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2015 Volume 32 Issue 6
2015, 32(6): 611-622
doi: 10.11944/j.issn.1000-0518.2015.06.140435
Abstract:
The bottleneck of the preparation of functional polymer materials is how to solve the compatibility problem of multiple materials,since traditional physical blending and addition polymerization techniques can not guarantee the stability and uniformity of materials. Pickering emulsions with low cost,low toxicity,environmental friendiness,good stability,structural stability of multi-material structures,etc.,have received more and more attention in the application of functional polymer materials. In this review,details of the research progress in the application of Pickering emulsions on the preparation of functional polymer materials are presented,some questions faced in this area are mentioned. Combined with the research of our group,its development prospects are discussed.
The bottleneck of the preparation of functional polymer materials is how to solve the compatibility problem of multiple materials,since traditional physical blending and addition polymerization techniques can not guarantee the stability and uniformity of materials. Pickering emulsions with low cost,low toxicity,environmental friendiness,good stability,structural stability of multi-material structures,etc.,have received more and more attention in the application of functional polymer materials. In this review,details of the research progress in the application of Pickering emulsions on the preparation of functional polymer materials are presented,some questions faced in this area are mentioned. Combined with the research of our group,its development prospects are discussed.
2015, 32(6): 623-628
doi: 10.11944/j.issn.1000-0518.2015.06.140337
Abstract:
Using the self-assembled anionic surfactant sodium n-dodecyl sulfonate(SDS) micelles as porous templates, a novel porous chitosan-graft-poly(acrylic acid)/Na-montmorillonit(CS-g-PAA/Na-MMT)superabsorbent composite was successfully prepared by grafting copolymerization of chitosan(CS),acrylic acid(AA) and Na-montmorillonite(Na-MMT),using ammonium persulfate(APS) as the initiator and N,N'-methylenebisacrylamide(MBA) as the crosslinker. The mechanism for this reaction was proposed. Scanning electron microscope(SEM) analysis demonstrated that the morphologies of the SDS-added sample displays homogeneous and well-defined porous structures. Effect of SDS concentration on the equilibrium swelling ratio and swelling rate of the hydrogels were evaluated. The results show that the equilibrium swelling ratio of the1.5 mmol/L SDS sample in distilled water and 0.9% mass fraction of Na Cl solution are improved to 53.9%and 35.3%,respectively. Compared to the sample without SDS,the initial swelling rate constant,Kis,is also improved from 1.2652 g/(g·s) to 5.1680 g/(g·s). In addition,the porous structure can accelerate the adsorption rate for Pb2+,which reaches the 95% saturation adsorption capacity during the initial 10 min,and achieves adsorption equilibrium within 30 min.
Using the self-assembled anionic surfactant sodium n-dodecyl sulfonate(SDS) micelles as porous templates, a novel porous chitosan-graft-poly(acrylic acid)/Na-montmorillonit(CS-g-PAA/Na-MMT)superabsorbent composite was successfully prepared by grafting copolymerization of chitosan(CS),acrylic acid(AA) and Na-montmorillonite(Na-MMT),using ammonium persulfate(APS) as the initiator and N,N'-methylenebisacrylamide(MBA) as the crosslinker. The mechanism for this reaction was proposed. Scanning electron microscope(SEM) analysis demonstrated that the morphologies of the SDS-added sample displays homogeneous and well-defined porous structures. Effect of SDS concentration on the equilibrium swelling ratio and swelling rate of the hydrogels were evaluated. The results show that the equilibrium swelling ratio of the1.5 mmol/L SDS sample in distilled water and 0.9% mass fraction of Na Cl solution are improved to 53.9%and 35.3%,respectively. Compared to the sample without SDS,the initial swelling rate constant,Kis,is also improved from 1.2652 g/(g·s) to 5.1680 g/(g·s). In addition,the porous structure can accelerate the adsorption rate for Pb2+,which reaches the 95% saturation adsorption capacity during the initial 10 min,and achieves adsorption equilibrium within 30 min.
2015, 32(6): 629-635
doi: 10.11944/j.issn.1000-0518.2015.06.140335
Abstract:
Three aromatic oligosulfonate-bridged macrocyclic compounds were synthesized using 4,6-dialkoxybenzene-1,3-disulfonyl dichlorides and aromatic diphenol as the starting materials,triethylamine as the acid binding agent,and dichloromethane as the solvent. The products were characterized by IR,1H NMR,13C NMR, MALDI-TOF techniques. The recognition capabilities of aromatic oligosulfonate-bridged macrocyclic compound 5 for 20 metal ions were studied by UV spectroscopy. Compound 5 has certain recognition abilities for Sn2+. If Bi3+solution is added into compound 5 and Sn2+ system,the absorption peak at 325 nm increases greatly in UV spectroscopy because of the synergy effect of Sn2+ and Bi3+,suggesting that compound 5 has better recognition ability for Bi3+than that for Sn2+.
Three aromatic oligosulfonate-bridged macrocyclic compounds were synthesized using 4,6-dialkoxybenzene-1,3-disulfonyl dichlorides and aromatic diphenol as the starting materials,triethylamine as the acid binding agent,and dichloromethane as the solvent. The products were characterized by IR,1H NMR,13C NMR, MALDI-TOF techniques. The recognition capabilities of aromatic oligosulfonate-bridged macrocyclic compound 5 for 20 metal ions were studied by UV spectroscopy. Compound 5 has certain recognition abilities for Sn2+. If Bi3+solution is added into compound 5 and Sn2+ system,the absorption peak at 325 nm increases greatly in UV spectroscopy because of the synergy effect of Sn2+ and Bi3+,suggesting that compound 5 has better recognition ability for Bi3+than that for Sn2+.
2015, 32(6): 636-640
doi: 10.11944/j.issn.1000-0518.2015.06.140375
Abstract:
Here we investigated the curing reaction between bisphenol epoxy resin E-51 and 1-hexyl-3-methylimidazole iron tetrachloride salt ([C6mim]FeCl4) by differential scanning calorimetry. It was confirmed that the multi-level amine structure makes [C6mim]FeCl4 possible to be used as high-temperature curing agent for E-51. The curing reaction can be divided into two stages:at the first stage,the exothermic peak is about 120℃; at the second stage,the exothermic peak changes with the volume of [C6mim]FeCl4. When[C6mim]FeCl4 reacts with the mixed-amine to form a new curing agent,they exhibit apparent synergistic effect. The DSC results show that the new curing agent can react with E-51 under room temperature. The duration of exothermic peak is about 5 min at 30℃,and moreover,the duration decreases with the increasing temperature. The activation energy of the reaction calculated by the method of non-isothermal kinetics is 979 J/mol,which is only about 17% of the mixed-amine system. Finally,as the reaction order of the curing reaction is 0.5,it is believed to be a kind of random reaction.
Here we investigated the curing reaction between bisphenol epoxy resin E-51 and 1-hexyl-3-methylimidazole iron tetrachloride salt ([C6mim]FeCl4) by differential scanning calorimetry. It was confirmed that the multi-level amine structure makes [C6mim]FeCl4 possible to be used as high-temperature curing agent for E-51. The curing reaction can be divided into two stages:at the first stage,the exothermic peak is about 120℃; at the second stage,the exothermic peak changes with the volume of [C6mim]FeCl4. When[C6mim]FeCl4 reacts with the mixed-amine to form a new curing agent,they exhibit apparent synergistic effect. The DSC results show that the new curing agent can react with E-51 under room temperature. The duration of exothermic peak is about 5 min at 30℃,and moreover,the duration decreases with the increasing temperature. The activation energy of the reaction calculated by the method of non-isothermal kinetics is 979 J/mol,which is only about 17% of the mixed-amine system. Finally,as the reaction order of the curing reaction is 0.5,it is believed to be a kind of random reaction.
2015, 32(6): 641-646
doi: 10.11944/j.issn.1000-0518.2015.06.140332
Abstract:
L-menthol was synthesized from the starting materials of 4-hydroxy-2-butanone and mesityl oxide in four steps consisting of aldol condensation,asymmetric hydrogenation,reduction of carbonyl group,and ruthenium catalyzed hydrogenation. The total yield is 33% and the diastereomeric excess is 93%.Furthermore,the effects of copper catalysts and their loading,chiral ligands,reaction time and solvents on the asymmetric hydrogenation of piperitenone were discussed in details. The intermediates and target compound were identified and characterized by 1H NMR,13C NMR and HRMS.
L-menthol was synthesized from the starting materials of 4-hydroxy-2-butanone and mesityl oxide in four steps consisting of aldol condensation,asymmetric hydrogenation,reduction of carbonyl group,and ruthenium catalyzed hydrogenation. The total yield is 33% and the diastereomeric excess is 93%.Furthermore,the effects of copper catalysts and their loading,chiral ligands,reaction time and solvents on the asymmetric hydrogenation of piperitenone were discussed in details. The intermediates and target compound were identified and characterized by 1H NMR,13C NMR and HRMS.
2015, 32(6): 647-651
doi: 10.11944/j.issn.1000-0518.2015.06.140342
Abstract:
A green process of the carboxylation reaction of o-cresol with CO2 using K3PO4 as a base was studied for the synthesis of 2-hydroxy-3-methylbenzoic acid(o-MSA) and related carboxylated products.Various reaction parameters such as temperature,pressure,and the ratio of the base to substrate had been tested. The results show that 95.4% total yield of all carboxylated products in this Koble-Schmitt reaction is obtained using K3PO4 as a base under 3.0 MPa CO2 and 150℃. Additionally,no CO2 is released during the neutralization process following the Koble-Schmitt reaction and the K3PO4 can be recovered and recycled by neutralization of KH2PO4 with KOH. Therefore,this process allows a green fixation of CO2.
A green process of the carboxylation reaction of o-cresol with CO2 using K3PO4 as a base was studied for the synthesis of 2-hydroxy-3-methylbenzoic acid(o-MSA) and related carboxylated products.Various reaction parameters such as temperature,pressure,and the ratio of the base to substrate had been tested. The results show that 95.4% total yield of all carboxylated products in this Koble-Schmitt reaction is obtained using K3PO4 as a base under 3.0 MPa CO2 and 150℃. Additionally,no CO2 is released during the neutralization process following the Koble-Schmitt reaction and the K3PO4 can be recovered and recycled by neutralization of KH2PO4 with KOH. Therefore,this process allows a green fixation of CO2.
2015, 32(6): 652-657
doi: 10.11944/j.issn.1000-0518.2015.06.140366
Abstract:
Polyethylene glycol 1000(PEG 1000) Vitamin E succinate was prepared by a two-step esterification reaction of Vitamin E using ionic liquids as reaction catalysts. Vitamin E succinate(TAS) was obtained via the esterification of vitamin E catalyzed by 1-(N',N'-dimethylamino-ethyl)-3-methyl-imidazolium tetrafluoroborate. Under the conditions of 1:1.2 molar ratio of Vitamin E and succinic anhydride in 1,2-dichloroethane at 80℃ for 4 h,the isolated yield reached 90%. Under 1:2 molar ratio of TAS and PEG 1000 for 5 h at 100℃,polyethylene glycol 1000 Vitamin E succinate was synthesized in 1-methyl-3-propyl sulfonic acid imidazolium hydrogen sulfate/toluene media with 91% yield.
Polyethylene glycol 1000(PEG 1000) Vitamin E succinate was prepared by a two-step esterification reaction of Vitamin E using ionic liquids as reaction catalysts. Vitamin E succinate(TAS) was obtained via the esterification of vitamin E catalyzed by 1-(N',N'-dimethylamino-ethyl)-3-methyl-imidazolium tetrafluoroborate. Under the conditions of 1:1.2 molar ratio of Vitamin E and succinic anhydride in 1,2-dichloroethane at 80℃ for 4 h,the isolated yield reached 90%. Under 1:2 molar ratio of TAS and PEG 1000 for 5 h at 100℃,polyethylene glycol 1000 Vitamin E succinate was synthesized in 1-methyl-3-propyl sulfonic acid imidazolium hydrogen sulfate/toluene media with 91% yield.
2015, 32(6): 658-665
doi: 10.11944/j.issn.1000-0518.2015.06.140338
Abstract:
Two series of catalysts, HPW/AC and TEAPW/AC, were prepared by impregnating tungstophosphoric acid and[TEAH]3PW12O40 solution on active carbon. The structure and acidic property of these catalysts were characterized by IR,XRD,N2adsorption-desorption and NH3-TPD techniques. Then these catalysts were used to catalyze the synthesis of 2-methacryloyloxyethyl phosphate, a functional phosphate,by using P2O5 as phosphorylation agent. These catalysts possess not only high activity but also high selectivity for the mono(2-methacryloyloxyethyl) phosphate since the formations of di(2-methacryloyloxyethyl)phosphate and tri(2-methacryloyloxyethyl) phosphate are restricted by the micropores of catalysts. Under the optimum conditions and on the optimal catalyst, the total ester yield and the selectivity of mono(2-methacryloyloxyethyl) phosphate are 94% and 95%,respectively. The catalyst can be isolated and recycled with high stability. This catalytic process not only avoids using chlorine-containing reagent in the synthesis,but also greatly increases monophoshpate content in the product.
Two series of catalysts, HPW/AC and TEAPW/AC, were prepared by impregnating tungstophosphoric acid and[TEAH]3PW12O40 solution on active carbon. The structure and acidic property of these catalysts were characterized by IR,XRD,N2adsorption-desorption and NH3-TPD techniques. Then these catalysts were used to catalyze the synthesis of 2-methacryloyloxyethyl phosphate, a functional phosphate,by using P2O5 as phosphorylation agent. These catalysts possess not only high activity but also high selectivity for the mono(2-methacryloyloxyethyl) phosphate since the formations of di(2-methacryloyloxyethyl)phosphate and tri(2-methacryloyloxyethyl) phosphate are restricted by the micropores of catalysts. Under the optimum conditions and on the optimal catalyst, the total ester yield and the selectivity of mono(2-methacryloyloxyethyl) phosphate are 94% and 95%,respectively. The catalyst can be isolated and recycled with high stability. This catalytic process not only avoids using chlorine-containing reagent in the synthesis,but also greatly increases monophoshpate content in the product.
2015, 32(6): 666-670
doi: 10.11944/j.issn.1000-0518.2015.06.140331
Abstract:
A 2,2,6,6-tetramethyl-1-piperidinyloxy catalytic system with sodium bromate and ferric chloride as accelorators(NaBrO3-FeCl3-TEMPO) was developed for efficient oxidation of alcohols. Taking example for benzyl alcohol,the molar ratios of TEMPO,NaBrO3,H2SO4,FeCl3·6H2O relative to the substrate are optimized at 2%,35%,3.7% and 2%,respectively. Aromatic alcohol,aliphatic alcohol and heterocyclic alcohol can be effectively oxidized to the corresponding carbonyl compounds with high yields up to 99% and selectivity up to 99% at room temperature even under anaerobic conditions.
A 2,2,6,6-tetramethyl-1-piperidinyloxy catalytic system with sodium bromate and ferric chloride as accelorators(NaBrO3-FeCl3-TEMPO) was developed for efficient oxidation of alcohols. Taking example for benzyl alcohol,the molar ratios of TEMPO,NaBrO3,H2SO4,FeCl3·6H2O relative to the substrate are optimized at 2%,35%,3.7% and 2%,respectively. Aromatic alcohol,aliphatic alcohol and heterocyclic alcohol can be effectively oxidized to the corresponding carbonyl compounds with high yields up to 99% and selectivity up to 99% at room temperature even under anaerobic conditions.
Hydroxylated Biotransformation of Flavone by Marine Fungi Induced Degradation of Benzene and Toluene
2015, 32(6): 671-675
doi: 10.11944/j.issn.1000-0518.2015.06.140346
Abstract:
Aromatic hydrocarbons can be degraded by fungi. However,the application of the highly active oxidases induced in the degradation process is still rare. This paper investigated the biotransformation of flavone by marine fungi Pseudallescheria boydii and Trichoderma erinaceum cultured in the media containing benzene and toluene. Pseudallescheria boydii and Trichoderma erinaceum show strong tolerance to benzene and toluene. The hydroxylation enzymes activated by the degradation processes of benzene and toluene are responsible for the biotransformation of flavones,which gives the only product 4'-hydroxy flavones with high regioselectivity. Furthermore,the transformation yield can reach up to 82%. This biotransformation induced by the degradation of benzene and toluene may have potential applications in the field of enzyme-catalyzed reactions.
Aromatic hydrocarbons can be degraded by fungi. However,the application of the highly active oxidases induced in the degradation process is still rare. This paper investigated the biotransformation of flavone by marine fungi Pseudallescheria boydii and Trichoderma erinaceum cultured in the media containing benzene and toluene. Pseudallescheria boydii and Trichoderma erinaceum show strong tolerance to benzene and toluene. The hydroxylation enzymes activated by the degradation processes of benzene and toluene are responsible for the biotransformation of flavones,which gives the only product 4'-hydroxy flavones with high regioselectivity. Furthermore,the transformation yield can reach up to 82%. This biotransformation induced by the degradation of benzene and toluene may have potential applications in the field of enzyme-catalyzed reactions.
2015, 32(6): 676-682
doi: 10.11944/j.issn.1000-0518.2015.06.140363
Abstract:
The TiO2-supported Ag nanoparticles were prepared by hydrolytic polycondensation of titanium tetrabutoxide with salicylaldimine Schiff base functional monomer. The prepared Ag/TiO2 nanocatalysts were characterized by FTIR,XRD,HRTEM and UV-Vis,and tested for CO oxidation. The particle size of Ag nanoparticles and the structure of TiO2 supports can be controlled by the content of functional monomer and calcined temperature,and therefore,the catalytic activity of Ag/TiO2 nanocatalysts can be controlled. The maximum conversion of CO reached 99.9% for the sample with 20% of the functional monomer and calcined at 873 K.
The TiO2-supported Ag nanoparticles were prepared by hydrolytic polycondensation of titanium tetrabutoxide with salicylaldimine Schiff base functional monomer. The prepared Ag/TiO2 nanocatalysts were characterized by FTIR,XRD,HRTEM and UV-Vis,and tested for CO oxidation. The particle size of Ag nanoparticles and the structure of TiO2 supports can be controlled by the content of functional monomer and calcined temperature,and therefore,the catalytic activity of Ag/TiO2 nanocatalysts can be controlled. The maximum conversion of CO reached 99.9% for the sample with 20% of the functional monomer and calcined at 873 K.
2015, 32(6): 683-688
doi: 10.11944/j.issn.1000-0518.2015.06.140349
Abstract:
Dimethyl toluene-2,4-dicarbamate(2,4-TDC) was selected as a model molecule to investigate the UV-shielding properties of TiO2 pigments. The results show that the degradation of 2,4-TDC follows the firstorder kinetics at different volume ratios of tetrahydrofuran to n-hexane. The decrease of the degradation kinetics constant of 2,4-TDC shows an exponential power tendency with the increase of the amount of TiO2.Moreover,it is found that the reactive species such as ·OH and holes still play a minor role on the photodegradation of 2,4-TDC in presence of TiO2 pigments. Based on the degradation kinetics constant of 2,4-TDC,the UV-shielding properties of different TiO2 pigments can be directly evaluated within four hours. This study might have potential applications in industrial production and practical use for evaluating the UVshielding properties of TiO2 particles as it has advantages like mild reaction conditions,simple operation and excellent reproducibility.
Dimethyl toluene-2,4-dicarbamate(2,4-TDC) was selected as a model molecule to investigate the UV-shielding properties of TiO2 pigments. The results show that the degradation of 2,4-TDC follows the firstorder kinetics at different volume ratios of tetrahydrofuran to n-hexane. The decrease of the degradation kinetics constant of 2,4-TDC shows an exponential power tendency with the increase of the amount of TiO2.Moreover,it is found that the reactive species such as ·OH and holes still play a minor role on the photodegradation of 2,4-TDC in presence of TiO2 pigments. Based on the degradation kinetics constant of 2,4-TDC,the UV-shielding properties of different TiO2 pigments can be directly evaluated within four hours. This study might have potential applications in industrial production and practical use for evaluating the UVshielding properties of TiO2 particles as it has advantages like mild reaction conditions,simple operation and excellent reproducibility.
2015, 32(6): 689-694
doi: 10.11944/j.issn.1000-0518.2015.06.140305
Abstract:
The dynamic surface tensions of different average ethylene oxide(EO) adduct number(10,12,14,16,and 20) of ethoxylated castor oil acid methyl esters(ECAME) were measured by maximum bubble pressure method(MBP). The effect of dynamic surface tension at different concentration,temperature and the presence of inorganic electrolyte were investigated. The dynamic surface tension parameters(EO adduct number n,equilibrium time t*,maximum slope of curve R1/2) of different concentration were discussed. The results show that dynamic surface tension increases with the average n increasing from 10 to 20,n decreases from 3.02 to 1.05,t* decreases from 14.45 to 2.29,and R1/2increases from 0.43 to 6.44,while the concentration of ECAME ranges from 0.5×10-5 to 10×10-5 mol/L. Therefore,the dynamic surface activity increases and the dynamic surface tension decreases. The dynamic surface tension decreases with the temperature increasing from 25℃ to 45℃. The initial adsorption dynamic surface tension increases with the increasing of inorganic electrolyte concentration and the late adsorption dynamic surface tension decreases with the increasing of inorganic electrolyte concentration. Comparing with conventional fatty acid methyl ester ethoxylate(FMEE),ECAME has an excellent dynamic surface activity. This indicates a new direction for the application of ECAME.
The dynamic surface tensions of different average ethylene oxide(EO) adduct number(10,12,14,16,and 20) of ethoxylated castor oil acid methyl esters(ECAME) were measured by maximum bubble pressure method(MBP). The effect of dynamic surface tension at different concentration,temperature and the presence of inorganic electrolyte were investigated. The dynamic surface tension parameters(EO adduct number n,equilibrium time t*,maximum slope of curve R1/2) of different concentration were discussed. The results show that dynamic surface tension increases with the average n increasing from 10 to 20,n decreases from 3.02 to 1.05,t* decreases from 14.45 to 2.29,and R1/2increases from 0.43 to 6.44,while the concentration of ECAME ranges from 0.5×10-5 to 10×10-5 mol/L. Therefore,the dynamic surface activity increases and the dynamic surface tension decreases. The dynamic surface tension decreases with the temperature increasing from 25℃ to 45℃. The initial adsorption dynamic surface tension increases with the increasing of inorganic electrolyte concentration and the late adsorption dynamic surface tension decreases with the increasing of inorganic electrolyte concentration. Comparing with conventional fatty acid methyl ester ethoxylate(FMEE),ECAME has an excellent dynamic surface activity. This indicates a new direction for the application of ECAME.
2015, 32(6): 695-700
doi: 10.11944/j.issn.1000-0518.2015.06.140348
Abstract:
Cyazofamid-pyraclostrobin(12.5%) oil dispersion was prepared by using methyloleate as the dispersing medium. The influence of adding hydrogenated rosin glycerin ester(HRGE),hydrogenated rosin pentaerythritol ester(HRPE) and rosin modified 4-tert-octylphenol resin(RMOR) on the physical stability and rheological behavior of the oil dispersion were investigated,respectively. The results of Fourier transform infrared spectroscopy(FTIR) indicated that the absorption peak of HRGE,HRPE and RMOR disappeared,meanwhile,the absorption peak of ester group was observed compared with rosin. This indicates that the softening point of different resin increases with the extension of carbon chain in their molecular structures.Moreover,the viscosity and the physical stability of the oil dispersion increase(lower oil separation ratio) with the increasing mass fraction of resin. The rheological tests show that the positive thixotropy is observed for the oil suspension prepared with modified resin. However,the oil suspension prepared with different resins significantly differs in the yield value,presented as RMOR >HRPE >HRGE >RA. The physical stability of different oil suspensions exhibits the same tendency. In conclusion,modified resins are capable of serving as the anti-settling agents in the preparation of oil dispersion of pesticides.
Cyazofamid-pyraclostrobin(12.5%) oil dispersion was prepared by using methyloleate as the dispersing medium. The influence of adding hydrogenated rosin glycerin ester(HRGE),hydrogenated rosin pentaerythritol ester(HRPE) and rosin modified 4-tert-octylphenol resin(RMOR) on the physical stability and rheological behavior of the oil dispersion were investigated,respectively. The results of Fourier transform infrared spectroscopy(FTIR) indicated that the absorption peak of HRGE,HRPE and RMOR disappeared,meanwhile,the absorption peak of ester group was observed compared with rosin. This indicates that the softening point of different resin increases with the extension of carbon chain in their molecular structures.Moreover,the viscosity and the physical stability of the oil dispersion increase(lower oil separation ratio) with the increasing mass fraction of resin. The rheological tests show that the positive thixotropy is observed for the oil suspension prepared with modified resin. However,the oil suspension prepared with different resins significantly differs in the yield value,presented as RMOR >HRPE >HRGE >RA. The physical stability of different oil suspensions exhibits the same tendency. In conclusion,modified resins are capable of serving as the anti-settling agents in the preparation of oil dispersion of pesticides.
2015, 32(6): 701-707
doi: 10.11944/j.issn.1000-0518.2015.06.140360
Abstract:
Mn3O4nanoparticles were prepared in alkaline solution and their electrochemical characteristics were investigated. The obtained Mn3O4 nanoparticles were characterized by scanning electron microscopy(SEM), X-ray diffraction analysis(XRD), cyclicvoltammetry(CV), galvanostatic charge/discharge(GC/D),and electrochemical impedance spectroscopy(EIS). The Mn3O4 nanoparticles can be prepared directly in NaOH and NH3 solution. MnCO3 is only obtained in Na2CO3 solution,and can be transformed to Mn3O4 nanoparticles in the presence of NaOH. The crystalline sizes of the Mn3O4 nanoparticles prepared in NaOH,NH3 and Na2CO3solution are 29.5 nm, 20.2 nm and 36.3 nm, respectively. The Mn3O4 nanoparticles could be conditioned and inverted to birnessite-type MnO2. A specific capacitance of 239 F/g is obtained for the conditioned Mn3O4 nanoparticles prepared in NH3 solution at a current rate of 0.25 A/g.Therefore,the Mn3O4 nanoparticles obtained in NH3 solution can be a promising electrode materials for supercapacitors.
Mn3O4nanoparticles were prepared in alkaline solution and their electrochemical characteristics were investigated. The obtained Mn3O4 nanoparticles were characterized by scanning electron microscopy(SEM), X-ray diffraction analysis(XRD), cyclicvoltammetry(CV), galvanostatic charge/discharge(GC/D),and electrochemical impedance spectroscopy(EIS). The Mn3O4 nanoparticles can be prepared directly in NaOH and NH3 solution. MnCO3 is only obtained in Na2CO3 solution,and can be transformed to Mn3O4 nanoparticles in the presence of NaOH. The crystalline sizes of the Mn3O4 nanoparticles prepared in NaOH,NH3 and Na2CO3solution are 29.5 nm, 20.2 nm and 36.3 nm, respectively. The Mn3O4 nanoparticles could be conditioned and inverted to birnessite-type MnO2. A specific capacitance of 239 F/g is obtained for the conditioned Mn3O4 nanoparticles prepared in NH3 solution at a current rate of 0.25 A/g.Therefore,the Mn3O4 nanoparticles obtained in NH3 solution can be a promising electrode materials for supercapacitors.
2015, 32(6): 708-719
doi: 10.11944/j.issn.1000-0518.2015.06.140356
Abstract:
A novel prototype of nano-structure glucose/O2 biofuel cell was constructed with immobilized enzyme on 4-mercapto benzoic acid(4-MBA) modified gold nanoparticles as electrical medium and enzyme carrier. It features with simple fabrication and favorable long-term usability. Glucose oxidase(GOx) and Laccase(Lac) molecules are tethered steadily to the surface of gold nanoparticles via interaction between modified group of gold nanoparticles and hydrophobic binding-sites in the vicinity of cofactor within enzyme.The as-prepared bioanode and biocathode are fabricated and denoted as GOx/4-MBA@GNP/Au and Lac/4-MBA@GNP/Au,respectively. Electrochemical results indicate that the direct electron transfer occurs between enzyme active sites and gold nanoparticles for both biocathode and bioanode in the absence of any mediator achieves with fast catalytic activity(turn-over frequency of bioanode and biocathode:1.3 and 0.5 s-1,onset potential according to the glucose catalytic oxidation and catalytic reduction of oxygen:-0.23 and 0.76 V). The power out-put performance of nano-structure with entrapped enzyme glucose/O2 biofuel cell was further evaluated after the constitution of cell via connection bioanode and biocathode on the basis of previous results. The results of test show that the open-circuit voltage and the maximum out-put energy density of this biocell amount to 0.56 V and 760.0 μW/cm-2 in the absence of Nafion ion-exchange membrane and anode protection gas of N2,respectively. The out-put density of biofuel cell after storage in refrigerator for one week can still retain ~88% of the initial value. Furthermore,this fuel cell shares the similar characteristics of pH dependence and thermal stability to those of free laccase. The key factor contributed to the performance of biofuel cell should be related to the catalytic oxygen reduction process at biocahode. Despite of the apparent influence of concomitant interferent-ascorbic acid on cell performance,this cell still shows superior out-put energy density(132.0 μW/cm-2,open circuit voltage:0.40 V) recorded in the circumstance of the human serum. This study may afford a new route to design in high performance glucose/O2 fuel cell and provide experimental basis and valuable enlightenment for the study of relationship between the structure of enzyme based cell and its performance.
A novel prototype of nano-structure glucose/O2 biofuel cell was constructed with immobilized enzyme on 4-mercapto benzoic acid(4-MBA) modified gold nanoparticles as electrical medium and enzyme carrier. It features with simple fabrication and favorable long-term usability. Glucose oxidase(GOx) and Laccase(Lac) molecules are tethered steadily to the surface of gold nanoparticles via interaction between modified group of gold nanoparticles and hydrophobic binding-sites in the vicinity of cofactor within enzyme.The as-prepared bioanode and biocathode are fabricated and denoted as GOx/4-MBA@GNP/Au and Lac/4-MBA@GNP/Au,respectively. Electrochemical results indicate that the direct electron transfer occurs between enzyme active sites and gold nanoparticles for both biocathode and bioanode in the absence of any mediator achieves with fast catalytic activity(turn-over frequency of bioanode and biocathode:1.3 and 0.5 s-1,onset potential according to the glucose catalytic oxidation and catalytic reduction of oxygen:-0.23 and 0.76 V). The power out-put performance of nano-structure with entrapped enzyme glucose/O2 biofuel cell was further evaluated after the constitution of cell via connection bioanode and biocathode on the basis of previous results. The results of test show that the open-circuit voltage and the maximum out-put energy density of this biocell amount to 0.56 V and 760.0 μW/cm-2 in the absence of Nafion ion-exchange membrane and anode protection gas of N2,respectively. The out-put density of biofuel cell after storage in refrigerator for one week can still retain ~88% of the initial value. Furthermore,this fuel cell shares the similar characteristics of pH dependence and thermal stability to those of free laccase. The key factor contributed to the performance of biofuel cell should be related to the catalytic oxygen reduction process at biocahode. Despite of the apparent influence of concomitant interferent-ascorbic acid on cell performance,this cell still shows superior out-put energy density(132.0 μW/cm-2,open circuit voltage:0.40 V) recorded in the circumstance of the human serum. This study may afford a new route to design in high performance glucose/O2 fuel cell and provide experimental basis and valuable enlightenment for the study of relationship between the structure of enzyme based cell and its performance.
2015, 32(6): 720-725
doi: 10.11944/j.issn.1000-0518.2015.06.140317
Abstract:
A Schiff base corrosion inhibitor named salicylaldehyde thiosemicarbazone(ST) was synthesized.The inhibition effect of ST on the mild steel(MS) in 1 mol/L HCl solution was investigated by mass loss measurements,potentiodynamic polarization and electrochemical impedance spectroscopy. Meanwhile,the surface morphology was observed by scanning electron microscopy. The results show that ST has an excellent inhibiting effect for Q235 steel in the HCl solution. ST acts as a good inhibitor,predominantly retarding with cathodic reaction through adsorption on a MS surface. The adsorption of ST on Q235 steel surface obeys the Langmuir adsorption isotherm.
A Schiff base corrosion inhibitor named salicylaldehyde thiosemicarbazone(ST) was synthesized.The inhibition effect of ST on the mild steel(MS) in 1 mol/L HCl solution was investigated by mass loss measurements,potentiodynamic polarization and electrochemical impedance spectroscopy. Meanwhile,the surface morphology was observed by scanning electron microscopy. The results show that ST has an excellent inhibiting effect for Q235 steel in the HCl solution. ST acts as a good inhibitor,predominantly retarding with cathodic reaction through adsorption on a MS surface. The adsorption of ST on Q235 steel surface obeys the Langmuir adsorption isotherm.
2015, 32(6): 726-732
doi: 10.11944/j.issn.1000-0518.2015.06.140365
Abstract:
Inspired by adhesive proteins in mussels,we prepared polydopamine(PDA) thin layer on the polyurethane sponge surface using dopamine self-polymerization under alkaline solution. Ag+ was reduced by glucose to form silver micro/nano-particles on the PDA thin layer,and then wrapped by polydimethylsiloxane(PDMS) to fabricate superhydrophobic surface. The prepared superhydrophobic sponge was characterized by water contact angle measurement, scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDS) and Fourier transform infrared spectra(FT-IR),respectively,and proved that silver micro/nano-particles and hydrophobic silicon methyl groups have been successfully modified onto the sponge surface. Treated sponge exhibits superior absorptivity and selectivity to organic solvents and different kinds of oil. Saturated gravimetric absorption capacity of this sponge to oil-like solvents reached at least 12 times its own mass. Solvents can be easily recycled by squeezing behavior and sponge can regain its elasticity and absorptivity. This study would provide an economical,efficient and environmental-friendly method for the oilwater separation and the oil recovery.
Inspired by adhesive proteins in mussels,we prepared polydopamine(PDA) thin layer on the polyurethane sponge surface using dopamine self-polymerization under alkaline solution. Ag+ was reduced by glucose to form silver micro/nano-particles on the PDA thin layer,and then wrapped by polydimethylsiloxane(PDMS) to fabricate superhydrophobic surface. The prepared superhydrophobic sponge was characterized by water contact angle measurement, scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDS) and Fourier transform infrared spectra(FT-IR),respectively,and proved that silver micro/nano-particles and hydrophobic silicon methyl groups have been successfully modified onto the sponge surface. Treated sponge exhibits superior absorptivity and selectivity to organic solvents and different kinds of oil. Saturated gravimetric absorption capacity of this sponge to oil-like solvents reached at least 12 times its own mass. Solvents can be easily recycled by squeezing behavior and sponge can regain its elasticity and absorptivity. This study would provide an economical,efficient and environmental-friendly method for the oilwater separation and the oil recovery.
