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2003 Volume 20 Issue 8
2003, 20(8): 715-718
Abstract:
The chitosan microsphere under protection of amino groups was cross linked with epichlorohydrin to get adsorbent insoluble in acid, which was reacted with chloroacetic acid to give carboxymethyl chitosan resin(CMCS). The FT-IR spectra and adsorption experiment for Pb2+ of the product showed that most Pb2+ were adsorbed on CMCS in the first 1 h and the pH value of the medium has great influence on the adsorption capacity. The adsorption capacity of CMCS towards Pb2+ was 1.12 mmol/g at pH=5, 70% higher than that of chitosan resin.
The chitosan microsphere under protection of amino groups was cross linked with epichlorohydrin to get adsorbent insoluble in acid, which was reacted with chloroacetic acid to give carboxymethyl chitosan resin(CMCS). The FT-IR spectra and adsorption experiment for Pb2+ of the product showed that most Pb2+ were adsorbed on CMCS in the first 1 h and the pH value of the medium has great influence on the adsorption capacity. The adsorption capacity of CMCS towards Pb2+ was 1.12 mmol/g at pH=5, 70% higher than that of chitosan resin.
2003, 20(8): 719-722
Abstract:
5-Methyl-isoxazole-3-formylhydrazine 2 was prepared by hydrazinolysis of the corresponding ester 1. Condensation of 2 with appropriate aldehydes produced corresponding hydrazones(3a~3h). Cyclization of (3a~3h) with acetic anhydride gave the title compounds in good yields. Structures of the intermediates and products were confirmed by means of 1H NMR, MS and elemental analyses.
5-Methyl-isoxazole-3-formylhydrazine 2 was prepared by hydrazinolysis of the corresponding ester 1. Condensation of 2 with appropriate aldehydes produced corresponding hydrazones(3a~3h). Cyclization of (3a~3h) with acetic anhydride gave the title compounds in good yields. Structures of the intermediates and products were confirmed by means of 1H NMR, MS and elemental analyses.
2003, 20(8): 723-726
Abstract:
In 0.2 mol/L NaOH, β-CD can cause a pair of reversible incision on dE/dt-E curve, and its depth would get shallow with increase of the inclusion complex of Cu2+-β-CD. A feasibe method for determination of Cu2+ in silicon brass was founded based on this oscillographic characteristic. The linear range of concentration for Cu2+ is 1.0×10-6~2.0×10-5 mol/L with detection limit 8.0×10-7 mol/L. The correlation equation coefficient is h(v)=-3.861×104 c+4.819(mol/L) and r=-0.999 2. The RSD for 7.0×10-6 mol/L Cu2+ is 2.1%(n=5), and average recovery 102.4%(n=5). Moreover, on addition of rutin to the 0.2mol/L NaOH solution of β-cyclodextrin the inclusion reaction between rutin and β-CD could be monitored by changing of the incision depth of β-CD.
In 0.2 mol/L NaOH, β-CD can cause a pair of reversible incision on dE/dt-E curve, and its depth would get shallow with increase of the inclusion complex of Cu2+-β-CD. A feasibe method for determination of Cu2+ in silicon brass was founded based on this oscillographic characteristic. The linear range of concentration for Cu2+ is 1.0×10-6~2.0×10-5 mol/L with detection limit 8.0×10-7 mol/L. The correlation equation coefficient is h(v)=-3.861×104 c+4.819(mol/L) and r=-0.999 2. The RSD for 7.0×10-6 mol/L Cu2+ is 2.1%(n=5), and average recovery 102.4%(n=5). Moreover, on addition of rutin to the 0.2mol/L NaOH solution of β-cyclodextrin the inclusion reaction between rutin and β-CD could be monitored by changing of the incision depth of β-CD.
2003, 20(8): 727-731
Abstract:
A kind of carbazole-based polymers containing nitro azobenzene group was prepared via a post azo coupling reaction. The structure of the polymer was characterized by IR, 1H NMR, UV-vis, DSC and GPC. The content of azo group grafed to the polymer chain was 92%(mole fraction) calculated from UV-vis spectra. The GPC results showed the molecular weight of the polymer Mw=27 400, higher than that of the polymer obtained by common method. The DSC result indicated that the glass transition temperature (Tg) and the melting temperature(Tm) of the polymer were 181℃ and 192℃, respectively, and it began to decompose above 232℃.
A kind of carbazole-based polymers containing nitro azobenzene group was prepared via a post azo coupling reaction. The structure of the polymer was characterized by IR, 1H NMR, UV-vis, DSC and GPC. The content of azo group grafed to the polymer chain was 92%(mole fraction) calculated from UV-vis spectra. The GPC results showed the molecular weight of the polymer Mw=27 400, higher than that of the polymer obtained by common method. The DSC result indicated that the glass transition temperature (Tg) and the melting temperature(Tm) of the polymer were 181℃ and 192℃, respectively, and it began to decompose above 232℃.
2003, 20(8): 732-735
Abstract:
A binary solvent dispersion(BSD) method has been investigated in preparation of nanoparticles of polylactide(PLA) and poly(DL-lactide-co-glycolide)(PLGA) as functions of polymer molecular weight and monomer ratio in copolymer:L/G ratio=m(PLA)/m(PLGA). The yield, particle size and size distribution of the nanoparticles obtained were examined. Both polymeric nanoparticles could be powderized via lyophilization, leading to the narrow size dirtribution of the particles. The effects of ethanol and acetone on the nanoparticles size and yield have been examined by using of could point titration method. It was found that the yield of nanoparticles increases with increase of ethanol in mixture with acetone and attains a maximum value near the cloud point, whereas the size of nanoparticles decreases with increases of ethanol in the solution with acetone and attains a minimum value near the cloud point. Therefore, the optimum condition for gaining desired yield and size of polymeric particles could be derived form the cloud point experimentation. The yield of nanoparticles was up to 90% with the average size being ranged in 130~180 nm for both PLA and PLGA.
A binary solvent dispersion(BSD) method has been investigated in preparation of nanoparticles of polylactide(PLA) and poly(DL-lactide-co-glycolide)(PLGA) as functions of polymer molecular weight and monomer ratio in copolymer:L/G ratio=m(PLA)/m(PLGA). The yield, particle size and size distribution of the nanoparticles obtained were examined. Both polymeric nanoparticles could be powderized via lyophilization, leading to the narrow size dirtribution of the particles. The effects of ethanol and acetone on the nanoparticles size and yield have been examined by using of could point titration method. It was found that the yield of nanoparticles increases with increase of ethanol in mixture with acetone and attains a maximum value near the cloud point, whereas the size of nanoparticles decreases with increases of ethanol in the solution with acetone and attains a minimum value near the cloud point. Therefore, the optimum condition for gaining desired yield and size of polymeric particles could be derived form the cloud point experimentation. The yield of nanoparticles was up to 90% with the average size being ranged in 130~180 nm for both PLA and PLGA.
2003, 20(8): 736-739
Abstract:
Silver nanoparticle array has been successfully fabricated on the silver substrate using p-aminothiophenol(PATP) as coupling reagent. Two-dimensional submonolayer structure of silver particles was observed in scanning electron microscope. Some a1 vibrations in surface enhanced Raman spectra are found to be greatly enhanced, and b2 vibrations is also observed. The results revealed that the electromagnetic enhancement should be predominant in such an assembly, howerver, it couldn't rule out the chemical enhancement due to the charge transfer between the smooth silver surface and p-aminothiophenol molecule. Both increasing potential on the assembly system or adsorption I- on the assembly array could strengthen the electrostatic interaction between silver particle and silver substrate and weaken the charge transfer between silver substrate and coupling molecules. On the contrary, adsorption of methylviologen cation could lead to the charge transfer in a more great extent.
Silver nanoparticle array has been successfully fabricated on the silver substrate using p-aminothiophenol(PATP) as coupling reagent. Two-dimensional submonolayer structure of silver particles was observed in scanning electron microscope. Some a1 vibrations in surface enhanced Raman spectra are found to be greatly enhanced, and b2 vibrations is also observed. The results revealed that the electromagnetic enhancement should be predominant in such an assembly, howerver, it couldn't rule out the chemical enhancement due to the charge transfer between the smooth silver surface and p-aminothiophenol molecule. Both increasing potential on the assembly system or adsorption I- on the assembly array could strengthen the electrostatic interaction between silver particle and silver substrate and weaken the charge transfer between silver substrate and coupling molecules. On the contrary, adsorption of methylviologen cation could lead to the charge transfer in a more great extent.
2003, 20(8): 740-743
Abstract:
CaX-Mg(ClO4)2 molecular sieve has been obtained from CaX in the presence of 20% Mg(ClO4)2 in mcrowave over of 650 W for 20 min. The product contains 17% Mg(ClO4)2 and has been characterized by XRD, IR, Hammett and BET measurements. The acid content of CaX-Mg(ClO4)2 increased obviously in comparison with CaX. When octanol was heated with equal mol of ethylene epoxide(EO) at 100℃ for 2 h using CaX-Mg(ClO4)2 catalyst,the conversion of alcohol was 77% and the concentration of (EO)1 and (EO)2 was 78%.
CaX-Mg(ClO4)2 molecular sieve has been obtained from CaX in the presence of 20% Mg(ClO4)2 in mcrowave over of 650 W for 20 min. The product contains 17% Mg(ClO4)2 and has been characterized by XRD, IR, Hammett and BET measurements. The acid content of CaX-Mg(ClO4)2 increased obviously in comparison with CaX. When octanol was heated with equal mol of ethylene epoxide(EO) at 100℃ for 2 h using CaX-Mg(ClO4)2 catalyst,the conversion of alcohol was 77% and the concentration of (EO)1 and (EO)2 was 78%.
2003, 20(8): 744-748
Abstract:
Three kinds of UV curable allyl ether modified polyurethane acrylate(PUAE), i.e., blended, blocked and terminated PUAEs were studied. It was found that the curing rate in oxygen investigated by DPC decreased in the order of blocked > terminated > blended. With increased allyloxy content, the final conversion of terminated PUAE reduced in nitrogen, but reversed in oxygen. IR showed that the conversion of allyloxy was higher in oxygen than in nitrogen, but reversed for acrylate which deceased from 75% in nitrogen to 60% in air. Thermogravimetric analysis(TGA) indicated that the mass loss of blended PUAE occurred at 118.74℃. The blocked and terminated PUAE were superior in thermal stability to the blended counterpart.
Three kinds of UV curable allyl ether modified polyurethane acrylate(PUAE), i.e., blended, blocked and terminated PUAEs were studied. It was found that the curing rate in oxygen investigated by DPC decreased in the order of blocked > terminated > blended. With increased allyloxy content, the final conversion of terminated PUAE reduced in nitrogen, but reversed in oxygen. IR showed that the conversion of allyloxy was higher in oxygen than in nitrogen, but reversed for acrylate which deceased from 75% in nitrogen to 60% in air. Thermogravimetric analysis(TGA) indicated that the mass loss of blended PUAE occurred at 118.74℃. The blocked and terminated PUAE were superior in thermal stability to the blended counterpart.
2003, 20(8): 749-753
Abstract:
The isothermal sorption kinetics of chitosan(CTS) for ferrous ions has been investigated. The structure of the chelate compound was confirmed by IR spectra、UV VIS spectra、elemental and thermal analysis. The results were satisfied with the Langmuir-single-molecule-layer adsorption mechanism and the Lagergren-one-order equation. The apparent adsorption activation energy is 20.23 kJ/mol and the sorption rate constant of the Lagergren one order sorption is 0.25 h-1 at 293.15 K.
The isothermal sorption kinetics of chitosan(CTS) for ferrous ions has been investigated. The structure of the chelate compound was confirmed by IR spectra、UV VIS spectra、elemental and thermal analysis. The results were satisfied with the Langmuir-single-molecule-layer adsorption mechanism and the Lagergren-one-order equation. The apparent adsorption activation energy is 20.23 kJ/mol and the sorption rate constant of the Lagergren one order sorption is 0.25 h-1 at 293.15 K.
2003, 20(8): 754-759
Abstract:
Solanesol was reacted with seven dibasic acid anhydrides to give corresponding monosolanesyl dibasic acid esters 2, which were reacted with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide to give corresponding solanesyl glucosyl dibasic esters 3, using tetrabutyl ammonium bromide as a phase-transfer catalyst.The method has advantages of mild reaction condition, easy seperation and high stereospecificity of the products. The structures of all the compounds 2 and 3 were confirmed by IR, NMR, MS and elemental analysis. Preliminary in vitro biological activity tests of three compounds of 2 and seven compounds of 3 against three kinds of human cancer cells showed that 3e has moderate inhibitory activity(~70%) on KB cells, and the other compounds have only low inhibitory ratios.
Solanesol was reacted with seven dibasic acid anhydrides to give corresponding monosolanesyl dibasic acid esters 2, which were reacted with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide to give corresponding solanesyl glucosyl dibasic esters 3, using tetrabutyl ammonium bromide as a phase-transfer catalyst.The method has advantages of mild reaction condition, easy seperation and high stereospecificity of the products. The structures of all the compounds 2 and 3 were confirmed by IR, NMR, MS and elemental analysis. Preliminary in vitro biological activity tests of three compounds of 2 and seven compounds of 3 against three kinds of human cancer cells showed that 3e has moderate inhibitory activity(~70%) on KB cells, and the other compounds have only low inhibitory ratios.
2003, 20(8): 760-763
Abstract:
The dehydration reaction of Cu(CH3COO)2·H2O has been studied isothermally and non isothermally by TG method.The data from isothermal studies were analyzed according to g(α)=A·exp(-E/RT)·t and ln t=E/RT+ln[g(α)/A] at the same conversion rate. The activation energy and possible kinetic functions were obtained. The data from non-isothermal experiments were analyzed by Coats-Redfern method. It was found that the integral kinetic equation for the dehydration of Cu(CH3COO)2·H2O is g(α)=1-(1-α)1/3, activation energy is E=120.5 kJ/mol, pre exponential factor A=1.872×1013 s-1,and kinetic compensation effect equation ln A=0.299 9E-5.252.
The dehydration reaction of Cu(CH3COO)2·H2O has been studied isothermally and non isothermally by TG method.The data from isothermal studies were analyzed according to g(α)=A·exp(-E/RT)·t and ln t=E/RT+ln[g(α)/A] at the same conversion rate. The activation energy and possible kinetic functions were obtained. The data from non-isothermal experiments were analyzed by Coats-Redfern method. It was found that the integral kinetic equation for the dehydration of Cu(CH3COO)2·H2O is g(α)=1-(1-α)1/3, activation energy is E=120.5 kJ/mol, pre exponential factor A=1.872×1013 s-1,and kinetic compensation effect equation ln A=0.299 9E-5.252.
2003, 20(8): 764-767
Abstract:
Extraction behaviour of N,N'-didodecyl(ethylenediamine diacetic acid)(H2R2Y) in chloroform for Cu(Ⅱ) has been investigated as function of acidity of the initial aq. phase, concentration of extractant and extraction temperature. The extraction ratio was found to be increased with concentration of H 2 R 2 Y and temperature. The highest extraction ratio of Cu(Ⅱ) has been achieved at pH≥6. The mole ratio of Cu2+ to ligand in extracted species was 1:1 as determinated by conductivity and mole ratio method. The extration system is efficient for separation Cu(Ⅱ) from transition metals such as Fe(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ) when pH=6.
Extraction behaviour of N,N'-didodecyl(ethylenediamine diacetic acid)(H2R2Y) in chloroform for Cu(Ⅱ) has been investigated as function of acidity of the initial aq. phase, concentration of extractant and extraction temperature. The extraction ratio was found to be increased with concentration of H 2 R 2 Y and temperature. The highest extraction ratio of Cu(Ⅱ) has been achieved at pH≥6. The mole ratio of Cu2+ to ligand in extracted species was 1:1 as determinated by conductivity and mole ratio method. The extration system is efficient for separation Cu(Ⅱ) from transition metals such as Fe(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ) when pH=6.
2003, 20(8): 768-772
Abstract:
The graft copolymers were synthesized by copolymerization of starch with mixture of acrylamide(AM) and acrylic acid(AC). The graft copolymerization was carried out in the systems of Span20, Span60, Tween20, Tween81, OP4, OP10 and their mixtures, respectively. The effects of kind of emulsifiers, emulsification method and emulsifier concentration on the monomer conversion and grafting yield and specific viscosity have been discussed. At the following conditions of copolymerization:m(Span20):m(OP4)=40:60 or m(Span20):m(OP10)=60:40, mass fraction of mixture emulsifier in oil was 6%~7%, V(oil):V(water)=1.2:1, m(starch):m(monomer)=1:1, m(AM):m(AC)=4:1, c((NH4)2S2O8)=2.4×10-4 mol/L,time 6 h, t=45℃, the grafting yield was 97%~98% and specific viscosity of the product was 1 010~1 020 mL/g.
The graft copolymers were synthesized by copolymerization of starch with mixture of acrylamide(AM) and acrylic acid(AC). The graft copolymerization was carried out in the systems of Span20, Span60, Tween20, Tween81, OP4, OP10 and their mixtures, respectively. The effects of kind of emulsifiers, emulsification method and emulsifier concentration on the monomer conversion and grafting yield and specific viscosity have been discussed. At the following conditions of copolymerization:m(Span20):m(OP4)=40:60 or m(Span20):m(OP10)=60:40, mass fraction of mixture emulsifier in oil was 6%~7%, V(oil):V(water)=1.2:1, m(starch):m(monomer)=1:1, m(AM):m(AC)=4:1, c((NH4)2S2O8)=2.4×10-4 mol/L,time 6 h, t=45℃, the grafting yield was 97%~98% and specific viscosity of the product was 1 010~1 020 mL/g.
2003, 20(8): 773-777
Abstract:
Solution polymerization and two different inverse emulsion polymerizations have been carried out to synthesize hydrophobically associative polyacrylate thickener. The thickening property of the products obtained were compared. The results showed that the inverse emulsion polymerization technology is more suitable for producing polyacrylate thickener than solution polymerization method. The anti electrolyte property of poly acrylate thickener obtained by inverse emulsion copolymerization of acrylic acid with hydrophobically associate monomer, synthesized from acylic acid and polyethylene fatty alcohol ether was found much improved. However, inverse emulsion copolymerization of acrylic acid with stearyl acrylate does not result in any improvement of anti electrolytic property of the thickener. When the amounts of NaHCO3 and thickener in water, whose solid content was about 50%, were 2% and 4% respectively, the viscosity of water was 31.5 mPa·s while the retention of viscosity was about 34%.
Solution polymerization and two different inverse emulsion polymerizations have been carried out to synthesize hydrophobically associative polyacrylate thickener. The thickening property of the products obtained were compared. The results showed that the inverse emulsion polymerization technology is more suitable for producing polyacrylate thickener than solution polymerization method. The anti electrolyte property of poly acrylate thickener obtained by inverse emulsion copolymerization of acrylic acid with hydrophobically associate monomer, synthesized from acylic acid and polyethylene fatty alcohol ether was found much improved. However, inverse emulsion copolymerization of acrylic acid with stearyl acrylate does not result in any improvement of anti electrolytic property of the thickener. When the amounts of NaHCO3 and thickener in water, whose solid content was about 50%, were 2% and 4% respectively, the viscosity of water was 31.5 mPa·s while the retention of viscosity was about 34%.
2003, 20(8): 778-782
Abstract:
A series of emulsion with largest ω (Si-1800) up to 20% were prepared by emulsion copolymerization of vinyl terminal polysiloxane, acted as macromonomer cross linker, butyl acrylate and methyl methacrylate. The products were characterized by cross linking degree, IR analysis of the cross linked parts, conversion of the monomers, size and size distribution of the latex particles, water resistance and mechanical property of the latex film. The influence of reaction condition on the copolymerization has been discussed based on the morphological analysis of some latexes. The results showed that semi continuous feeding process improves the cross linking degree of products to 62.6%, whereas batch process to 11.6%. Feeding process of reagents and feeding time also show effects on the water absorption and mechanical property of latex film. Higher cross linking degree was obtained when more initiator was used. With the increase of ω (Si-1800), the break stress of the latex film dropped to 0.9 MPa while break elongation ascended to 62.6%, and water resistance property of latex film was improved.
A series of emulsion with largest ω (Si-1800) up to 20% were prepared by emulsion copolymerization of vinyl terminal polysiloxane, acted as macromonomer cross linker, butyl acrylate and methyl methacrylate. The products were characterized by cross linking degree, IR analysis of the cross linked parts, conversion of the monomers, size and size distribution of the latex particles, water resistance and mechanical property of the latex film. The influence of reaction condition on the copolymerization has been discussed based on the morphological analysis of some latexes. The results showed that semi continuous feeding process improves the cross linking degree of products to 62.6%, whereas batch process to 11.6%. Feeding process of reagents and feeding time also show effects on the water absorption and mechanical property of latex film. Higher cross linking degree was obtained when more initiator was used. With the increase of ω (Si-1800), the break stress of the latex film dropped to 0.9 MPa while break elongation ascended to 62.6%, and water resistance property of latex film was improved.
2003, 20(8): 783-787
Abstract:
The cationic anionic surfactant mixtures are able to form an aqueous two phase system(ATPS). The pseudo ternary phase diagram of SDS/CTAB/H2O/Na2SO4 system has been examined in the paper. The factors relating the formation time of ATPS and the distribution coefficient of bovine serum albumin(BSA) and tryptophane(Trp) in different ATPS regions have been investigated. It is shown that salt kind and its concentration and the phase volume ratio of system have important influence on the ATPS forming time. It needs at least 30 h for SDS/CTAB/H2O system to form ATPS. However, the ATPS forming time would reduce to 1 min if there is 0.5 mol/L NaSO4 in the system. When the ratio of top volume to bottom volume is 1, the ATPS forming time is shortest. The higher the hydrophobicity of the compound, the easier it would be extracted by the surfactant rich phase. Small water soluble compound can not be extracted in ATPS. When the electricity of compound is just opposite to that of the ordered combining structure of surfactant rich phase, the distribution coefficient would be much high.
The cationic anionic surfactant mixtures are able to form an aqueous two phase system(ATPS). The pseudo ternary phase diagram of SDS/CTAB/H2O/Na2SO4 system has been examined in the paper. The factors relating the formation time of ATPS and the distribution coefficient of bovine serum albumin(BSA) and tryptophane(Trp) in different ATPS regions have been investigated. It is shown that salt kind and its concentration and the phase volume ratio of system have important influence on the ATPS forming time. It needs at least 30 h for SDS/CTAB/H2O system to form ATPS. However, the ATPS forming time would reduce to 1 min if there is 0.5 mol/L NaSO4 in the system. When the ratio of top volume to bottom volume is 1, the ATPS forming time is shortest. The higher the hydrophobicity of the compound, the easier it would be extracted by the surfactant rich phase. Small water soluble compound can not be extracted in ATPS. When the electricity of compound is just opposite to that of the ordered combining structure of surfactant rich phase, the distribution coefficient would be much high.
2003, 20(8): 788-790
Abstract:
Some complexs of Ag(PPh3)nX(n=1,2,3;X=Cl,Br,I) were electrosynthesized using NH4X or I2 in non aqueous medium, in yield >95%. The mechanism of electrochemical reaction and the effect of material ratio on the complexes have been studied. When n(PPh3):n(NH4X)=3:1, Ag(PPh3)2X(X=Cl,Br) were obtained; when n(PPh3):n(NH4I/I2)=1:1, AgPPh3I was obtained; when n(PPh3):n(NH4I)=2:1 or 3:1, Ag(PPh3)3I was obtained. This method is better than the traditional chemical synthesis.
Some complexs of Ag(PPh3)nX(n=1,2,3;X=Cl,Br,I) were electrosynthesized using NH4X or I2 in non aqueous medium, in yield >95%. The mechanism of electrochemical reaction and the effect of material ratio on the complexes have been studied. When n(PPh3):n(NH4X)=3:1, Ag(PPh3)2X(X=Cl,Br) were obtained; when n(PPh3):n(NH4I/I2)=1:1, AgPPh3I was obtained; when n(PPh3):n(NH4I)=2:1 or 3:1, Ag(PPh3)3I was obtained. This method is better than the traditional chemical synthesis.
2003, 20(8): 791-793
Abstract:
A Nafion 117 complex membrane with low Pd content was prepared. It was found that at room temperature the diffusivity of methanol through this membrane was reduced to one fifth of that through bare Nafion 117 membrane. The proton conductivity of the modified membrane was also increased, significantly improving the discharge performance of the direct methanol fuel cell(DMFC).
A Nafion 117 complex membrane with low Pd content was prepared. It was found that at room temperature the diffusivity of methanol through this membrane was reduced to one fifth of that through bare Nafion 117 membrane. The proton conductivity of the modified membrane was also increased, significantly improving the discharge performance of the direct methanol fuel cell(DMFC).
2003, 20(8): 794-796
Abstract:
The α-Fe2O3 sol was prepared by a sol gel method from FeCl3·6H2O. Thin nano particulate films of the α-Fe2O3 were deposited on glass substrate by dip coating sol gel technique. The structure and morphology of the thin films were characterized by XRD, UV-Vis and AFM analysis methods. The XRD results revealed that the nano crystal with (104) preferential orientation has been formed on glass substrate. The UV-Vis spectra showed that the nano particulate films obtained from Fe2O3 aqueous colloidal sols are well transferred to glass substrate at dip coating rate of 80 mm/min. The α-Fe2O3 particles are ellipsoidal shaped, with particle size of about 5~7 nm. The multilayer films exhibited high sensitivity to ethanol vapor at room temperature.
The α-Fe2O3 sol was prepared by a sol gel method from FeCl3·6H2O. Thin nano particulate films of the α-Fe2O3 were deposited on glass substrate by dip coating sol gel technique. The structure and morphology of the thin films were characterized by XRD, UV-Vis and AFM analysis methods. The XRD results revealed that the nano crystal with (104) preferential orientation has been formed on glass substrate. The UV-Vis spectra showed that the nano particulate films obtained from Fe2O3 aqueous colloidal sols are well transferred to glass substrate at dip coating rate of 80 mm/min. The α-Fe2O3 particles are ellipsoidal shaped, with particle size of about 5~7 nm. The multilayer films exhibited high sensitivity to ethanol vapor at room temperature.
2003, 20(8): 797-799
Abstract:
As a synergistic anti tumor agent, N-Solanesyl-N,N'-bis(3,4-dimethoxybenzyl) ethylenediamine(5) was synthesized starting from vanillin and solanesol. Methylation of vanillin gave veratradehyde(1), which after coupling with ethylenediamine was then catalytically reduced to N,N'-bis(3,4-dimethoxybenzyl) ethylenediamine(3), which was coupled with solanesol bromide (4) to give (5). The processes of synthesis of (3) and separation of (5) have been improved with total reaction yield being increased. The structures of the compounds were confirmed by IR, 1H NMR, MS and elemental analysis.
As a synergistic anti tumor agent, N-Solanesyl-N,N'-bis(3,4-dimethoxybenzyl) ethylenediamine(5) was synthesized starting from vanillin and solanesol. Methylation of vanillin gave veratradehyde(1), which after coupling with ethylenediamine was then catalytically reduced to N,N'-bis(3,4-dimethoxybenzyl) ethylenediamine(3), which was coupled with solanesol bromide (4) to give (5). The processes of synthesis of (3) and separation of (5) have been improved with total reaction yield being increased. The structures of the compounds were confirmed by IR, 1H NMR, MS and elemental analysis.
2003, 20(8): 800-802
Abstract:
A pH sensitive membrane based on Rhodamine B immobilized in a PVC membrane was prepared. The membrane is sensitive towards pH change of solution it contacted with due to the fluorescence spectral change of Rhodamine B in it. The membrane is sensitive towards pH in range from 2.0 to 4.0 in solution with response time ≤120 s and good reversibility, reproducibility and stability.
A pH sensitive membrane based on Rhodamine B immobilized in a PVC membrane was prepared. The membrane is sensitive towards pH change of solution it contacted with due to the fluorescence spectral change of Rhodamine B in it. The membrane is sensitive towards pH in range from 2.0 to 4.0 in solution with response time ≤120 s and good reversibility, reproducibility and stability.
2003, 20(8): 803-805
Abstract:
The Hofmann reactions of five polyacrylamides(PAM) with different molecular weights of two different concentrations were carried out to get better understanding the mechanisms of the reaction. The results show that the maximum conversion of N-chloroamides increased with molecular weights of PAM and got to the highest value at 9×104, then decreased. The changes in maximum conversion of amino groups are similar to those of N-chloroamides, the maximum content of amino group of PAM studied was 97%. However, the time to reach maximum conversion of amino groups appeared to be independent of the molecular weights in the range investigated.
The Hofmann reactions of five polyacrylamides(PAM) with different molecular weights of two different concentrations were carried out to get better understanding the mechanisms of the reaction. The results show that the maximum conversion of N-chloroamides increased with molecular weights of PAM and got to the highest value at 9×104, then decreased. The changes in maximum conversion of amino groups are similar to those of N-chloroamides, the maximum content of amino group of PAM studied was 97%. However, the time to reach maximum conversion of amino groups appeared to be independent of the molecular weights in the range investigated.
2003, 20(8): 806-808
Abstract:
The title complex ZnCl2 (salaad)2 (salaad=N-Salicylidene-1-aminoadamantane) was synthesized and characterized by X-ray diffraction analysis. The crystal crystallizes in orthorhombic system, space group Pbca with a=1.503 2(3), b=1.819 5(4), c=2.330 2(5) nm, V=6.373(2) nm, Z=8, Dc=1.348 g/cm3, μ=0.971 mm-1 (Mo Kα), F(000)=2.720. The structure was refined to R=0.048 9 and wR=0.094 3 for observed 2 978 reflections with I≥2σ(I). The Zn(Ⅱ) ion has a distorted tetrahedral coordination consisting of two chlorine ions and the two oxygen atoms from two Schiff base ligands.
The title complex ZnCl2 (salaad)2 (salaad=N-Salicylidene-1-aminoadamantane) was synthesized and characterized by X-ray diffraction analysis. The crystal crystallizes in orthorhombic system, space group Pbca with a=1.503 2(3), b=1.819 5(4), c=2.330 2(5) nm, V=6.373(2) nm, Z=8, Dc=1.348 g/cm3, μ=0.971 mm-1 (Mo Kα), F(000)=2.720. The structure was refined to R=0.048 9 and wR=0.094 3 for observed 2 978 reflections with I≥2σ(I). The Zn(Ⅱ) ion has a distorted tetrahedral coordination consisting of two chlorine ions and the two oxygen atoms from two Schiff base ligands.
2003, 20(8): 809-810
Abstract:
The solid condensation of isopropylidene malonate with aromatic aldehydes were carried out by grinding at room temperature or heating at 110~120℃ to give 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-dione. Both conditions afford the condensation high reaction activity. The yield of the product under grinding for 20 min followed by standing for 48 h at room temperature is 56%~80% and that by heating at 110~120℃ for 12 min is 55%~74%, respectively.
The solid condensation of isopropylidene malonate with aromatic aldehydes were carried out by grinding at room temperature or heating at 110~120℃ to give 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-dione. Both conditions afford the condensation high reaction activity. The yield of the product under grinding for 20 min followed by standing for 48 h at room temperature is 56%~80% and that by heating at 110~120℃ for 12 min is 55%~74%, respectively.
2003, 20(8): 811-813
Abstract:
Eight 2-t-butyl-4-chloro-5-[5-aryl-2-(1,3,4-thiadiazole)]amino-3(2H) pyridazinones were synthesized and their insecticidal activities were examined. Some of them(e.g. 3b,3e,3g) showed a moderate insecticidal activity against Mythimna separata Walker and Aphis rumicis Linnaeus.
Eight 2-t-butyl-4-chloro-5-[5-aryl-2-(1,3,4-thiadiazole)]amino-3(2H) pyridazinones were synthesized and their insecticidal activities were examined. Some of them(e.g. 3b,3e,3g) showed a moderate insecticidal activity against Mythimna separata Walker and Aphis rumicis Linnaeus.
2003, 20(8): 814-816
Abstract:
A water-soluble PU macromonomer was synthesized starting from polyethylene glycol oxide, 2,4-toluene diisocyanate, using hydroxyethyl acrylate as end chain termination agent. It is revealed that the intrinsic viscosity of the aqueous solution and cloud point of the macromonomer became lower, and the association of the macromonomer became apparent as hydrophobic mass fraction in the macromonomer composition increased. It is also found that the aggregation state of PU macromonomer in aqueous solution is strikingly dependent on temperature and concentration. Hydrophobic association occurred between macromonomers themselves as the concentration of aqueous solution increased. At higher temperature the HLB value of the macromonomer became lower, and micelle formed at the temperature over 75℃.
A water-soluble PU macromonomer was synthesized starting from polyethylene glycol oxide, 2,4-toluene diisocyanate, using hydroxyethyl acrylate as end chain termination agent. It is revealed that the intrinsic viscosity of the aqueous solution and cloud point of the macromonomer became lower, and the association of the macromonomer became apparent as hydrophobic mass fraction in the macromonomer composition increased. It is also found that the aggregation state of PU macromonomer in aqueous solution is strikingly dependent on temperature and concentration. Hydrophobic association occurred between macromonomers themselves as the concentration of aqueous solution increased. At higher temperature the HLB value of the macromonomer became lower, and micelle formed at the temperature over 75℃.
