equilibrium supramolecular self-assembly system based on urea-urease timing reaction, characterization of assembly performance, and exploration of the mechanisms of non-equilibrium assembly and disassembly. Through the practice of this experiment, students can deepen their understanding of supramolecular interactions, master the preparation and characterization methods of relevant polymer hydrogels, as well as consolidate the use of some commonly used instruments. By combining teaching and practice, we establish a bridge between teaching and scientific research to broaden students' scientific perspectives, stimulate their research interests, and cultivate students' innovative abilities and scientific thinking.
In order to enable undergraduate students majoring in chemistry and related fields to understand the basic characteristics of hydrogel materials and their applications in macroscopic non-equilibrium supramolecular self-assembly, we have introduced a comprehensive research-oriented experiment titled "Macroscopic Non-equilibrium Supramolecular Self-Assembly Experiment". This experiment mainly includes the preparation method of polyelectrolyte hydrogels based on homogeneous free radical polymerization, the construction method of macroscopic non-equilibrium supramolecular self-assembly system based on urea-urease timing reaction, characterization of assembly performance, and exploration of the mechanisms of non-equilibrium assembly and disassembly. Through the practice of this experiment, students can deepen their understanding of supramolecular interactions, master the preparation and characterization methods of relevant polymer hydrogels, as well as consolidate the use of some commonly used instruments. By combining teaching and practice, we establish a bridge between teaching and scientific research to broaden students' scientific perspectives, stimulate their research interests, and cultivate students' innovative abilities and scientific thinking.
2024, 39(1): 134-141
doi: 10.3866/PKU.DXHX202305088
Abstract:
The "Alginate microcapsule preparation, drug encapsulation, and sustained controlled release analysis experiment" serves as a prominent research-oriented experiment within Type II analytical chemistry experiments. It encompasses essential training in basic scientific research skills, including the exploration of microcapsule formation principles, experimental condition design, and microcapsule performance characterization. In this experiment, a mixed solution of sodium alginate and methylene blue was dropped into 3% CaCl2 solution and 1% chitosan solution, respectively, resulting in the preparation of two microcapsules with distinct properties. The concentration of the solution was measured at various time intervals using spectrophotometry to derive sustained-release curves, facilitating a comparative analysis of the sustained-release properties of the two microcapsules. Additionally, a subsequent exploration experiment employed both one-step and two-step methods for microcapsule preparation, combining the advantages of both systems to achieve microcapsules with optimal sustained-release and stability characteristics.
The "Alginate microcapsule preparation, drug encapsulation, and sustained controlled release analysis experiment" serves as a prominent research-oriented experiment within Type II analytical chemistry experiments. It encompasses essential training in basic scientific research skills, including the exploration of microcapsule formation principles, experimental condition design, and microcapsule performance characterization. In this experiment, a mixed solution of sodium alginate and methylene blue was dropped into 3% CaCl2 solution and 1% chitosan solution, respectively, resulting in the preparation of two microcapsules with distinct properties. The concentration of the solution was measured at various time intervals using spectrophotometry to derive sustained-release curves, facilitating a comparative analysis of the sustained-release properties of the two microcapsules. Additionally, a subsequent exploration experiment employed both one-step and two-step methods for microcapsule preparation, combining the advantages of both systems to achieve microcapsules with optimal sustained-release and stability characteristics.
2024, 39(1): 142-147
doi: 10.3866/PKU.DXHX202306056
Abstract:
Flame atomic absorption spectrometry (FAAS) is an important experiment in instrumental analysis laboratory teaching for undergraduates. Atomic absorption spectroscopy (AAS) is used to quantitatively determine a specific element in real samples, which has the advantages of high accuracy, precision, and selectivity. Zinc gluconate oral solution is a common over-the-counter zinc supplement in daily life. Through independent experiments of undergraduates, a simple and easy-to-operate FAAS method is established to determine the zinc content in zinc gluconate oral solution. This experiment aims to cultivate students' ability to apply theoretical knowledge learned in class to solve practical problems, and achieve the educational goal of "learning for application, and application to promote learning".
Flame atomic absorption spectrometry (FAAS) is an important experiment in instrumental analysis laboratory teaching for undergraduates. Atomic absorption spectroscopy (AAS) is used to quantitatively determine a specific element in real samples, which has the advantages of high accuracy, precision, and selectivity. Zinc gluconate oral solution is a common over-the-counter zinc supplement in daily life. Through independent experiments of undergraduates, a simple and easy-to-operate FAAS method is established to determine the zinc content in zinc gluconate oral solution. This experiment aims to cultivate students' ability to apply theoretical knowledge learned in class to solve practical problems, and achieve the educational goal of "learning for application, and application to promote learning".
2024, 39(1): 148-156
doi: 10.3866/PKU.DXHX202305074
Abstract:
In this paper, two kinds of functional dyes with both photoluminescence and chemiluminescence properties were synthesized under the same reaction conditions through a micro-reaction of tens of milligrams. Red dyes have red light emitting properties, while blue dyes have near infrared emitting properties. The ultraviolet-visible absorption spectrum, fluorescence emission spectrum and chemiluminescence spectrum were measured by ultraviolet spectrometer and fluorescence spectrometer. In this experiment, the progress of the reaction was monitored by thin-layer chromatography, and the product was separated and purified by preparative thin-layer chromatography to minimize the possible pollution caused by dye synthesis. The photoluminescence phenomenon can be visually observed by using red and green laser pointers to irradiate the dye solution and the dye-containing film respectively. Green laser light can be absorbed by red dyes and converted into red light through the phenomenon of photoluminescence. The red laser can be directly converted into near-infrared luminescence by near-infrared luminescent dyes. In the chemiluminescent system, the two dyes emit bright red light and near-infrared light, respectively. This experiment introduces optical functional materials into undergraduate teaching experiments, which not only trains students' micro-organic synthesis and separation techniques, but also stimulates students' curiosity and enhances the fun of experiments.
In this paper, two kinds of functional dyes with both photoluminescence and chemiluminescence properties were synthesized under the same reaction conditions through a micro-reaction of tens of milligrams. Red dyes have red light emitting properties, while blue dyes have near infrared emitting properties. The ultraviolet-visible absorption spectrum, fluorescence emission spectrum and chemiluminescence spectrum were measured by ultraviolet spectrometer and fluorescence spectrometer. In this experiment, the progress of the reaction was monitored by thin-layer chromatography, and the product was separated and purified by preparative thin-layer chromatography to minimize the possible pollution caused by dye synthesis. The photoluminescence phenomenon can be visually observed by using red and green laser pointers to irradiate the dye solution and the dye-containing film respectively. Green laser light can be absorbed by red dyes and converted into red light through the phenomenon of photoluminescence. The red laser can be directly converted into near-infrared luminescence by near-infrared luminescent dyes. In the chemiluminescent system, the two dyes emit bright red light and near-infrared light, respectively. This experiment introduces optical functional materials into undergraduate teaching experiments, which not only trains students' micro-organic synthesis and separation techniques, but also stimulates students' curiosity and enhances the fun of experiments.
2024, 39(1): 157-165
doi: 10.3866/PKU.DXHX202305093
Abstract:
While the existing university chemistry experimental teaching content is comprehensive, it often lacks a connection with cutting-edge scientific research, particularly in trending fields. In this study, we introduce the experiment "Kaempferol as an AIE-active natural product probe for selective Al3+ detection" into teaching practice. Through this experiment, students gain an understanding of the contributions made by Chinese scientists in the field of aggregation-induced emission (AIE) research. They also learn about the fundamental principles and applications of fluorescence, and gain intuitive insights into the distinctions between aggregation-induced emission and aggregation-induced quenching. The experiment encompasses complex structure analysis, spectral analysis, and instrumental characterization, offering both comprehensiveness and ease of operation. By engaging in this teaching practice, students develop their innovative thinking and comprehensive abilities, while simultaneously reinforcing their commitment to environmentally friendly development and enhancing a sense of national pride.
While the existing university chemistry experimental teaching content is comprehensive, it often lacks a connection with cutting-edge scientific research, particularly in trending fields. In this study, we introduce the experiment "Kaempferol as an AIE-active natural product probe for selective Al3+ detection" into teaching practice. Through this experiment, students gain an understanding of the contributions made by Chinese scientists in the field of aggregation-induced emission (AIE) research. They also learn about the fundamental principles and applications of fluorescence, and gain intuitive insights into the distinctions between aggregation-induced emission and aggregation-induced quenching. The experiment encompasses complex structure analysis, spectral analysis, and instrumental characterization, offering both comprehensiveness and ease of operation. By engaging in this teaching practice, students develop their innovative thinking and comprehensive abilities, while simultaneously reinforcing their commitment to environmentally friendly development and enhancing a sense of national pride.
2024, 39(1): 166-172
doi: 10.3866/PKU.DXHX202306034
Abstract:
This paper introduces a college comprehensive chemical experiment about the synthesis, characterization and luminescence measurement of long-persistent phosphors. The experiment covers various aspects, including the preparation of spinel structure alkaline earth aluminate phosphors, phase and luminescent properties characterization, and so on. The experimental process is not only safe, but also fast, simple, easy to operate, and visually appealing. By actively engaging in this experiment, students can gain a better understanding of the physical and chemical mechanisms involved in solution combustion reactions, as well as enhance their practical laboratory skills. Furthermore, it serves as a platform to showcase the beauty of chemistry, unravel the limitless allure of science, and ignite students' curiosity for scientific research.
This paper introduces a college comprehensive chemical experiment about the synthesis, characterization and luminescence measurement of long-persistent phosphors. The experiment covers various aspects, including the preparation of spinel structure alkaline earth aluminate phosphors, phase and luminescent properties characterization, and so on. The experimental process is not only safe, but also fast, simple, easy to operate, and visually appealing. By actively engaging in this experiment, students can gain a better understanding of the physical and chemical mechanisms involved in solution combustion reactions, as well as enhance their practical laboratory skills. Furthermore, it serves as a platform to showcase the beauty of chemistry, unravel the limitless allure of science, and ignite students' curiosity for scientific research.
2024, 39(1): 173-177
doi: 10.3866/PKU.DXHX202306079
Abstract:
At present, commercial systems are usually used in pressure swing adsorption (PSA) experiments. However, the purchased equipment has disadvantages such as large size, complicated tubing design and high price, which are not conducive to undergraduate laboratory teaching. In this paper, a low-cost benchtop design of PSA system is proposed, with which students can build their own PSA equipment with common laboratory materials and conduct the testing and operation on their own. Using Li-exchanged zeolite as the adsorbent, the system can produce high-purity oxygen with a concentration up to 95.8%, which is comparable to that of commercial oxygen concentrator. The designed system can be disassembled and reassembled repeatedly and the process of building and testing is safe and fun. The proposed design can be used in the PSA experimental teaching for undergraduate students who major in applied chemistry, chemical engineering and other related subjects. We believe that students' interest in creating experimental equipment can be intrigued and their ability to solve practical problems can be improved during the build and testing process of the proposed PSA system.
At present, commercial systems are usually used in pressure swing adsorption (PSA) experiments. However, the purchased equipment has disadvantages such as large size, complicated tubing design and high price, which are not conducive to undergraduate laboratory teaching. In this paper, a low-cost benchtop design of PSA system is proposed, with which students can build their own PSA equipment with common laboratory materials and conduct the testing and operation on their own. Using Li-exchanged zeolite as the adsorbent, the system can produce high-purity oxygen with a concentration up to 95.8%, which is comparable to that of commercial oxygen concentrator. The designed system can be disassembled and reassembled repeatedly and the process of building and testing is safe and fun. The proposed design can be used in the PSA experimental teaching for undergraduate students who major in applied chemistry, chemical engineering and other related subjects. We believe that students' interest in creating experimental equipment can be intrigued and their ability to solve practical problems can be improved during the build and testing process of the proposed PSA system.
2024, 39(1): 178-184
doi: 10.3866/PKU.DXHX202307004
Abstract:
Herein, we propose a comprehensive chemical experiment that include the preparation, characterization and lithium storage performance evaluation of mesoporous carbon-coated iron oxide nanoparticles. Students are guided to acquaint themselves with the characterization methods of material structure, the operation of battery assembly and battery testing technique. This experiment will disclose the interrelationship between material structure and performance to students, and cultivate their experiment skills, scientific literacy, and practical innovation ability. Furthermore, this experiment serves as a gateway for students to explore the frontier in new energy, and stimulate their scientific interest. Therefore, this experiment is recommended as a comprehensive chemical experiment course for senior undergraduates majoring in materials chemistry or applied chemistry.
Herein, we propose a comprehensive chemical experiment that include the preparation, characterization and lithium storage performance evaluation of mesoporous carbon-coated iron oxide nanoparticles. Students are guided to acquaint themselves with the characterization methods of material structure, the operation of battery assembly and battery testing technique. This experiment will disclose the interrelationship between material structure and performance to students, and cultivate their experiment skills, scientific literacy, and practical innovation ability. Furthermore, this experiment serves as a gateway for students to explore the frontier in new energy, and stimulate their scientific interest. Therefore, this experiment is recommended as a comprehensive chemical experiment course for senior undergraduates majoring in materials chemistry or applied chemistry.
2024, 39(1): 185-190
doi: 10.3866/PKU.DXHX202306024
Abstract:
Different from the basic chemistry experiment course in the lower grades of the university, the higher grades offer self-designed experiments, focusing on independent thinking and active exploration. Taking the "determination of N content in TiCN-based alloys" as an example, this paper introduces the whole process of self-designed experiments, including the digestion of solid samples, the extraction of substances to be measured, analysis and testing, data processing and evaluation, and introduces theoretical knowledge into practical problems, and uses experimental methods to deeply integrate the two, improving students' ability to judge, solve problems and comprehensive quality.
Different from the basic chemistry experiment course in the lower grades of the university, the higher grades offer self-designed experiments, focusing on independent thinking and active exploration. Taking the "determination of N content in TiCN-based alloys" as an example, this paper introduces the whole process of self-designed experiments, including the digestion of solid samples, the extraction of substances to be measured, analysis and testing, data processing and evaluation, and introduces theoretical knowledge into practical problems, and uses experimental methods to deeply integrate the two, improving students' ability to judge, solve problems and comprehensive quality.
2024, 39(1): 191-200
doi: 10.3866/PKU.DXHX202306049
Abstract:
With the backdrop of "Carbon peaking and carbon neutrality goals", the development of renewable energy and solar energy storage has gained countless attention recently. However, the lack of experiments involving energy conversion in undergraduate curricula has limited students' understanding of low-carbon and green chemistry to remain largely theoretical. This experimental protocol aims to synthesize hydrogen peroxide (H2O2), utilizing the solar-to-chemical conversion, all while aligning with cutting-edge scientific advancements. The entire experimental process refrains from the use of any toxic or hazardous reagents, truly embodying the principles of green and low-carbon chemistry. Illustrating with the synthesis of graphitic carbon nitride (g-C3N4) nanosheets via dicyandiamide, this experiment delves into the mechanism of polymerization reaction. This approach integrates fundamental operations from inorganic, physical, and analytical chemistry, coupled with modern analytical methods, to conduct open-ended comprehensive experiments on the g-C3N4 catalyzed generation of H2O2 and quantification. By combining the polymerization reaction of inorganic and organic materials within an aerobic experimental environment and employing UV spectrophotometry for yield measurement, this experiment effectively enhances students' comprehensive qualities and innovative abilities, achieving the goal of "integrating current affairs into teaching and cultivating well-rounded students".
With the backdrop of "Carbon peaking and carbon neutrality goals", the development of renewable energy and solar energy storage has gained countless attention recently. However, the lack of experiments involving energy conversion in undergraduate curricula has limited students' understanding of low-carbon and green chemistry to remain largely theoretical. This experimental protocol aims to synthesize hydrogen peroxide (H2O2), utilizing the solar-to-chemical conversion, all while aligning with cutting-edge scientific advancements. The entire experimental process refrains from the use of any toxic or hazardous reagents, truly embodying the principles of green and low-carbon chemistry. Illustrating with the synthesis of graphitic carbon nitride (g-C3N4) nanosheets via dicyandiamide, this experiment delves into the mechanism of polymerization reaction. This approach integrates fundamental operations from inorganic, physical, and analytical chemistry, coupled with modern analytical methods, to conduct open-ended comprehensive experiments on the g-C3N4 catalyzed generation of H2O2 and quantification. By combining the polymerization reaction of inorganic and organic materials within an aerobic experimental environment and employing UV spectrophotometry for yield measurement, this experiment effectively enhances students' comprehensive qualities and innovative abilities, achieving the goal of "integrating current affairs into teaching and cultivating well-rounded students".
2024, 39(1): 201-209
doi: 10.3866/PKU.DXHX202306004
Abstract:
Low-dimensional perovskite solar cells (LD PSCs) are a new type of stable and hydrophobic perovskite photovoltaic device, which have attracted broad interest in the field of renewable energy. In this experiment, focusing on the advanced development of LD PSCs, butylammonium and cysteamine (2-Amino-3-mercaptopropionic acid, Cys) are employed as organic spacer cations to synthesize LD perovskite crystals, and (BA)2(MA)n-1PbnI3n+1 or (Cys)2(MA)n-1PbnI3n+1 is used as the active layer to fabricate PSCs. Detections of X-ray diffraction and UV-Vis absorption spectroscopy are employed to characterize the morphology and optical properties of the perovskite film. Finally, the power conversion efficiency of the LD PSCs is measured. The difficulty of this experiment is moderate, involving in the fabrication and characterization of photovoltaic devices. This designed experiment aims for stimulating undergraduates' interest on the cutting-edge optoelectronic research and cultivate their scientific research ability.
Low-dimensional perovskite solar cells (LD PSCs) are a new type of stable and hydrophobic perovskite photovoltaic device, which have attracted broad interest in the field of renewable energy. In this experiment, focusing on the advanced development of LD PSCs, butylammonium and cysteamine (2-Amino-3-mercaptopropionic acid, Cys) are employed as organic spacer cations to synthesize LD perovskite crystals, and (BA)2(MA)n-1PbnI3n+1 or (Cys)2(MA)n-1PbnI3n+1 is used as the active layer to fabricate PSCs. Detections of X-ray diffraction and UV-Vis absorption spectroscopy are employed to characterize the morphology and optical properties of the perovskite film. Finally, the power conversion efficiency of the LD PSCs is measured. The difficulty of this experiment is moderate, involving in the fabrication and characterization of photovoltaic devices. This designed experiment aims for stimulating undergraduates' interest on the cutting-edge optoelectronic research and cultivate their scientific research ability.
2024, 39(1): 210-217
doi: 10.3866/PKU.DXHX202306046
Abstract:
The photo-nickel synergistic catalytic reaction emerges as a promising synthetic method, offering advantages such as high yields, mild reaction conditions, and broad scope. Guided by the principles of sustainable development, we have successfully synthesized valued aromatic ketone derivatives utilizing prevalent industrial feedstocks, aromatic carboxylic acids and ethylene under mild reaction conditions. It would be the first example of photo-nickel synergistic catalyzed reaction between aromatic acids and ethylene under air atmosphere. This synthetic method features in a high efficiency utilization of resource, simple operation and easy access for the students to grasp. This approach not only bridges a knowledge gap in teaching photochemical reactions within foundational organic chemistry experiments but also holds substantial practical and pedagogical merit.
The photo-nickel synergistic catalytic reaction emerges as a promising synthetic method, offering advantages such as high yields, mild reaction conditions, and broad scope. Guided by the principles of sustainable development, we have successfully synthesized valued aromatic ketone derivatives utilizing prevalent industrial feedstocks, aromatic carboxylic acids and ethylene under mild reaction conditions. It would be the first example of photo-nickel synergistic catalyzed reaction between aromatic acids and ethylene under air atmosphere. This synthetic method features in a high efficiency utilization of resource, simple operation and easy access for the students to grasp. This approach not only bridges a knowledge gap in teaching photochemical reactions within foundational organic chemistry experiments but also holds substantial practical and pedagogical merit.
2024, 39(1): 218-228
doi: 10.3866/PKU.DXHX202306054
Abstract:
Under the dual pressure of increasing energy demand and achieving dual carbon goals, developing clean energy is extremely urgent. Hydrogen energy stands out from all kinds of energy carriers with its unique advantages. In the future, hydrogen cycle is expected to facilitate carbon cycle to achieve dual carbon goals. This paper is focused on the hydrogen production in the hydrogen cycle. Two methods of hydrogen generation via photovoltaic electrocatalysis and photocatalysis are introduced in detail. In addition, popular science programs for different groups of people are designed, which will make them learn about the advantages of green hydrogen production via photochemistry and the significance of developing hydrogen energy.
Under the dual pressure of increasing energy demand and achieving dual carbon goals, developing clean energy is extremely urgent. Hydrogen energy stands out from all kinds of energy carriers with its unique advantages. In the future, hydrogen cycle is expected to facilitate carbon cycle to achieve dual carbon goals. This paper is focused on the hydrogen production in the hydrogen cycle. Two methods of hydrogen generation via photovoltaic electrocatalysis and photocatalysis are introduced in detail. In addition, popular science programs for different groups of people are designed, which will make them learn about the advantages of green hydrogen production via photochemistry and the significance of developing hydrogen energy.
2024, 39(1): 229-238
doi: 10.3866/PKU.DXHX202307007
Abstract:
This paper builds upon the university chemistry experiment "Electrochemical Preparation of Conductive Polymers". By incorporating molecularly imprinted polymers and elements of food safety, a simple task-oriented preparation experiment has been successfully transformed into a comprehensive experiment that combines the preparation of molecularly imprinted conductive polymers, performance characterization, and the highly selective detection of stimulants in beverages. The enriched and improved experiment content is engaging, relevant to real-world scenarios, and introduces cutting-edge analytical techniques, aiming to enhance students' integrated skills and fostering scientific thinking.
This paper builds upon the university chemistry experiment "Electrochemical Preparation of Conductive Polymers". By incorporating molecularly imprinted polymers and elements of food safety, a simple task-oriented preparation experiment has been successfully transformed into a comprehensive experiment that combines the preparation of molecularly imprinted conductive polymers, performance characterization, and the highly selective detection of stimulants in beverages. The enriched and improved experiment content is engaging, relevant to real-world scenarios, and introduces cutting-edge analytical techniques, aiming to enhance students' integrated skills and fostering scientific thinking.
2024, 39(1): 239-247
doi: 10.3866/PKU.DXHX202306025
Abstract:
The Beckmann rearrangement, a pivotal reaction wherein carbonyl-rich aldehydes and ketones engage with hydroxylamines to forge organoximes, undergoes a rearrangement in the catalyst's presence and holds significant importance in organic synthesis. Addressing the perceptual gaps in understanding the experimental principles and the insufficient verification of reaction mechanisms during the instruction of Beckmann rearrangement of organoximes, this study utilizes the reaction between benzophenone and hydroxylamine hydrochloride. This reaction results in benzophenone oxime, which undergoes molecular rearrangement catalyzed by polyphosphoric acid to produce benzoyl aniline. This exercise adeptly interweaves elements from inorganic, analytical, and instrumental analysis chemistry, augmenting holistic design and innovative capabilities of students. Employing tools like melting point assessment, infrared spectroscopy, and nuclear magnetic resonance, this study elucidates the nuanced structures of both intermediate and final products. By juxtaposing macroscopic physicochemical attributes with their microscopic counterparts, it robustly deciphers and authenticates the underlying reaction mechanism, enhancing the pedagogical efficacy of the Beckmann rearrangement and kindling innovative sense. This paper can serve as a reference for comprehensive and design-focused experiments on oxime-type Beckmann rearrangements, and also provide valuable insights for the enhancement of teaching materials and experimental procedures.
The Beckmann rearrangement, a pivotal reaction wherein carbonyl-rich aldehydes and ketones engage with hydroxylamines to forge organoximes, undergoes a rearrangement in the catalyst's presence and holds significant importance in organic synthesis. Addressing the perceptual gaps in understanding the experimental principles and the insufficient verification of reaction mechanisms during the instruction of Beckmann rearrangement of organoximes, this study utilizes the reaction between benzophenone and hydroxylamine hydrochloride. This reaction results in benzophenone oxime, which undergoes molecular rearrangement catalyzed by polyphosphoric acid to produce benzoyl aniline. This exercise adeptly interweaves elements from inorganic, analytical, and instrumental analysis chemistry, augmenting holistic design and innovative capabilities of students. Employing tools like melting point assessment, infrared spectroscopy, and nuclear magnetic resonance, this study elucidates the nuanced structures of both intermediate and final products. By juxtaposing macroscopic physicochemical attributes with their microscopic counterparts, it robustly deciphers and authenticates the underlying reaction mechanism, enhancing the pedagogical efficacy of the Beckmann rearrangement and kindling innovative sense. This paper can serve as a reference for comprehensive and design-focused experiments on oxime-type Beckmann rearrangements, and also provide valuable insights for the enhancement of teaching materials and experimental procedures.
2024, 39(1): 248-253
doi: 10.3866/PKU.DXHX202307059
Abstract:
Expanding upon the "Basic Physical Chemistry Laboratory" module focused on the measurement of primary battery electromotive force (EMF), this paper introduces a novel experimental design. The design incorporates the often-neglected liquid junction potential, investigating its relationship with reversible battery EMF and the total EMF of the primary battery. The revised apparatus is cost-effective, straightforward, and offers stable and reproducible measurements for liquid junction potential. This improved experiment provides a more comprehensive and accurate representation of the components contributing to the total EMF of the primary battery, transcending the limitations of merely measuring reversible battery EMF. As a result, the experiment aids students in forming a well-rounded and accurate understanding of primary batteries and the underlying principles of electrochemistry. Furthermore, the measured liquid junction potential is applicable in calculating ion transference numbers, allowing for the integration of this advanced concept into the curriculum and thereby bolstering students' comprehensive skill set.
Expanding upon the "Basic Physical Chemistry Laboratory" module focused on the measurement of primary battery electromotive force (EMF), this paper introduces a novel experimental design. The design incorporates the often-neglected liquid junction potential, investigating its relationship with reversible battery EMF and the total EMF of the primary battery. The revised apparatus is cost-effective, straightforward, and offers stable and reproducible measurements for liquid junction potential. This improved experiment provides a more comprehensive and accurate representation of the components contributing to the total EMF of the primary battery, transcending the limitations of merely measuring reversible battery EMF. As a result, the experiment aids students in forming a well-rounded and accurate understanding of primary batteries and the underlying principles of electrochemistry. Furthermore, the measured liquid junction potential is applicable in calculating ion transference numbers, allowing for the integration of this advanced concept into the curriculum and thereby bolstering students' comprehensive skill set.
2024, 39(1): 254-263
doi: 10.3866/PKU.DXHX202308024
Abstract:
To promote the integration of science and education, cutting-edge research of "MXene synthesis, ink formulation and flexible micro-supercapacitor fabrication via screen printing" has been transformed into a comprehensive chemistry experiment for upper-level undergraduates. The experiment involves novel materials, devices, and techniques, bridging the disciplines of chemistry, materials science, electronics, and energy. Moreover, it inherently includes ideological and political elements, aiming to cultivate students' practical ability, exploratory spirit, and innovative consciousness. It strengthens students' sense of commitment to contributing to the nation through science and technology, ultimately aiding in the development of well-rounded talents in the fields of chemistry and materials science.
To promote the integration of science and education, cutting-edge research of "MXene synthesis, ink formulation and flexible micro-supercapacitor fabrication via screen printing" has been transformed into a comprehensive chemistry experiment for upper-level undergraduates. The experiment involves novel materials, devices, and techniques, bridging the disciplines of chemistry, materials science, electronics, and energy. Moreover, it inherently includes ideological and political elements, aiming to cultivate students' practical ability, exploratory spirit, and innovative consciousness. It strengthens students' sense of commitment to contributing to the nation through science and technology, ultimately aiding in the development of well-rounded talents in the fields of chemistry and materials science.
2024, 39(1): 264-272
doi: 10.3866/PKU.DXHX202306016
Abstract:
Traditional luminescent materials often suffer from aggregation-caused quenching effects, diminishing the appeal of experimental instruction. The development of unconventional fluorescent materials is therefore of utmost research importance. This paper presents a series of fluorescent molecules with acrylonitrile structures, synthesized via Knoevenagel condensation reactions. By incorporating the cutting-edge science of aggregation-induced emission (AIE), led by Chinese scientists, into experimental teaching, we can effectively bolster students' national pride. Through this experiment, students will not only learn the mechanism of the Knoevenagel condensation reaction and master basic organic experimental operations, but also enhance their interest in learning, cultivate scientific thinking, and contribute to the ideological and political construction of the organic experiments course.
Traditional luminescent materials often suffer from aggregation-caused quenching effects, diminishing the appeal of experimental instruction. The development of unconventional fluorescent materials is therefore of utmost research importance. This paper presents a series of fluorescent molecules with acrylonitrile structures, synthesized via Knoevenagel condensation reactions. By incorporating the cutting-edge science of aggregation-induced emission (AIE), led by Chinese scientists, into experimental teaching, we can effectively bolster students' national pride. Through this experiment, students will not only learn the mechanism of the Knoevenagel condensation reaction and master basic organic experimental operations, but also enhance their interest in learning, cultivate scientific thinking, and contribute to the ideological and political construction of the organic experiments course.
2024, 39(1): 273-279
doi: 10.3866/PKU.DXHX202307045
Abstract:
In the context of innovative education, the electrocatalytic reduction of nitrate for ammonia synthesis is taken as a case example to integrate research outcomes into experimental teaching. On the basis of students' pre-existing experimental skills and foundational electrochemical knowledge, electrochemical measurement, nuclear magnetic resonance spectroscopy, ultraviolet spectrophotometry and other techniques are used to evaluate the performance of catalysts for nitrate electroreduction to ammonia. Students can further understand the basic principle of electrocatalysis, master the electrochemical measurement method via this experiment and stimulate their interests in electrosynthesis. The content of this teaching experiment is informative and involves multidisciplinary knowledge. It can satisfy the needs of interdisciplinary integration and cultivate the divergent thinking of students, which meets the requirements of subject education in the new area.
In the context of innovative education, the electrocatalytic reduction of nitrate for ammonia synthesis is taken as a case example to integrate research outcomes into experimental teaching. On the basis of students' pre-existing experimental skills and foundational electrochemical knowledge, electrochemical measurement, nuclear magnetic resonance spectroscopy, ultraviolet spectrophotometry and other techniques are used to evaluate the performance of catalysts for nitrate electroreduction to ammonia. Students can further understand the basic principle of electrocatalysis, master the electrochemical measurement method via this experiment and stimulate their interests in electrosynthesis. The content of this teaching experiment is informative and involves multidisciplinary knowledge. It can satisfy the needs of interdisciplinary integration and cultivate the divergent thinking of students, which meets the requirements of subject education in the new area.
2024, 39(1): 280-286
doi: 10.3866/PKU.DXHX202307031
Abstract:
Mass spectrometry experiment is an important course in instrumental chemistry. Based on our long-term practical exploration, we chose Methyl salicylate (methyl o-hydroxy Methyl benzoate) as the experimental object for mass spectrometry analysis, and compared it with its isomers 3-Hydroxybenzoic acid methyl ester, nipagin methyl ester (methyl 4-Hydroxybenzoic acid), vanillin (3-nenenebe methoxy 4-hydroxy Benzaldehyde), 2,4-dihydroxy Acetophenone and 3,4-dihydroxy Acetophenone. Through this experiment, students will master the mass spectrum pyrolysis characteristics of benzene ring, carbonyl group, Methoxy group, aldehyde group, phenols etc., and become familiar with the molecular rearrangement phenomenon of "Alpha effect of aromatic ring". This experiment is practical, interesting with moderate difficulty. It can help students to consolidate theoretical knowledge and exercise thinking, improving practical application ability. It is suitable for students major in pharmacy, chemistry, food or other related ones, and also can be used as experimental training materials for graduate students.
Mass spectrometry experiment is an important course in instrumental chemistry. Based on our long-term practical exploration, we chose Methyl salicylate (methyl o-hydroxy Methyl benzoate) as the experimental object for mass spectrometry analysis, and compared it with its isomers 3-Hydroxybenzoic acid methyl ester, nipagin methyl ester (methyl 4-Hydroxybenzoic acid), vanillin (3-nenenebe methoxy 4-hydroxy Benzaldehyde), 2,4-dihydroxy Acetophenone and 3,4-dihydroxy Acetophenone. Through this experiment, students will master the mass spectrum pyrolysis characteristics of benzene ring, carbonyl group, Methoxy group, aldehyde group, phenols etc., and become familiar with the molecular rearrangement phenomenon of "Alpha effect of aromatic ring". This experiment is practical, interesting with moderate difficulty. It can help students to consolidate theoretical knowledge and exercise thinking, improving practical application ability. It is suitable for students major in pharmacy, chemistry, food or other related ones, and also can be used as experimental training materials for graduate students.
2024, 39(1): 287-293
doi: 10.3866/PKU.DXHX202307042
Abstract:
6,6'-Dibromo-1,1'-bi-2-naphthol is a derivative of 1,1'-bi-2-naphthol (BINOL), both of which are archetypal axially chiral organic molecules. The study of the synthesis and separation of such molecules is crucial for undergraduates to deepen their understanding of axially chiral compounds. Considering the high cost of (±)-BINOL and its derivatives, which hinders extensive synthesis and separation experiments for educational purposes, this study employs microwave-assisted synthesis for the coupling of 6,6'-ibromo-1,1'-bi-2-naphthol. In addition, we have developed a microwave synthesis method for the chiral separating agent, N-benzylcinchonidine chloride, and used it directly for the chemical separation of 6,6'-dibromo-1,1'-bi-2-naphthol. By introducing microwave-assisted synthesis, optimizing the solvents for the synthetic reactions, and recycling the separating agent, this experiment aligns more closely with the principles of green chemistry. Pedagogically, the experiment involves multiple operations, serving as a comprehensive test of students' experimental skills and offering significant educational value.
6,6'-Dibromo-1,1'-bi-2-naphthol is a derivative of 1,1'-bi-2-naphthol (BINOL), both of which are archetypal axially chiral organic molecules. The study of the synthesis and separation of such molecules is crucial for undergraduates to deepen their understanding of axially chiral compounds. Considering the high cost of (±)-BINOL and its derivatives, which hinders extensive synthesis and separation experiments for educational purposes, this study employs microwave-assisted synthesis for the coupling of 6,6'-ibromo-1,1'-bi-2-naphthol. In addition, we have developed a microwave synthesis method for the chiral separating agent, N-benzylcinchonidine chloride, and used it directly for the chemical separation of 6,6'-dibromo-1,1'-bi-2-naphthol. By introducing microwave-assisted synthesis, optimizing the solvents for the synthetic reactions, and recycling the separating agent, this experiment aligns more closely with the principles of green chemistry. Pedagogically, the experiment involves multiple operations, serving as a comprehensive test of students' experimental skills and offering significant educational value.
2024, 39(1): 294-304
doi: 10.3866/PKU.DXHX202307044
Abstract:
A comprehensive experiment was devised focusing on the preparation, characterization, and antiscalant performance of fluorescent and hydroxy-modified polyaspartic acid. Initially, a water-soluble fluorescent material and polysuccinimide (PSI) were synthesized. The PSI was then modified using the fluorescent material and ethanolamine, followed by alkaline hydrolysis to obtain the target antiscalant. The antiscalant was characterized using 1H NMR, gel permeation chromatography, and fluorescence spectrophotometry, and its antiscalant efficacy was evaluated through static scaling tests. This experiment integrates concepts from polymer chemistry, organic chemistry, and analytical chemistry, embodying the scientific research process of "synthesis-characterization-analysis". It emphasizes the research thinking model of "substance-structure-property", aiming to cultivate students' experimental proficiency and research capabilities.
A comprehensive experiment was devised focusing on the preparation, characterization, and antiscalant performance of fluorescent and hydroxy-modified polyaspartic acid. Initially, a water-soluble fluorescent material and polysuccinimide (PSI) were synthesized. The PSI was then modified using the fluorescent material and ethanolamine, followed by alkaline hydrolysis to obtain the target antiscalant. The antiscalant was characterized using 1H NMR, gel permeation chromatography, and fluorescence spectrophotometry, and its antiscalant efficacy was evaluated through static scaling tests. This experiment integrates concepts from polymer chemistry, organic chemistry, and analytical chemistry, embodying the scientific research process of "synthesis-characterization-analysis". It emphasizes the research thinking model of "substance-structure-property", aiming to cultivate students' experimental proficiency and research capabilities.
2024, 39(1): 305-308
doi: 10.3866/PKU.DXHX202305080
Abstract:
There are several proton transfer reactions and multiple chemical equilibria in NaHCO3 aqueous solution. As the concentration of the solution changes, the contents of H2CO3, H+, OH- and CO32-, which are related to proton transfer reactions, also change. The diagram of [H2CO3], [H+], [OH-] and [CO32-] with solution concentration c is plotted. From the diagram, we can directly observe which species are the major and which are the minor. In a high concentration, [H2CO3] ≈ [CO32-] >> [OH-] >> [H+], indicating that the proton reactions which can produce H+ or OH- are negligible, and HCO3- + HCO3- ⇌ H2CO3 + CO32- is the dominant. In 9.1×10-6 mol·L-1 solution, [OH-] ≈ [H2CO3] >> [H+] ≈ [CO32-], indicating that H2O + HCO3- ⇌ H2CO3 + OH- is the dominant. In an extremely dilute solution, [OH-] ≈ [H+] >> [H2CO3] > [CO32-], indicating that H2O ⇌ H+ + OH- dominates.
There are several proton transfer reactions and multiple chemical equilibria in NaHCO3 aqueous solution. As the concentration of the solution changes, the contents of H2CO3, H+, OH- and CO32-, which are related to proton transfer reactions, also change. The diagram of [H2CO3], [H+], [OH-] and [CO32-] with solution concentration c is plotted. From the diagram, we can directly observe which species are the major and which are the minor. In a high concentration, [H2CO3] ≈ [CO32-] >> [OH-] >> [H+], indicating that the proton reactions which can produce H+ or OH- are negligible, and HCO3- + HCO3- ⇌ H2CO3 + CO32- is the dominant. In 9.1×10-6 mol·L-1 solution, [OH-] ≈ [H2CO3] >> [H+] ≈ [CO32-], indicating that H2O + HCO3- ⇌ H2CO3 + OH- is the dominant. In an extremely dilute solution, [OH-] ≈ [H+] >> [H2CO3] > [CO32-], indicating that H2O ⇌ H+ + OH- dominates.
2024, 39(1): 309-313
doi: 10.3866/PKU.DXHX202305062
Abstract:
Based on matrix multiplication, the third symmetric operation, which is equivalent to the product of different symmetric operations, was deduced in this paper. Furthermore, it was proposed how the group containing different symmetric elements can be derived from the direct product of its subgroups. At the same time, the new symmetric elements can be derived from the multiplication of its group elements.
Based on matrix multiplication, the third symmetric operation, which is equivalent to the product of different symmetric operations, was deduced in this paper. Furthermore, it was proposed how the group containing different symmetric elements can be derived from the direct product of its subgroups. At the same time, the new symmetric elements can be derived from the multiplication of its group elements.
2024, 39(1): 314-319
doi: 10.3866/PKU.DXHX202306053
Abstract:
Taking the explanation of heat conduction in the heat transfer chapter of the chemical engineering transmission course as an example, this paper expounds on innovative teaching considerations based on the "fun, learn, apply" three-level teaching method. It analyzes the transient and steady-state heat transfer processes in cooking, increasing the interest in teaching. At the same time, analogical teaching is conducted, from heat transfer analogy to mass transfer processes, allowing students to learn the similarity between heat transfer and mass transfer. Furthermore, the analogy of heat and mass transfer is further extended to the synthesis of new materials, enabling students to apply the knowledge learned.
Taking the explanation of heat conduction in the heat transfer chapter of the chemical engineering transmission course as an example, this paper expounds on innovative teaching considerations based on the "fun, learn, apply" three-level teaching method. It analyzes the transient and steady-state heat transfer processes in cooking, increasing the interest in teaching. At the same time, analogical teaching is conducted, from heat transfer analogy to mass transfer processes, allowing students to learn the similarity between heat transfer and mass transfer. Furthermore, the analogy of heat and mass transfer is further extended to the synthesis of new materials, enabling students to apply the knowledge learned.
2024, 39(1): 320-324
doi: 10.3866/PKU.DXHX202306057
Abstract:
In the teaching of university-level physical chemistry, the Arrhenius formula elucidates the relationship between the rate constant of a reaction, temperature, and activation energy. However, it is difficult for students to understand and master the formula simply from its expression. Taking the reaction of isopropyl nitrate with Cl atoms, OH and NO3 radicals as examples, the rate constants of the reactions at different temperatures were calculated based on the potential energy surface by the Transition State Theory. The change trends of rate constants with temperature for the reactions with different energy barriers have been visually analyzed. We hope to help students understand Arrhenius formula in essence by analyzing specific cases, so as to broaden their knowledge and cultivate their scientific inquiry ability.
In the teaching of university-level physical chemistry, the Arrhenius formula elucidates the relationship between the rate constant of a reaction, temperature, and activation energy. However, it is difficult for students to understand and master the formula simply from its expression. Taking the reaction of isopropyl nitrate with Cl atoms, OH and NO3 radicals as examples, the rate constants of the reactions at different temperatures were calculated based on the potential energy surface by the Transition State Theory. The change trends of rate constants with temperature for the reactions with different energy barriers have been visually analyzed. We hope to help students understand Arrhenius formula in essence by analyzing specific cases, so as to broaden their knowledge and cultivate their scientific inquiry ability.
2024, 39(1): 325-331
doi: 10.3866/PKU.DXHX202307060
Abstract:
The conformations of alkanes and their stability are important topics in basic organic chemistry. Among them, the staggered and eclipsed conformations of ethane are the most fundamental. Current undergraduate organic chemistry textbooks both domestically and internationally provide different explanations for the stability of the staggered conformation of ethane compared to the eclipsed conformation, leading to confusion and making it difficult for undergraduate teaching. In this study, we conducted a survey of literatures, organized different arguments and evidence for the stability of the staggered conformation of ethane, and pointed out the shortcomings of analysis and calculation methods in previous literatures. Through literature research, we believe that both hyperconjugation and steric hindrance should be included in the textbooks.
The conformations of alkanes and their stability are important topics in basic organic chemistry. Among them, the staggered and eclipsed conformations of ethane are the most fundamental. Current undergraduate organic chemistry textbooks both domestically and internationally provide different explanations for the stability of the staggered conformation of ethane compared to the eclipsed conformation, leading to confusion and making it difficult for undergraduate teaching. In this study, we conducted a survey of literatures, organized different arguments and evidence for the stability of the staggered conformation of ethane, and pointed out the shortcomings of analysis and calculation methods in previous literatures. Through literature research, we believe that both hyperconjugation and steric hindrance should be included in the textbooks.
2024, 39(1): 332-339
doi: 10.3866/PKU.DXHX202305082
Abstract:
Introducing the Materials Studio software into the course teaching of computational theory, such as computational chemistry, computational materials science, and applying the mode of "computational theory explanation + practical operation of research case by computational software" can significantly improve the teaching efficiency, realizing scientific research feeding the high-quality teaching. Application of the Materials Studio software in the course teaching can make students to apply and consolidate the theoretical knowledge concepts in the practice operations of software, and improve students' theoretical method level and software operation skill level. Meanwhile, it makes the teaching content more vivid and specific, stimulates students' interest in the course teaching of computational chemistry and computational materials science, and cultivate students' scientific research thinking and exploration ability, realizing teaching supporting the high-level scientific research.
Introducing the Materials Studio software into the course teaching of computational theory, such as computational chemistry, computational materials science, and applying the mode of "computational theory explanation + practical operation of research case by computational software" can significantly improve the teaching efficiency, realizing scientific research feeding the high-quality teaching. Application of the Materials Studio software in the course teaching can make students to apply and consolidate the theoretical knowledge concepts in the practice operations of software, and improve students' theoretical method level and software operation skill level. Meanwhile, it makes the teaching content more vivid and specific, stimulates students' interest in the course teaching of computational chemistry and computational materials science, and cultivate students' scientific research thinking and exploration ability, realizing teaching supporting the high-level scientific research.
2024, 39(1): 340-350
doi: 10.3866/PKU.DXHX202305077
Abstract:
Both acid-base titration curve and titration end point error are two important teaching contents in the chapter of acid-base titration in analytical chemistry textbook. In view of the above two problems, it is proposed that a new general teaching strategy of ‘strengthening of modeling capability, integrating of information technology into analytical chemistry, enhancement of visualization and avoiding of formularization memory’. The strategy is carried out in two steps. Specifically, in the first step, the acid-base titration problem is converted into a mathematic model by means of three underlying logic tools, namely charge balance equation, dilution law and distribution coefficient of species. The building modeling process is referred to as three-step modeling method. In the second step, visualization and digital solution on the built models are realized by the aid of GeoGebra software.
Both acid-base titration curve and titration end point error are two important teaching contents in the chapter of acid-base titration in analytical chemistry textbook. In view of the above two problems, it is proposed that a new general teaching strategy of ‘strengthening of modeling capability, integrating of information technology into analytical chemistry, enhancement of visualization and avoiding of formularization memory’. The strategy is carried out in two steps. Specifically, in the first step, the acid-base titration problem is converted into a mathematic model by means of three underlying logic tools, namely charge balance equation, dilution law and distribution coefficient of species. The building modeling process is referred to as three-step modeling method. In the second step, visualization and digital solution on the built models are realized by the aid of GeoGebra software.
2024, 39(1): 351-358
doi: 10.3866/PKU.DXHX202306006
Abstract:
Cyclooctatetraene is a cyclic polyene composed of eight sp2 carbon atoms. Understanding its structure and properties involves the application of various fundamental chemical theories and concepts. This article guides undergraduate students to use computational chemistry methods to investigate the electronic structure, geometric configuration, aromaticity, and isomerization reactions of cyclooctatetraene, with the aim of helping students achieve the following learning objectives:1) understand the scientific concept that structure determines properties and properties respond to structure; 2) understand the limitation of the Hückel molecular orbital method (HMO) in dealing with 4n-type π-electron systems; 3) distinguish fundamental concepts such as aromaticity, antiaromaticity, and non-aromaticity and comprehend the Hückel's rule for determining the aromaticity of the ground state (singlet state) of a conjugated π-electron system, as well as the Baird's rule for determining the aromaticity of excited states (triplet state); and 4) clearly recognize that computational chemistry methods are essential tools for understanding the structure and properties of materials.
Cyclooctatetraene is a cyclic polyene composed of eight sp2 carbon atoms. Understanding its structure and properties involves the application of various fundamental chemical theories and concepts. This article guides undergraduate students to use computational chemistry methods to investigate the electronic structure, geometric configuration, aromaticity, and isomerization reactions of cyclooctatetraene, with the aim of helping students achieve the following learning objectives:1) understand the scientific concept that structure determines properties and properties respond to structure; 2) understand the limitation of the Hückel molecular orbital method (HMO) in dealing with 4n-type π-electron systems; 3) distinguish fundamental concepts such as aromaticity, antiaromaticity, and non-aromaticity and comprehend the Hückel's rule for determining the aromaticity of the ground state (singlet state) of a conjugated π-electron system, as well as the Baird's rule for determining the aromaticity of excited states (triplet state); and 4) clearly recognize that computational chemistry methods are essential tools for understanding the structure and properties of materials.
2024, 39(1): 359-363
doi: 10.3866/PKU.DXHX202307025
Abstract:
Through the introduction of the molar gravitational potential energy for component B, we derive the fundamental thermodynamic equations for a multi-component system in a gravitational field. The gravitational chemical potential is defined, allowing for the determination of the direction and extent of changes. Concluding, we provide application examples of the criteria based on the gravitational chemical potential:the pressure distribution formula for an ideal gas as a function of altitude, and the sedimentation equilibrium formula for sol particles in a medium.
Through the introduction of the molar gravitational potential energy for component B, we derive the fundamental thermodynamic equations for a multi-component system in a gravitational field. The gravitational chemical potential is defined, allowing for the determination of the direction and extent of changes. Concluding, we provide application examples of the criteria based on the gravitational chemical potential:the pressure distribution formula for an ideal gas as a function of altitude, and the sedimentation equilibrium formula for sol particles in a medium.
2024, 39(1): 364-368
doi: 10.3866/PKU.DXHX202307033
Abstract:
Graphene and hexagonal boron nitride (h-BN) are isoelectronic materials. Depite their similar structures, they exhibit stark differences in electrical conductivities. Graphene is an excellent conductivity, while h-BN is an insulator. Based on the quantum chemistry calculations, the electronic structures of model molecules, C24H12 and B12N12H12, have been studied by the topological analysis of electron density, natural bond orbital analysis, nucleus-independent chemical shift, and magnetic induced current density analysis. The study provides theoretical explanations for the conductivity differences between graphene and h-BN. These findings can enhance students' understanding of the fundametal concepts such as isoelectronic species, localization and delocalized π bond.
Graphene and hexagonal boron nitride (h-BN) are isoelectronic materials. Depite their similar structures, they exhibit stark differences in electrical conductivities. Graphene is an excellent conductivity, while h-BN is an insulator. Based on the quantum chemistry calculations, the electronic structures of model molecules, C24H12 and B12N12H12, have been studied by the topological analysis of electron density, natural bond orbital analysis, nucleus-independent chemical shift, and magnetic induced current density analysis. The study provides theoretical explanations for the conductivity differences between graphene and h-BN. These findings can enhance students' understanding of the fundametal concepts such as isoelectronic species, localization and delocalized π bond.
2024, 39(1): 369-376
doi: 10.3866/PKU.DXHX202307061
Abstract:
The BET (Brunauer-Emmett-Teller) theory of multimolecular adsorption is abstract yet widely applicable, and its equation involves complex mathematical derivations that are often difficult for students to grasp. Consequently, students may struggle to correctly interpret adsorption-desorption isotherms and specific surface area data generated by automated specific surface analyzers, leading to unsatisfactory educational outcomes. This paper introduces the use of computer simulations to model the adsorption-desorption process of gas molecules on solid surfaces. By adjusting the adsorption-desorption constants, the simulations can generate Type I, II, and III adsorption isotherms. The real-time visualization allows students to intuitively understand the dynamics of gas molecule adsorption and desorption on solid surfaces, thereby enhancing their comprehension of BET theory. The incorporation of computer simulation into teaching not only enlivens the classroom environment but also fosters an interactive teaching-learning experience, stimulating students' curiosity and research interest while improving the overall quality of education.
The BET (Brunauer-Emmett-Teller) theory of multimolecular adsorption is abstract yet widely applicable, and its equation involves complex mathematical derivations that are often difficult for students to grasp. Consequently, students may struggle to correctly interpret adsorption-desorption isotherms and specific surface area data generated by automated specific surface analyzers, leading to unsatisfactory educational outcomes. This paper introduces the use of computer simulations to model the adsorption-desorption process of gas molecules on solid surfaces. By adjusting the adsorption-desorption constants, the simulations can generate Type I, II, and III adsorption isotherms. The real-time visualization allows students to intuitively understand the dynamics of gas molecule adsorption and desorption on solid surfaces, thereby enhancing their comprehension of BET theory. The incorporation of computer simulation into teaching not only enlivens the classroom environment but also fosters an interactive teaching-learning experience, stimulating students' curiosity and research interest while improving the overall quality of education.
2024, 39(1): 377-385
doi: 10.3866/PKU.DXHX202306026
Abstract:
Based on modern Python programming technology, we independently developed a graphical user interface (GUI) acid-base titration learning software. It can achieve the visualization of titration curve images for different acid-base systems such as monobasic strong acid (base), monobasic weak acid (base), polybasic acid (base), and mixed acid (base), as well as the calculation of stoichiometric points, titration jump ranges, and titration errors. The application of software makes the teaching content more intuitive and visualized, helping to gain a perceptual understanding of the changes in titration curves and a profound comprehension of its concepts and principles.
Based on modern Python programming technology, we independently developed a graphical user interface (GUI) acid-base titration learning software. It can achieve the visualization of titration curve images for different acid-base systems such as monobasic strong acid (base), monobasic weak acid (base), polybasic acid (base), and mixed acid (base), as well as the calculation of stoichiometric points, titration jump ranges, and titration errors. The application of software makes the teaching content more intuitive and visualized, helping to gain a perceptual understanding of the changes in titration curves and a profound comprehension of its concepts and principles.
2024, 39(1): 386-395
doi: 10.3866/PKU.DXHX202311002
Abstract:
