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2004 Volume 21 Issue 8
2004, 21(8): 757-761
Abstract:
The pressure-volume-temperature (P-V-T) properties of four kinds of polypropylene (PPR) random copolymer were measured on the PVT-100 apparatus. Their thermal expansion coefficient (α) and isothermal compressibility (β) were evaluated using the definition method and Tait equation, respectively. The results obtained by two methods agree with each other when the calculation is done for temperatures higher than the crystallization temperature(TC). It is also found that at 20~30 MPa or 80~100 MPa, β and TC of QiLu random copolymer polypropylene(QLPPR) are lower than that of others.
The pressure-volume-temperature (P-V-T) properties of four kinds of polypropylene (PPR) random copolymer were measured on the PVT-100 apparatus. Their thermal expansion coefficient (α) and isothermal compressibility (β) were evaluated using the definition method and Tait equation, respectively. The results obtained by two methods agree with each other when the calculation is done for temperatures higher than the crystallization temperature(TC). It is also found that at 20~30 MPa or 80~100 MPa, β and TC of QiLu random copolymer polypropylene(QLPPR) are lower than that of others.
2004, 21(8): 762-765
Abstract:
The CdS particles of average size of 3.2 nm were produced from 0.1 mol/L Na2S and CdCl2 solutions via transmembrane transportation and molecular assembly under inducement of polytetrafluoroethylene (PTFE) porous membrane. XRD results indicated that the products are of cubic zinc blende structure. The particles exhibit a strong emission peak at 522 nm in the photoluminescence (PL) spectrum. The surface of CdS nanoparticles have been modified with HSCH2COOH, and there is a characteristic peak of the group -C=O at 1680 cm-1 in the FTIR spectrum of the modified crystals.
The CdS particles of average size of 3.2 nm were produced from 0.1 mol/L Na2S and CdCl2 solutions via transmembrane transportation and molecular assembly under inducement of polytetrafluoroethylene (PTFE) porous membrane. XRD results indicated that the products are of cubic zinc blende structure. The particles exhibit a strong emission peak at 522 nm in the photoluminescence (PL) spectrum. The surface of CdS nanoparticles have been modified with HSCH2COOH, and there is a characteristic peak of the group -C=O at 1680 cm-1 in the FTIR spectrum of the modified crystals.
2004, 21(8): 766-769
Abstract:
The acid dissociation constants of seven phenoxy acetic acids were determined by potentiometric titration. It has been shown that phenoxy acetic acids exhibit stronger acidity than both acetic acid and benzoic acid due to the induction and conjugation of the oxygen atom on -OCH2COOH that links to the benzene ring. Acidity of phenoxy acetic acids containing two or more -OCH2COOH groups is lower than that of phenoxy acetic acid by reason of electron donation of oxygen atom to the benzene ring. Quantum chemical calculation of the phenoxy acetic acids was carried out using CNDO/2 method. The bond charge density (ρ) of O-H and C-O bond in carboxyl group of seven phenoxy acetic acids was calculated, and the value f=ρO-H/ρC-O, was figured out. The f value of the carboxyl group in phenoxy acetic acid as well as the f values of the most likely dissociated carboxyl group in other six phenoxyl acetic acid derivatives are changed in the corresponding change order of their pKa or pKa1 values. It is concluded that the f value can be used as a judgement criterion of relative acidity for phenoxy acetic acids.
The acid dissociation constants of seven phenoxy acetic acids were determined by potentiometric titration. It has been shown that phenoxy acetic acids exhibit stronger acidity than both acetic acid and benzoic acid due to the induction and conjugation of the oxygen atom on -OCH2COOH that links to the benzene ring. Acidity of phenoxy acetic acids containing two or more -OCH2COOH groups is lower than that of phenoxy acetic acid by reason of electron donation of oxygen atom to the benzene ring. Quantum chemical calculation of the phenoxy acetic acids was carried out using CNDO/2 method. The bond charge density (ρ) of O-H and C-O bond in carboxyl group of seven phenoxy acetic acids was calculated, and the value f=ρO-H/ρC-O, was figured out. The f value of the carboxyl group in phenoxy acetic acid as well as the f values of the most likely dissociated carboxyl group in other six phenoxyl acetic acid derivatives are changed in the corresponding change order of their pKa or pKa1 values. It is concluded that the f value can be used as a judgement criterion of relative acidity for phenoxy acetic acids.
2004, 21(8): 770-774
Abstract:
The overall protonation constants of five porphyrin-anthraquinone compounds were determined by spectrophotometric method. The changes of standard molar enthalpy △rHθm<0 and standard molar entropy △rSmθ0 in the protonation reaction were calculated from the plots of lg Kθ vs 1/T. The in electron effect and steric hindrance of substituent groups on overall protonation constants were discussed.The net charge at=N-atom as well as the frontier orbital energy difference of porphyrin molecules were calculated by using semiempirical PM3 method. Experimental data showed that the protonation degree of porphyrins depends on the net charge at=N-atom as well as the frontier orbital energy difference of porphyrin and steric hindrance of substituent group.
The overall protonation constants of five porphyrin-anthraquinone compounds were determined by spectrophotometric method. The changes of standard molar enthalpy △rHθm<0 and standard molar entropy △rSmθ0 in the protonation reaction were calculated from the plots of lg Kθ vs 1/T. The in electron effect and steric hindrance of substituent groups on overall protonation constants were discussed.The net charge at=N-atom as well as the frontier orbital energy difference of porphyrin molecules were calculated by using semiempirical PM3 method. Experimental data showed that the protonation degree of porphyrins depends on the net charge at=N-atom as well as the frontier orbital energy difference of porphyrin and steric hindrance of substituent group.
2004, 21(8): 775-778
Abstract:
SnO2-CuO composite nanoparticles were prepared by co-precipitation method. The particle size, structure, morphology and composition of the product were characterized by TG, XRD, TEM and EDS. The cataly-tic activity of the product in the thermal decomposition of cyclotrimethylene trinitramine(RDX) was determined. The average particle size of the product were in the range of 4 to 10 nm as the calcination temperature of the precursors was from 400℃ to 600℃. The SnO2-CuO nanoparticles exhibit high catalytic activity in the thermal decomposition of RDX. The peak temperature of thermal decomposition of RDX decreased by 9℃, and the decomposition enthalpy △H of RDX increased by 422 J/g, in the presence of SnO2-CuO composite nanoparticles.
SnO2-CuO composite nanoparticles were prepared by co-precipitation method. The particle size, structure, morphology and composition of the product were characterized by TG, XRD, TEM and EDS. The cataly-tic activity of the product in the thermal decomposition of cyclotrimethylene trinitramine(RDX) was determined. The average particle size of the product were in the range of 4 to 10 nm as the calcination temperature of the precursors was from 400℃ to 600℃. The SnO2-CuO nanoparticles exhibit high catalytic activity in the thermal decomposition of RDX. The peak temperature of thermal decomposition of RDX decreased by 9℃, and the decomposition enthalpy △H of RDX increased by 422 J/g, in the presence of SnO2-CuO composite nanoparticles.
2004, 21(8): 779-782
Abstract:
Cationic ionomer modified Pt nano-particles were synthesized by chemical reduction using polydiallyldimethylammonium chloride(PDDA) as a modification ion. From a reaction solution containing a mixture of PDDA(Mw=5 000) and Pt with n(PDDA):n(Pt)=10:1 and pH value of 8.5, Pt nano-particles sized in ~4.5 nm were obtained in 5 min reaction. The reduction reaction rate increased with the decrease of the PDDA content and the increase of the pH. The steric hinderance effect of the modifier becomes greater and the electrostatic effect of the modifier reduces as a result of the increase in the degree of polymerization of PDDA. Therefore, the content of PDDA necessary for obtaining stable Pt particles first increases and then decreases as polymerization degree of PDDA increases.
Cationic ionomer modified Pt nano-particles were synthesized by chemical reduction using polydiallyldimethylammonium chloride(PDDA) as a modification ion. From a reaction solution containing a mixture of PDDA(Mw=5 000) and Pt with n(PDDA):n(Pt)=10:1 and pH value of 8.5, Pt nano-particles sized in ~4.5 nm were obtained in 5 min reaction. The reduction reaction rate increased with the decrease of the PDDA content and the increase of the pH. The steric hinderance effect of the modifier becomes greater and the electrostatic effect of the modifier reduces as a result of the increase in the degree of polymerization of PDDA. Therefore, the content of PDDA necessary for obtaining stable Pt particles first increases and then decreases as polymerization degree of PDDA increases.
2004, 21(8): 783-787
Abstract:
Polypropylene/attapulgite(PP/AT) nanocomposites were prepared by melt-compounding. The nonisothermal crystallization kinetics of polypropylene(PP) and PP/AT nanocomposites were investigated by differential scanning calorimetry(DSC). The Jeziorny, Ozawa and Liu methods were employed to analyze the DSC data. The results show that both Jeziorny method and Liu method could describe this system very well. The activation energies of the nonisothermal crystallization of PP and PP/AT nanocomposite evaluated by Arrhenius equation were 194.1 kJ/mol and 162.8 kJ/mol, respectively. Compounding with attapulgite decreases the activation energy of crystallization of PP. Attapulgite could be used as nucleating agent in nonisothermal crystallization process of PP.
Polypropylene/attapulgite(PP/AT) nanocomposites were prepared by melt-compounding. The nonisothermal crystallization kinetics of polypropylene(PP) and PP/AT nanocomposites were investigated by differential scanning calorimetry(DSC). The Jeziorny, Ozawa and Liu methods were employed to analyze the DSC data. The results show that both Jeziorny method and Liu method could describe this system very well. The activation energies of the nonisothermal crystallization of PP and PP/AT nanocomposite evaluated by Arrhenius equation were 194.1 kJ/mol and 162.8 kJ/mol, respectively. Compounding with attapulgite decreases the activation energy of crystallization of PP. Attapulgite could be used as nucleating agent in nonisothermal crystallization process of PP.
2004, 21(8): 788-792
Abstract:
Selenium nanoparticles have been synthesized in an aqueous solution by using chitosan(CTS) as a soft template. The factors on synthesis, such as reaction time, concentration of reactants, temperature, and ultrasonic irradiation were studied. The uniform stable selenium nanospheres were obtained in conditions of 1.20×10-4(mass fraction) CTS, n(Vc):n(H2SeO3)=4:1 and 2 h after the initiation of the reaction at room temperature. The average particle size of selenium is about 50 nm and decreases with increase of the total concentration of the reactants. Selenium nanorods were obtained at 80℃. The products were characterized by UV, IR, XRD and TEM.
Selenium nanoparticles have been synthesized in an aqueous solution by using chitosan(CTS) as a soft template. The factors on synthesis, such as reaction time, concentration of reactants, temperature, and ultrasonic irradiation were studied. The uniform stable selenium nanospheres were obtained in conditions of 1.20×10-4(mass fraction) CTS, n(Vc):n(H2SeO3)=4:1 and 2 h after the initiation of the reaction at room temperature. The average particle size of selenium is about 50 nm and decreases with increase of the total concentration of the reactants. Selenium nanorods were obtained at 80℃. The products were characterized by UV, IR, XRD and TEM.
2004, 21(8): 793-796
Abstract:
The title compounds, 3a~3h, were synthesized from 5,5-dimethyl-2-chloro-2-oxo-1,3,2-dioxaphosphosrinane, hydrazine hydrate and substituted benzaldehydes. The structures of the compounds were confirmed by IR, 1H NMR, MS and elemental analysis. TG and DTA analysis showed that some of the compounds e.g. 3e began to decompose at 220℃ and have certain thermal stability. They decomposed rapidly at temperature range 220~400℃. Prelimary test showed the title compounds have high flame retardance activity for alkyd resin and epoxy E-44 varnish.
The title compounds, 3a~3h, were synthesized from 5,5-dimethyl-2-chloro-2-oxo-1,3,2-dioxaphosphosrinane, hydrazine hydrate and substituted benzaldehydes. The structures of the compounds were confirmed by IR, 1H NMR, MS and elemental analysis. TG and DTA analysis showed that some of the compounds e.g. 3e began to decompose at 220℃ and have certain thermal stability. They decomposed rapidly at temperature range 220~400℃. Prelimary test showed the title compounds have high flame retardance activity for alkyd resin and epoxy E-44 varnish.
2004, 21(8): 797-800
Abstract:
Two terthiophene derivatives containing an alkylamide group, N,N'-dialkyl-5,5"-dichloro-2,2':5',2"-terthiophene-4,4"-dicarboxamide(DNCnDI3T,n=8,18) and N,N'-dialkyl-5,5"-diiodo-2,2':5',2"-terthiophene-4,4"-dicarboxamide(DNCnDI3T,n=8,18) were synthesized, their thermal behavior were examined. Polarized light microscopy and differential scanning calorimetry reveal DNC18Dl3T and DNC18DI3T exhibit smectic A phase, whereas DNC8Dl3T and DNC8DI3T do not form liquid crystal phase. It indicated that the alkyl chain length shows great effects on the liquid crystal phase formation.
Two terthiophene derivatives containing an alkylamide group, N,N'-dialkyl-5,5"-dichloro-2,2':5',2"-terthiophene-4,4"-dicarboxamide(DNCnDI3T,n=8,18) and N,N'-dialkyl-5,5"-diiodo-2,2':5',2"-terthiophene-4,4"-dicarboxamide(DNCnDI3T,n=8,18) were synthesized, their thermal behavior were examined. Polarized light microscopy and differential scanning calorimetry reveal DNC18Dl3T and DNC18DI3T exhibit smectic A phase, whereas DNC8Dl3T and DNC8DI3T do not form liquid crystal phase. It indicated that the alkyl chain length shows great effects on the liquid crystal phase formation.
2004, 21(8): 801-805
Abstract:
The microstructure and electrochemical performance of coated graphite obtained by ultrasonic impregnation technique were investigated. The results show that ultrasonic impregnation technique favors coating of graphite profoundly and uniformly, at the same time prevents the co-intercalation of solvated lithium ions into graphite layers effectively. The charge-discharge capacity of the composite material attains 308.2 mA·h/g in 1 mol/L LiClO4/EC+DMC(1:1) electrolyte. The electrode can also be recycled in propylene carbonate based electrolyte solution.
The microstructure and electrochemical performance of coated graphite obtained by ultrasonic impregnation technique were investigated. The results show that ultrasonic impregnation technique favors coating of graphite profoundly and uniformly, at the same time prevents the co-intercalation of solvated lithium ions into graphite layers effectively. The charge-discharge capacity of the composite material attains 308.2 mA·h/g in 1 mol/L LiClO4/EC+DMC(1:1) electrolyte. The electrode can also be recycled in propylene carbonate based electrolyte solution.
2004, 21(8): 806-809
Abstract:
A surface-active macromonomer(VBDMOAC) was synthesized from p-vinyl benzyl chloride and octadecyl dimethyl amine. Its structure was identified by measurement of chlorine content, IR and 1H NMR. Its cmc and γcmc were determined to be 1.19×10-4 mol/L and 41.4 mN/m, respectively. Compared to AM-AA copolymer prepared in the same conditions, the intrinsic viscosities of the copolymers obtained from ternary polymerization of VBDMOAC, AM and AA in aqueous solvent showed that VBDMOAC have a higher polymerization activity. The terpolymer (VBDMOAC-AM-AA) was verified by its UV band at 224 nm and IR band at 1454 cm-1.
A surface-active macromonomer(VBDMOAC) was synthesized from p-vinyl benzyl chloride and octadecyl dimethyl amine. Its structure was identified by measurement of chlorine content, IR and 1H NMR. Its cmc and γcmc were determined to be 1.19×10-4 mol/L and 41.4 mN/m, respectively. Compared to AM-AA copolymer prepared in the same conditions, the intrinsic viscosities of the copolymers obtained from ternary polymerization of VBDMOAC, AM and AA in aqueous solvent showed that VBDMOAC have a higher polymerization activity. The terpolymer (VBDMOAC-AM-AA) was verified by its UV band at 224 nm and IR band at 1454 cm-1.
2004, 21(8): 810-813
Abstract:
Superfine NaHCO3 powder and its composite particles with carbon-white were prepared. The size, shape, structure and application performance of the composite particles have been characterized. The results show that the tight ball-shape NaHCO3/SiO2 composite particles are formed as a result of physical adsorption of NaHCO3 particles on the surface or hole of carbon-white. There are no new materials formed in the mixing process. During the mixing, the strong mechanical force makes the surface structure of the NaHCO3 distorted and both the distortion of crystal structure and the amorphous level of the particle surface increased with increasing of the composite time. The dispersion and suspension stability of NaHCO3 powder in the air have been improved. The cold aerosol fire extinguishing agent prepared from composite particles shows good fire extinguishing quality.
Superfine NaHCO3 powder and its composite particles with carbon-white were prepared. The size, shape, structure and application performance of the composite particles have been characterized. The results show that the tight ball-shape NaHCO3/SiO2 composite particles are formed as a result of physical adsorption of NaHCO3 particles on the surface or hole of carbon-white. There are no new materials formed in the mixing process. During the mixing, the strong mechanical force makes the surface structure of the NaHCO3 distorted and both the distortion of crystal structure and the amorphous level of the particle surface increased with increasing of the composite time. The dispersion and suspension stability of NaHCO3 powder in the air have been improved. The cold aerosol fire extinguishing agent prepared from composite particles shows good fire extinguishing quality.
2004, 21(8): 814-817
Abstract:
The Fe2O3-PMMA composite nanoparticles were prepared from Fe2O3 and PMMA via in-situ polymerisation of MMA. The powder is characterized by TEM, XRD, FTIR and magnetic-balance. The result shows that the Fe2O3-PMMA powder is cubic system with average diameter and magnetic susceptibility 30.3 nm and 1.44×10 -7 m3/mol respectively. The compound has solubility of 0.6% in physiological saline at 37℃.
The Fe2O3-PMMA composite nanoparticles were prepared from Fe2O3 and PMMA via in-situ polymerisation of MMA. The powder is characterized by TEM, XRD, FTIR and magnetic-balance. The result shows that the Fe2O3-PMMA powder is cubic system with average diameter and magnetic susceptibility 30.3 nm and 1.44×10 -7 m3/mol respectively. The compound has solubility of 0.6% in physiological saline at 37℃.
2004, 21(8): 818-820
Abstract:
Synthesis of diallylmethylamine from lower concentration methylamine water solution and allylchloride has been performed using polyglycol-400(PEG-400) as phase transfer catalyst. The results show that the reaction time can be efficiently shortened and product yield can be significantly increased. The orthogonal experimental method has been used to optimize the experiment conditions. The optimal condition are as follows:PEG-400 phase transfer catalyst, mole ratios of allylchloride:methylamine=2.2:1, the two periods of reaction temperature and time 20℃(1 h) and 60℃(6 h), diallylmethylamine is obtained in 75.6% yield. The product is characterized by IR, GC-MS and 1H NMR.
Synthesis of diallylmethylamine from lower concentration methylamine water solution and allylchloride has been performed using polyglycol-400(PEG-400) as phase transfer catalyst. The results show that the reaction time can be efficiently shortened and product yield can be significantly increased. The orthogonal experimental method has been used to optimize the experiment conditions. The optimal condition are as follows:PEG-400 phase transfer catalyst, mole ratios of allylchloride:methylamine=2.2:1, the two periods of reaction temperature and time 20℃(1 h) and 60℃(6 h), diallylmethylamine is obtained in 75.6% yield. The product is characterized by IR, GC-MS and 1H NMR.
2004, 21(8): 821-823
Abstract:
Poly(methyl methacrylate)-titania(PMMA-TiO2) nanocomposites were synthesized from tetrabutyl titanate(TBT) and methyl methacrylate(MMA) by sol-gel process using methacryloyloxypropyl trimethoxy siliane(MPTMS) as coupling agent and dilute hydrochloric acid as catalyst. Reaction parameters affecting the character of the products, such as the concentration of HCl, amount of water and coupling agent were discussed. The results showed that considerable good product can be obtained when the concentration of HCl is (0.3±0.02) mol/L,n(TBT):n(H2O) >5:1 and n(MPTMS)/n(TBT) >1. The chemical structure of PMMA-TiO2 was characterized by IR, TEM and TG/DTA.
Poly(methyl methacrylate)-titania(PMMA-TiO2) nanocomposites were synthesized from tetrabutyl titanate(TBT) and methyl methacrylate(MMA) by sol-gel process using methacryloyloxypropyl trimethoxy siliane(MPTMS) as coupling agent and dilute hydrochloric acid as catalyst. Reaction parameters affecting the character of the products, such as the concentration of HCl, amount of water and coupling agent were discussed. The results showed that considerable good product can be obtained when the concentration of HCl is (0.3±0.02) mol/L,n(TBT):n(H2O) >5:1 and n(MPTMS)/n(TBT) >1. The chemical structure of PMMA-TiO2 was characterized by IR, TEM and TG/DTA.
2004, 21(8): 824-825
Abstract:
The synthesis of photosensitive 1-(3-aminophenyl)-3-(4-aminophenyl)-2-propen-1-one(Ⅵ) was carried out by an adol condensation reaction of 3-acetylacetanilide and 4-acetamidobenzaldehyde using NaOH solution as catalyst with total yield of 61.9%. The optimum synthesis conditions were obtained. The method has the advantages of low cost, high yield and easy operation. The target compound was characterized by elemental analysis, IR and NMR. Its maximal UV-Vis absorption is at 349 nm.
The synthesis of photosensitive 1-(3-aminophenyl)-3-(4-aminophenyl)-2-propen-1-one(Ⅵ) was carried out by an adol condensation reaction of 3-acetylacetanilide and 4-acetamidobenzaldehyde using NaOH solution as catalyst with total yield of 61.9%. The optimum synthesis conditions were obtained. The method has the advantages of low cost, high yield and easy operation. The target compound was characterized by elemental analysis, IR and NMR. Its maximal UV-Vis absorption is at 349 nm.
2004, 21(8): 826-828
Abstract:
Difluoro-4-alkoxyphenols were prepared from 2,3-difluoro-4-alkoxy bromobenzene with Mg, B(OCH3)3 and H2O2 at -30℃. Three ester liquid crystal compounds were synthesized by their esterification with 4-(trans-4'-alkylohexyl) compounds. The structures of the liquid crystal compounds were confirmed by IR, 1H NMR, MS and elemental analysis and the phase transition temperatures were measured by DSC.
Difluoro-4-alkoxyphenols were prepared from 2,3-difluoro-4-alkoxy bromobenzene with Mg, B(OCH3)3 and H2O2 at -30℃. Three ester liquid crystal compounds were synthesized by their esterification with 4-(trans-4'-alkylohexyl) compounds. The structures of the liquid crystal compounds were confirmed by IR, 1H NMR, MS and elemental analysis and the phase transition temperatures were measured by DSC.
2004, 21(8): 829-831
Abstract:
The synthesis of a tripod Schiff-base ligand and its eight complexes with rare earth metals are reported. All compounds were characterized by elemental analysis, IR, 1H NMR, TG-DTA and molar conductance measurements. The results show that these complexes[LnL(NO3)2]NO3·nH2O(n=3,Ln=La,Sm,Eu,Gd; n=4, Ln=Tb,Dy,Yb,Y) are 1:1 electrolyte, where one nitrate radical is free, the other two nitrate radicals are in mono-dentate coordination with Ln(Ⅲ) ions; the coordination number is 9. The ligand exhibits good antioxidative activity at concentration of 1×10-4 mol/L.
The synthesis of a tripod Schiff-base ligand and its eight complexes with rare earth metals are reported. All compounds were characterized by elemental analysis, IR, 1H NMR, TG-DTA and molar conductance measurements. The results show that these complexes[LnL(NO3)2]NO3·nH2O(n=3,Ln=La,Sm,Eu,Gd; n=4, Ln=Tb,Dy,Yb,Y) are 1:1 electrolyte, where one nitrate radical is free, the other two nitrate radicals are in mono-dentate coordination with Ln(Ⅲ) ions; the coordination number is 9. The ligand exhibits good antioxidative activity at concentration of 1×10-4 mol/L.
2004, 21(8): 832-834
Abstract:
Penicillinase was immobilized by glutaraldehyde-bovine serum albumin and sodium alginate was used for the construction of enzyme biosensors in determination of trace penicillin in milk. Penicillinase activity was determined by potentionmetric method. At low concentrations, the response time of the electrode modified by the method of crossing-link was 30~60 s, and the electrode showed high sensitivity. Linear detection range from 1.40×10-3 to 3.36×10-2 mmol/L in PBS and from 5.61×10-2 to 3.36×10-1 mmol/L in milk were achieved. The electrode can be used for at least 7 d with perfect reproducibility during the first 4 d. The life of the electrode was 30 d.
Penicillinase was immobilized by glutaraldehyde-bovine serum albumin and sodium alginate was used for the construction of enzyme biosensors in determination of trace penicillin in milk. Penicillinase activity was determined by potentionmetric method. At low concentrations, the response time of the electrode modified by the method of crossing-link was 30~60 s, and the electrode showed high sensitivity. Linear detection range from 1.40×10-3 to 3.36×10-2 mmol/L in PBS and from 5.61×10-2 to 3.36×10-1 mmol/L in milk were achieved. The electrode can be used for at least 7 d with perfect reproducibility during the first 4 d. The life of the electrode was 30 d.
2004, 21(8): 835-837
Abstract:
A Schiff base derived from 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone(PMBP) with p-aminodimethyl aniline and its complexes with Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ) have been prepared and characterized by elemental analysis, IR, UV and 1H NMR techniques. The ligand and the complexes particurally the Co(Ⅱ) complex have antibacterial activities against Escherichia cocli and Staphylococcus aureus.
A Schiff base derived from 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone(PMBP) with p-aminodimethyl aniline and its complexes with Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ) have been prepared and characterized by elemental analysis, IR, UV and 1H NMR techniques. The ligand and the complexes particurally the Co(Ⅱ) complex have antibacterial activities against Escherichia cocli and Staphylococcus aureus.
2004, 21(8): 838-840
Abstract:
The title compound was prepared in yield of 93.3% by reaction of phenyl isocyanate with 2-chloro-4-amino pyridine. The latter was obtained by nitrification, reduction of 2-chloropyridine-N-oxide. The best conditions of the reaction were given.
The title compound was prepared in yield of 93.3% by reaction of phenyl isocyanate with 2-chloro-4-amino pyridine. The latter was obtained by nitrification, reduction of 2-chloropyridine-N-oxide. The best conditions of the reaction were given.
2004, 21(8): 841-843
Abstract:
The 2-(carboxymethoxyl)benzaldehyde benzoyl hydrazone(H2L) was prepared by condensation of O-formylphenoxy acetic acid with benzoyl hydrazine in ethanol. Eight rare earth complexes with H2 were synthesized in methanol and characterized by elemental analysis, IR, 1H NMR, EI-MS and molar conductivity measurement. The results indicated the molecular formula of H2L is C16H24N2O4 and the composition of rare earth complexes is REL3·nH2O(where n=1~2, RE=La, Sm, Eu, Gd, Tb, Dy, Yb and Y). The H2L as a tridentate ligand coordinates with rare earth ion and forms nine-coordination complexes. The K-B method tests showed the title complexes only have a low bacteriostatic activity against staphylocus auteus, escherichia coil and bacillus subtilis.
The 2-(carboxymethoxyl)benzaldehyde benzoyl hydrazone(H2L) was prepared by condensation of O-formylphenoxy acetic acid with benzoyl hydrazine in ethanol. Eight rare earth complexes with H2 were synthesized in methanol and characterized by elemental analysis, IR, 1H NMR, EI-MS and molar conductivity measurement. The results indicated the molecular formula of H2L is C16H24N2O4 and the composition of rare earth complexes is REL3·nH2O(where n=1~2, RE=La, Sm, Eu, Gd, Tb, Dy, Yb and Y). The H2L as a tridentate ligand coordinates with rare earth ion and forms nine-coordination complexes. The K-B method tests showed the title complexes only have a low bacteriostatic activity against staphylocus auteus, escherichia coil and bacillus subtilis.
2004, 21(8): 844-846
Abstract:
The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is determined from the absorbance change of bromophenol blue solution as function of copolymer concentration, which is about 1×10-6 mol/L. The critical coagulation concentration (ccz) of electrolytes with different valence(z) for the copolymer micelles are examined by visual method and compared with that obtained by experiential formula ccz∝z-6. The relation formula for different cations is deduced:ccz∝z -4, which indicates the electronegative character of the micelle surface.
The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is determined from the absorbance change of bromophenol blue solution as function of copolymer concentration, which is about 1×10-6 mol/L. The critical coagulation concentration (ccz) of electrolytes with different valence(z) for the copolymer micelles are examined by visual method and compared with that obtained by experiential formula ccz∝z-6. The relation formula for different cations is deduced:ccz∝z -4, which indicates the electronegative character of the micelle surface.
2004, 21(8): 847-849
Abstract:
Two benzothiazospironaphtopyran photochromic compounds have been synthesized by reacting 2-hydroxy naphthaldehyde with 2-methylenebenzothiazole derivatives respectively, under microwave irradiation in good yields:61% for SP1 and 59% for SP2. Triethylamine was used as catalyst and anhydrous ethanol as solvent. The elemental analysis, IR, MS, 1H NMR were used to identify the title compounds. Their spectral properties were studied. The λmax values of their corresponding ring-opening compounds were linearly correlated with the polarity of solvents.
Two benzothiazospironaphtopyran photochromic compounds have been synthesized by reacting 2-hydroxy naphthaldehyde with 2-methylenebenzothiazole derivatives respectively, under microwave irradiation in good yields:61% for SP1 and 59% for SP2. Triethylamine was used as catalyst and anhydrous ethanol as solvent. The elemental analysis, IR, MS, 1H NMR were used to identify the title compounds. Their spectral properties were studied. The λmax values of their corresponding ring-opening compounds were linearly correlated with the polarity of solvents.
2004, 21(8): 850-852
Abstract:
The pentadecanolide was biosynthesized in cyclohexane from 15-hydroxypentadecanoic acid, which as prepared from 15-tetracosenoic acid in Malania Olcifera Chum oil using lipase as catalyst. The effect of lipase activity on the lactonization was investigated. Lipases from fiften strains (13 strains of Candida and 2 strains of Penicillium) showed different catalytic effects to the synthesis reactions. The lipases from strains of Penicillium sp. and 4 strains of Candida sp. have catalytic lactonization activity, and the conversion ratio of substrate reached 88% by using lipase Candida sp.GXU01.
The pentadecanolide was biosynthesized in cyclohexane from 15-hydroxypentadecanoic acid, which as prepared from 15-tetracosenoic acid in Malania Olcifera Chum oil using lipase as catalyst. The effect of lipase activity on the lactonization was investigated. Lipases from fiften strains (13 strains of Candida and 2 strains of Penicillium) showed different catalytic effects to the synthesis reactions. The lipases from strains of Penicillium sp. and 4 strains of Candida sp. have catalytic lactonization activity, and the conversion ratio of substrate reached 88% by using lipase Candida sp.GXU01.
2004, 21(8): 853-855
Abstract:
1,1'-Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O'-di(3,5-dimethylbenzoyl)N,N'-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane):V(2-propanol)=95:5 was used as mobile phase at a flow rate of 1.0 mL/min at 25℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1'-Bi-2-naphthyl di-P-toluenesulfonate, 1,1'-bi-2-naphthyl diacetate and 1,1'-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.
1,1'-Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O'-di(3,5-dimethylbenzoyl)N,N'-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane):V(2-propanol)=95:5 was used as mobile phase at a flow rate of 1.0 mL/min at 25℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1'-Bi-2-naphthyl di-P-toluenesulfonate, 1,1'-bi-2-naphthyl diacetate and 1,1'-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.
2004, 21(8): 856-858
Abstract:
Nylon 66 membranes prepared by phase inversion method were modified with supercritical CO2. XRD, SEM and water flux measurements were used to assess properties of membrane in modification. The intensity of diffraction peak of modified membrane increased as shown in XRD, it indicates that the degree of crystallinity of the membrane rised after modification. In fact, different structures could be made with CO2 pressure:cellular structure at 8 MPa and lacy structure at 16 MPa. Water fluxes of the modified membranes were higher than that of the initial nylon 66 membrane which was 2.178×10-5 g/(s·m2·Pa). In the pressure range of 8~14 MPa, the water fluxes was reduced from 13.18×10-5 g/(s·m2·Pa) to 4.828×10-5 g/(s·m2·Pa), and was raised to 6.411×10-5 g/(s·m2·Pa) at pressure over 16 MPa.
Nylon 66 membranes prepared by phase inversion method were modified with supercritical CO2. XRD, SEM and water flux measurements were used to assess properties of membrane in modification. The intensity of diffraction peak of modified membrane increased as shown in XRD, it indicates that the degree of crystallinity of the membrane rised after modification. In fact, different structures could be made with CO2 pressure:cellular structure at 8 MPa and lacy structure at 16 MPa. Water fluxes of the modified membranes were higher than that of the initial nylon 66 membrane which was 2.178×10-5 g/(s·m2·Pa). In the pressure range of 8~14 MPa, the water fluxes was reduced from 13.18×10-5 g/(s·m2·Pa) to 4.828×10-5 g/(s·m2·Pa), and was raised to 6.411×10-5 g/(s·m2·Pa) at pressure over 16 MPa.
2004, 21(8): 859-861
Abstract:
The platinum catalyst supported on carbon covered γ-Al2O3(CCA) or γ-Al2O3 with K2O as assistant was prepared and used for preparation of o-phenylphenol(OPP) by dehydrogenation of 2-cyclohexenyl-cyclohexanone. The catalyst was pre-poisoned with CS2 to improve its catalytic activity. The results showed that the catalytic performance of Pt supported on CCA is better than that supported on γ-Al2O3. When the catalyst consists of[ω(Pt)=0.5%, ω(K2O)=1%]/CCA[ω(C)=1.5%] and m(CS2):m(Pt) is 1.0:100, the selectivity of OPP was more 96% in a reaction condition of 350℃ and flow rate of H2 at 60 mL/min.
The platinum catalyst supported on carbon covered γ-Al2O3(CCA) or γ-Al2O3 with K2O as assistant was prepared and used for preparation of o-phenylphenol(OPP) by dehydrogenation of 2-cyclohexenyl-cyclohexanone. The catalyst was pre-poisoned with CS2 to improve its catalytic activity. The results showed that the catalytic performance of Pt supported on CCA is better than that supported on γ-Al2O3. When the catalyst consists of[ω(Pt)=0.5%, ω(K2O)=1%]/CCA[ω(C)=1.5%] and m(CS2):m(Pt) is 1.0:100, the selectivity of OPP was more 96% in a reaction condition of 350℃ and flow rate of H2 at 60 mL/min.
2004, 21(8): 862-864
Abstract:
The acylation of isobutylbenzene by using catalytic amount of Bi(OTf)3 has been investigated as function of reaction time, reaction temperature, catalyst dosage and acetyl chloride. It was found that the catalytic activity of Bi(OTf)3 could be greatly enhanced in the presence of LiClO4 in nitromethane. Under the optimum condition:Bi(OTf)320%, 4 mol/L LiClO4-CH3NO2, 8 h and 100℃, the yield of 4-isobutylacetophenone was up to 90%.
The acylation of isobutylbenzene by using catalytic amount of Bi(OTf)3 has been investigated as function of reaction time, reaction temperature, catalyst dosage and acetyl chloride. It was found that the catalytic activity of Bi(OTf)3 could be greatly enhanced in the presence of LiClO4 in nitromethane. Under the optimum condition:Bi(OTf)320%, 4 mol/L LiClO4-CH3NO2, 8 h and 100℃, the yield of 4-isobutylacetophenone was up to 90%.
