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2006 Volume 23 Issue 9
2006, 23(9): 945-948
Abstract:
The ordered double perovskites SrLaMnBO6(B: Mo,W) were prepared by sol-gel reaction.The XRD results suggest that the crystal structure of SrLaMnMoO6 belongs to the monoclinic P21/n space group and that of SrLaMnWO6 belongs to the tetragonal I4/m space group.The competition between band filling effect and steric effect results in the expansion of cell volume for SrLaMnBO6(B: Mo,W).Magnetic measurements indicated that both samples showed very weak ferro-/ferrimagntism,but the magnetic moments at H=0 extrapolated from the magnetic moment vs applied magnetic field curves are 0.72μB and 0.16μB for SrLaMnMoO6 and SrLaMnWO6,respectively,much smaller than the expected net magnetic moments.From the temperature dependence of magnetization for SrLaMnMoO6,ferromagnetic-paramagnetic transition is observed,which is not shown for SrLaMnWO6.
The ordered double perovskites SrLaMnBO6(B: Mo,W) were prepared by sol-gel reaction.The XRD results suggest that the crystal structure of SrLaMnMoO6 belongs to the monoclinic P21/n space group and that of SrLaMnWO6 belongs to the tetragonal I4/m space group.The competition between band filling effect and steric effect results in the expansion of cell volume for SrLaMnBO6(B: Mo,W).Magnetic measurements indicated that both samples showed very weak ferro-/ferrimagntism,but the magnetic moments at H=0 extrapolated from the magnetic moment vs applied magnetic field curves are 0.72μB and 0.16μB for SrLaMnMoO6 and SrLaMnWO6,respectively,much smaller than the expected net magnetic moments.From the temperature dependence of magnetization for SrLaMnMoO6,ferromagnetic-paramagnetic transition is observed,which is not shown for SrLaMnWO6.
2006, 23(9): 949-952
Abstract:
Hydrilla verticillata(L. f.) Royle is a perennial submerged macrophyte.It plays an important role in the phytoremediation of eutrophic lake.In order to develop effective approach for the utilization of submerged macrophyte,the chemical composition of Hydrilla verticillata(L. f.) Royle was analyzed with sequential solvent extraction and separation on silica gel column.Two compounds were first isolated from the ethyl acetate extract of the plant.They were identified as 6-hydroxy-stigmast-4-en-3-one and octadecanoic acid on the basis of spectroscopic analyses with IR,MS,1H NMR and 13C NMR.6-hydroxy-stigmast-4-en-3-one belongs to the family of steroids in which most of the members found in plants have biological activities.The biological activities of 6-hydroxy-stigmast-4-en-3-one have not been found in literatures.Further work on its biological activity test needs to be carried out.Octadecanoic acid and its derivatives can ben used as pharmaceutical material for moisturizing the intestine and inducing lax.The results have provided a new approach for the utility of Hydrilla verticillata(L. f.) Royle.
Hydrilla verticillata(L. f.) Royle is a perennial submerged macrophyte.It plays an important role in the phytoremediation of eutrophic lake.In order to develop effective approach for the utilization of submerged macrophyte,the chemical composition of Hydrilla verticillata(L. f.) Royle was analyzed with sequential solvent extraction and separation on silica gel column.Two compounds were first isolated from the ethyl acetate extract of the plant.They were identified as 6-hydroxy-stigmast-4-en-3-one and octadecanoic acid on the basis of spectroscopic analyses with IR,MS,1H NMR and 13C NMR.6-hydroxy-stigmast-4-en-3-one belongs to the family of steroids in which most of the members found in plants have biological activities.The biological activities of 6-hydroxy-stigmast-4-en-3-one have not been found in literatures.Further work on its biological activity test needs to be carried out.Octadecanoic acid and its derivatives can ben used as pharmaceutical material for moisturizing the intestine and inducing lax.The results have provided a new approach for the utility of Hydrilla verticillata(L. f.) Royle.
2006, 23(9): 953-956
Abstract:
A new tetrathiafulvalene(TTF) modified silver colloid was prepared and characterized by means of TEM,IR,UV-Vis,Raman,and cyclic voltammogram.The surface of the silver nanoparticles was coordinated with 3,4-ethylenedisulfanyl-TTF thiolate.The TTF-modified Ag nanoparticles about 70 nm were monodispersed.Cyclic voltammogram of the TTF-Ag nanoparticles on a Pt electrode showed that it was a redox active nano-system.Two pairs of quasi-reversible redox waves appeared at E1/2=+0.67 V and E1/2=+0.86 V,corresponding to TTF/TTF·+ and TTF·+/TTF2+,respectively.
A new tetrathiafulvalene(TTF) modified silver colloid was prepared and characterized by means of TEM,IR,UV-Vis,Raman,and cyclic voltammogram.The surface of the silver nanoparticles was coordinated with 3,4-ethylenedisulfanyl-TTF thiolate.The TTF-modified Ag nanoparticles about 70 nm were monodispersed.Cyclic voltammogram of the TTF-Ag nanoparticles on a Pt electrode showed that it was a redox active nano-system.Two pairs of quasi-reversible redox waves appeared at E1/2=+0.67 V and E1/2=+0.86 V,corresponding to TTF/TTF·+ and TTF·+/TTF2+,respectively.
2006, 23(9): 957-960
Abstract:
The binding reaction between enrofloxacin(EFLX) and bovine serum albumin(BSA) in an aqueous solution of methanol was studied by means of fluorescence and UV-Vis.The results indicate that the association constant(KA) is 4.16×105 L/mol,and they reacted in a molar ratio of 1:1 with a binding distance r=4.40 nm.The Stern-Volmer curve illustrates that the combination reaction of EFLX and BSA is a static quenching process.
The binding reaction between enrofloxacin(EFLX) and bovine serum albumin(BSA) in an aqueous solution of methanol was studied by means of fluorescence and UV-Vis.The results indicate that the association constant(KA) is 4.16×105 L/mol,and they reacted in a molar ratio of 1:1 with a binding distance r=4.40 nm.The Stern-Volmer curve illustrates that the combination reaction of EFLX and BSA is a static quenching process.
2006, 23(9): 961-964
Abstract:
Deuteroheminchloride(4),3,8-[2,7,12,18-tetramethal-21H,23H-porphyrin-13,17-diyl]-dipropionyloxy-dimethylester(5) and [3,17-bis(-2-methoxy-carbonylethyl)-2,7,12,18-tetramethyl-porphyrinato]-Cu(Ⅱ)(6) were synthesized.The effects of the amount of resorcin on the yield of compound 4 were studied and the results indicated that the best yield could reach to 95.7% at n(resiorcin):n(hemin)=25:1.The effects of the operation modes of extraction on the yield of compound 5 were studied and the results showed that the yield could be improved to 85% in a system of 200 mL of dichloromethane,100 mL of 10%ammnia and 100 mL of water.The effects of the cupric reagents on the yield of compound 6 were also studied and the results showed that the best yield was nearly to 100% when cupric nitrate was used.The structures of compound 5 and compound 6 were confirmed by mp,TCL,IR,MS,and 1H NMR.
Deuteroheminchloride(4),3,8-[2,7,12,18-tetramethal-21H,23H-porphyrin-13,17-diyl]-dipropionyloxy-dimethylester(5) and [3,17-bis(-2-methoxy-carbonylethyl)-2,7,12,18-tetramethyl-porphyrinato]-Cu(Ⅱ)(6) were synthesized.The effects of the amount of resorcin on the yield of compound 4 were studied and the results indicated that the best yield could reach to 95.7% at n(resiorcin):n(hemin)=25:1.The effects of the operation modes of extraction on the yield of compound 5 were studied and the results showed that the yield could be improved to 85% in a system of 200 mL of dichloromethane,100 mL of 10%ammnia and 100 mL of water.The effects of the cupric reagents on the yield of compound 6 were also studied and the results showed that the best yield was nearly to 100% when cupric nitrate was used.The structures of compound 5 and compound 6 were confirmed by mp,TCL,IR,MS,and 1H NMR.
2006, 23(9): 965-969
Abstract:
The block copolymers of poly(γ-benzyl L-glutamate) and poly (ethylene glycol)(PBLG-PEG-PBLG,GEG) were prepared via ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride initiated by amine-terminated PEG(AT-PEG).The copolymer structure was characterized by GPC,IR and1H NMR.CHO cells were incubated on the polymer surfaces for 24 h by direct contact method,and then observed via photo electron microscope and SEM.The results demonstrate that GEG could be obtained with AT-PEG as initiator and all the polymers were nontoxic to CHO cells.The SEM results show that the adhesion and proliferation of the cells were better on some of the copolymers than on PBLG.When the molecular weight of PEG was 2 000 dalton,and the molar ratio of EG monomer was 59% of the total monomer in the block copolymer,the cells could not adhere to the copolymer surfaces.Controlling the content of PEG in the copolymer could adjust the adhesion and proliferation of the cells on copolymer surfaces.
The block copolymers of poly(γ-benzyl L-glutamate) and poly (ethylene glycol)(PBLG-PEG-PBLG,GEG) were prepared via ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride initiated by amine-terminated PEG(AT-PEG).The copolymer structure was characterized by GPC,IR and1H NMR.CHO cells were incubated on the polymer surfaces for 24 h by direct contact method,and then observed via photo electron microscope and SEM.The results demonstrate that GEG could be obtained with AT-PEG as initiator and all the polymers were nontoxic to CHO cells.The SEM results show that the adhesion and proliferation of the cells were better on some of the copolymers than on PBLG.When the molecular weight of PEG was 2 000 dalton,and the molar ratio of EG monomer was 59% of the total monomer in the block copolymer,the cells could not adhere to the copolymer surfaces.Controlling the content of PEG in the copolymer could adjust the adhesion and proliferation of the cells on copolymer surfaces.
2006, 23(9): 970-973
Abstract:
The dendritic polymer(PAMAM)/hydroxyapatite composite coatings were deposited on titanium electrode by means of the double potential step technique.The morphologies of coatings were investigated by SEM.The results show that the PAMAM quality affects the morphology and size of the coatings.The bioactivities of PAMAM/HA coatings were tested in simulated body fluid(SBF),and good bioactivity was observed.The corrosion properties and the superior toughness and strength of the coating were also investigated.
The dendritic polymer(PAMAM)/hydroxyapatite composite coatings were deposited on titanium electrode by means of the double potential step technique.The morphologies of coatings were investigated by SEM.The results show that the PAMAM quality affects the morphology and size of the coatings.The bioactivities of PAMAM/HA coatings were tested in simulated body fluid(SBF),and good bioactivity was observed.The corrosion properties and the superior toughness and strength of the coating were also investigated.
2006, 23(9): 974-977
Abstract:
The physicochemical properties of Radix Pueraria thomsonii starch were investigated and compared with that of potato starch.The results show that Radix Pueraria thomsonii starch contains an apparent amylose content of 35.7%,much higher than that of potato starch(23.6%),and has a granule size between 5~20 μm with round,and polygonal shapes.Radix Pueraria thomsonii starch shows a strong 2θ intensity at 15°,17° and 23°,and medium intensity at 22°.It displays A type X-ray diffraction pattern,different from that of potato.The peak and cold viscosity of Radix Pueraria thomsonii starch were higher than the corresponding ones of potato starch.Radix Pueraria thomsonii starch also has lower breakdown and higher setback.It's pasting temperature is 75℃,higher than the one determined for potato starch,64.3℃.At 25℃,4% Radix Pueraria thomsonii and potato starch pastes both behaved as pseudoplastic characteristics.The flow index of Radix Pueraria thomsonii and potato starch pastes were 0.62 and 0.52.The shear stress and apparent viscosity of Radix Pueraria thomsonii starch pastes were lower than the corresponding ones of potato starch pastes at low shear rate,but were higher at high shear rate,showing higher resistance to shear-thinning.
The physicochemical properties of Radix Pueraria thomsonii starch were investigated and compared with that of potato starch.The results show that Radix Pueraria thomsonii starch contains an apparent amylose content of 35.7%,much higher than that of potato starch(23.6%),and has a granule size between 5~20 μm with round,and polygonal shapes.Radix Pueraria thomsonii starch shows a strong 2θ intensity at 15°,17° and 23°,and medium intensity at 22°.It displays A type X-ray diffraction pattern,different from that of potato.The peak and cold viscosity of Radix Pueraria thomsonii starch were higher than the corresponding ones of potato starch.Radix Pueraria thomsonii starch also has lower breakdown and higher setback.It's pasting temperature is 75℃,higher than the one determined for potato starch,64.3℃.At 25℃,4% Radix Pueraria thomsonii and potato starch pastes both behaved as pseudoplastic characteristics.The flow index of Radix Pueraria thomsonii and potato starch pastes were 0.62 and 0.52.The shear stress and apparent viscosity of Radix Pueraria thomsonii starch pastes were lower than the corresponding ones of potato starch pastes at low shear rate,but were higher at high shear rate,showing higher resistance to shear-thinning.
2006, 23(9): 978-981
Abstract:
The effect of nano-Al2O3 doping on the grain boundary(GB) conductivity of polycrystalline Ce0.8Y0.2O2-δ was investigated.It was found that the addition of Al2O3 leads to a decrease in GB activation energy,and an increase in the GB conductivity at low and moderate temperatures obviously.The results indicate that the effect is attributed to the improvement of oxygen-ion migration structure in the grain boundary due to the doping of Al2O3.
The effect of nano-Al2O3 doping on the grain boundary(GB) conductivity of polycrystalline Ce0.8Y0.2O2-δ was investigated.It was found that the addition of Al2O3 leads to a decrease in GB activation energy,and an increase in the GB conductivity at low and moderate temperatures obviously.The results indicate that the effect is attributed to the improvement of oxygen-ion migration structure in the grain boundary due to the doping of Al2O3.
2006, 23(9): 982-987
Abstract:
A new reductive protocol of desulfurization was developed to desulfurate benzothiophene with KBH4 as reductant.Experimentally,the appropriate masses of CoCl2·6H2O and KBH4 were 0.50 g and 0.40 g, respectively;the volume of CH3OH was 20 mL,and the sulfur was reduced from 1.420×10-3 g/g to 1.75×10-4 g/g,the desulfurization percentage was 88%;the reaction time was 20 min;and temperature should be controled under 15℃;the sulfur obtained by desulfurating benzothiophene was retained in active cobalt boride formed during the reaction.The proposed mechanism is that the reduction reaction occurred between CoCl2·6H2O and the reductant in protic solvent,then black cobalt boride and H2 were formed;the hydrogenation desulfurization mechanism was deduced according the product distribution,and the reduction of benzothiophene was carried out through both the hydrogenation and direct hydrogenolysis routes;the substantive nascent hydrogen was absorbed and activated on the surface of the active solid,and was further transformed into transient intermediates,which attack the unsaturated bonds of benzothiophene and then led to the cleavage of C-S or C-C bond.
A new reductive protocol of desulfurization was developed to desulfurate benzothiophene with KBH4 as reductant.Experimentally,the appropriate masses of CoCl2·6H2O and KBH4 were 0.50 g and 0.40 g, respectively;the volume of CH3OH was 20 mL,and the sulfur was reduced from 1.420×10-3 g/g to 1.75×10-4 g/g,the desulfurization percentage was 88%;the reaction time was 20 min;and temperature should be controled under 15℃;the sulfur obtained by desulfurating benzothiophene was retained in active cobalt boride formed during the reaction.The proposed mechanism is that the reduction reaction occurred between CoCl2·6H2O and the reductant in protic solvent,then black cobalt boride and H2 were formed;the hydrogenation desulfurization mechanism was deduced according the product distribution,and the reduction of benzothiophene was carried out through both the hydrogenation and direct hydrogenolysis routes;the substantive nascent hydrogen was absorbed and activated on the surface of the active solid,and was further transformed into transient intermediates,which attack the unsaturated bonds of benzothiophene and then led to the cleavage of C-S or C-C bond.
2006, 23(9): 988-991
Abstract:
Amphoteric polyacrylamide emulsion,which has an intrinsic viscosity up to 26.7 dL/g,was synthesized by inverse emulsion copolymerization,with latex particle size of 0.6~8 μm based on SEM.By means of FTIR measurement,it is demonstrated that the synthesized amphoteric polyacrylamide is composed of chain units of acrylamide(AM),sodium acrylate(NaAA),and acryloyloxyethyl trimethylammonium chloride (DAC).The effects of DAC/NaAA feeding ratio,polymer intrinsic viscosity and dosage on the flocculability of bauxite red mud were studied.The amphoteric polyacrylamide emulsion is quickly dissolved in water,and the flocculating efficiency of it to the bauxite red mud is obvious.When the mass percent of the APPAME was 0.005%,the precipitating time was only 3 min,with the deposited thinkness less than 40%,and the transmittance of fall-off liquid could reach 65%. Synergetic effect of electrostatic interaction and adsorption-bridging action between amphoteric polyacrylamide and slurry particles can further improve flocculating efficiency.
Amphoteric polyacrylamide emulsion,which has an intrinsic viscosity up to 26.7 dL/g,was synthesized by inverse emulsion copolymerization,with latex particle size of 0.6~8 μm based on SEM.By means of FTIR measurement,it is demonstrated that the synthesized amphoteric polyacrylamide is composed of chain units of acrylamide(AM),sodium acrylate(NaAA),and acryloyloxyethyl trimethylammonium chloride (DAC).The effects of DAC/NaAA feeding ratio,polymer intrinsic viscosity and dosage on the flocculability of bauxite red mud were studied.The amphoteric polyacrylamide emulsion is quickly dissolved in water,and the flocculating efficiency of it to the bauxite red mud is obvious.When the mass percent of the APPAME was 0.005%,the precipitating time was only 3 min,with the deposited thinkness less than 40%,and the transmittance of fall-off liquid could reach 65%. Synergetic effect of electrostatic interaction and adsorption-bridging action between amphoteric polyacrylamide and slurry particles can further improve flocculating efficiency.
2006, 23(9): 992-995
Abstract:
Ethyl(S)-2-ethoxy-3-(4-hydroxyphenyl)propionate(1) was prepared via a racemic synthetic route.Ethyl 2-chloride-2-ethoxyacetate(3) was synthesized from ethyl 2,2-diethoxyacetate(2) in a yield of 93%,which reacted with triethyl phosphate to give triethyl phosphonocetate(4) in a yield of 95%.Compound 4 was condensed with 4-benzyloxybenzaldehyd by Horner Wadswordth Emmons reaction to produce ethyl(Z,E)-2-ethoxy-3-(4-benzyloxy phenyl)propenonate(5) in a yield of 94%,which was hydrogenated to give ethyl(R,S)-2-ethoxy-3-(4-hydroxyphenyl) propionate(6) in a yield of 98%.The corresponding carboxylic acid(7) was obtained by the hydrolysis of compound 6 under basic conditions in a yield of 96%.Chemical resolution of compound 7 with chiral amine R-(α)-methyl benzamethanamine produced compound 8.The esterification of compound 8 produced product 1,and its yield and ee value were 95% and 98.3%,respectively.
Ethyl(S)-2-ethoxy-3-(4-hydroxyphenyl)propionate(1) was prepared via a racemic synthetic route.Ethyl 2-chloride-2-ethoxyacetate(3) was synthesized from ethyl 2,2-diethoxyacetate(2) in a yield of 93%,which reacted with triethyl phosphate to give triethyl phosphonocetate(4) in a yield of 95%.Compound 4 was condensed with 4-benzyloxybenzaldehyd by Horner Wadswordth Emmons reaction to produce ethyl(Z,E)-2-ethoxy-3-(4-benzyloxy phenyl)propenonate(5) in a yield of 94%,which was hydrogenated to give ethyl(R,S)-2-ethoxy-3-(4-hydroxyphenyl) propionate(6) in a yield of 98%.The corresponding carboxylic acid(7) was obtained by the hydrolysis of compound 6 under basic conditions in a yield of 96%.Chemical resolution of compound 7 with chiral amine R-(α)-methyl benzamethanamine produced compound 8.The esterification of compound 8 produced product 1,and its yield and ee value were 95% and 98.3%,respectively.
2006, 23(9): 996-999
Abstract:
Four new cinnamic amides(T1~T4) were synthesized,and their inhibitory activities for α-glucosidase were assayed in vitro.All compounds display inhibitory activities against α-glucosidase.The α-glucosidase inhibitory ratios of compound T2(88.13%) and T3(90.41%) are higher than that of control drug acarbose(87.25%) at a concentration of 0.01×10-3 g/mL.
Four new cinnamic amides(T1~T4) were synthesized,and their inhibitory activities for α-glucosidase were assayed in vitro.All compounds display inhibitory activities against α-glucosidase.The α-glucosidase inhibitory ratios of compound T2(88.13%) and T3(90.41%) are higher than that of control drug acarbose(87.25%) at a concentration of 0.01×10-3 g/mL.
2006, 23(9): 1000-1005
Abstract:
A Waugh type polyoxometalate H12[MnMo9O32(KO)6] was synthesized and structurally characterized by means of single crystal X-ray diffraction,IR,XRD and TG.The compound crystallized in the trigonal system with space group R3,a=15.538 0(6) nm,b=15.538 0(6) nm,c=12.377 7(5) nm,α=90°,β=90°,γ=120°,V=2 587.98(18) nm3,Z=3,R1=0.013 4,ωR2=0.030 8.The catalytic activity of the title compound for the dehydration of cyclohexanol was studied.The conversion of C6H11OH reached to 69.6 % and the selectivity of C6H10 was 96% when the amount of catalyst,temperature range and reaction time were 6.6%,170~180℃,30 min,respectively.
A Waugh type polyoxometalate H12[MnMo9O32(KO)6] was synthesized and structurally characterized by means of single crystal X-ray diffraction,IR,XRD and TG.The compound crystallized in the trigonal system with space group R3,a=15.538 0(6) nm,b=15.538 0(6) nm,c=12.377 7(5) nm,α=90°,β=90°,γ=120°,V=2 587.98(18) nm3,Z=3,R1=0.013 4,ωR2=0.030 8.The catalytic activity of the title compound for the dehydration of cyclohexanol was studied.The conversion of C6H11OH reached to 69.6 % and the selectivity of C6H10 was 96% when the amount of catalyst,temperature range and reaction time were 6.6%,170~180℃,30 min,respectively.
2006, 23(9): 1006-1009
Abstract:
A method for simultaneous determination of zinc,cadmium and lead by potential stripping analysis(PSA) using solid silver amalgam electrode(Ag-SAE) is described.The above mentioned cations were electrochemically accumulated for 60 s at-1.30 V(vs.SCE) in a HAc-NaAc(pH=5) buffer solution.Then the concentrated metals were stripped by PSA with the peaks appeared at -0.96 V for zinc, -0.66 V for cadmium and -0.49 V(vs.SCE) for lead respectively with the oxygen in the solution as the oxidant.The peak current linearly changed with the ion concentration in the range of 0~200 μg/L for Zn2+ and 0~100 μg/L for Cd2+ and Pb2+ respectively.The detection limits were 0.54 μg/L for Zn2+,0.30 μg/L for Cd2+ and 0.22 μg/L for Pb2+.The method has been applied to the determination of trace level of zinc, cadmium and lead in ground-water samples with satisfactory results.
A method for simultaneous determination of zinc,cadmium and lead by potential stripping analysis(PSA) using solid silver amalgam electrode(Ag-SAE) is described.The above mentioned cations were electrochemically accumulated for 60 s at-1.30 V(vs.SCE) in a HAc-NaAc(pH=5) buffer solution.Then the concentrated metals were stripped by PSA with the peaks appeared at -0.96 V for zinc, -0.66 V for cadmium and -0.49 V(vs.SCE) for lead respectively with the oxygen in the solution as the oxidant.The peak current linearly changed with the ion concentration in the range of 0~200 μg/L for Zn2+ and 0~100 μg/L for Cd2+ and Pb2+ respectively.The detection limits were 0.54 μg/L for Zn2+,0.30 μg/L for Cd2+ and 0.22 μg/L for Pb2+.The method has been applied to the determination of trace level of zinc, cadmium and lead in ground-water samples with satisfactory results.
2006, 23(9): 1010-1013
Abstract:
Starch acetates(SA) with different degrees of substitution were synthesized by reaction of corn starch and acetic acid/acetic anhydride catalyzed with concentrated.H2SO4.By means of FTIR,SEM,DSC,TGA and XRD,we studied the microstructure,particle shape,meltage temperature,decomposition temperature and crystal degree,and gained better understanding about influences of different degrees of substitution on microstructure and thermal property of starch acetates.With concentrated sulfuric acid as catalyst instead of methyl sulfuric acid,optimal reaction conditions are: refluxing temperature is in the range of 75~80℃, reaction time is 3 h with 0.38 mL of concentrate sulfuric acid.With the increasing of degree of substitution,the crystallinity of the starch acetate decreased from 37.95% to 0,Td increased from 327.32℃ to 381.35℃.
Starch acetates(SA) with different degrees of substitution were synthesized by reaction of corn starch and acetic acid/acetic anhydride catalyzed with concentrated.H2SO4.By means of FTIR,SEM,DSC,TGA and XRD,we studied the microstructure,particle shape,meltage temperature,decomposition temperature and crystal degree,and gained better understanding about influences of different degrees of substitution on microstructure and thermal property of starch acetates.With concentrated sulfuric acid as catalyst instead of methyl sulfuric acid,optimal reaction conditions are: refluxing temperature is in the range of 75~80℃, reaction time is 3 h with 0.38 mL of concentrate sulfuric acid.With the increasing of degree of substitution,the crystallinity of the starch acetate decreased from 37.95% to 0,Td increased from 327.32℃ to 381.35℃.
2006, 23(9): 1014-1018
Abstract:
A comb-like EVOH based single ion polymer electrolyte(EVOH-g-nSPEG) was synthesized by a two-step reaction.The main chain of the comb-like polymer consists of polyethylene segments;the side chains consists of poly(ethylene glycol)(PEG) segments.The structure of EVOH-g-nSPEG was studied by FTIR.The proton conductivity of the hydrated membrane was also measured by a.c.impedance.The comb-like EVOH-g-nSPEG polymer electrolyte grafted with 2 PEG side chains provides the highest proton conductivity (1.65×10-3 S/cm).
A comb-like EVOH based single ion polymer electrolyte(EVOH-g-nSPEG) was synthesized by a two-step reaction.The main chain of the comb-like polymer consists of polyethylene segments;the side chains consists of poly(ethylene glycol)(PEG) segments.The structure of EVOH-g-nSPEG was studied by FTIR.The proton conductivity of the hydrated membrane was also measured by a.c.impedance.The comb-like EVOH-g-nSPEG polymer electrolyte grafted with 2 PEG side chains provides the highest proton conductivity (1.65×10-3 S/cm).
2006, 23(9): 1019-1022
Abstract:
Nano-sized S42-/TiO2 particles were prepared from TiCl4 and (NH4)2SO4 by the Sol-Gel method and characterized by XRD and FTIR.Photocatalytic degradation of methylene blue solution under ultraviolet radiation was carried out by using nanoparticle TiO2 doped with S42- as the photocatalyst.It was found that doping of S42- into TiO2 by the Sol-Gel method remarkably improved its structure.The reaction of photo-catalysis for methylene blue is in conformity with the first order kinetic law in appearance within the concentration range between 6 mg/L and 15 mg/L.The appearance rate constant of the reaction decreases and the half-life period of the reaction increases with increasing of initial concentration of methylene blue in water, respectively.
Nano-sized S42-/TiO2 particles were prepared from TiCl4 and (NH4)2SO4 by the Sol-Gel method and characterized by XRD and FTIR.Photocatalytic degradation of methylene blue solution under ultraviolet radiation was carried out by using nanoparticle TiO2 doped with S42- as the photocatalyst.It was found that doping of S42- into TiO2 by the Sol-Gel method remarkably improved its structure.The reaction of photo-catalysis for methylene blue is in conformity with the first order kinetic law in appearance within the concentration range between 6 mg/L and 15 mg/L.The appearance rate constant of the reaction decreases and the half-life period of the reaction increases with increasing of initial concentration of methylene blue in water, respectively.
2006, 23(9): 1023-1026
Abstract:
The reaction of 4'-hydroxy-4-methyl azobenzene(1) and 1,6-dibromohexane afforded 6-bromo-1-((4-((4-methylphenyl)azo)phenyl)oxy)hexane(2),which was further reacted with p-tert-butylcalix[4] arene to give calix[4] arene derivative(3), whose lower rim was modified by azobenzene photochromic group.The structure of compound 3 was characterized by 1H NMR and ESI-MS.The fluorescence intensity of compound 3 is 2~4 times higher than that of compounds 1 and 2 as the azobenzene group concentration was in the range of 8.0×10-5 to 8.0×10-4 mol/L,indicating that the fluorescence quantum yield of azobenzene group can be improved by attaching it to the calix[4] arene skeleton.The liquid crystalline behavior of compound 3 was studied by POM and DSC.Compound 3 exhibited enhanced texture of smectic liquid crystal from 209.4℃ to 219.5℃ on heating,while compound 2 exhibited liquid crystalline phase from 87.4 to 84.2℃ on cooling.It was found that the calix[4] arene skeleton can fix the conformation of the azobenzene photochromic group and help the formation of liquid crystalline morphology.
The reaction of 4'-hydroxy-4-methyl azobenzene(1) and 1,6-dibromohexane afforded 6-bromo-1-((4-((4-methylphenyl)azo)phenyl)oxy)hexane(2),which was further reacted with p-tert-butylcalix[4] arene to give calix[4] arene derivative(3), whose lower rim was modified by azobenzene photochromic group.The structure of compound 3 was characterized by 1H NMR and ESI-MS.The fluorescence intensity of compound 3 is 2~4 times higher than that of compounds 1 and 2 as the azobenzene group concentration was in the range of 8.0×10-5 to 8.0×10-4 mol/L,indicating that the fluorescence quantum yield of azobenzene group can be improved by attaching it to the calix[4] arene skeleton.The liquid crystalline behavior of compound 3 was studied by POM and DSC.Compound 3 exhibited enhanced texture of smectic liquid crystal from 209.4℃ to 219.5℃ on heating,while compound 2 exhibited liquid crystalline phase from 87.4 to 84.2℃ on cooling.It was found that the calix[4] arene skeleton can fix the conformation of the azobenzene photochromic group and help the formation of liquid crystalline morphology.
2006, 23(9): 1027-1031
Abstract:
Three poly(amic acid) copolymers(CPAAs) were synthesized from 4,4'-diamino diphenyl methane(DDM),3,3'-dihydroxy-4,4'-diamino-biphenyl(HAB) and pyromellitic dianhydride(PMDA) by condensation in N,N-dimethylacetamide at room temperature.Thermal cyclodehydration of CPAA cast films led to the formation of copolyimides(CPIs),which were rearranged to DDM-PMDA-HAB benzoxazole-imide copolymers(CPBIs) by further thermal treatment at 500℃ under nitrogen.ATR spectra showed the charac-teristic structure of CPIs and CPBIs.TGA analysis confirmed the rearrangement to the formation of Polybenzoxazoles(PBOs).All the CPBI films displayed excellent thermal stability,shown by Td,the temperature at which the mass loss of the polymer is 5%.Td values of CPBI films are 93~138℃ higher than that of corresponding CPIs,and 65~86℃ higher than that of PMDA-HAB PBO.The molar ratio of cheap DDM among diamines can increase up to 75%,while the CPBIs still have the excellent heat resistance(Td is 573℃).
Three poly(amic acid) copolymers(CPAAs) were synthesized from 4,4'-diamino diphenyl methane(DDM),3,3'-dihydroxy-4,4'-diamino-biphenyl(HAB) and pyromellitic dianhydride(PMDA) by condensation in N,N-dimethylacetamide at room temperature.Thermal cyclodehydration of CPAA cast films led to the formation of copolyimides(CPIs),which were rearranged to DDM-PMDA-HAB benzoxazole-imide copolymers(CPBIs) by further thermal treatment at 500℃ under nitrogen.ATR spectra showed the charac-teristic structure of CPIs and CPBIs.TGA analysis confirmed the rearrangement to the formation of Polybenzoxazoles(PBOs).All the CPBI films displayed excellent thermal stability,shown by Td,the temperature at which the mass loss of the polymer is 5%.Td values of CPBI films are 93~138℃ higher than that of corresponding CPIs,and 65~86℃ higher than that of PMDA-HAB PBO.The molar ratio of cheap DDM among diamines can increase up to 75%,while the CPBIs still have the excellent heat resistance(Td is 573℃).
2006, 23(9): 1032-1036
Abstract:
XRD,XPS,EDS and electrochemical methods were used to characterize the physical and chemical properties of the carbon-supported PtRuMo catalyst prepared by the liquid-phase reduction method.It was found that there were crystalline face-centered cubic phases in the Pt/C,PtRu/C,PtRuMo/C catalysts,and PtRu alloy and MoOx species in catalyst PtRuMo/C.The particle size of the catalyst PtRuMo/C powder was about 7 nm determined by means of XRD.Membrane-electrode assemblies with the home-made anode(PtRuMo/C) and cathode(Pt/C) catalysts were manufactured and tested in DMFC.The results show that the PtRuMo/C catalyst has a good electrocatalytic activity,and a high proton conductivity in the active catalyst layer.
XRD,XPS,EDS and electrochemical methods were used to characterize the physical and chemical properties of the carbon-supported PtRuMo catalyst prepared by the liquid-phase reduction method.It was found that there were crystalline face-centered cubic phases in the Pt/C,PtRu/C,PtRuMo/C catalysts,and PtRu alloy and MoOx species in catalyst PtRuMo/C.The particle size of the catalyst PtRuMo/C powder was about 7 nm determined by means of XRD.Membrane-electrode assemblies with the home-made anode(PtRuMo/C) and cathode(Pt/C) catalysts were manufactured and tested in DMFC.The results show that the PtRuMo/C catalyst has a good electrocatalytic activity,and a high proton conductivity in the active catalyst layer.
2006, 23(9): 1037-1041
Abstract:
Magnetic amino phenolic resin(F53-NH) was synthesized by the reaction between epoxy phenolic resin and tetraethylene pentamine,and dithiocarboxylic sodium formate phenolic resin(F53-CSSNa).Toluene diisocyanate phenolic resin(F53-TDI) and thiosemicarbazide phenolic resin(F53-CSNH2) were synthesized respectively through the reactions between F53-NH and each of CS2,TDI,NH2NHCSNH2.The adsorption and swelling properties of the resins for metal ions Cu2+,Pb2+,Co2+,Ni2+,Ag+,Zn2+,Cd2+ were studied.The results show that the swelling properties of the synthetic resins in polar solvents are better than those in nonpolar solvents.F53-NH resin has preferable adsorption properties for all of the determined metal ions, however,the other three kinds of resins have obviously selectivity for determined metal ions,and adsorption capacities of the synthesized resins for Zn2+ are 2.821,3.481,3.400 and 3.622 mmol/g respectively,especially higher than those for other metal ions.
Magnetic amino phenolic resin(F53-NH) was synthesized by the reaction between epoxy phenolic resin and tetraethylene pentamine,and dithiocarboxylic sodium formate phenolic resin(F53-CSSNa).Toluene diisocyanate phenolic resin(F53-TDI) and thiosemicarbazide phenolic resin(F53-CSNH2) were synthesized respectively through the reactions between F53-NH and each of CS2,TDI,NH2NHCSNH2.The adsorption and swelling properties of the resins for metal ions Cu2+,Pb2+,Co2+,Ni2+,Ag+,Zn2+,Cd2+ were studied.The results show that the swelling properties of the synthetic resins in polar solvents are better than those in nonpolar solvents.F53-NH resin has preferable adsorption properties for all of the determined metal ions, however,the other three kinds of resins have obviously selectivity for determined metal ions,and adsorption capacities of the synthesized resins for Zn2+ are 2.821,3.481,3.400 and 3.622 mmol/g respectively,especially higher than those for other metal ions.
2006, 23(9): 1042-1046
Abstract:
Effect of 2 organic additives,acetone and SN-A,on tin electrodeposition in acid solution was investigated by cyclic voltammetry,potential step,and AC impedance.The results show that the potential seperation between anodic and cathodic peaks in the electrodeposition of tin with the organic additives added reached up to 0.9 V,indicating that the electrode process was irreversible.In addition,an inductive current cycle appeared,which indicated the presence of nucleation.It was found that acetone and SN-A inhibited tin electrodeposition,leading to a more negative deposition potential of tin.The electrochemistry impedance Rct of tin electrodeposition in the presence of acetone additive was 1.5×104 Ω·cm2,which is much larger than that caused by SN-A additive.Acetone could also inhibit hydrogen evolution.The cathode overpotential of tin electrodeposition in the presence of the two organic additives increased 280 mV,which is benefical to the gloss of the tin layer.The I2/Im2~t/tm curves of tin electrodeposition was close to theoretical instantaneous nucleation curve.The electrocrystallization of tin in the presence of organic additives followed the mechanism of instantaneous nucleation and three dimensional growth.
Effect of 2 organic additives,acetone and SN-A,on tin electrodeposition in acid solution was investigated by cyclic voltammetry,potential step,and AC impedance.The results show that the potential seperation between anodic and cathodic peaks in the electrodeposition of tin with the organic additives added reached up to 0.9 V,indicating that the electrode process was irreversible.In addition,an inductive current cycle appeared,which indicated the presence of nucleation.It was found that acetone and SN-A inhibited tin electrodeposition,leading to a more negative deposition potential of tin.The electrochemistry impedance Rct of tin electrodeposition in the presence of acetone additive was 1.5×104 Ω·cm2,which is much larger than that caused by SN-A additive.Acetone could also inhibit hydrogen evolution.The cathode overpotential of tin electrodeposition in the presence of the two organic additives increased 280 mV,which is benefical to the gloss of the tin layer.The I2/Im2~t/tm curves of tin electrodeposition was close to theoretical instantaneous nucleation curve.The electrocrystallization of tin in the presence of organic additives followed the mechanism of instantaneous nucleation and three dimensional growth.
2006, 23(9): 1047-1051
Abstract:
The supported catalyst P1 was prepared with hydrazine hydrate and potassium borohydride as co-reducers in a mixed solvent consisting of methanol,ethanol and water in a proper proportion.The catalyst was a kind of nanosized amorphous alloy characterized by TEM,XRD and SAED.Catalyst P1 was used to catalyze the hydrogenation of o-chloronitrobenzene,and compared with the amorphous catalyst P2 prepared by the common method.As it is shown in the results,the activity and selectivity of P1 are slightly higher than those of P2,and the amount of potassium borohydride consumed in the preparation of P1 was only half of that in the preparation of P2.The effects of hydrazine hydrate,potassium borohydride,pH and solvent on the properties of the catalyst were also discussed.
The supported catalyst P1 was prepared with hydrazine hydrate and potassium borohydride as co-reducers in a mixed solvent consisting of methanol,ethanol and water in a proper proportion.The catalyst was a kind of nanosized amorphous alloy characterized by TEM,XRD and SAED.Catalyst P1 was used to catalyze the hydrogenation of o-chloronitrobenzene,and compared with the amorphous catalyst P2 prepared by the common method.As it is shown in the results,the activity and selectivity of P1 are slightly higher than those of P2,and the amount of potassium borohydride consumed in the preparation of P1 was only half of that in the preparation of P2.The effects of hydrazine hydrate,potassium borohydride,pH and solvent on the properties of the catalyst were also discussed.
2006, 23(9): 1052-1054
Abstract:
The HPLC analysis of amino acids in subcrtical hydrolysate of the fish solid waste was set up.In this method,DNFB was used as derivatizing agent.The derivatizing reaction conditions were: pH>7,reaction temperature 60℃,and reaction time 1 h.The HPLC analysis conditions were:chromatographic column hypeoil ODS-C18(100 mm×4.6 mm i.d.,5 μm);mobile phase: sodium acetate and acetonitrile-water;detection wavelength 360 nm,column temperature 45℃;linear gradient elution program.The recovery rate was 90.40%~110.80% and Cv was 0.91%~8.58%.Under these conditions,17 kinds of amino acids were separated completely in 55 minutes and 14 kinds of amino acids such as Asp,Glu,Ala,Leu and so on in the hydrolysate from fish protein hydrolysis in subcritical water were determined.
The HPLC analysis of amino acids in subcrtical hydrolysate of the fish solid waste was set up.In this method,DNFB was used as derivatizing agent.The derivatizing reaction conditions were: pH>7,reaction temperature 60℃,and reaction time 1 h.The HPLC analysis conditions were:chromatographic column hypeoil ODS-C18(100 mm×4.6 mm i.d.,5 μm);mobile phase: sodium acetate and acetonitrile-water;detection wavelength 360 nm,column temperature 45℃;linear gradient elution program.The recovery rate was 90.40%~110.80% and Cv was 0.91%~8.58%.Under these conditions,17 kinds of amino acids were separated completely in 55 minutes and 14 kinds of amino acids such as Asp,Glu,Ala,Leu and so on in the hydrolysate from fish protein hydrolysis in subcritical water were determined.
2006, 23(9): 1055-1057
Abstract:
Complex {[Nd2(2,4-DMBA)6(bipy)2]5.5H2O} was synthesized(2,4-DMBA:2,4-dimethylbenzoate;bipy:2,2'-bipyridine).The crystal structure of the complex was determined by the X-ray diffraction method.The complex crystallized in the triclinic system with space group P1,a=1.121 96(15) nm,b=1.236 39(17) nm,c=1.594 5(2) nm,α=69.636(2)°,β=71.641(2)°,γ=83.271(2)°.M=797.45,V=1.960(7) nm3,Z=2,Dcalc=1.351 Mg/m3).Two metal ions were bridged by four carboxyl groups of 2,4-dimethylbenzoate,forming a binuclear complex.The coordination number of the metal ion is nine.
Complex {[Nd2(2,4-DMBA)6(bipy)2]5.5H2O} was synthesized(2,4-DMBA:2,4-dimethylbenzoate;bipy:2,2'-bipyridine).The crystal structure of the complex was determined by the X-ray diffraction method.The complex crystallized in the triclinic system with space group P1,a=1.121 96(15) nm,b=1.236 39(17) nm,c=1.594 5(2) nm,α=69.636(2)°,β=71.641(2)°,γ=83.271(2)°.M=797.45,V=1.960(7) nm3,Z=2,Dcalc=1.351 Mg/m3).Two metal ions were bridged by four carboxyl groups of 2,4-dimethylbenzoate,forming a binuclear complex.The coordination number of the metal ion is nine.
2006, 23(9): 1058-1060
Abstract:
In comparison with those of 1,8-dihydric anthraquinones,the characteristic TG-DTA curves of the free anthraquinones(Rhein,Emodin,Aloe-emodin,Chrysophanol and Physcion) from Rheum were determined.The results showed that they had similar TG curves.However,due to the different substituents attached on the 1,8-dihydrox anthraquinones,each sample had different weight loss.On the DTA curves of free anthraquinones,there are two obviously characteristic peaks,while there are obviously differences between their curve shapes,peak location and peak values,therefore,free anthraquinones distilled and sublimated from Rheum can be determined by TG-DTA.
In comparison with those of 1,8-dihydric anthraquinones,the characteristic TG-DTA curves of the free anthraquinones(Rhein,Emodin,Aloe-emodin,Chrysophanol and Physcion) from Rheum were determined.The results showed that they had similar TG curves.However,due to the different substituents attached on the 1,8-dihydrox anthraquinones,each sample had different weight loss.On the DTA curves of free anthraquinones,there are two obviously characteristic peaks,while there are obviously differences between their curve shapes,peak location and peak values,therefore,free anthraquinones distilled and sublimated from Rheum can be determined by TG-DTA.
2006, 23(9): 1061-1062
Abstract:
An RP-HPLC method was used to determine the rhynchophylline content in five kinds of uncaria.The mobile phase was a mixture of V(CH3OH):V(0.02%(volume fraction) C2H5)3N)=70:30, detection wavelength 250 nm,and the average recovery of rhynchophylline was 98.98%,RSD=1.31%(n=5).The methods is simple and accurate.
An RP-HPLC method was used to determine the rhynchophylline content in five kinds of uncaria.The mobile phase was a mixture of V(CH3OH):V(0.02%(volume fraction) C2H5)3N)=70:30, detection wavelength 250 nm,and the average recovery of rhynchophylline was 98.98%,RSD=1.31%(n=5).The methods is simple and accurate.
2006, 23(9): 1063-1065
Abstract:
The α-methylstyrene cyclic dimer,liner dimer~trimer,pentamer~octamer, and 2,4-diphenyl-4-methyl-amylene-(1) were synthesized from α-methylstyrene(α-MS) with activated clay or strong acidic cation exchange resin as catalyst.With strong acidic cation exchange resin as catalyst,the reaction temperature was 140℃,the quantity of catalyst was 0.05 times as much as the amount of α-MS,and the reaction time was 4 h,the yield of α-MS cyclic dimer was 87.2%.The structure of the products was determined by IR,MS and NMR.
The α-methylstyrene cyclic dimer,liner dimer~trimer,pentamer~octamer, and 2,4-diphenyl-4-methyl-amylene-(1) were synthesized from α-methylstyrene(α-MS) with activated clay or strong acidic cation exchange resin as catalyst.With strong acidic cation exchange resin as catalyst,the reaction temperature was 140℃,the quantity of catalyst was 0.05 times as much as the amount of α-MS,and the reaction time was 4 h,the yield of α-MS cyclic dimer was 87.2%.The structure of the products was determined by IR,MS and NMR.
2006, 23(9): 1066-1068
Abstract:
In order to find out effective solvents in extractive distillation,relative volatilities were calculated by means of the Flash unit in Aspen Plus 10.2 simulator.Two Flash operational types and some different thermodynamic models in phase equilibrium were considered respectively.For an acetic acid-water system,the relative volatility of water to acetic acid was given by this method.N-methylacetamide and sulfolane were selected as effective solvents,which have relatively high volatility values.Furthermore,VLE phase diagrams for acetic acid-water-solvent systems were obtained to observe the effect in the whole range of concentration.A binary system of N,N-dimethyl formamide-acetic acid was also calculated,showing the formation of a binary azeotrope.
In order to find out effective solvents in extractive distillation,relative volatilities were calculated by means of the Flash unit in Aspen Plus 10.2 simulator.Two Flash operational types and some different thermodynamic models in phase equilibrium were considered respectively.For an acetic acid-water system,the relative volatility of water to acetic acid was given by this method.N-methylacetamide and sulfolane were selected as effective solvents,which have relatively high volatility values.Furthermore,VLE phase diagrams for acetic acid-water-solvent systems were obtained to observe the effect in the whole range of concentration.A binary system of N,N-dimethyl formamide-acetic acid was also calculated,showing the formation of a binary azeotrope.
