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2014 Volume 31 Issue 8
2014, 31(8): 871-877
doi: 10.3724/SP.J.1095.2014.30444
Abstract:
Graphene/carbon nanotube composite materials have the common characteristics of both graphene and carbon nanotubes. The composite materials overcome the discontinuous faults of graphene and network clearance of carbon nanotubes. In this paper,the recent progress in the preparation of graghene/carbon nanotubes composite film was described. In situ,self-assembly and chemical-free syntheses of graphene/carbon nanotubes composite film with thin thickness,high strength and high specific capacitance characteristics,respectively,were summarized. The application of graphene/carbon nanotubes composite film in sensor,lithium battery and supercapacitor were proposed.
Graphene/carbon nanotube composite materials have the common characteristics of both graphene and carbon nanotubes. The composite materials overcome the discontinuous faults of graphene and network clearance of carbon nanotubes. In this paper,the recent progress in the preparation of graghene/carbon nanotubes composite film was described. In situ,self-assembly and chemical-free syntheses of graphene/carbon nanotubes composite film with thin thickness,high strength and high specific capacitance characteristics,respectively,were summarized. The application of graphene/carbon nanotubes composite film in sensor,lithium battery and supercapacitor were proposed.
2014, 31(8): 878-884
doi: 10.3724/SP.J.1095.2014.30400
Abstract:
Poly(ether ether ketone)(PEEK) was synthesized by the aromatic nucleophilic polycondensation reaction of 4,4'-difluorobenzophenone,bisphenol A and 2-methylhydroquinone. Double-arm PEEK macroinitiator containing isopropyl bromide end groups was obtained by bromination with N-bromosuccinimide(NBS),hydroxylation with dimethylol propionate sodium and esterification reaction with bromo-2-methylpropionyl bromide. The membranes of PEEK-g-StSO3Na were prepared by solution casting. A mixed solvent of water and N-methyl-2-pyrrolidone(NMP) was used to design the membrane morphology. The structure and morphology of PEEK-g-StSO3Na membranes were characterized by FT-IR,1H NMR,TGA and SEM. The synthesized PEEK-g-StSO3Na was found to improve hydrophilic/hydrophobic phase separation. With the increase of the grafting density of StSO3Na,the ion exchange capacity(IEC) increases from 0.643 to 2.034 mmol/g and the conductivities of the membrane is 8.34×10-2 S/cm. The PEEK-g-StSO3Na membranes have higher proton conductivities and lower swelling ratio than Nafion 117.
Poly(ether ether ketone)(PEEK) was synthesized by the aromatic nucleophilic polycondensation reaction of 4,4'-difluorobenzophenone,bisphenol A and 2-methylhydroquinone. Double-arm PEEK macroinitiator containing isopropyl bromide end groups was obtained by bromination with N-bromosuccinimide(NBS),hydroxylation with dimethylol propionate sodium and esterification reaction with bromo-2-methylpropionyl bromide. The membranes of PEEK-g-StSO3Na were prepared by solution casting. A mixed solvent of water and N-methyl-2-pyrrolidone(NMP) was used to design the membrane morphology. The structure and morphology of PEEK-g-StSO3Na membranes were characterized by FT-IR,1H NMR,TGA and SEM. The synthesized PEEK-g-StSO3Na was found to improve hydrophilic/hydrophobic phase separation. With the increase of the grafting density of StSO3Na,the ion exchange capacity(IEC) increases from 0.643 to 2.034 mmol/g and the conductivities of the membrane is 8.34×10-2 S/cm. The PEEK-g-StSO3Na membranes have higher proton conductivities and lower swelling ratio than Nafion 117.
2014, 31(8): 885-891
doi: 10.3724/SP.J.1095.2014.30629
Abstract:
PP-g-(MAH/St) and PP-g-MAH were prepared by melt grafting polypropylene(PP) resin with maleic anhydride(MAH) and styrene(St) in a torque rheometer,and were used as compatiblizers in polypropylene/wood flour composites. The structures of PP-g-(MAH/St) and PP-g-MAH were confirmed by FTIR analysis. The effect of these two compatiblizers on the microstructure and crystal properties of PP/wood flour composites was examined by SEM and DSC to interpret and explain the difference of processing and mechanical properties of PP/wood flour composites. SEM analysis indicates that wood flour modified by PP-g-(MAH/St) has better dispersion in the PP matrix with a blurrier interface and better compatibility than that modified by PP-g-MAH. DSC results show that the heterogeneous nucleation of wood flour to PP in PP-g-(MAH/St) modified system is stronger and their crystallization temperature and crystallinity increase. The processing and mechanical properties of PP/wood flour composites reveal that PP-g-(MAH/St) has better performance than PP-g-MAH. The melt-mess flow rate of the two kinds of composites shows a steady downward trend with the increase of compatiblizer contents,while the tensile and flexural strength of PP-g-(MAH/St) modified system show a steady upward trend,and reach a maximum at 4.8 g PP-g-(MAH/St)/100 g PP. The tensile strength reachs to 40.62 MPa which is 1.29 and 1.17 times of the unmodified system and PP-g-MAH system,respectively,and at the meantime the flexural strength rises to 45.72 MPa which is 1.23 and 1.59 times as high as those of the unmodified system and PP-g-MAH system. At 3.6 g PP-g-(MAH/St)/100 g PP,the unnotched impact strength of PP-g-(MAH/St) system is 13.35 kJ/m2 which is 1.62 and 1.42 times as high as that of unmodified and PP-g-MAH system,respectively.
PP-g-(MAH/St) and PP-g-MAH were prepared by melt grafting polypropylene(PP) resin with maleic anhydride(MAH) and styrene(St) in a torque rheometer,and were used as compatiblizers in polypropylene/wood flour composites. The structures of PP-g-(MAH/St) and PP-g-MAH were confirmed by FTIR analysis. The effect of these two compatiblizers on the microstructure and crystal properties of PP/wood flour composites was examined by SEM and DSC to interpret and explain the difference of processing and mechanical properties of PP/wood flour composites. SEM analysis indicates that wood flour modified by PP-g-(MAH/St) has better dispersion in the PP matrix with a blurrier interface and better compatibility than that modified by PP-g-MAH. DSC results show that the heterogeneous nucleation of wood flour to PP in PP-g-(MAH/St) modified system is stronger and their crystallization temperature and crystallinity increase. The processing and mechanical properties of PP/wood flour composites reveal that PP-g-(MAH/St) has better performance than PP-g-MAH. The melt-mess flow rate of the two kinds of composites shows a steady downward trend with the increase of compatiblizer contents,while the tensile and flexural strength of PP-g-(MAH/St) modified system show a steady upward trend,and reach a maximum at 4.8 g PP-g-(MAH/St)/100 g PP. The tensile strength reachs to 40.62 MPa which is 1.29 and 1.17 times of the unmodified system and PP-g-MAH system,respectively,and at the meantime the flexural strength rises to 45.72 MPa which is 1.23 and 1.59 times as high as those of the unmodified system and PP-g-MAH system. At 3.6 g PP-g-(MAH/St)/100 g PP,the unnotched impact strength of PP-g-(MAH/St) system is 13.35 kJ/m2 which is 1.62 and 1.42 times as high as that of unmodified and PP-g-MAH system,respectively.
2014, 31(8): 892-900
doi: 10.3724/SP.J.1095.2014.30665
Abstract:
The novel cellulose resin crosslinked with perylene tetracarboxylic diimides 3 was synthesized and its structure was characterized by elemental analysis,Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM). Dye adsorption experiments of polymer 3 suggested that it exhibited excellent adsorption capacities for four tested dyes[orange G sodium salt(OG),brilliant ponceau 5R(BP),methylene blue(MB) and crystal violet(CV)]. The adsorption capacities for OG,BP,MB,CV were as high as 1.04,1.21,1.14 and 0.96 mmol/g,respectively. The adsorption processes obeyed a pseudo second-order model,followed the Langmuir isotherm equation,and were exothermic and spontaneous. The pH values between 2~12 had slight influences on adsorption capacities. The adsorption results indicated that the electrostatic action,hydrogen bond and π-π stacking action played important roles in adsorption processes.
The novel cellulose resin crosslinked with perylene tetracarboxylic diimides 3 was synthesized and its structure was characterized by elemental analysis,Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM). Dye adsorption experiments of polymer 3 suggested that it exhibited excellent adsorption capacities for four tested dyes[orange G sodium salt(OG),brilliant ponceau 5R(BP),methylene blue(MB) and crystal violet(CV)]. The adsorption capacities for OG,BP,MB,CV were as high as 1.04,1.21,1.14 and 0.96 mmol/g,respectively. The adsorption processes obeyed a pseudo second-order model,followed the Langmuir isotherm equation,and were exothermic and spontaneous. The pH values between 2~12 had slight influences on adsorption capacities. The adsorption results indicated that the electrostatic action,hydrogen bond and π-π stacking action played important roles in adsorption processes.
2014, 31(8): 901-910
doi: 10.3724/SP.J.1095.2014.30574
Abstract:
The nitrochlorobenzene(a mixture of o-nitrochlorobenzene and p-nitrochlorobenzene) made by mononitrating chlorobenzene using mixed acid was transformed into 2,4-dinitro-chlorobenzene at the ratio of n(nitrochlorobenzene):n(nitric acid):n(sulfuric acid)=1.00:1.10~1.15:2.20,and at(100 ±5)℃ for 65~75 min. The resulting compound was then attacked by nuceophilic diethanol amine in ethyl acetate at the ratio of n(2,4-dinitrochloro-benzene):n(diethanol amine)=1.00:2.20 and at 65~70℃ for 4 h to give N,N-bis(β-hydroxyethyl)-2,4-dinitroaniline,of which the chemical structure was determined by melting point measurement,IR,and NMR. The final product was transferred into a yellow polyurethane elastic membrane when mixed with other diols in a certain proportion,and then by reacting with diisocyanate. The performance of the designed target molecule is better than that of the corresponding reaction dyes from Japan or Korea,but comparable to that from Milken Co. Ltd. USA by investigating the color fastness,tensile strength,and breaking elongation of polyurethane elastic membrane.
The nitrochlorobenzene(a mixture of o-nitrochlorobenzene and p-nitrochlorobenzene) made by mononitrating chlorobenzene using mixed acid was transformed into 2,4-dinitro-chlorobenzene at the ratio of n(nitrochlorobenzene):n(nitric acid):n(sulfuric acid)=1.00:1.10~1.15:2.20,and at(100 ±5)℃ for 65~75 min. The resulting compound was then attacked by nuceophilic diethanol amine in ethyl acetate at the ratio of n(2,4-dinitrochloro-benzene):n(diethanol amine)=1.00:2.20 and at 65~70℃ for 4 h to give N,N-bis(β-hydroxyethyl)-2,4-dinitroaniline,of which the chemical structure was determined by melting point measurement,IR,and NMR. The final product was transferred into a yellow polyurethane elastic membrane when mixed with other diols in a certain proportion,and then by reacting with diisocyanate. The performance of the designed target molecule is better than that of the corresponding reaction dyes from Japan or Korea,but comparable to that from Milken Co. Ltd. USA by investigating the color fastness,tensile strength,and breaking elongation of polyurethane elastic membrane.
2014, 31(8): 911-915
doi: 10.3724/SP.J.1095.2014.30569
Abstract:
An intermediate[1,2,5] oxadiazolo[3,4-e] tetrazolo[1,5-a] pyridine-3-oxide(4b) was synthesized using 2,6-dichloropyridine as a primary material,followed by nitration,azide,and cyclization. Compound 4b reacted with concentrated sulfuric acid and potassium nitrate,sodium methoxide,aqueous methylamine to afford 5-substituted furoxano[3,4-b] pyridine derivatives 5~7,respectively. The furoxano group of compound 4b was stable in the presence of strong acid,strong base and weak base,but the tetrazolo group formed by azido group at the ortho-position of the pyridine ring was labile.
An intermediate[1,2,5] oxadiazolo[3,4-e] tetrazolo[1,5-a] pyridine-3-oxide(4b) was synthesized using 2,6-dichloropyridine as a primary material,followed by nitration,azide,and cyclization. Compound 4b reacted with concentrated sulfuric acid and potassium nitrate,sodium methoxide,aqueous methylamine to afford 5-substituted furoxano[3,4-b] pyridine derivatives 5~7,respectively. The furoxano group of compound 4b was stable in the presence of strong acid,strong base and weak base,but the tetrazolo group formed by azido group at the ortho-position of the pyridine ring was labile.
Synthesis and Fluorescence Properties of Hyaluronic Acid Derivatives Containing Fluorinated Coumarin
2014, 31(8): 916-921
doi: 10.3724/SP.J.1095.2014.30493
Abstract:
4-Trifluoromethyl-7-amino coumarin obtained from m-aminophenol and ethyl trifluoroacetoacetate,further reacted with chloroacetic chloride to generate 4-trifluoromethyl-7-chloro-acetylamino coumarin. Then,the product was treated with sodium hyaluronate to give hyaluronic acid derivatives containing fluorinated coumarin. The influences of concentration,pH and temperature on fluorescence intensity of hyaluronic acid derivatives were studied. The influence of different metal ions on fluorescence intensity of hyaluronic acid derivatives was also investigated. The results show that the fluorescence intensity of hyaluronic acid derivatives is enhanced with increased concentration,kept stable when the pH ranges from 3.86 to 8.85,and decreased when temperature increased from 10℃ to 80℃. In addition,Fe3+ leads to significantly reduced fluorescence intensity of hyaluronic acid derivatives in the presence of other interfering metal ions. These provide good experimental basis to explore the mechanism as well as the targeting behavior of hyaluronic acid as drug carrier.
4-Trifluoromethyl-7-amino coumarin obtained from m-aminophenol and ethyl trifluoroacetoacetate,further reacted with chloroacetic chloride to generate 4-trifluoromethyl-7-chloro-acetylamino coumarin. Then,the product was treated with sodium hyaluronate to give hyaluronic acid derivatives containing fluorinated coumarin. The influences of concentration,pH and temperature on fluorescence intensity of hyaluronic acid derivatives were studied. The influence of different metal ions on fluorescence intensity of hyaluronic acid derivatives was also investigated. The results show that the fluorescence intensity of hyaluronic acid derivatives is enhanced with increased concentration,kept stable when the pH ranges from 3.86 to 8.85,and decreased when temperature increased from 10℃ to 80℃. In addition,Fe3+ leads to significantly reduced fluorescence intensity of hyaluronic acid derivatives in the presence of other interfering metal ions. These provide good experimental basis to explore the mechanism as well as the targeting behavior of hyaluronic acid as drug carrier.
2014, 31(8): 922-927
doi: 10.3724/SP.J.1095.2014.30474
Abstract:
The key intermediate iminophosphorane was prepared from 5-aminopyrazole in the presence of triphenylphosphine and hexachloroethane. Eleven 6-alkylamino(oxy)-3-methylthio-1H-pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives were designed and synthesized via a tandem aza-Wittig reaction. The structures of target compounds were confirmed by 1H NMR,EI-MS,IR spectroscopy and elemental analyses. The results of preliminary bioassay indicate that some compounds possess good herbicidal activity against the roots of Rape and Barnyard grass.
The key intermediate iminophosphorane was prepared from 5-aminopyrazole in the presence of triphenylphosphine and hexachloroethane. Eleven 6-alkylamino(oxy)-3-methylthio-1H-pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives were designed and synthesized via a tandem aza-Wittig reaction. The structures of target compounds were confirmed by 1H NMR,EI-MS,IR spectroscopy and elemental analyses. The results of preliminary bioassay indicate that some compounds possess good herbicidal activity against the roots of Rape and Barnyard grass.
2014, 31(8): 928-936
doi: 10.3724/SP.J.1095.2014.30502
Abstract:
The three kinds of 1-methyl-5-substituted-pyrazole-3-carboxylic acid(2a~2c) were obtained by 5-substituted-1H-pyrazole-3-ethyl formate based on methylation and hydrolysis of the ester. Then the six kinds of 3-substituted-4-amino-5-mercapto-1,2,4-triazale(3a~3f) were obtained using the substituted carboxylic acid by a series of reaction; Finally,eighteen novel 1,2,4-triazolo[3,4-b] -1,3,4-thiadiazoles compounds(4a~4r) were synthesized by phosphorus chloride treatment of compounds(2a~2c,3a~3f). The structures of all new compounds were characterized by IR,1H NMR,13C NMR and elemental analyses. The preliminary test shows that all the compounds(4a~4r) display auxin activity and fungicidal activity to some extent. Among these compounds,minimum inhibitory concentrations(MIC) were measured for the superior two by antimicrobial.
The three kinds of 1-methyl-5-substituted-pyrazole-3-carboxylic acid(2a~2c) were obtained by 5-substituted-1H-pyrazole-3-ethyl formate based on methylation and hydrolysis of the ester. Then the six kinds of 3-substituted-4-amino-5-mercapto-1,2,4-triazale(3a~3f) were obtained using the substituted carboxylic acid by a series of reaction; Finally,eighteen novel 1,2,4-triazolo[3,4-b] -1,3,4-thiadiazoles compounds(4a~4r) were synthesized by phosphorus chloride treatment of compounds(2a~2c,3a~3f). The structures of all new compounds were characterized by IR,1H NMR,13C NMR and elemental analyses. The preliminary test shows that all the compounds(4a~4r) display auxin activity and fungicidal activity to some extent. Among these compounds,minimum inhibitory concentrations(MIC) were measured for the superior two by antimicrobial.
2014, 31(8): 937-942
doi: 10.3724/SP.J.1095.2014.30495
Abstract:
A novel tricyclohexyltin complex Cy3SnOC9NH6 was synthesized by the reaction of 8-quinolinol with tricyclohexyltin hydroxide under microwave irradiation,and characterized by UV,IR,1H and 13C NMR,elemental analysis and X-ray crystal diffraction. The crystal belongs to triclinic system,space group P1 with the cell parameters:a=0.99530(5) nm,b=1.01129(5) nm,c=2.58327(13) nm,α=89.1880(10)°,β=86.6290(10)°,γ=81.2490(10)°,Z=4,V=2.5654(2) nm3,Dc=1.326 Mg/m3,μ(MoKα)=1.013 mm-1,F(000)=1064,R1=0.0447,wR2=0.0891. The complex is stable up to ~200℃. It displays strong in vitro anticancer activity against four human cancer cell lines,Colo205,HepG2,MCF-7 and NCI-H460.
A novel tricyclohexyltin complex Cy3SnOC9NH6 was synthesized by the reaction of 8-quinolinol with tricyclohexyltin hydroxide under microwave irradiation,and characterized by UV,IR,1H and 13C NMR,elemental analysis and X-ray crystal diffraction. The crystal belongs to triclinic system,space group P1 with the cell parameters:a=0.99530(5) nm,b=1.01129(5) nm,c=2.58327(13) nm,α=89.1880(10)°,β=86.6290(10)°,γ=81.2490(10)°,Z=4,V=2.5654(2) nm3,Dc=1.326 Mg/m3,μ(MoKα)=1.013 mm-1,F(000)=1064,R1=0.0447,wR2=0.0891. The complex is stable up to ~200℃. It displays strong in vitro anticancer activity against four human cancer cell lines,Colo205,HepG2,MCF-7 and NCI-H460.
2014, 31(8): 943-946
doi: 10.3724/SP.J.1095.2014.30524
Abstract:
A series of aroyl cyanides was synthesized by nucleophilic substitution reactions of aromatic acids with thionyl chloride and potassium ferricyanide in one-pot under solvent-free and catalyst-free conditions. The effects of the reaction temperature and time on the yield of the products were investigated. The yields of aroyl cyanides were up to 71%~92% when the reactions were performed at 180℃ for 2 h. The structures of the products were confirmed by IR,1H NMR and 13C NMR spectroscopy. This method has advantages of simple work-up procedure,high yield,and eco-friendly solvent-free and catalyst-free conditions.
A series of aroyl cyanides was synthesized by nucleophilic substitution reactions of aromatic acids with thionyl chloride and potassium ferricyanide in one-pot under solvent-free and catalyst-free conditions. The effects of the reaction temperature and time on the yield of the products were investigated. The yields of aroyl cyanides were up to 71%~92% when the reactions were performed at 180℃ for 2 h. The structures of the products were confirmed by IR,1H NMR and 13C NMR spectroscopy. This method has advantages of simple work-up procedure,high yield,and eco-friendly solvent-free and catalyst-free conditions.
2014, 31(8): 947-951
doi: 10.3724/SP.J.1095.2014.30521
Abstract:
A green and facile approach to swep is reported in this paper. With cheap,easily available and recyclable nonmetal selenium as the catalyst and CO instead of virulent phosgene as the carbonylation reagent,swep was obtained directly for the first time by one-pot selenium-catalyzed oxidative carbonylation of 3,4-dichloroaniline with methanol. The effects of reaction pressure,molar ratio of 3,4-dichloroaniline to methanol,content of selenium,solvent,reaction time,reaction temperature and co-catalyst on the reaction were investigated. The optimal reaction conditions for preparing the target product swep with a yield of 67% are as followings when the reaction is conducted in a 100 mL autoclave:the reaction pressure is 3 MPa(n(CO):n(O2)=9:1),contents of 3,4-dichloroaniline,methanol,selenium,ethyl acetate and triethylamine are 5 mmol,75 mmol,0.25 mmol,10 mL and 10 mmol,respectively,the reaction time is 5 h,and the reaction temperature is 130℃. This method has the merits of short synthetic route,green approach and easy operation.
A green and facile approach to swep is reported in this paper. With cheap,easily available and recyclable nonmetal selenium as the catalyst and CO instead of virulent phosgene as the carbonylation reagent,swep was obtained directly for the first time by one-pot selenium-catalyzed oxidative carbonylation of 3,4-dichloroaniline with methanol. The effects of reaction pressure,molar ratio of 3,4-dichloroaniline to methanol,content of selenium,solvent,reaction time,reaction temperature and co-catalyst on the reaction were investigated. The optimal reaction conditions for preparing the target product swep with a yield of 67% are as followings when the reaction is conducted in a 100 mL autoclave:the reaction pressure is 3 MPa(n(CO):n(O2)=9:1),contents of 3,4-dichloroaniline,methanol,selenium,ethyl acetate and triethylamine are 5 mmol,75 mmol,0.25 mmol,10 mL and 10 mmol,respectively,the reaction time is 5 h,and the reaction temperature is 130℃. This method has the merits of short synthetic route,green approach and easy operation.
2014, 31(8): 952-957
doi: 10.3724/SP.J.1095.2014.30510
Abstract:
A series of oxovanadium 1,3,5-benzenetricarboxylate complex catalysts was prepared and characterized by FT-IR,diffuse reflectance UV-Vis(DR UV-Vis) and TG,respectively. The effects of catalyst,promoter such as ionic liquid,ionic liquid amount and reaction time on the oxidation of isoeugenol to vanillin were investigated systematically. VO(BTC)-1 with a molar ratio of VO2+ and BTC(1,3,5-benzenetricarboxylate) as 1:1 exhibits better catalytic performance. Complete conversion of isoeugenol and 87.c% yield of vanillin are achieved using VO(BTC)-1 as catalyst,1-dodecyl-3-methylimidazolium chloride([C12mim]Cl) as additive with the molar ratio of isoeugenol,H2O2 and [C12mim]Cl as 1:2:0.01 after 24 h reaction at 20℃ in acetone. The formation of a highly effective oxidation system from [C12mim]Cl/VO(BTC)-1 and H2O2 is beneficial in the mild conversion of isoeugenol,as indicated by spectral characterization and the reaction results.
A series of oxovanadium 1,3,5-benzenetricarboxylate complex catalysts was prepared and characterized by FT-IR,diffuse reflectance UV-Vis(DR UV-Vis) and TG,respectively. The effects of catalyst,promoter such as ionic liquid,ionic liquid amount and reaction time on the oxidation of isoeugenol to vanillin were investigated systematically. VO(BTC)-1 with a molar ratio of VO2+ and BTC(1,3,5-benzenetricarboxylate) as 1:1 exhibits better catalytic performance. Complete conversion of isoeugenol and 87.c% yield of vanillin are achieved using VO(BTC)-1 as catalyst,1-dodecyl-3-methylimidazolium chloride([C12mim]Cl) as additive with the molar ratio of isoeugenol,H2O2 and [C12mim]Cl as 1:2:0.01 after 24 h reaction at 20℃ in acetone. The formation of a highly effective oxidation system from [C12mim]Cl/VO(BTC)-1 and H2O2 is beneficial in the mild conversion of isoeugenol,as indicated by spectral characterization and the reaction results.
2014, 31(8): 958-964
doi: 10.3724/SP.J.1095.2014.30534
Abstract:
Several triethylamine(TEA) salts of heteropolyacids were synthesized by acid-base reaction using Keggin-type heteropolyacids and TEA as raw materials. These salts were used to catalyze the oxidation of benzyl alcohol to benzaldehyde in water with 30% aqueous hydrogen peroxide as oxidant without employment of phase transfer catalyst with long chain. These salts possess higher catalytic activities or selectivities than the corresponding acids.[TEAH]H2PW12O40 exhibits the best performance of all catalysts. Under the optimum reaction conditions,the conversion of benzyl alcohol and the selectivity of benzaldehyde is over 99.5% and ~100%,respectively,over [TEAH]H2PW12O40. After the reaction,the catalyst can be isolated and used for next oxidation cycle,and the activity and selectivity are maintained in recycle. In view of the fact that water is used as reaction medium instead of organic solvent,this system is effective and green for selective oxidation of benzyl alcohol.
Several triethylamine(TEA) salts of heteropolyacids were synthesized by acid-base reaction using Keggin-type heteropolyacids and TEA as raw materials. These salts were used to catalyze the oxidation of benzyl alcohol to benzaldehyde in water with 30% aqueous hydrogen peroxide as oxidant without employment of phase transfer catalyst with long chain. These salts possess higher catalytic activities or selectivities than the corresponding acids.[TEAH]H2PW12O40 exhibits the best performance of all catalysts. Under the optimum reaction conditions,the conversion of benzyl alcohol and the selectivity of benzaldehyde is over 99.5% and ~100%,respectively,over [TEAH]H2PW12O40. After the reaction,the catalyst can be isolated and used for next oxidation cycle,and the activity and selectivity are maintained in recycle. In view of the fact that water is used as reaction medium instead of organic solvent,this system is effective and green for selective oxidation of benzyl alcohol.
2014, 31(8): 965-970
doi: 10.3724/SP.J.1095.2014.30533
Abstract:
A solid photocatalyst of Keggin-type Cr(Ⅲ) substituted heteropolytungstates immobilized on the surface of alkalescent anionic exchange resin D301R(PW11Cr/D301R) was prepared. Its visible light photocatalytic activity was assessed through the degradation of a model pollutant rhodamine B(RhB). The photocatalysis mechanism was discussed and influences of the PW11Cr/D301R dosage,the solution pH and the common anions existing in solution on the photocatalytic degradation rate of RhB were also examined. The time required to achieve a complete degradation of RhB is only 30 min in the presence of 100 mg PW11Cr/D301R when a solution containing 10 μmol/L RhB is exposed to irradiation of the 200 W metal halide lamp. This process is three times faster than that in the PW11Cr homogeneous system. Approximate 84% of the total organic carbon(TOC) removal is reached at 180 min. The PW11Cr/D301R dosage,the solution pH,and existing anion such as Cl-,SO42- or PO43- all have an obvious influence on the photocatalytic degradation rate of RhB. There is no obvious lost of photocatalytic activity of PW11Cr/D301R after seven repetitive uses.
A solid photocatalyst of Keggin-type Cr(Ⅲ) substituted heteropolytungstates immobilized on the surface of alkalescent anionic exchange resin D301R(PW11Cr/D301R) was prepared. Its visible light photocatalytic activity was assessed through the degradation of a model pollutant rhodamine B(RhB). The photocatalysis mechanism was discussed and influences of the PW11Cr/D301R dosage,the solution pH and the common anions existing in solution on the photocatalytic degradation rate of RhB were also examined. The time required to achieve a complete degradation of RhB is only 30 min in the presence of 100 mg PW11Cr/D301R when a solution containing 10 μmol/L RhB is exposed to irradiation of the 200 W metal halide lamp. This process is three times faster than that in the PW11Cr homogeneous system. Approximate 84% of the total organic carbon(TOC) removal is reached at 180 min. The PW11Cr/D301R dosage,the solution pH,and existing anion such as Cl-,SO42- or PO43- all have an obvious influence on the photocatalytic degradation rate of RhB. There is no obvious lost of photocatalytic activity of PW11Cr/D301R after seven repetitive uses.
2014, 31(8): 971-976
doi: 10.3724/SP.J.1095.2014.30453
Abstract:
In conventional azeotropic distillation process,surface modifiers such as stearic acid(St),zinc stearate(ZnSt) and rare earth coupling agent(WOT) were firstly introduced to realize simultaneous drying and surface modification of Mg(OH)2 nanoparticles(NPs). The structure,morphologies and properties of surfacemodified Mg(OH)2 NPs were characterized by XRD,TEM,FT-IR,TG,CAM(contact angle measurement). The results indicate that surface modifiers not only react with the exterior hydroxyls of Mg(OH) 2 NPs to form surface modified layer via chemical bond to weaken the possibility of hard agglomeration,but also change the surface character of Mg(OH) 2 NPs from hydrophilicity to hydrophobicity. In addition,the surface modification mechanism in azeotropic distillation was also discussed. This study provides a novel surface modified route for other nanoparticles.
In conventional azeotropic distillation process,surface modifiers such as stearic acid(St),zinc stearate(ZnSt) and rare earth coupling agent(WOT) were firstly introduced to realize simultaneous drying and surface modification of Mg(OH)2 nanoparticles(NPs). The structure,morphologies and properties of surfacemodified Mg(OH)2 NPs were characterized by XRD,TEM,FT-IR,TG,CAM(contact angle measurement). The results indicate that surface modifiers not only react with the exterior hydroxyls of Mg(OH) 2 NPs to form surface modified layer via chemical bond to weaken the possibility of hard agglomeration,but also change the surface character of Mg(OH) 2 NPs from hydrophilicity to hydrophobicity. In addition,the surface modification mechanism in azeotropic distillation was also discussed. This study provides a novel surface modified route for other nanoparticles.
2014, 31(8): 977-982
doi: 10.3724/SP.J.1095.2014.30518
Abstract:
ZnO-MnO2-MOF(metalloriganic frameworks) nanocomposite array electrode was fabricated by multi-step chronopotentiometry and standing without disturbance,in which zinc nitrate,manganese nitrate and hexamethylenetetramine were the raw materials. The morphology and structure of the composite were investigated by scanning electron microscopy,transmission electron microscope,X-ray photoelectron spectroscopy,and X-ray diffraction,respectively. The electrochemical properties of the electrode were studied by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance spectroscopy in 0.5 mol/L sodium sulfate. The results show that,in comparison with ZnO-MnO2 composite(Csp=121 F/g,j=2.5 A/g),ZnO-MnO2-MOF nanocomposite array electrode shows a lower internal resistance,a higher reversible Faradic reaction,and a better rate performance owing to synergistic effects between MnO2 and MOF,and its specific capacitance(Csp=146 F/g,j=2.5 A/g) is 20% higher than that of the ZnO-MnO2 composite.
ZnO-MnO2-MOF(metalloriganic frameworks) nanocomposite array electrode was fabricated by multi-step chronopotentiometry and standing without disturbance,in which zinc nitrate,manganese nitrate and hexamethylenetetramine were the raw materials. The morphology and structure of the composite were investigated by scanning electron microscopy,transmission electron microscope,X-ray photoelectron spectroscopy,and X-ray diffraction,respectively. The electrochemical properties of the electrode were studied by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance spectroscopy in 0.5 mol/L sodium sulfate. The results show that,in comparison with ZnO-MnO2 composite(Csp=121 F/g,j=2.5 A/g),ZnO-MnO2-MOF nanocomposite array electrode shows a lower internal resistance,a higher reversible Faradic reaction,and a better rate performance owing to synergistic effects between MnO2 and MOF,and its specific capacitance(Csp=146 F/g,j=2.5 A/g) is 20% higher than that of the ZnO-MnO2 composite.
2014, 31(8): 983-989
doi: 10.3724/SP.J.1095.2014.30469
Abstract:
An electrochemical sensor for simultaneous determination of catechol(CC) and hydroquinone(HQ) based on carbon nanotubes(CNTs)-graphene nanosheet(GNS) hybrid film modified gold electrode(GE) was prepared. The electrochemical behavior of CC and HQ at the CNTs-GNS modified GE was investigated by cyclic voltammetry(CV). The results showed that the electrocatalytic activity of CC and HQ was significantly enhanced by the modification of CNTs-GNS hybrid films. The electrochemical sensor based on the hybrid modified GE exhibited excellent analytical performance for CC and HQ detection with a low detection limit of 5 nmol/L and 4.8 nmol/L(S/N=3),respectively,and a wide linear range of 0.5~600 μmol/L for both CC and HQ. Moreover,the CNTs-GNS/GE also showed good selectivity and stability.
An electrochemical sensor for simultaneous determination of catechol(CC) and hydroquinone(HQ) based on carbon nanotubes(CNTs)-graphene nanosheet(GNS) hybrid film modified gold electrode(GE) was prepared. The electrochemical behavior of CC and HQ at the CNTs-GNS modified GE was investigated by cyclic voltammetry(CV). The results showed that the electrocatalytic activity of CC and HQ was significantly enhanced by the modification of CNTs-GNS hybrid films. The electrochemical sensor based on the hybrid modified GE exhibited excellent analytical performance for CC and HQ detection with a low detection limit of 5 nmol/L and 4.8 nmol/L(S/N=3),respectively,and a wide linear range of 0.5~600 μmol/L for both CC and HQ. Moreover,the CNTs-GNS/GE also showed good selectivity and stability.
2014, 31(8): 990-992
doi: 10.3724/SP.J.1095.2014.30587
Abstract:
The composite nickel phosphotungstate(NiPW)-HZSM-5 catalyst was prepared by the impregnating technique on nanocrystalline HZSM-5 zeolite. The catalysts were characterized by in-situ electron paramagnetic resonance and in-situ pyridine adsorption Fourier-transform infrared. The results show that the deep hydrodesulfurization of fluid catalytic cracking(FCC) gasoline are enhanced over the NiPW-HZSM-5 catalyst. Heteropoly acid(HPW(Ⅲ))-Ni(Ⅱ) on the nanocrystalline HZSM-5 zeolite is the active center of deep hydrodesulfurization of FCC gasoline. The effect of the acidity on the activity over different catalysts in deep hydrodesulfurization of FCC gasoline was investigated.
The composite nickel phosphotungstate(NiPW)-HZSM-5 catalyst was prepared by the impregnating technique on nanocrystalline HZSM-5 zeolite. The catalysts were characterized by in-situ electron paramagnetic resonance and in-situ pyridine adsorption Fourier-transform infrared. The results show that the deep hydrodesulfurization of fluid catalytic cracking(FCC) gasoline are enhanced over the NiPW-HZSM-5 catalyst. Heteropoly acid(HPW(Ⅲ))-Ni(Ⅱ) on the nanocrystalline HZSM-5 zeolite is the active center of deep hydrodesulfurization of FCC gasoline. The effect of the acidity on the activity over different catalysts in deep hydrodesulfurization of FCC gasoline was investigated.
