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2018 Volume 35 Issue 5
2018, 35(5): 491-499
doi: 10.11944/j.issn.1000-0518.2018.05.170280
Abstract:
The halogenation is an invaluable approach for structural modification of drugs in medicine chemistry development. It increases the lipo-solubility, influences on the space charge distribution and improves their drug metabolic activity. Nucleic acid, as antiviral agent, antitumor agent, interferon inducer and immunopotentiator, can also be modified by halogenation. In this review we will discuss the effect on the bioactivity of modified nucleic acids on pyrimidines, purines and ribose by halogenation, and summarize the latest developments in drug research and development of modified nucleic acid.
The halogenation is an invaluable approach for structural modification of drugs in medicine chemistry development. It increases the lipo-solubility, influences on the space charge distribution and improves their drug metabolic activity. Nucleic acid, as antiviral agent, antitumor agent, interferon inducer and immunopotentiator, can also be modified by halogenation. In this review we will discuss the effect on the bioactivity of modified nucleic acids on pyrimidines, purines and ribose by halogenation, and summarize the latest developments in drug research and development of modified nucleic acid.
2018, 35(5): 500-510
doi: 10.11944/j.issn.1000-0518.2018.05.170243
Abstract:
Metal-organic frameworks(MOFs) have the diversity of topological structure and rich surface area, which make it have potential application value in the field of catalysis and adsorption. Because of the bimetallic MOFs have two metal centers, it has higher catalytic activity sites and adsorption sites than the single metal MOFs. So the selectivity of adsorption, catalytic activity, and stability of structure have all been improved. In this review, the synthesis methods, structure properties, performance improvement and application prospects of bimetallic MOFs are summarized.
Metal-organic frameworks(MOFs) have the diversity of topological structure and rich surface area, which make it have potential application value in the field of catalysis and adsorption. Because of the bimetallic MOFs have two metal centers, it has higher catalytic activity sites and adsorption sites than the single metal MOFs. So the selectivity of adsorption, catalytic activity, and stability of structure have all been improved. In this review, the synthesis methods, structure properties, performance improvement and application prospects of bimetallic MOFs are summarized.
2018, 35(5): 511-517
doi: 10.11944/j.issn.1000-0518.2018.05.170162
Abstract:
In this paper, the experimental methods for the synthesis of t-butyl peroxide compounds were discussed, in which benzoyl imidazole and t-butyl hydroperoxide(TBHP) were used as reactants, 1, 8-diazabicycloundec-7-ene(DBU) was used as the catalyst and acetonitrile(CH3CN) was used as the reaction solvent. The effect of catalysts and their dosage, raw material ratios, solvents and temperature on the yield were investigated. A total of 25 target products were obtained under the optimum conditions with yields of 45%~99%. The molecular structures of the products were analyzed by nuclear magnetic resonance spectroscopy(1H NMR and 13C NMR) and mass spectrometry. The method has the advantage of easily available material, easy operation, mild reaction conditions and a wide range of functional group tolerance, and has provided a new idea for the synthesis of t-butyl peroxide compounds.
In this paper, the experimental methods for the synthesis of t-butyl peroxide compounds were discussed, in which benzoyl imidazole and t-butyl hydroperoxide(TBHP) were used as reactants, 1, 8-diazabicycloundec-7-ene(DBU) was used as the catalyst and acetonitrile(CH3CN) was used as the reaction solvent. The effect of catalysts and their dosage, raw material ratios, solvents and temperature on the yield were investigated. A total of 25 target products were obtained under the optimum conditions with yields of 45%~99%. The molecular structures of the products were analyzed by nuclear magnetic resonance spectroscopy(1H NMR and 13C NMR) and mass spectrometry. The method has the advantage of easily available material, easy operation, mild reaction conditions and a wide range of functional group tolerance, and has provided a new idea for the synthesis of t-butyl peroxide compounds.
2018, 35(5): 518-525
doi: 10.11944/j.issn.1000-0518.2018.05.170220
Abstract:
4H-Pyrans and 4H-pyran-annulated heterocyclic scaffolds are the key building blocks of numerous natural products and represent a "drug-like" structural motif with a broad spectrum of applications in organic synthesis and medicinal chemistry. In this paper, a convenient one-pot three-component strategy was conducted successfully under catalyst-free condition employing water as reaction medium and ethanol as co-solvent. Three kinds, over fifty 2-amino-3-cyano-4H-pyran derivatives were synthesized in good to excellent yields by the condensation of a series of aromatic aldehydes with malononitrile and different 1, 3-dicarbonyl compounds. Broad substrate scope, systematic characterization, eliminated catalyst, mild reaction condition, simple purification procedure are the best advantages in this methodology.
4H-Pyrans and 4H-pyran-annulated heterocyclic scaffolds are the key building blocks of numerous natural products and represent a "drug-like" structural motif with a broad spectrum of applications in organic synthesis and medicinal chemistry. In this paper, a convenient one-pot three-component strategy was conducted successfully under catalyst-free condition employing water as reaction medium and ethanol as co-solvent. Three kinds, over fifty 2-amino-3-cyano-4H-pyran derivatives were synthesized in good to excellent yields by the condensation of a series of aromatic aldehydes with malononitrile and different 1, 3-dicarbonyl compounds. Broad substrate scope, systematic characterization, eliminated catalyst, mild reaction condition, simple purification procedure are the best advantages in this methodology.
2018, 35(5): 526-531
doi: 10.11944/j.issn.1000-0518.2018.05.170200
Abstract:
Pyrazolo[1, 5-a]pyridine-3-carboxylate derivatives were obtained from 1, 3-dipolar cycloaddition reaction with ethyl propionate and N-aminopyridine sulfates synthesized by the reactions of substituted pyridines and hydroxylamine-O-sulfonic acid. They were further treated with 30%NaOH aqueous solution to give corresponding substituted pyrazolo[1, 5-a]pyridine-3-carboxylic acid derivatives. In this method, N-aminopyridine sulfates were directly put into the next reaction, which eliminated the step of converting sulfate into iodine salt in the traditional method and solved the problem that the iodine salt was difficult to precipitate. N-aminopyridine sulfate and ethyl propionate were dissolved in water and N, N-dimethylformamide, respectively, and then mixed to increase the solubility of reactants. Six compounds(4a~4f) were successfully synthesized with yields of 88%~93%. The method is mild, easy to process and low cost as a new process for mass production.
Pyrazolo[1, 5-a]pyridine-3-carboxylate derivatives were obtained from 1, 3-dipolar cycloaddition reaction with ethyl propionate and N-aminopyridine sulfates synthesized by the reactions of substituted pyridines and hydroxylamine-O-sulfonic acid. They were further treated with 30%NaOH aqueous solution to give corresponding substituted pyrazolo[1, 5-a]pyridine-3-carboxylic acid derivatives. In this method, N-aminopyridine sulfates were directly put into the next reaction, which eliminated the step of converting sulfate into iodine salt in the traditional method and solved the problem that the iodine salt was difficult to precipitate. N-aminopyridine sulfate and ethyl propionate were dissolved in water and N, N-dimethylformamide, respectively, and then mixed to increase the solubility of reactants. Six compounds(4a~4f) were successfully synthesized with yields of 88%~93%. The method is mild, easy to process and low cost as a new process for mass production.
2018, 35(5): 532-537
doi: 10.11944/j.issn.1000-0518.2018.05.170197
Abstract:
A coumarin type fluorescent probe was synthesized from 1H-indole-3-carbohydrazide hydrazide and 8-formyl 7-hydroxy-4-methylcoumarin, which was obtained by Pechmann condensation of resorcinol and ethyl acetoacetate followed by formylation employing hexamethylenetetramine. The structure and fluorescence properties of this probe were characterized by nuclear magnetic resonance spectroscopy(NMR), mass spectrometry(MS), fluorescence emission spectrometer and UV-visible absorption spectrum. The probe coordinated with Zn2+ in 1:1 ratio and led to high selectivity for the detection of Zn2+ with a detection limit at 3.6×10-8 mol/L. These demonstrate potential application of the probe for the detection of Zn2+ in biological studies.
A coumarin type fluorescent probe was synthesized from 1H-indole-3-carbohydrazide hydrazide and 8-formyl 7-hydroxy-4-methylcoumarin, which was obtained by Pechmann condensation of resorcinol and ethyl acetoacetate followed by formylation employing hexamethylenetetramine. The structure and fluorescence properties of this probe were characterized by nuclear magnetic resonance spectroscopy(NMR), mass spectrometry(MS), fluorescence emission spectrometer and UV-visible absorption spectrum. The probe coordinated with Zn2+ in 1:1 ratio and led to high selectivity for the detection of Zn2+ with a detection limit at 3.6×10-8 mol/L. These demonstrate potential application of the probe for the detection of Zn2+ in biological studies.
2018, 35(5): 538-543
doi: 10.11944/j.issn.1000-0518.2018.05.170279
Abstract:
Two Coumarin Schiff base derivatives were synthesized from 2, 3, 4-trimethoxybenzaldehyde by demethylation, Knoevenagel and nucleophilic addition reaction. Structures of the corresponding products were elucidated through the analysis of 1H NMR and MS spectra. The antioxidant activities of two derivatives were evaluated by quenching 2, 2'-diphenyl-1-picrylhydrazyl radical(DPPH), 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulphonate) ammonium salt cationic radical(ABTS), and hydroxyl free radical. The result shows that the target compounds can quench the three types of free radicals. Compared to 7, 8-dimethoxy-3-aminocoumarin, two coumarin Schiff base derivatives have higher quenching activity for DPPH and hydroxyl free radical and have higher antioxidant activity.
Two Coumarin Schiff base derivatives were synthesized from 2, 3, 4-trimethoxybenzaldehyde by demethylation, Knoevenagel and nucleophilic addition reaction. Structures of the corresponding products were elucidated through the analysis of 1H NMR and MS spectra. The antioxidant activities of two derivatives were evaluated by quenching 2, 2'-diphenyl-1-picrylhydrazyl radical(DPPH), 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulphonate) ammonium salt cationic radical(ABTS), and hydroxyl free radical. The result shows that the target compounds can quench the three types of free radicals. Compared to 7, 8-dimethoxy-3-aminocoumarin, two coumarin Schiff base derivatives have higher quenching activity for DPPH and hydroxyl free radical and have higher antioxidant activity.
2018, 35(5): 544-551
doi: 10.11944/j.issn.1000-0518.2018.05.170256
Abstract:
Two novel ligands, 3, 5-bis(4-(8-hydroxyquinoline-5-methyleneamino)phenoxy)octyl benzoate(B8HQO) and 3, 5-bis(4-(8-hydroxyquinoline-5-methyleneamino)phenoxy)hexadecyl benzoate(B8HQH) were synthesized and coordinated with Zn(Ⅱ) and Al(Ⅲ), respectively, to get the four corresponding coordination polymers(B8HQO-Zn, B8HQH-Zn, B8HQO-Al and B8HQH-Al). Their structures and properties were characterized by elemental analysis, Fourier transform infrared spectrometer(FTIR), UV-visible absorption(UV-Vis), proton nuclear magnetic resonance spectroscopy(1H NMR), inductively coupled plasma optical emission spectroscopy(ICP-OES), thermal gravimetric analyzer(TGA) and fluorescence spectroscopy. The results indicate that compared with B8HQO and B8HQH, the solubility of the four coordination polymers is reduced, but can be partially soluble in N, N-dimethyl formamide(DMF), N, N-dimethyl acetamide(DMAC), dimethylsulfone(DMSO), N-methylpyrrolidone(NMP). The 5% mass loss temperatures of zinc and aluminum coordination polymers at around 378 and 364℃, respectively, show that they have good thermal stability. The fluorescence measurement shows that they emit green luminescence at 478~502 nm in DMF solution(3×10-5 mol/L) and their fluorescence quantum efficiency is 28%~37%. The four coordination polymers emitting strong green luminescence at 528~553 nm in the solid state show that they have good luminescent properties.
Two novel ligands, 3, 5-bis(4-(8-hydroxyquinoline-5-methyleneamino)phenoxy)octyl benzoate(B8HQO) and 3, 5-bis(4-(8-hydroxyquinoline-5-methyleneamino)phenoxy)hexadecyl benzoate(B8HQH) were synthesized and coordinated with Zn(Ⅱ) and Al(Ⅲ), respectively, to get the four corresponding coordination polymers(B8HQO-Zn, B8HQH-Zn, B8HQO-Al and B8HQH-Al). Their structures and properties were characterized by elemental analysis, Fourier transform infrared spectrometer(FTIR), UV-visible absorption(UV-Vis), proton nuclear magnetic resonance spectroscopy(1H NMR), inductively coupled plasma optical emission spectroscopy(ICP-OES), thermal gravimetric analyzer(TGA) and fluorescence spectroscopy. The results indicate that compared with B8HQO and B8HQH, the solubility of the four coordination polymers is reduced, but can be partially soluble in N, N-dimethyl formamide(DMF), N, N-dimethyl acetamide(DMAC), dimethylsulfone(DMSO), N-methylpyrrolidone(NMP). The 5% mass loss temperatures of zinc and aluminum coordination polymers at around 378 and 364℃, respectively, show that they have good thermal stability. The fluorescence measurement shows that they emit green luminescence at 478~502 nm in DMF solution(3×10-5 mol/L) and their fluorescence quantum efficiency is 28%~37%. The four coordination polymers emitting strong green luminescence at 528~553 nm in the solid state show that they have good luminescent properties.
2018, 35(5): 552-558
doi: 10.11944/j.issn.1000-0518.2018.05.170146
Abstract:
A cationic Gemini asphalt emulsifier with benzene ring(symbolized as G-T) was synthesized with aniline, epichlorohydrin and N, N-dimethyltetradecylamine by two steps. The product was characterized by Fourier transform infrared spectroscopy(FT-IR), mass spectroscopy, and proton nuclear magnetic resonance(1H NMR) spectroscopy. The Krafft point, emulsifying power and performance of emulsified asphalt were studied. The critical micelle concentration(cmc) and surface tension(γcmc) of G-T were measured from 25℃ to 40℃ and thermodynamic parameters of the micellization were calculated. The results show that the Krafft point of G-T is below 0℃, and the stable time of the emulsified liquid is up to 309 s. The cmc and γcmc are 1.269×10-3 mol/L and 38.33 mN/m at 25℃, respectively. With the rise of temperature, the cmc increases, the γcmc decreases, the maximum surface adsorption capacity(Γmax) decreases and the minimum molecule area(Amin) increases. Emulsified asphalt test shows that G-T is a slow-crack asphalt emulsifier. The prepared emulsified asphalt meets the technical specifications of micro-surfacing.
A cationic Gemini asphalt emulsifier with benzene ring(symbolized as G-T) was synthesized with aniline, epichlorohydrin and N, N-dimethyltetradecylamine by two steps. The product was characterized by Fourier transform infrared spectroscopy(FT-IR), mass spectroscopy, and proton nuclear magnetic resonance(1H NMR) spectroscopy. The Krafft point, emulsifying power and performance of emulsified asphalt were studied. The critical micelle concentration(cmc) and surface tension(γcmc) of G-T were measured from 25℃ to 40℃ and thermodynamic parameters of the micellization were calculated. The results show that the Krafft point of G-T is below 0℃, and the stable time of the emulsified liquid is up to 309 s. The cmc and γcmc are 1.269×10-3 mol/L and 38.33 mN/m at 25℃, respectively. With the rise of temperature, the cmc increases, the γcmc decreases, the maximum surface adsorption capacity(Γmax) decreases and the minimum molecule area(Amin) increases. Emulsified asphalt test shows that G-T is a slow-crack asphalt emulsifier. The prepared emulsified asphalt meets the technical specifications of micro-surfacing.
2018, 35(5): 559-563
doi: 10.11944/j.issn.1000-0518.2018.05.170154
Abstract:
The synthesis of pyridine and 3-picoline from the reaction of acrolein diethyl acetal, water and ammonia was conducted in a fixed-bed reactor. The catalytic activities of La- and KF-modified Y zeolites were compared. Various influencing parameters, including the loadings and modified ways of La species, the loadings of KF and the calcination temperature of KF/Y, were systematically investigated. Compared to pure Y zeolite, La- and KF-modifications can enhance the catalytic activities. The catalytic activity of La-modified Y through ion exchange is better than that of the sample through wet impregnation. The total yield of pyridine and 3-picoline reaches the maximum while the loading of La via the wet-impregnation method is 1% mass fraction and the calcination temperature of KF/Y is 700℃.
The synthesis of pyridine and 3-picoline from the reaction of acrolein diethyl acetal, water and ammonia was conducted in a fixed-bed reactor. The catalytic activities of La- and KF-modified Y zeolites were compared. Various influencing parameters, including the loadings and modified ways of La species, the loadings of KF and the calcination temperature of KF/Y, were systematically investigated. Compared to pure Y zeolite, La- and KF-modifications can enhance the catalytic activities. The catalytic activity of La-modified Y through ion exchange is better than that of the sample through wet impregnation. The total yield of pyridine and 3-picoline reaches the maximum while the loading of La via the wet-impregnation method is 1% mass fraction and the calcination temperature of KF/Y is 700℃.
2018, 35(5): 574-581
doi: 10.11944/j.issn.1000-0518.2018.05.170139
Abstract:
Graphite phase carbon nitride(g-C3N4), a new type and non-metallic organic semiconductor material has attracted widespread attention in the photocatalysis area. In this paper, we combined a seed-mediated growth way with one pot method to synthesize Au nanorods/g-C3N4 composites to improve its photoelectrochemical properties. The results demonstrate that Au nanorods can decrease the recombination rate of photogenerated carriers. Therefore, the composites present excellent photoelectrochemical properties, and the photocurrent density can reach 17.18 μA/cm2(vs RHE)which is 2.5 times higher than that of pristine samples.
Graphite phase carbon nitride(g-C3N4), a new type and non-metallic organic semiconductor material has attracted widespread attention in the photocatalysis area. In this paper, we combined a seed-mediated growth way with one pot method to synthesize Au nanorods/g-C3N4 composites to improve its photoelectrochemical properties. The results demonstrate that Au nanorods can decrease the recombination rate of photogenerated carriers. Therefore, the composites present excellent photoelectrochemical properties, and the photocurrent density can reach 17.18 μA/cm2(vs RHE)which is 2.5 times higher than that of pristine samples.
2018, 35(5): 582-588
doi: 10.11944/j.issn.1000-0518.2018.05.170238
Abstract:
A novel Ti/TiO2 nanotube arrays(NTs)/PbO2-Pr electrode for the degradation of organic wastewater was fabricated by the pulse electrodeposition method. Pr-doped PbO2 nanoparticles were deposited on the TiO2 nanotube array substrate. Cyclic voltammetry(CV) and linear sweep voltammetry(LSV) were utilized to study the electrochemical performance of electrodes. The results demonstrate that Ti/TiO2NTs/nanoPbO2-Pr electrodes(P) possess excellent electrocatalytic properties. The morphology, crystallinity and elemental composition of Ti/TiO2NTs/nanoPbO2-Pr electrodes were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS). The β-PbO2 nanoparticles are dispersed inside the TiO2 nanotubes and the doped Pr exists in the form of Pr2O3. The degradation of methylene blue was carried out to test electrocatalytic performance of this novel electrode. A 99.8% removal of methylene blue of Ti/TiO2NTs/nanoPbO2-Pr electrode within 120 min indicates its good activity.
A novel Ti/TiO2 nanotube arrays(NTs)/PbO2-Pr electrode for the degradation of organic wastewater was fabricated by the pulse electrodeposition method. Pr-doped PbO2 nanoparticles were deposited on the TiO2 nanotube array substrate. Cyclic voltammetry(CV) and linear sweep voltammetry(LSV) were utilized to study the electrochemical performance of electrodes. The results demonstrate that Ti/TiO2NTs/nanoPbO2-Pr electrodes(P) possess excellent electrocatalytic properties. The morphology, crystallinity and elemental composition of Ti/TiO2NTs/nanoPbO2-Pr electrodes were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS). The β-PbO2 nanoparticles are dispersed inside the TiO2 nanotubes and the doped Pr exists in the form of Pr2O3. The degradation of methylene blue was carried out to test electrocatalytic performance of this novel electrode. A 99.8% removal of methylene blue of Ti/TiO2NTs/nanoPbO2-Pr electrode within 120 min indicates its good activity.
2018, 35(5): 589-593
doi: 10.11944/j.issn.1000-0518.2018.05.170263
Abstract:
A new tetra-capped Keggin molybdenum-vanadium polyoxometalate[H3Mo8ⅥV8ⅣO40(AsO4)](en)2(4, 4-bipy)7·9H2O(en:ethylenediamine, bipy:bipyridine)(1) was prepared under hydrothermal conditions, and characterized by elemental analysis, FT-IR, X-ray photoelectron spectroscopy(XPS) and single crystal X-ray diffraction analysis. The title compound crystallized in a triclinic system, P1 space group, a=1.47395(5) nm, b=1.48172(6) nm, c=1.62881(7) nm, α=66.16(3)°, β=87.15(2)°, γ=63.42(1)°, V=2.8723(2) nm3, Z=1, R1=0.0728, wR2=0.2014. Compound 1 is composed of a tetra-capped Keggin polyoxoanion, 4, 4'-bipyridine, ethylenediamines and lattice water molecules. The rich hydrogen bonds among polyoxoanion and water molecules make the compound molecules forming three dimensional supramolecular array. The compound 1 exhibits strong fluorescent emission and may be an excellent candidate for potential photoactive materials.
A new tetra-capped Keggin molybdenum-vanadium polyoxometalate[H3Mo8ⅥV8ⅣO40(AsO4)](en)2(4, 4-bipy)7·9H2O(en:ethylenediamine, bipy:bipyridine)(1) was prepared under hydrothermal conditions, and characterized by elemental analysis, FT-IR, X-ray photoelectron spectroscopy(XPS) and single crystal X-ray diffraction analysis. The title compound crystallized in a triclinic system, P1 space group, a=1.47395(5) nm, b=1.48172(6) nm, c=1.62881(7) nm, α=66.16(3)°, β=87.15(2)°, γ=63.42(1)°, V=2.8723(2) nm3, Z=1, R1=0.0728, wR2=0.2014. Compound 1 is composed of a tetra-capped Keggin polyoxoanion, 4, 4'-bipyridine, ethylenediamines and lattice water molecules. The rich hydrogen bonds among polyoxoanion and water molecules make the compound molecules forming three dimensional supramolecular array. The compound 1 exhibits strong fluorescent emission and may be an excellent candidate for potential photoactive materials.
2018, 35(5): 594-599
doi: 10.11944/j.issn.1000-0518.2018.05.170193
Abstract:
Adsorption of methyl orange(MO) and alizarin green(AG-25) onto a novel magnetic covalent organic frameworks(COF) were studied via static adsorption method. The maximal adsorption capacities reach 997 mg/g for MO and 1314 mg/g for AG-25 within the pH range of 6~8 at 25℃. The adsorption isotherms follow Langmuir isothermal adsorption model, indicating a monolayer adsorption. The pseudo-second-order model best fits adsorption kinetics data, implying the adsorption processes are mainly chemical adsorption. Magnetic COF shows advantages of excellent adsorption performance and rapid separation, which is believed to enlarge the application of COF on the removal of anionic dyes from wastewaters.
Adsorption of methyl orange(MO) and alizarin green(AG-25) onto a novel magnetic covalent organic frameworks(COF) were studied via static adsorption method. The maximal adsorption capacities reach 997 mg/g for MO and 1314 mg/g for AG-25 within the pH range of 6~8 at 25℃. The adsorption isotherms follow Langmuir isothermal adsorption model, indicating a monolayer adsorption. The pseudo-second-order model best fits adsorption kinetics data, implying the adsorption processes are mainly chemical adsorption. Magnetic COF shows advantages of excellent adsorption performance and rapid separation, which is believed to enlarge the application of COF on the removal of anionic dyes from wastewaters.
2018, 35(5): 600-608
doi: 10.11944/j.issn.1000-0518.2018.05.170138
Abstract:
Hydroxybenzoic acid compounds are used widely and have strong polarity. The separation, purification and analysis of their analogues in complex aqueous solution are very difficult. In this paper, magnetic surface molecularly imprinted polymer(MIP) was prepared using nano magnetic Fe3O4 as the carrier and gallic acid(GA) as the template molecule, and characterized by transmission electron microscopy, infrared spectroscopy and magnetic intensity measurement. Then its adsorption properties and adsorptive selectivity were studied by the static adsorption and dynamic adsorption experiments to compare the adsorption properties of GA on MIP with those of 2, 4-dihydroxybenzoic acid, salicylic acid and benzoic acid. The results show that the MIP with GA as the template has a core-shell structure with a strong bonding effect, the adsorption process belongs to Langmuir monolayer adsorption and the adsorption kinetics can satisfy the pseudo-second-order kinetic equation model. The MIP exhibits an excellent selectivity for GA, and its adsorption capacity(37.736 mg/g at 318 K) is much higher than those of other structural analogues. The MIP prepared by this method can not only recognize the template molecule, but also be magnetically controlled. The high separation efficiency is applicable to the solid phase extraction.
Hydroxybenzoic acid compounds are used widely and have strong polarity. The separation, purification and analysis of their analogues in complex aqueous solution are very difficult. In this paper, magnetic surface molecularly imprinted polymer(MIP) was prepared using nano magnetic Fe3O4 as the carrier and gallic acid(GA) as the template molecule, and characterized by transmission electron microscopy, infrared spectroscopy and magnetic intensity measurement. Then its adsorption properties and adsorptive selectivity were studied by the static adsorption and dynamic adsorption experiments to compare the adsorption properties of GA on MIP with those of 2, 4-dihydroxybenzoic acid, salicylic acid and benzoic acid. The results show that the MIP with GA as the template has a core-shell structure with a strong bonding effect, the adsorption process belongs to Langmuir monolayer adsorption and the adsorption kinetics can satisfy the pseudo-second-order kinetic equation model. The MIP exhibits an excellent selectivity for GA, and its adsorption capacity(37.736 mg/g at 318 K) is much higher than those of other structural analogues. The MIP prepared by this method can not only recognize the template molecule, but also be magnetically controlled. The high separation efficiency is applicable to the solid phase extraction.
2018, 35(5): 609-612
doi: 10.11944/j.issn.1000-0518.2018.05.170210
Abstract:
Based on the similarity of the fluorescence properties of three estrogens, a new fluorescence method for direct determination of the total amount of three estrogens(estradiol, estriol, ethinyloestradiol) in milk powder was developed. Taking estriol as the standard reference material, the standard curve method was adopted. The fluorescence intensity of estriol has a linear relationship with the concentration in the range of 1.00~2000 nmol/L and the detection limit of 0.16 nmol/L. The recovery is in the range of 89.11%~98.49%. This method is simple, rapid, highly accurate and sensitive and has been successfully applied to determine the total estrogens in milk powder with satisfactory results.
Based on the similarity of the fluorescence properties of three estrogens, a new fluorescence method for direct determination of the total amount of three estrogens(estradiol, estriol, ethinyloestradiol) in milk powder was developed. Taking estriol as the standard reference material, the standard curve method was adopted. The fluorescence intensity of estriol has a linear relationship with the concentration in the range of 1.00~2000 nmol/L and the detection limit of 0.16 nmol/L. The recovery is in the range of 89.11%~98.49%. This method is simple, rapid, highly accurate and sensitive and has been successfully applied to determine the total estrogens in milk powder with satisfactory results.
2018, 35(5): 564-573
doi: 10.11944/j.issn.1000-0518.2018.05.170150
Abstract:
In this work, a microfluidic approach was reported for the synthesis of carbon-supported PtRu nanoparticles(PtRu/C) for high efficient methanol electro-oxidation. By varying the flow rate of reactants in the simple custom-made microfluidic reactor, a series of PtRu/C catalysts was obtained with size ranging from 1.4 to 2.0 nm. Electrochemical measurements show that the superior activity of catalyst obtained with flow rate of 90 μL/min for methanol electro-oxidation could be attributed to its large electrochemically active surface area(ECSA) and the high content of metallic Pt(0). This method for the preparation of catalyst holds great promise for potential applications in important energy conversion and environmental fields.
In this work, a microfluidic approach was reported for the synthesis of carbon-supported PtRu nanoparticles(PtRu/C) for high efficient methanol electro-oxidation. By varying the flow rate of reactants in the simple custom-made microfluidic reactor, a series of PtRu/C catalysts was obtained with size ranging from 1.4 to 2.0 nm. Electrochemical measurements show that the superior activity of catalyst obtained with flow rate of 90 μL/min for methanol electro-oxidation could be attributed to its large electrochemically active surface area(ECSA) and the high content of metallic Pt(0). This method for the preparation of catalyst holds great promise for potential applications in important energy conversion and environmental fields.
