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2015 Volume 32 Issue 5
2015, 32(5): 489-497
doi: 10.11944/j.issn.1000-0518.2015.05.140288
Abstract:
Thermosetting polyimide resins exhibit the best high temperature performance among all matrix resins.Therefore,composites based on thermosetting polyimides have been widely used in modern industry,particularly in the aerospace industry.Herein,the research progress on thermosetting polyimides was reviewed,and some insights were also provided regarding the research trends and outlooks in this field.
Thermosetting polyimide resins exhibit the best high temperature performance among all matrix resins.Therefore,composites based on thermosetting polyimides have been widely used in modern industry,particularly in the aerospace industry.Herein,the research progress on thermosetting polyimides was reviewed,and some insights were also provided regarding the research trends and outlooks in this field.
2015, 32(5): 498-503
doi: 10.11944/j.issn.1000-0518.2015.05.140307
Abstract:
The CTS-PVP film with iodine was prepared by chitosan(CTS) grafted polyvinyl pyrrolidone(PVP) in the protection of N2 with dimethyl 2,2'-azobis(2-methylpropionate)(AIBME) as initiator followed by addition of a certain amounts of iodine in ethanol solution and a gelatin solution.The properties of the film were characterized by infrared(IR),scan electron microscopy(SEM),UV-visible spectroscopy(UV-Vis),differential scanning calorimetry(DSC),etc.The UV-Vis spectrum shows a strong absorption between 200~600 nm for the CTS-PVP film with iodine.The glass transition temperature at 319℃ indicates a good thermal stability.The antimicrobial test result shows that the inhibition zone diameters increase along with the increasing amounts of CTS-PVP-I2 complex liquid.The inhibition zone diameters against Staphylococcus aureus and Escherichia coli are in the range of 16~36mm,when the added volume of CTS-PVP-I2 complex fluid is 10 mL or more,implying its high sensitivity and good antibacterial properties.
The CTS-PVP film with iodine was prepared by chitosan(CTS) grafted polyvinyl pyrrolidone(PVP) in the protection of N2 with dimethyl 2,2'-azobis(2-methylpropionate)(AIBME) as initiator followed by addition of a certain amounts of iodine in ethanol solution and a gelatin solution.The properties of the film were characterized by infrared(IR),scan electron microscopy(SEM),UV-visible spectroscopy(UV-Vis),differential scanning calorimetry(DSC),etc.The UV-Vis spectrum shows a strong absorption between 200~600 nm for the CTS-PVP film with iodine.The glass transition temperature at 319℃ indicates a good thermal stability.The antimicrobial test result shows that the inhibition zone diameters increase along with the increasing amounts of CTS-PVP-I2 complex liquid.The inhibition zone diameters against Staphylococcus aureus and Escherichia coli are in the range of 16~36mm,when the added volume of CTS-PVP-I2 complex fluid is 10 mL or more,implying its high sensitivity and good antibacterial properties.
2015, 32(5): 504-509
doi: 10.11944/j.issn.1000-0518.2015.05.140330
Abstract:
A series of random copolymers of poly(aryl ether ketone) was prepared by copolymerization of bisphenol A,4,4'-difluorobenzophenone and benzimidazolone(BPA-DFK-HBI).High relative molecular mass copolymers were prepared via the nucleophilic polycondensation and C-N coupling polycondensation.The structure of the copolymers was characterized by FTIR and 1H NMR.The heat resistant properties of the copolymers were studied by DSC and TGA.As the feed ratio of benzimidazolone and bisphenol A increases,the solvent resistance properties of copolymers are improved in polar solvents such as DMF and THF.The thermal stability is enhanced,and the Tg is significantly increased to as high as 236℃.It is difficult to obtain high relative molecular mass polymer when the molar ratio of benzimidazolone and bisphenol A is higher than 7:3 because precipitation occurs in the early stage of the reaction due to the poor solubility of copolymers.
A series of random copolymers of poly(aryl ether ketone) was prepared by copolymerization of bisphenol A,4,4'-difluorobenzophenone and benzimidazolone(BPA-DFK-HBI).High relative molecular mass copolymers were prepared via the nucleophilic polycondensation and C-N coupling polycondensation.The structure of the copolymers was characterized by FTIR and 1H NMR.The heat resistant properties of the copolymers were studied by DSC and TGA.As the feed ratio of benzimidazolone and bisphenol A increases,the solvent resistance properties of copolymers are improved in polar solvents such as DMF and THF.The thermal stability is enhanced,and the Tg is significantly increased to as high as 236℃.It is difficult to obtain high relative molecular mass polymer when the molar ratio of benzimidazolone and bisphenol A is higher than 7:3 because precipitation occurs in the early stage of the reaction due to the poor solubility of copolymers.
2015, 32(5): 510-518
doi: 10.11944/j.issn.1000-0518.2015.05.140315
Abstract:
A series of vanadium(Ⅲ) complexes 2a~2e bearing pyridyldiimine,pyridyl-imineamine and pyridyldiamine ligands was designed,synthesized,and characterized by IR and elemental analysis.Upon treatment with Et2 AlC l and CCl3COOEt(ETA),these catalysts displayed high catalytic activity towards ethylene polymerization even at elevated reaction temperature,affording polymers with high relative molecular mass and unimodal relative molecular mass distributions,indicating the formation of a single active site during the polymerization.It was found that ligands structures exerted great influence on the polymerization behavior.Complex 2e (2,6-bis[2,6-(iPr)2PhNC(Me)]2(C5H3N)VCl) supported by dianionic pyridyldiamine showed an activity of 6.96 kg PE/(mmolV·h) at 50℃ and the activity was well kept at the elevated temperature(70℃).Efficient copolymerization of ethylene with NBE or 1-hexene was also observed.Poly(ethylene-co-NBE) with the NBE content up to 37.7% was obtained by complex 2e under mild condition,and the incorporation of 4.8% 1-hexene was observed in poly(ethylene-co-1-hexene) by complex 2d.
A series of vanadium(Ⅲ) complexes 2a~2e bearing pyridyldiimine,pyridyl-imineamine and pyridyldiamine ligands was designed,synthesized,and characterized by IR and elemental analysis.Upon treatment with Et2 AlC l and CCl3COOEt(ETA),these catalysts displayed high catalytic activity towards ethylene polymerization even at elevated reaction temperature,affording polymers with high relative molecular mass and unimodal relative molecular mass distributions,indicating the formation of a single active site during the polymerization.It was found that ligands structures exerted great influence on the polymerization behavior.Complex 2e (2,6-bis[2,6-(iPr)2PhNC(Me)]2(C5H3N)VCl) supported by dianionic pyridyldiamine showed an activity of 6.96 kg PE/(mmolV·h) at 50℃ and the activity was well kept at the elevated temperature(70℃).Efficient copolymerization of ethylene with NBE or 1-hexene was also observed.Poly(ethylene-co-NBE) with the NBE content up to 37.7% was obtained by complex 2e under mild condition,and the incorporation of 4.8% 1-hexene was observed in poly(ethylene-co-1-hexene) by complex 2d.
2015, 32(5): 519-526
doi: 10.11944/j.issn.1000-0518.2015.05.140451
Abstract:
Due to the constraints of the factors such as poor injectivity,mechanical shearing degradability,temperature-tolerated and salt-resisted ability,hydrolyzed polyacrylamide(HPAM) with high relative molecular mass has no obvious oil recovery in polymer flooding in mid-low permeability oil reservoirs.The temperature-tolerated and salt-resisted copolymer P(AM/AMPSNa/AANa) with micro-branched structure was synthesized by solution polymerization of acrylamide(AM),2-acrylamide-2-methylpropanesulfonic acid(AMPS) with ammonium persulfate(APS)/N,N-dimethylaminoethyl methacrylate(DMAEMA) as initiating system.Influences of the reaction temperature,chain transfer agent,initiator content on the intrinsic viscosity of copolymer were investigated.The structure of copolymer was characterized by IR and 13C NMR spectra.The properties of copolymer with intrinsic viscosity 1915 mL/g were evaluated.The results indicate that the copolymer has superior shear-resistence,temperature-tolerance,salt-resisting,aging property,injection and displacement efficiency,which can be used as targeted flooding polymer in high-temperature and high-salinity oil reservoir with mid-low permeability.
Due to the constraints of the factors such as poor injectivity,mechanical shearing degradability,temperature-tolerated and salt-resisted ability,hydrolyzed polyacrylamide(HPAM) with high relative molecular mass has no obvious oil recovery in polymer flooding in mid-low permeability oil reservoirs.The temperature-tolerated and salt-resisted copolymer P(AM/AMPSNa/AANa) with micro-branched structure was synthesized by solution polymerization of acrylamide(AM),2-acrylamide-2-methylpropanesulfonic acid(AMPS) with ammonium persulfate(APS)/N,N-dimethylaminoethyl methacrylate(DMAEMA) as initiating system.Influences of the reaction temperature,chain transfer agent,initiator content on the intrinsic viscosity of copolymer were investigated.The structure of copolymer was characterized by IR and 13C NMR spectra.The properties of copolymer with intrinsic viscosity 1915 mL/g were evaluated.The results indicate that the copolymer has superior shear-resistence,temperature-tolerance,salt-resisting,aging property,injection and displacement efficiency,which can be used as targeted flooding polymer in high-temperature and high-salinity oil reservoir with mid-low permeability.
2015, 32(5): 527-534
doi: 10.11944/j.issn.1000-0518.2015.05.140326
Abstract:
Linear dimethyltetrasiloxane(MD4M) was synthesized using octamethylcyclotetrasiloxane(D4) and hexamethyldisiloxane(MM) as raw materials and solid super acid(SA) TiO2/SO42- as catalyst.The influence of reaction time,reaction temperature,amount of relative molecular mass modifier(MM) and catalyst dosage on the degree of polymerization and the content of the product was studied by uniform design experiments and single factor experiments.Experiment results showed that the optimum reaction conditions are as follows:the molar ratio of octamethylcyclotetrasiloxane to hexamethyldisiloxane) is 0.75:1,the catalyst loading is 2%(mass fraction) of the total reactants,the reaction temperature is 100℃ and the reaction time is 7 h.The reaction conversion is 87% and the yield of MD4M is 16.8% which is 1.6% more than the sulfuric acid system.The catalyst(SA) can be recycled more than 3 times without the loss of its catalytic activity.The macro-kinetics model of the ring-opening polymerization of D4 with solid super acid as the heterogeneous catalyst was also created using the quasi-homogeneous system.
Linear dimethyltetrasiloxane(MD4M) was synthesized using octamethylcyclotetrasiloxane(D4) and hexamethyldisiloxane(MM) as raw materials and solid super acid(SA) TiO2/SO42- as catalyst.The influence of reaction time,reaction temperature,amount of relative molecular mass modifier(MM) and catalyst dosage on the degree of polymerization and the content of the product was studied by uniform design experiments and single factor experiments.Experiment results showed that the optimum reaction conditions are as follows:the molar ratio of octamethylcyclotetrasiloxane to hexamethyldisiloxane) is 0.75:1,the catalyst loading is 2%(mass fraction) of the total reactants,the reaction temperature is 100℃ and the reaction time is 7 h.The reaction conversion is 87% and the yield of MD4M is 16.8% which is 1.6% more than the sulfuric acid system.The catalyst(SA) can be recycled more than 3 times without the loss of its catalytic activity.The macro-kinetics model of the ring-opening polymerization of D4 with solid super acid as the heterogeneous catalyst was also created using the quasi-homogeneous system.
2015, 32(5): 535-541
doi: 10.11944/j.issn.1000-0518.2015.05.140303
Abstract:
A serials of hydroxypropyl cellulose esters graft copolymers with different phase change temperature was prepared.In these materials,semi-flexible hydroxypropyl celluloses serve as skeleton,and flexible alkanoic acid molecules serve as functional branch chains.The structures of the copolymers were characterized using FT-IR and NMR techniques.Their phase change properties and crystallization behavior were analyzed by DSC,TGA and X-ray scattering techniques.The results show that the temperatures at which the products absorb or release heat(melting or crystallization of the side chains) increase with the increase of side chain length.The phase change temperature of the materials can be adjusted by varying the length of the side chain.The fusion enthalpy reaches 60 J/g in case palmitic acid,stearic acid and eicosanoic acid are used.Furthermore,it is found that when mixed long-chain alkanoic acids are used as the reactant,the phase change temperatures of the products can be easily adjusted by changing the ratio of components in the mixture.This result are also proven by X-ray scattering results,the d-Spacing of hydroxypropyl cellulose mixed esters falls in between two single hydroxypropyl cellulose esters indicating that an effective grafting of both kinds of alkanoic acids on to the same hydroxypropyl cellulose chains.The results provide a facile method in preparing phase change temperature tunable polymer based solid-state phase change materials within certain temperature range.
A serials of hydroxypropyl cellulose esters graft copolymers with different phase change temperature was prepared.In these materials,semi-flexible hydroxypropyl celluloses serve as skeleton,and flexible alkanoic acid molecules serve as functional branch chains.The structures of the copolymers were characterized using FT-IR and NMR techniques.Their phase change properties and crystallization behavior were analyzed by DSC,TGA and X-ray scattering techniques.The results show that the temperatures at which the products absorb or release heat(melting or crystallization of the side chains) increase with the increase of side chain length.The phase change temperature of the materials can be adjusted by varying the length of the side chain.The fusion enthalpy reaches 60 J/g in case palmitic acid,stearic acid and eicosanoic acid are used.Furthermore,it is found that when mixed long-chain alkanoic acids are used as the reactant,the phase change temperatures of the products can be easily adjusted by changing the ratio of components in the mixture.This result are also proven by X-ray scattering results,the d-Spacing of hydroxypropyl cellulose mixed esters falls in between two single hydroxypropyl cellulose esters indicating that an effective grafting of both kinds of alkanoic acids on to the same hydroxypropyl cellulose chains.The results provide a facile method in preparing phase change temperature tunable polymer based solid-state phase change materials within certain temperature range.
2015, 32(5): 542-546
doi: 10.11944/j.issn.1000-0518.2015.05.140302
Abstract:
Zn(Ⅱ),Co(Ⅱ) and Mn(Ⅱ) complexes of 5-(2-nitro-4,5-methylenedioxy) phenyl-10,15,20-triphenyl-porphyrin and 5-(2-nitro-4,5-methylenedioxy) phenyl-10,15,20-tri(p-chlorophenyl)-porphyrin were synthesized by microwave irradiation.Their structures were characterized by UV-Vis,IR,fluoresence spectroscopies.The bactericidal activities of these metal compounds on Escherichia coli aureu(Ec) and Staphylococcusaureu(Sa) were studied with the inhibition ring test.These complexes show photosensitive antibacterial activities against these two bacteria.The Co(Ⅱ) complexes have obvious bacteriostatic activities against Ec and Sa at the concentration of 0.32 mmol/L and 0.02 mmol/L,respectively,and some bacteriostatic effects.The Zn(Ⅱ) and Co(Ⅱ) complexes have moderate antibacterial effects at 0.16~0.32 mmol/L.The order of the antibacterial activity of these complexes is Por(Co)>Por(Mn)≈Por(Zn).The bacteriostatic effects of the complexes on Ec are 10%~20% higher than those on Sa.
Zn(Ⅱ),Co(Ⅱ) and Mn(Ⅱ) complexes of 5-(2-nitro-4,5-methylenedioxy) phenyl-10,15,20-triphenyl-porphyrin and 5-(2-nitro-4,5-methylenedioxy) phenyl-10,15,20-tri(p-chlorophenyl)-porphyrin were synthesized by microwave irradiation.Their structures were characterized by UV-Vis,IR,fluoresence spectroscopies.The bactericidal activities of these metal compounds on Escherichia coli aureu(Ec) and Staphylococcusaureu(Sa) were studied with the inhibition ring test.These complexes show photosensitive antibacterial activities against these two bacteria.The Co(Ⅱ) complexes have obvious bacteriostatic activities against Ec and Sa at the concentration of 0.32 mmol/L and 0.02 mmol/L,respectively,and some bacteriostatic effects.The Zn(Ⅱ) and Co(Ⅱ) complexes have moderate antibacterial effects at 0.16~0.32 mmol/L.The order of the antibacterial activity of these complexes is Por(Co)>Por(Mn)≈Por(Zn).The bacteriostatic effects of the complexes on Ec are 10%~20% higher than those on Sa.
2015, 32(5): 547-551
doi: 10.11944/j.issn.1000-0518.2015.05.140301
Abstract:
α-Hydroxy-α-carbamoylamides are important synthetic intermediates and also serve as valuable agents in medicinal chemistry.Herein,a novel method for synthesis of α-hydroxy-α-carbamoylamides was developed and the reaction mechanism involving two intermediates was proposed.Good yields of α-hydroxy-α-carbamoylamides or α-trimethylsiloxy-α-carbamoylamides are obtained by the addition of N,Ndimethylcarbamoyl(trimethyl) silane to a series of α-ketoamides under anhydrous condition at 105℃.Their structures were characterized by elemental analysis,1H NMR,13C NMR and IR spectra.The steric hindrance is found to be an important factor in the addition reaction and the electronic effect can influence the rate of the reaction.
α-Hydroxy-α-carbamoylamides are important synthetic intermediates and also serve as valuable agents in medicinal chemistry.Herein,a novel method for synthesis of α-hydroxy-α-carbamoylamides was developed and the reaction mechanism involving two intermediates was proposed.Good yields of α-hydroxy-α-carbamoylamides or α-trimethylsiloxy-α-carbamoylamides are obtained by the addition of N,Ndimethylcarbamoyl(trimethyl) silane to a series of α-ketoamides under anhydrous condition at 105℃.Their structures were characterized by elemental analysis,1H NMR,13C NMR and IR spectra.The steric hindrance is found to be an important factor in the addition reaction and the electronic effect can influence the rate of the reaction.
2015, 32(5): 552-556
doi: 10.11944/j.issn.1000-0518.2015.05.140311
Abstract:
Alkali-metal modified metal organic frameworks MOF-5(denoted by M-MOF-5,M=Li,Na,K,Mg) were prepared by ‘one-step’ synthesis.The theoretical calculation(IAST,ideal adsorbed solution theory)was performed to compare the adsorption selectivity of materials.It is found that alkali-metal incorporated MOF-5 can reduce the interpenetration level of MOF-5 framework.The experiment results also show that M-MOF-5 can significantly improve the CO2/CH4 adsorption selectivity compared to MOF-5(3.79),especially Li-MOF-5(7.39) at ambient conditions.Furthermore,the CO2 capacity of Li-MOF-5 is also enhanced.
Alkali-metal modified metal organic frameworks MOF-5(denoted by M-MOF-5,M=Li,Na,K,Mg) were prepared by ‘one-step’ synthesis.The theoretical calculation(IAST,ideal adsorbed solution theory)was performed to compare the adsorption selectivity of materials.It is found that alkali-metal incorporated MOF-5 can reduce the interpenetration level of MOF-5 framework.The experiment results also show that M-MOF-5 can significantly improve the CO2/CH4 adsorption selectivity compared to MOF-5(3.79),especially Li-MOF-5(7.39) at ambient conditions.Furthermore,the CO2 capacity of Li-MOF-5 is also enhanced.
2015, 32(5): 557-561
doi: 10.11944/j.issn.1000-0518.2015.05.140287
Abstract:
A novel Cu(Ⅱ) compound,C32H46 CuN2O4([CuL]),has been synthesized in ethanol by the reaction of H2L(H2L=4,4',6,6'-tetra(tert-butyl)-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol)with copper(Ⅱ) acetate monohydrate at room temperature and characterized by IR spectroscopy,elemental analyses and X-ray crystallography.The X-ray crystal structure of[CuL]crystallizes in a monoclinic system,space group C2/c,with a=2.7231(3) nm,b=1.1196(3) nm,c=1.0704(2) nm,α=90.00°,β=101.293(2) °,γ=90.00°,V=3.2002(11) nm3,Z=4,Mr=586.25,Dc=1.217 g/cm3,μ=0.718mm-1,F(000)=1252,R1=0.0957,wR2=0.2297.The symmetric unit in[CuL]contains one Cu(Ⅱ) atom and one coordinated L molecule.The central Cu(Ⅱ) atom are four-coordinated by N1,N1#,O2 and O2# atoms from the coordinated L unit.A slightly distorted tetrahedral geometry is formed around the central Cu(Ⅱ) atom.The antibacterial activities of H2L and[CuL] are investigated using K-B method,the results indicate that[CuL] has remarkable antibacterial effect on Staphylococcus aureus,Escherichia coli and Withered grass bacillus.[CuL] has stronger activities against the three bacterias than the H2L ligand.
A novel Cu(Ⅱ) compound,C32H46 CuN2O4([CuL]),has been synthesized in ethanol by the reaction of H2L(H2L=4,4',6,6'-tetra(tert-butyl)-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol)with copper(Ⅱ) acetate monohydrate at room temperature and characterized by IR spectroscopy,elemental analyses and X-ray crystallography.The X-ray crystal structure of[CuL]crystallizes in a monoclinic system,space group C2/c,with a=2.7231(3) nm,b=1.1196(3) nm,c=1.0704(2) nm,α=90.00°,β=101.293(2) °,γ=90.00°,V=3.2002(11) nm3,Z=4,Mr=586.25,Dc=1.217 g/cm3,μ=0.718mm-1,F(000)=1252,R1=0.0957,wR2=0.2297.The symmetric unit in[CuL]contains one Cu(Ⅱ) atom and one coordinated L molecule.The central Cu(Ⅱ) atom are four-coordinated by N1,N1#,O2 and O2# atoms from the coordinated L unit.A slightly distorted tetrahedral geometry is formed around the central Cu(Ⅱ) atom.The antibacterial activities of H2L and[CuL] are investigated using K-B method,the results indicate that[CuL] has remarkable antibacterial effect on Staphylococcus aureus,Escherichia coli and Withered grass bacillus.[CuL] has stronger activities against the three bacterias than the H2L ligand.
2015, 32(5): 562-569
doi: 10.11944/j.issn.1000-0518.2015.05.140324
Abstract:
2-(Salicyloylhydrazone) propionic acid dibutytin complex was synthesized via the reaction of 2-(salicyloylhydrazone) propionic acid with dibutyltin oxide.The complex was characterized by IR,1H NMR,13C NMR spectroscopy,and elemental analysis.The crystal structure was determined to be a tetragonal system by single crystal X-ray diffraction.The crystal structure of the complex belongs to a centrosymmetric structure mode with a four-member central Sn2O2 unit,in which the central Sn atom is seven-coordinated in a distorted pentagonal pyramid configuration.The complex is stable below 103℃ according to thermal analysis.The interaction between the complex and Herring sperm DNA was studied by UV spectroscopy,ethidium bromide(EB) fluorescent probe and viscosity,and the results suggest the intercalation interaction between the complex and Herring sperm DNA.
2-(Salicyloylhydrazone) propionic acid dibutytin complex was synthesized via the reaction of 2-(salicyloylhydrazone) propionic acid with dibutyltin oxide.The complex was characterized by IR,1H NMR,13C NMR spectroscopy,and elemental analysis.The crystal structure was determined to be a tetragonal system by single crystal X-ray diffraction.The crystal structure of the complex belongs to a centrosymmetric structure mode with a four-member central Sn2O2 unit,in which the central Sn atom is seven-coordinated in a distorted pentagonal pyramid configuration.The complex is stable below 103℃ according to thermal analysis.The interaction between the complex and Herring sperm DNA was studied by UV spectroscopy,ethidium bromide(EB) fluorescent probe and viscosity,and the results suggest the intercalation interaction between the complex and Herring sperm DNA.
2015, 32(5): 570-575
doi: 10.11944/j.issn.1000-0518.2015.05.140295
Abstract:
The CuO-ZnO/Al2O3 catalysts were successfully prepared using the coprecipitation-azeotropic distillation method using isobutyl alcohol as the azeotropic solvent.The catalysts were characterized by X-ray diffraction and thermogravimetry/differential thermal analysis and scanning electron microscopy.The results show that azeotropic distillation can effectively remove free water in the precursor sol to inhibit particle agglomeration and partial sintering caused by the heating process.At the same time combination of isobutanol and polyethylene glycol inhibits theOstwald ripening of particles to obtain uniform particle size distribution and excellent dispersion of CuO components in catalyst particles.Direct hydrogenation of CO2 to methanol was carried out in a fixed bed flow reactor.The experiments show that the catalysts prepared by the azeotropic distillation have better catalytic performance and stability than those the direct drying method.
The CuO-ZnO/Al2O3 catalysts were successfully prepared using the coprecipitation-azeotropic distillation method using isobutyl alcohol as the azeotropic solvent.The catalysts were characterized by X-ray diffraction and thermogravimetry/differential thermal analysis and scanning electron microscopy.The results show that azeotropic distillation can effectively remove free water in the precursor sol to inhibit particle agglomeration and partial sintering caused by the heating process.At the same time combination of isobutanol and polyethylene glycol inhibits theOstwald ripening of particles to obtain uniform particle size distribution and excellent dispersion of CuO components in catalyst particles.Direct hydrogenation of CO2 to methanol was carried out in a fixed bed flow reactor.The experiments show that the catalysts prepared by the azeotropic distillation have better catalytic performance and stability than those the direct drying method.
2015, 32(5): 576-582
doi: 10.11944/j.issn.1000-0518.2015.05.140284
Abstract:
Due to the earth-abundance and prevalence in photovoltaic industries,silicon was used as lightharvesting material to from a composite with amorphous cobalt oxides oxygen-evolving catalyst(OEC) to carry out the solar-driven water-splitting in near-neutral conditions for hydrogen production.The device can efficiently utilize the solar spectrum for the photon-charge conversion and allow water splitting.The Co-OEC prepared by electrolysis deposition for 400 s exhibits excellent oxygen evolution properties,with a current density of 1.7×10-2A/cm-2 and a oxygen evolution rate of 1.28 mol/(h·m-2) in the potassium tetraborate buffer solution(pH=9.2) at 0V vs.NHE under AM1.5 simulated sunlight.
Due to the earth-abundance and prevalence in photovoltaic industries,silicon was used as lightharvesting material to from a composite with amorphous cobalt oxides oxygen-evolving catalyst(OEC) to carry out the solar-driven water-splitting in near-neutral conditions for hydrogen production.The device can efficiently utilize the solar spectrum for the photon-charge conversion and allow water splitting.The Co-OEC prepared by electrolysis deposition for 400 s exhibits excellent oxygen evolution properties,with a current density of 1.7×10-2A/cm-2 and a oxygen evolution rate of 1.28 mol/(h·m-2) in the potassium tetraborate buffer solution(pH=9.2) at 0V vs.NHE under AM1.5 simulated sunlight.
2015, 32(5): 583-590
doi: 10.11944/j.issn.1000-0518.2015.05.140321
Abstract:
The graphene(GNS)/Co-Ni layered double hydroxides(LDH) composites were synthesized through a chemical co-precipitation process of Co2+ and Ni2+ using NH3·H2O as a precipitator in the presence of graphene.The compositions,microstructures and morphologies of these samples were systematically characterized by Fourier transform infrared(FT-IR) spectroscopy,X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM) and nitrogen adsorption(BET).The electrochemical performance of these composites was investigated by cyclic voltammetry and constant current charge/discharge techniques.It is found that Co-Ni LDH nanoparticles are well dispersed on the surface of GNS as the spacer to prevent the GNS from aggregation and improve the conductivity and structure stability of the Co-Ni LDH.The results show that the GNS/Co-Ni LDH electrode exhibits excellent electrochemical performance.Its specific capacitance as a single electrode is up to 2770 F/g and remains about 93.4% of the initial value after 500 potential cycles at the current density of 1 A/g.
The graphene(GNS)/Co-Ni layered double hydroxides(LDH) composites were synthesized through a chemical co-precipitation process of Co2+ and Ni2+ using NH3·H2O as a precipitator in the presence of graphene.The compositions,microstructures and morphologies of these samples were systematically characterized by Fourier transform infrared(FT-IR) spectroscopy,X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM) and nitrogen adsorption(BET).The electrochemical performance of these composites was investigated by cyclic voltammetry and constant current charge/discharge techniques.It is found that Co-Ni LDH nanoparticles are well dispersed on the surface of GNS as the spacer to prevent the GNS from aggregation and improve the conductivity and structure stability of the Co-Ni LDH.The results show that the GNS/Co-Ni LDH electrode exhibits excellent electrochemical performance.Its specific capacitance as a single electrode is up to 2770 F/g and remains about 93.4% of the initial value after 500 potential cycles at the current density of 1 A/g.
2015, 32(5): 591-596
doi: 10.11944/j.issn.1000-0518.2015.05.140300
Abstract:
A series of porous carbons(PC-1,PC-2 and PC-3) with microporous and suitable mesoporous was successfully prepared by pyrolysis in the absence(PC-1) and existence of ZnCl2(PC-2),or ZnCl2/LiCl(PC-3) activators utilizing soaked scaphium scaphigerum as the precursor.The specific capacitance of PC-1,PC-2and PC-3 electrodes at the current density of 0.5 A/g in three-electrode system is 69,132 and 228 F/g,respectively.Moreover,a specific capacitance up to 166 F/g at the current density of 10 A/g indicates a good rate performance of PC-3.These desirable results reveal that the porous carbons prepared from scaphium scaphigerum by ZnCl2/LiCl activation can be used as high performance electrode materials in supercapacitor.
A series of porous carbons(PC-1,PC-2 and PC-3) with microporous and suitable mesoporous was successfully prepared by pyrolysis in the absence(PC-1) and existence of ZnCl2(PC-2),or ZnCl2/LiCl(PC-3) activators utilizing soaked scaphium scaphigerum as the precursor.The specific capacitance of PC-1,PC-2and PC-3 electrodes at the current density of 0.5 A/g in three-electrode system is 69,132 and 228 F/g,respectively.Moreover,a specific capacitance up to 166 F/g at the current density of 10 A/g indicates a good rate performance of PC-3.These desirable results reveal that the porous carbons prepared from scaphium scaphigerum by ZnCl2/LiCl activation can be used as high performance electrode materials in supercapacitor.
2015, 32(5): 597-603
doi: 10.11944/j.issn.1000-0518.2015.05.140308
Abstract:
A series of quasi ternary phase diagrams of alkyl phenol polyoxyethylene ether(OP-10)+n-octanol+n-hexane+water(brine) system has been drawn based on experiments.We investigated the influence of cosurfactant n-octanol and CaCl2 solution on the microemulsion region respectively.The results show that the relative area of microemulsion region in the ternary system gradually increases with the mass ratio of n-octanol to OP-10 increasing.When the mass ratio of n-octanol to OP-10 is 1:2.5,the microemulsion region has the largest relative area,and then the relative area of microemulsion region decreases as the proportion of n-octanol is increased.An appropriate amount of cosurfactant n-octanol promotes the formation of microemulsion phase,whereas excessive n-octanol is unfavorable to the formation of microemulsion phase.By fixing the mass ratio of n-octanol to OP-10 at 1:2.5 and changing the molar concentration of CaCl2,the microemulsion region exhibits the largest relative area in quasi ternary phase diagram of OP-10+octanol+cyclohexane+CaCl2 aqueous solution system when CaCl2 concentration is 0.1 mol/L.Therefore,microemulsions have been prepared with five different molar ratios of barium ions to calcium ions,and a calcium carbonate and barium carbonate coprecipitation product are obtained by the reaction with an equi molar amount of sodium carbonate.The coprecipitation product were characterized by scanning electron microscopy(SEM).The precipitation mainly tends to form large cubic structure when the composition of microemulsion is calcium salt.However,when the molar ratios of Ca2+ and Ba2+ are 3:1,1:1,or 1:3,mainly rectangular pyramid,spherical,and corn cob shape precipitation particles are formed,respectively,and the barium salt fully converts into irregular polyhedron shape as well.
A series of quasi ternary phase diagrams of alkyl phenol polyoxyethylene ether(OP-10)+n-octanol+n-hexane+water(brine) system has been drawn based on experiments.We investigated the influence of cosurfactant n-octanol and CaCl2 solution on the microemulsion region respectively.The results show that the relative area of microemulsion region in the ternary system gradually increases with the mass ratio of n-octanol to OP-10 increasing.When the mass ratio of n-octanol to OP-10 is 1:2.5,the microemulsion region has the largest relative area,and then the relative area of microemulsion region decreases as the proportion of n-octanol is increased.An appropriate amount of cosurfactant n-octanol promotes the formation of microemulsion phase,whereas excessive n-octanol is unfavorable to the formation of microemulsion phase.By fixing the mass ratio of n-octanol to OP-10 at 1:2.5 and changing the molar concentration of CaCl2,the microemulsion region exhibits the largest relative area in quasi ternary phase diagram of OP-10+octanol+cyclohexane+CaCl2 aqueous solution system when CaCl2 concentration is 0.1 mol/L.Therefore,microemulsions have been prepared with five different molar ratios of barium ions to calcium ions,and a calcium carbonate and barium carbonate coprecipitation product are obtained by the reaction with an equi molar amount of sodium carbonate.The coprecipitation product were characterized by scanning electron microscopy(SEM).The precipitation mainly tends to form large cubic structure when the composition of microemulsion is calcium salt.However,when the molar ratios of Ca2+ and Ba2+ are 3:1,1:1,or 1:3,mainly rectangular pyramid,spherical,and corn cob shape precipitation particles are formed,respectively,and the barium salt fully converts into irregular polyhedron shape as well.
2015, 32(5): 604-610
doi: 10.11944/j.issn.1000-0518.2015.05.140334
Abstract:
On the basis of a starburst small molecular gelator N5 which consists of a triphenylamine core,carbazole terminals and tetraphenyl arms,highly efficient fluorescent film sensors have been demonstrated for the detection of TNT saturated vapor.Different from the model compound N2 with monophenyl arms,compound N5 can easily form gels in benzene-containing solvents due to inter molecular π-π interactions caused by the presence of tetraphenyl groups.In addition,the obtained compound N5 film fabricated via spincoating from the toluene solution exhibits porous morphology with some nano-fibrous assemblies,favorable for the permeation of vapor molecules.As a result,when used as the film sensor for TNT vapor,compound N5 shows faster quenching response rate and higher quenching efficiency than those of compound N2.Most interestingly,its thickness nearly has no effect on the sensor property.Even for a 94 nm-thick film,the fluorescence can still be quenched by about 44% and 90% at 1min and 30min,respectively.
On the basis of a starburst small molecular gelator N5 which consists of a triphenylamine core,carbazole terminals and tetraphenyl arms,highly efficient fluorescent film sensors have been demonstrated for the detection of TNT saturated vapor.Different from the model compound N2 with monophenyl arms,compound N5 can easily form gels in benzene-containing solvents due to inter molecular π-π interactions caused by the presence of tetraphenyl groups.In addition,the obtained compound N5 film fabricated via spincoating from the toluene solution exhibits porous morphology with some nano-fibrous assemblies,favorable for the permeation of vapor molecules.As a result,when used as the film sensor for TNT vapor,compound N5 shows faster quenching response rate and higher quenching efficiency than those of compound N2.Most interestingly,its thickness nearly has no effect on the sensor property.Even for a 94 nm-thick film,the fluorescence can still be quenched by about 44% and 90% at 1min and 30min,respectively.
