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2020 Volume 37 Issue 7
2020, 37(7): 733-745
doi: 10.11944/j.issn.1000-0518.2020.07.200058
Abstract:
Transition metal phosphides (TMPs) have been widely recognized as favorable electrocatalytic materials for hydrogen evolution reaction (HER) due to their high conductivity and good stability. In this review, we highlight the progress on the synthesis and characterization of Ni, Co and Fe based phosphides nanomaterials, as well as the HER activities of TMPs in alkaline solutions. The TMPs show low overpotential at a specific current density and have good stability, indicating that more phosphorus-rich phases exhibit higher HER activities within certain limits, which provides a direction for our future research.
Transition metal phosphides (TMPs) have been widely recognized as favorable electrocatalytic materials for hydrogen evolution reaction (HER) due to their high conductivity and good stability. In this review, we highlight the progress on the synthesis and characterization of Ni, Co and Fe based phosphides nanomaterials, as well as the HER activities of TMPs in alkaline solutions. The TMPs show low overpotential at a specific current density and have good stability, indicating that more phosphorus-rich phases exhibit higher HER activities within certain limits, which provides a direction for our future research.
2020, 37(7): 746-755
doi: 10.11944/j.issn.1000-0518.2020.07.200024
Abstract:
The microporous poly(styrene-divinylbenzene) (PS-DVB) microspheres have the advantages of stable physical and chemical properties, large specific surface area, low production cost, and controllable particle sizes. It has broad application prospects in the fields of biomedicine, adsorption, separation and catalyst support. Three kinds of porous polymer microspheres (PPMs) were prepared by introducing the functional monomers acrylonitrile (AN), acrylamide (AA) and N-vinyl carbazole (VC). The results show that, on the one hand, polypropylenes are microspheres and nanofibers due to the template effect and confined effect. On the other hand, the load of Ti and Mg in the Ziegler-Natta catalyst supported by PPM-AN increases with the increase of specific surface area of the support. The results of propylene polymerization show that under the same pressure, the overall trend of molecular mass (Mw), molecular mass distribution (PDI) and isotacticity increase with the increase of pore size because the propylene monomer is restricted by PPM-AN support.
The microporous poly(styrene-divinylbenzene) (PS-DVB) microspheres have the advantages of stable physical and chemical properties, large specific surface area, low production cost, and controllable particle sizes. It has broad application prospects in the fields of biomedicine, adsorption, separation and catalyst support. Three kinds of porous polymer microspheres (PPMs) were prepared by introducing the functional monomers acrylonitrile (AN), acrylamide (AA) and N-vinyl carbazole (VC). The results show that, on the one hand, polypropylenes are microspheres and nanofibers due to the template effect and confined effect. On the other hand, the load of Ti and Mg in the Ziegler-Natta catalyst supported by PPM-AN increases with the increase of specific surface area of the support. The results of propylene polymerization show that under the same pressure, the overall trend of molecular mass (Mw), molecular mass distribution (PDI) and isotacticity increase with the increase of pore size because the propylene monomer is restricted by PPM-AN support.
2020, 37(7): 756-763
doi: 10.11944/j.issn.1000-0518.2020.07.200016
Abstract:
Dopamine (DA) has been proved to be able to oxidize and polymerize into polydopamine (PDA) on the surface of a variety of materials, however, the mechanism of the DA polymerization on strongly electronegative surfaces and the formed morphologies of PDA are not clear yet. In order to investigate the influence of the surface electronegativity and oxidation conditions on the rate of the oxidized self-polymerization and the morphology of the PDA layer, herein, polystyrene/polyacrylic acid nanoparticles (PS/PAA NPs) with PS as the core and PAA as the shell were prepared by soap-free emulsion polymerization. Then, PDA was coated on the surface of the PS/PAA NPs and the effect of different pH buffers, reaction time and the amount of DA on the polymerization process and the PDA morphologies were investigated. The morphology and size of the nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Zeta potential. The results show that small PDA NPs are polymerized on the PS/PAA NPs surface to form the raspberry structure in the Tris buffer solution with a pH of 8.5, and the mass ratio of DA to PS/PAA NPs is 1:1. The formed PDA NPs become bigger with higher DA contents and longer reaction time. When DA is excess, it eventually forms a uniform PDA shell on the surface of microspheres. Zeta potential results show that the raspberry-like structure is formed due to the balance between electrostatic interaction and charge repulsion in the surface polymerization of PAA. A larger amount of DA and a longer reaction time result in the reduction of charge repulsion to form a dense uniform PDA shell layer. In addition, uniform PDA shell layers form on the surface of PS/SDS microspheres with less electronegativity and nonionic PS microspheres. Therefore, the PDA deposition on the surface of the anionic materials is influenced by the negative value of the surface.
Dopamine (DA) has been proved to be able to oxidize and polymerize into polydopamine (PDA) on the surface of a variety of materials, however, the mechanism of the DA polymerization on strongly electronegative surfaces and the formed morphologies of PDA are not clear yet. In order to investigate the influence of the surface electronegativity and oxidation conditions on the rate of the oxidized self-polymerization and the morphology of the PDA layer, herein, polystyrene/polyacrylic acid nanoparticles (PS/PAA NPs) with PS as the core and PAA as the shell were prepared by soap-free emulsion polymerization. Then, PDA was coated on the surface of the PS/PAA NPs and the effect of different pH buffers, reaction time and the amount of DA on the polymerization process and the PDA morphologies were investigated. The morphology and size of the nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Zeta potential. The results show that small PDA NPs are polymerized on the PS/PAA NPs surface to form the raspberry structure in the Tris buffer solution with a pH of 8.5, and the mass ratio of DA to PS/PAA NPs is 1:1. The formed PDA NPs become bigger with higher DA contents and longer reaction time. When DA is excess, it eventually forms a uniform PDA shell on the surface of microspheres. Zeta potential results show that the raspberry-like structure is formed due to the balance between electrostatic interaction and charge repulsion in the surface polymerization of PAA. A larger amount of DA and a longer reaction time result in the reduction of charge repulsion to form a dense uniform PDA shell layer. In addition, uniform PDA shell layers form on the surface of PS/SDS microspheres with less electronegativity and nonionic PS microspheres. Therefore, the PDA deposition on the surface of the anionic materials is influenced by the negative value of the surface.
2020, 37(7): 764-771
doi: 10.11944/j.issn.1000-0518.2020.07.190360
Abstract:
Use of amphiphilic block copolymers as templates is one of the effective methods to construct conducting polymer nanostructures and adjust their morphologies and sizes. The change of the length of core-forming block has a significant effect on their micellization behavior, and then changes the morphology and size of conducting polymers limited by their micelle morphology. The change of morphology and size will inevitably lead to the change of electrochemical properties of conducting polymers. In this paper, the morphology and size of polyaniline (PANI) were controlled and its electrochemical performance was optimized by block copolymer template induction. Polystyrene-b-poly(acrylic acid) (PSx-b-PAA70, x=38, 64, 101) was successfully synthesized by reversible addition-fragmentation chain transfer radical polymerization (RAFT) and its self-assembled micelles were used as templates to prepare PANI. When the length of core forming block is shorter, the PANI shows rod-like particles with diameters 100~200 nm. When x=101, PANI presents spatial network structure and has the highest discharge specific capacitance. When the current density is 1 A/g, its discharge specific capacity can reach 386.71 F/g.
Use of amphiphilic block copolymers as templates is one of the effective methods to construct conducting polymer nanostructures and adjust their morphologies and sizes. The change of the length of core-forming block has a significant effect on their micellization behavior, and then changes the morphology and size of conducting polymers limited by their micelle morphology. The change of morphology and size will inevitably lead to the change of electrochemical properties of conducting polymers. In this paper, the morphology and size of polyaniline (PANI) were controlled and its electrochemical performance was optimized by block copolymer template induction. Polystyrene-b-poly(acrylic acid) (PSx-b-PAA70, x=38, 64, 101) was successfully synthesized by reversible addition-fragmentation chain transfer radical polymerization (RAFT) and its self-assembled micelles were used as templates to prepare PANI. When the length of core forming block is shorter, the PANI shows rod-like particles with diameters 100~200 nm. When x=101, PANI presents spatial network structure and has the highest discharge specific capacitance. When the current density is 1 A/g, its discharge specific capacity can reach 386.71 F/g.
2020, 37(7): 772-777
doi: 10.11944/j.issn.1000-0518.2020.07.190339
Abstract:
Ethylene-vinyl acetate copolymer (EVA) is a commonly used pour point depressants (PPDs) for crude oil, but its molecular structure is relatively simple and it has poor pour point depressing effect on some oils. In order to enhance its effect on pour point, long alkyl side chain modified EVA was prepared by a simple method of direct reaction of stearoyl chloride with hydroxylated EVA, and was compounded with alkyl long-chain silsesquioxane nanoparticles (SS). The pour point depressant effect and the mechanism of modified EVA and SS compound pour point depressants on wax oil were studied. The compounded pour point depressant provides crystal nuclei for the wax, making the wax crystals smaller and difficult to overlap and reducing the amount of wax precipitation. When the compounding ratio is m(EVA-g):m(SS-L)=1:2 and the mass fraction in wax oil is 0.1%, the pour point is reduced by 25 ℃.
Ethylene-vinyl acetate copolymer (EVA) is a commonly used pour point depressants (PPDs) for crude oil, but its molecular structure is relatively simple and it has poor pour point depressing effect on some oils. In order to enhance its effect on pour point, long alkyl side chain modified EVA was prepared by a simple method of direct reaction of stearoyl chloride with hydroxylated EVA, and was compounded with alkyl long-chain silsesquioxane nanoparticles (SS). The pour point depressant effect and the mechanism of modified EVA and SS compound pour point depressants on wax oil were studied. The compounded pour point depressant provides crystal nuclei for the wax, making the wax crystals smaller and difficult to overlap and reducing the amount of wax precipitation. When the compounding ratio is m(EVA-g):m(SS-L)=1:2 and the mass fraction in wax oil is 0.1%, the pour point is reduced by 25 ℃.
2020, 37(7): 778-784
doi: 10.11944/j.issn.1000-0518.2020.07.200012
Abstract:
A silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH570) was used to modify multi-walled carbon nanotubes (MWNTs) to graft allyl functional groups on the surface, and in situ polymerization with acrylate monomers was performed to prepare a high temperature-resistant acrylate pressure sensitive adhesive (PSA). The structure and properties of MWNTs and PSA were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of the mass fraction of modified MWNTs on PSA's heat resistance and adhesive properties were studied. The results show that when the mass fraction of the modified MWNTs is 1.5%, the heat resistance and adhesive properties of the modified PSA are the best. The thermal decomposition temperature increases from 360 to 382 ℃, the heat resistant temperature increases from 80 to 155 ℃, and the initial adhesion, the holding power and the 180° peel increase from ball No.12, 2 h and 13.66 N/25 mm to ball No.17, 27 h and 17.34 N/25 mm, respectively.
A silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH570) was used to modify multi-walled carbon nanotubes (MWNTs) to graft allyl functional groups on the surface, and in situ polymerization with acrylate monomers was performed to prepare a high temperature-resistant acrylate pressure sensitive adhesive (PSA). The structure and properties of MWNTs and PSA were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of the mass fraction of modified MWNTs on PSA's heat resistance and adhesive properties were studied. The results show that when the mass fraction of the modified MWNTs is 1.5%, the heat resistance and adhesive properties of the modified PSA are the best. The thermal decomposition temperature increases from 360 to 382 ℃, the heat resistant temperature increases from 80 to 155 ℃, and the initial adhesion, the holding power and the 180° peel increase from ball No.12, 2 h and 13.66 N/25 mm to ball No.17, 27 h and 17.34 N/25 mm, respectively.
2020, 37(7): 785-792
doi: 10.11944/j.issn.1000-0518.2020.07.200020
Abstract:
Rubusoside is a rare natural sweetener. In this experiment, a β-glucosidase from Aspergillus niger was screened from some glycosidases, which was used to proficiently produce rubusoside from stevioside. The optimum rubusoside yield and the stevioside conversion reach 90.4% and 98.8% in 12 h, respectively. Subsequently, the cytotoxicity of rubusoside on human gastrointestinal and liver cells was investigated, which includes 3 normal and 11 cancer cell lines. At a mass concentration of 250 μg/mL, rubusoside is not toxic to the normal cells, and its inhibition rate of rubusoside on BEL-7404 is 30% of that 5-fluorouracil proceeded.
Rubusoside is a rare natural sweetener. In this experiment, a β-glucosidase from Aspergillus niger was screened from some glycosidases, which was used to proficiently produce rubusoside from stevioside. The optimum rubusoside yield and the stevioside conversion reach 90.4% and 98.8% in 12 h, respectively. Subsequently, the cytotoxicity of rubusoside on human gastrointestinal and liver cells was investigated, which includes 3 normal and 11 cancer cell lines. At a mass concentration of 250 μg/mL, rubusoside is not toxic to the normal cells, and its inhibition rate of rubusoside on BEL-7404 is 30% of that 5-fluorouracil proceeded.
2020, 37(7): 803-809
doi: 10.11944/j.issn.1000-0518.2020.07.190356
Abstract:
The extraction of vanadium from stone coal by acid leaching has attracted much attention because of its characteristic of environment friendly and high metal yield. However, the process is seriously affected by concentrated Fe3+ in the vanadium mother solution. In this paper, a system (P507(2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester)+N235(Trioctyl/tridecylaklylamines)+sulfonated kerosene) based on the "depressing extraction-extraction" effect was proposed to separate V from Fe. The influence of various factors on the separation and enrichment of V over Fe was studied in details. Results show that P507 is responsible for extraction of Fe and V, while N235 suppresses the extraction of Fe3+. The higher the concentration of N235, the less Fe3+ is extracted. The separation efficiency of V over Fe is high in the raw solution at pH≤0.4, demonstrating the applicability of the designed "depressing extraction-extraction" mixed extractants toward concentrated acid leaching solution. When 6 mol/L ammonia is used, more than 99% of vanadium can be stripped. Under the condition of 25 ℃, V(organic phase):V(aqueous phase)=2:1 the stripping pregnant solution is obtained, in which the mass concentration of vanadium is 14.73 g/L, the mass concentration of iron is less than 0.022 g/L, and the mass ratio of vanadium to iron is more than 669.5. It is evident that the "depressing extraction-extraction" is a method of easy operation, being economic and efficient, and great industrial prospect.
The extraction of vanadium from stone coal by acid leaching has attracted much attention because of its characteristic of environment friendly and high metal yield. However, the process is seriously affected by concentrated Fe3+ in the vanadium mother solution. In this paper, a system (P507(2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester)+N235(Trioctyl/tridecylaklylamines)+sulfonated kerosene) based on the "depressing extraction-extraction" effect was proposed to separate V from Fe. The influence of various factors on the separation and enrichment of V over Fe was studied in details. Results show that P507 is responsible for extraction of Fe and V, while N235 suppresses the extraction of Fe3+. The higher the concentration of N235, the less Fe3+ is extracted. The separation efficiency of V over Fe is high in the raw solution at pH≤0.4, demonstrating the applicability of the designed "depressing extraction-extraction" mixed extractants toward concentrated acid leaching solution. When 6 mol/L ammonia is used, more than 99% of vanadium can be stripped. Under the condition of 25 ℃, V(organic phase):V(aqueous phase)=2:1 the stripping pregnant solution is obtained, in which the mass concentration of vanadium is 14.73 g/L, the mass concentration of iron is less than 0.022 g/L, and the mass ratio of vanadium to iron is more than 669.5. It is evident that the "depressing extraction-extraction" is a method of easy operation, being economic and efficient, and great industrial prospect.
2020, 37(7): 810-815
doi: 10.11944/j.issn.1000-0518.2020.07.200008
Abstract:
The purity of o-chlorobenzylidene malononitrile (CS) was measured by differential scanning calorimeter (DSC) using the monopeak method. Considering the volatility of CS, the experiment was conducted by optimization of different heating rates and different qualities. Meanwhile, the purity of CS was also tested by high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). We compared their difference. The purities of CS are 99.89%, 99.92%, 99.25%, and 94.0% by DSC, HPLC, GC-MS and NMR, respectively, and the maximum discrepancy is 4.92%. We also discuss the reason for the differences.
The purity of o-chlorobenzylidene malononitrile (CS) was measured by differential scanning calorimeter (DSC) using the monopeak method. Considering the volatility of CS, the experiment was conducted by optimization of different heating rates and different qualities. Meanwhile, the purity of CS was also tested by high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). We compared their difference. The purities of CS are 99.89%, 99.92%, 99.25%, and 94.0% by DSC, HPLC, GC-MS and NMR, respectively, and the maximum discrepancy is 4.92%. We also discuss the reason for the differences.
2020, 37(7): 816-822
doi: 10.11944/j.issn.1000-0518.2020.07.200017
Abstract:
Nonylcyclohexanol polyoxyethylene ethers (NCEOn) are novel potential upgraded products for replacing the non-eco-friendly nonylphenol polyoxyethylene ethers (NPEOn). The product qualities of NCEOn were determined revolving the residual nonylcyclohexanol (NC) by normal phase high performance liquid chromatography (NP HPLC), the polyethylene glycol (PEG) content by Weilbull procedure and the polydispersity index (PDI) by electrospray ionization mass spectrometry (ESI MS) technique. An NP HPLC program was finally proposed for rapidly determining the residual NC in NCEOn by combining an Inertsil NH2 column, a refractive index detector with the eluent of ethyl acetate on the basis of five preliminary experiments of NP HPLC and reversed phase HPLC. This setup achieves a recovery of 91.77%~107.6%, a relative standard deviation (RSD) of 1.59%~4.46% and a limit of detection (LOD) 9.8 μg/mL. NCEO7 and NCEO9 contain 0.158% and 0.139% of NC, and 7.1% and 7.3% of PEG, respectively, which indicates that the NCEOn products have good qualities with a low NC residue, a low PEG content and a narrow distribution characteristic. Therefore, NCEOn is a potential substitute of NPEOn used in daily chemicals such as cosmetics, personal care products and toiletries.
Nonylcyclohexanol polyoxyethylene ethers (NCEOn) are novel potential upgraded products for replacing the non-eco-friendly nonylphenol polyoxyethylene ethers (NPEOn). The product qualities of NCEOn were determined revolving the residual nonylcyclohexanol (NC) by normal phase high performance liquid chromatography (NP HPLC), the polyethylene glycol (PEG) content by Weilbull procedure and the polydispersity index (PDI) by electrospray ionization mass spectrometry (ESI MS) technique. An NP HPLC program was finally proposed for rapidly determining the residual NC in NCEOn by combining an Inertsil NH2 column, a refractive index detector with the eluent of ethyl acetate on the basis of five preliminary experiments of NP HPLC and reversed phase HPLC. This setup achieves a recovery of 91.77%~107.6%, a relative standard deviation (RSD) of 1.59%~4.46% and a limit of detection (LOD) 9.8 μg/mL. NCEO7 and NCEO9 contain 0.158% and 0.139% of NC, and 7.1% and 7.3% of PEG, respectively, which indicates that the NCEOn products have good qualities with a low NC residue, a low PEG content and a narrow distribution characteristic. Therefore, NCEOn is a potential substitute of NPEOn used in daily chemicals such as cosmetics, personal care products and toiletries.
2020, 37(7): 823-829
doi: 10.11944/j.issn.1000-0518.2020.07.200079
Abstract:
Dihydrogen phosphate anion (H2PO4-) solution has important research value in biological buffering, molecular recognition and crystal growth. Taking KH2PO4 (KDP) and NaH2PO4 (NaDP) solutions as research objects, the influence of sodium and potassium ions on cluster aggregation and chemical bond vibration of H2PO4- solution was studied by in situ micro-Raman spectra. It was discussed that the difference of monovalent ions (K+, Na+) and the concentration of the solution played an important role in the Raman shift variation and nucleation induction time of H2PO4- vibration. The results show that the variation of Raman shift and the nucleation induction time increase with the increase of the solution-phase electronegativity of cations and the decrease of the concentration. In the Raman spectra, it is observed that the P(OH)2 and PO2 bands shift in the process of nucleation. It means that the cluster configuration is gradually stable and chemical bonding becomes clear, which deepens the understanding of solution structure and chemical bond during crystallization.
Dihydrogen phosphate anion (H2PO4-) solution has important research value in biological buffering, molecular recognition and crystal growth. Taking KH2PO4 (KDP) and NaH2PO4 (NaDP) solutions as research objects, the influence of sodium and potassium ions on cluster aggregation and chemical bond vibration of H2PO4- solution was studied by in situ micro-Raman spectra. It was discussed that the difference of monovalent ions (K+, Na+) and the concentration of the solution played an important role in the Raman shift variation and nucleation induction time of H2PO4- vibration. The results show that the variation of Raman shift and the nucleation induction time increase with the increase of the solution-phase electronegativity of cations and the decrease of the concentration. In the Raman spectra, it is observed that the P(OH)2 and PO2 bands shift in the process of nucleation. It means that the cluster configuration is gradually stable and chemical bonding becomes clear, which deepens the understanding of solution structure and chemical bond during crystallization.
2020, 37(7): 830-838
doi: 10.11944/j.issn.1000-0518.2020.07.190318
Abstract:
Nitrogen doped fluorescence carbon dots (N-CDs) were successfully synthesized by a facile one step solid phase pyrolysis treatment using malic acid as the carbon source and ammonium phosphate as the nitrogen source. The fluorescence quantum yield of the obtained N-CDs reaches 20.7% and the N-CDs have approximately spherical morphology with an average diameter of 3.3 nm. The as prepared N-CDs were used as the fluorescent probe to detect ciprofloxacin (CIP) based on the enhancement of N-CDs fluorescence upon adding CIP. The optimal experimental mass conditions are 7.5 μg/mL of N-CDs, pH=5.91, and 5 min of incubation time for the detection of CIP. The enhancement of N-CDs fluorescence exhibits a good linear relationship with the concentration of CIP ranged from 0.39 μmol/L to 40.0 μmol/L under the optimal conditions. The linear regression equation is ΔF=1.61×107[CIP]-3.28 with a correlation coefficient R2=0.994. The detection limit and relative standard deviation (n=5) are estimated to be 0.12 mol/L and 4.2%, respectively. The interference experiments indicate that potential coexistence substances (except copper ions) have ignorable effects on the detection of CIP, and the interference of copper ions could be masked with 4% ammonium oxalate solution. Finally, the proposed sensor was successfully applied to analyze real samples with satisfactory results.
Nitrogen doped fluorescence carbon dots (N-CDs) were successfully synthesized by a facile one step solid phase pyrolysis treatment using malic acid as the carbon source and ammonium phosphate as the nitrogen source. The fluorescence quantum yield of the obtained N-CDs reaches 20.7% and the N-CDs have approximately spherical morphology with an average diameter of 3.3 nm. The as prepared N-CDs were used as the fluorescent probe to detect ciprofloxacin (CIP) based on the enhancement of N-CDs fluorescence upon adding CIP. The optimal experimental mass conditions are 7.5 μg/mL of N-CDs, pH=5.91, and 5 min of incubation time for the detection of CIP. The enhancement of N-CDs fluorescence exhibits a good linear relationship with the concentration of CIP ranged from 0.39 μmol/L to 40.0 μmol/L under the optimal conditions. The linear regression equation is ΔF=1.61×107[CIP]-3.28 with a correlation coefficient R2=0.994. The detection limit and relative standard deviation (n=5) are estimated to be 0.12 mol/L and 4.2%, respectively. The interference experiments indicate that potential coexistence substances (except copper ions) have ignorable effects on the detection of CIP, and the interference of copper ions could be masked with 4% ammonium oxalate solution. Finally, the proposed sensor was successfully applied to analyze real samples with satisfactory results.
2020, 37(7): 839-846
doi: 10.11944/j.issn.1000-0518.2020.07.200004
Abstract:
Two novel naphthalimide-benzimidazolium based receptors 1 and 2 were synthesized. The anion (F-, Cl-, Br-, I-, CH3COO-, HSO4-, H2PO4-, ClO4-, NO3-) binding properties of two receptors were evaluated in CH3CN by fluorescence spectroscopy. Two receptors display fluorescent quenching effect with H2PO4- and the quench percentages for receptors 1 and 2 are 98%and 24%, respectively. The results indicate that receptor 1 is more closely matched to H2PO4- in configuration, and receptor 1 behaves as a "turn-off" fluorescence sensor for H2PO4-. Job-plot shows that receptor 1 and H2PO4- form a 1:1 complex, and the binding constant is (1.25±0.11)×105 L/mol, the detection limit is 6.90×10-6 mol/L.
Two novel naphthalimide-benzimidazolium based receptors 1 and 2 were synthesized. The anion (F-, Cl-, Br-, I-, CH3COO-, HSO4-, H2PO4-, ClO4-, NO3-) binding properties of two receptors were evaluated in CH3CN by fluorescence spectroscopy. Two receptors display fluorescent quenching effect with H2PO4- and the quench percentages for receptors 1 and 2 are 98%and 24%, respectively. The results indicate that receptor 1 is more closely matched to H2PO4- in configuration, and receptor 1 behaves as a "turn-off" fluorescence sensor for H2PO4-. Job-plot shows that receptor 1 and H2PO4- form a 1:1 complex, and the binding constant is (1.25±0.11)×105 L/mol, the detection limit is 6.90×10-6 mol/L.
2020, 37(7): 847-854
doi: 10.11944/j.issn.1000-0518.2020.07.200025
Abstract:
In order to recognize small-molecule biothiols selectively, quinolinone was used as a fluorophore. Since thiol molecules can easily break the Se—N bond, a new fluorescent probe (E)-N-(4-methyl-2-oxo-1, 2-dihydroquinolin-7-yl)-3-(5-((4-(3-oxobenzo[d][1, 2]selenazol-2(3H)-yl)phenyl)thio)-1, 3, 4-oxadiazol-2-yl)acrylamide (MNQ) was designed and synthesized by splicing quinolinone (E)-3-(5-mercapto-1, 3, 4-oxadiazol-2-yl)-N-(4-methyl-2-oxo-1, 2-dihydroquinolin-7-yl)acrylamide (MQ5) with ebselen 2-(4-bromophenyl)benzo[d][1, 2]selenazol-3(2H)-one (SQ6). The structure was characterized by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (HRMS), and its fluorescence properties were explored by fluorescence spectroscopy. The result shows that MNQ has obvious fluorescence quenching ability for glutathione (GSH). When other amino acids exist, the probe has good anti-interference ability, and can be used as a fluorescence quenching probe for identifying and detecting GSH. The detection limit is 2.99×10-7 mol/L, and the response time can be as low as 35 s. It has potential application as a fluorescent probe for detecting GSH.
In order to recognize small-molecule biothiols selectively, quinolinone was used as a fluorophore. Since thiol molecules can easily break the Se—N bond, a new fluorescent probe (E)-N-(4-methyl-2-oxo-1, 2-dihydroquinolin-7-yl)-3-(5-((4-(3-oxobenzo[d][1, 2]selenazol-2(3H)-yl)phenyl)thio)-1, 3, 4-oxadiazol-2-yl)acrylamide (MNQ) was designed and synthesized by splicing quinolinone (E)-3-(5-mercapto-1, 3, 4-oxadiazol-2-yl)-N-(4-methyl-2-oxo-1, 2-dihydroquinolin-7-yl)acrylamide (MQ5) with ebselen 2-(4-bromophenyl)benzo[d][1, 2]selenazol-3(2H)-one (SQ6). The structure was characterized by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (HRMS), and its fluorescence properties were explored by fluorescence spectroscopy. The result shows that MNQ has obvious fluorescence quenching ability for glutathione (GSH). When other amino acids exist, the probe has good anti-interference ability, and can be used as a fluorescence quenching probe for identifying and detecting GSH. The detection limit is 2.99×10-7 mol/L, and the response time can be as low as 35 s. It has potential application as a fluorescent probe for detecting GSH.
2020, 37(7): 793-802
doi: 10.11944/j.issn.1000-0518.2020.07.200030
Abstract:
Materials with both superhydrophobicity and superoleophilicity have attracted considerable attention due to the potential application in the removal of the spilled oil from water. In the past decades, numerous techniques have been adopted to construct superhydrophobic and superoleophilic materials, but it is still a great challenge to obtain this kind of material via a more facile, low cost and environmentally friendly method. Herein, corn straw fibers with superhydrophobicity and superoleophilicity were obtained by dip-coating TiO2 sol and subsequent surface modification with octyltrimethoxysilane (OTS). The contact angle of water droplets and oil droplets on the as-prepared sample is 160° and 0°, respectively. The results indicate that the superhydrophobicity is attributed to the joint effects of natural hierarchical structures with micro/nanometer scale of corn straw fibers and the chemical composition with low surface energy induced by the hydrophobic surface modification. With the characteristics of water repellency and selective oil adsorption, the as-prepared corn straw fibers could be chosen to remove the spilled oil from water with high separation efficiency, stable durability and recyclability. The method presented here is expected to be employed as a technique to prepare oil absorbent with superhydrophobicity and superoleophilicity, which may be used to treat the oily wastewater in practical application with the advantages of low cost, simple method and easy biodegradability as well as stable recyclability.
Materials with both superhydrophobicity and superoleophilicity have attracted considerable attention due to the potential application in the removal of the spilled oil from water. In the past decades, numerous techniques have been adopted to construct superhydrophobic and superoleophilic materials, but it is still a great challenge to obtain this kind of material via a more facile, low cost and environmentally friendly method. Herein, corn straw fibers with superhydrophobicity and superoleophilicity were obtained by dip-coating TiO2 sol and subsequent surface modification with octyltrimethoxysilane (OTS). The contact angle of water droplets and oil droplets on the as-prepared sample is 160° and 0°, respectively. The results indicate that the superhydrophobicity is attributed to the joint effects of natural hierarchical structures with micro/nanometer scale of corn straw fibers and the chemical composition with low surface energy induced by the hydrophobic surface modification. With the characteristics of water repellency and selective oil adsorption, the as-prepared corn straw fibers could be chosen to remove the spilled oil from water with high separation efficiency, stable durability and recyclability. The method presented here is expected to be employed as a technique to prepare oil absorbent with superhydrophobicity and superoleophilicity, which may be used to treat the oily wastewater in practical application with the advantages of low cost, simple method and easy biodegradability as well as stable recyclability.
