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2000 Volume 17 Issue 1
2000, 17(1): 1-5
Abstract:
The exchange reaction kinetics of verapamil hydrochloride(VH)w ith the strongly acidic cation exchange resin (001×7)and the release property of VH from the drug-resin complexes in deionic water, 0.5~2.0 mol/L NaCl and 0.5 mol/L HCl as well as 0.5 mol/L KCl solutions have been studied. It is found that the ex change rate increases with increase of temperature.The equilibrium constant of VH was 0.0527(298 K).The exchange reaction of VH with 001×7 was found to be controlled by particle diffusion process. The study of drug release in vitro showed that no VH release was found from drug-resin complexes in deionic water medium. The release rate increased with increase of ionic streng th of the release medium.The release of VH from drug-resin complexes could be effectively controlled by the strongly acidic cation exchange resin (001×7). The diffusion of VH within the resin particles was controlled by a particle diffusion process acco rding to Visw anathan's equation. The diffusion coefficients increased with the increase of the ionic streng th of the releasing media.
The exchange reaction kinetics of verapamil hydrochloride(VH)w ith the strongly acidic cation exchange resin (001×7)and the release property of VH from the drug-resin complexes in deionic water, 0.5~2.0 mol/L NaCl and 0.5 mol/L HCl as well as 0.5 mol/L KCl solutions have been studied. It is found that the ex change rate increases with increase of temperature.The equilibrium constant of VH was 0.0527(298 K).The exchange reaction of VH with 001×7 was found to be controlled by particle diffusion process. The study of drug release in vitro showed that no VH release was found from drug-resin complexes in deionic water medium. The release rate increased with increase of ionic streng th of the release medium.The release of VH from drug-resin complexes could be effectively controlled by the strongly acidic cation exchange resin (001×7). The diffusion of VH within the resin particles was controlled by a particle diffusion process acco rding to Visw anathan's equation. The diffusion coefficients increased with the increase of the ionic streng th of the releasing media.
2000, 17(1): 6-10
Abstract:
Four hydrophobic phenanthroline iron(Ⅱ)complexes, tris(5-lauramido-1, 10-phenanthroline) iron (Ⅱ) perchlorate, tris (5-myristamido-1, 10-phenanthroline) iron (Ⅱ) perchlo rate, tris (5-palmitamido-1, 10-phenanthroline)iron (Ⅱ) perchlo rate and tris (5-stearamido-1, 10-phenanthroline) iron(Ⅱ) perchlorate, have been sy nthesized and characterized by elemental analysis, IR, 1H NMR, 1H-1H COSY and LD-MS. 1H NMR spectra of these complexes showed that each of them exists in two isomers in relative proportion of 1:1. The electrochemical behavior of these Fe(Ⅱ) complexes have been investigated with cyclic voltammetry and square-wave voltammetry.
Four hydrophobic phenanthroline iron(Ⅱ)complexes, tris(5-lauramido-1, 10-phenanthroline) iron (Ⅱ) perchlorate, tris (5-myristamido-1, 10-phenanthroline) iron (Ⅱ) perchlo rate, tris (5-palmitamido-1, 10-phenanthroline)iron (Ⅱ) perchlo rate and tris (5-stearamido-1, 10-phenanthroline) iron(Ⅱ) perchlorate, have been sy nthesized and characterized by elemental analysis, IR, 1H NMR, 1H-1H COSY and LD-MS. 1H NMR spectra of these complexes showed that each of them exists in two isomers in relative proportion of 1:1. The electrochemical behavior of these Fe(Ⅱ) complexes have been investigated with cyclic voltammetry and square-wave voltammetry.
2000, 17(1): 11-13
Abstract:
As potential materials for optical biosensor, the surface property of the monolayer film consisted of a mixture of 10, 12-pentacosadiynoic acid (PDA) and its α-D-mannopyranoside (MPDA)at water-gas interface has been investigated at different pH and temperature.The results show that the monolayer is rigid and more stable when pH=5.16~5.64 and subphase temperature below 14℃.
As potential materials for optical biosensor, the surface property of the monolayer film consisted of a mixture of 10, 12-pentacosadiynoic acid (PDA) and its α-D-mannopyranoside (MPDA)at water-gas interface has been investigated at different pH and temperature.The results show that the monolayer is rigid and more stable when pH=5.16~5.64 and subphase temperature below 14℃.
2000, 17(1): 14-17
Abstract:
The polybuty lacrylate(PBA)has been intercalated into the kaolinite nanolayers of Baini (a mixtute of kaolinite and muscovite) by multi-step exchange reaction and diffusion polymerization. The structure changes of the Baini compounds have been recorded by XRD.The hy brid nanocomposite thermoplastic elastomers have been prepared by melt-blending of Baini-PBA with SBS triblock copoly mer at 160℃. The tensile streng th, elong ation at break and glass transition temperature (Tg2)of the elastomer with Baini-PBA content of 0.5% to 6.0% were increased from 15.70 MPa, 598.3% and 96℃ to 26.76 MPa, 846.0% and 156℃ of the parent SBS copolymer respectively, but the transparency and the Tg1 remained unchanged(-76℃).
The polybuty lacrylate(PBA)has been intercalated into the kaolinite nanolayers of Baini (a mixtute of kaolinite and muscovite) by multi-step exchange reaction and diffusion polymerization. The structure changes of the Baini compounds have been recorded by XRD.The hy brid nanocomposite thermoplastic elastomers have been prepared by melt-blending of Baini-PBA with SBS triblock copoly mer at 160℃. The tensile streng th, elong ation at break and glass transition temperature (Tg2)of the elastomer with Baini-PBA content of 0.5% to 6.0% were increased from 15.70 MPa, 598.3% and 96℃ to 26.76 MPa, 846.0% and 156℃ of the parent SBS copolymer respectively, but the transparency and the Tg1 remained unchanged(-76℃).
2000, 17(1): 18-21
Abstract:
The stereospecific polymerization of methyl methacrylate has been studied using (C9H7)2Y(μ-Et)2AlEt2 as a single-component catalyst and its combination with (i-Bu)3Al as a two-component catalyst. By using the former catalyst PMMA with molecular weight of 3.4×106 and isotactic content of 93% was obtained. The latter catalyst system gave PMMA with molecular weight of about 0.6×106 and syndiotactic content of 65%.
The stereospecific polymerization of methyl methacrylate has been studied using (C9H7)2Y(μ-Et)2AlEt2 as a single-component catalyst and its combination with (i-Bu)3Al as a two-component catalyst. By using the former catalyst PMMA with molecular weight of 3.4×106 and isotactic content of 93% was obtained. The latter catalyst system gave PMMA with molecular weight of about 0.6×106 and syndiotactic content of 65%.
Distribution of Rare Earth Elements in Polyethylene glycol-Ammonium Sulphate Aqueous Biphasic System
2000, 17(1): 22-25
Abstract:
The ditribution behavior of La, Yb, Eu and asenazo Ⅲ in the polyethylene glycol-ammonium sulphate aqueous biphasic system have been investigated. It is showed that the distribution ratios of rare earth elements in the presence of arsenazo Ⅲ increased with the increasing of PEG molecular weight, asenazo Ⅲ concentration and their complex constants. The interaction of arsenazo Ⅲ and rare earth elements with the polyethylene glycol has been discussed.
The ditribution behavior of La, Yb, Eu and asenazo Ⅲ in the polyethylene glycol-ammonium sulphate aqueous biphasic system have been investigated. It is showed that the distribution ratios of rare earth elements in the presence of arsenazo Ⅲ increased with the increasing of PEG molecular weight, asenazo Ⅲ concentration and their complex constants. The interaction of arsenazo Ⅲ and rare earth elements with the polyethylene glycol has been discussed.
2000, 17(1): 26-30
Abstract:
The interaction of title benzoic acid compound with pepsin in pH 2.15 solution has been studied by UV spectrophotometric method.It is considered that the binding of two compounds is mainly due to the electrostatic force. The influences of acidity, sodium chloride concentration, tem perature, reaction time and other proteins on the interaction have been investigated. The apparent molar absorptivity of the binded compound and the maximum binding value were determined to be ε=3.16×105 L/mol·cm and 100, respectively. The Scatchard model is appropriate for the spectral data treatment.
The interaction of title benzoic acid compound with pepsin in pH 2.15 solution has been studied by UV spectrophotometric method.It is considered that the binding of two compounds is mainly due to the electrostatic force. The influences of acidity, sodium chloride concentration, tem perature, reaction time and other proteins on the interaction have been investigated. The apparent molar absorptivity of the binded compound and the maximum binding value were determined to be ε=3.16×105 L/mol·cm and 100, respectively. The Scatchard model is appropriate for the spectral data treatment.
2000, 17(1): 31-34
Abstract:
An active PbO2 electrode was prepared from Pb-Cd alloy. The existence of amorphous phase in the electrode surface has been confirmed by TEM, XRD and XPS. The results show ed that the lower the content of Pb in alloy, the higher the crystallinity of the active PbO2 and the discharge capacity of the electrode.
An active PbO2 electrode was prepared from Pb-Cd alloy. The existence of amorphous phase in the electrode surface has been confirmed by TEM, XRD and XPS. The results show ed that the lower the content of Pb in alloy, the higher the crystallinity of the active PbO2 and the discharge capacity of the electrode.
2000, 17(1): 35-38
Abstract:
The α-Ni(OH)2⇌γ-NiOOH electrochemical process of α-Ni(OH)2 stabilized by doping with Al has been studied by cyclic voltammetry in simulated battery and AA MH/Ni battery. The XRD results showed that the characteristic structure of α-Ni(OH)2 after one-year rest and many time charge/discharge cy cles in AA MH/Ni battery remained unchanged. The α⇌γ phase tranformation had an advantage over βⅡ⇌βⅢ transformation in some electrochemical properties.
The α-Ni(OH)2⇌γ-NiOOH electrochemical process of α-Ni(OH)2 stabilized by doping with Al has been studied by cyclic voltammetry in simulated battery and AA MH/Ni battery. The XRD results showed that the characteristic structure of α-Ni(OH)2 after one-year rest and many time charge/discharge cy cles in AA MH/Ni battery remained unchanged. The α⇌γ phase tranformation had an advantage over βⅡ⇌βⅢ transformation in some electrochemical properties.
2000, 17(1): 39-42
Abstract:
The standard electrode potentials of the elements in the 1st, 2nd and 7th major groups and the transition elements in the 4th period have been related with the topological indices of element bond parameters and ino rganic compound parameters respectively. A good linear relationship has been obtained.
The standard electrode potentials of the elements in the 1st, 2nd and 7th major groups and the transition elements in the 4th period have been related with the topological indices of element bond parameters and ino rganic compound parameters respectively. A good linear relationship has been obtained.
2000, 17(1): 43-46
Abstract:
The stability constants lg K of the ternary Zn2+, Cd2+ complexes of the M (A) (B) and their corresponding constants Δlg K and lg X have been determined by po tentiometric titration(I=0.1 mol/L KNO3)at 15, 25, 35, and 45℃, respectively, where lig and A is 2, 2'-bipyridyl(bipy), 1, 10-phenanthroline(phen); ligand B is salicylic acid(sali), 3, 5-dinitrosalicylic acid(dini). The thermody namic function changes ΔG, ΔH and ΔS of the coordination reactions were obtained from Van't Hoff equation and thermody namic relations. Comparison of the values of Δlg K, lg X with corresponding statistical values Δlg K (S)and lg X (S)shows that the stability of the ternary complex containing sali is enhanced, but this enhacement is greatly weakened for the ternary com plexes containing dini because of the effect from nitro groups.
The stability constants lg K of the ternary Zn2+, Cd2+ complexes of the M (A) (B) and their corresponding constants Δlg K and lg X have been determined by po tentiometric titration(I=0.1 mol/L KNO3)at 15, 25, 35, and 45℃, respectively, where lig and A is 2, 2'-bipyridyl(bipy), 1, 10-phenanthroline(phen); ligand B is salicylic acid(sali), 3, 5-dinitrosalicylic acid(dini). The thermody namic function changes ΔG, ΔH and ΔS of the coordination reactions were obtained from Van't Hoff equation and thermody namic relations. Comparison of the values of Δlg K, lg X with corresponding statistical values Δlg K (S)and lg X (S)shows that the stability of the ternary complex containing sali is enhanced, but this enhacement is greatly weakened for the ternary com plexes containing dini because of the effect from nitro groups.
2000, 17(1): 47-50
Abstract:
The effects of H2SO4 concentration in stripping phase, H+ concentration in feed phase and temperature on the transport of zinc(Ⅱ) ions through a bulk liquid membrane containing di(2-ethylhexyl) phosphoric acid in kerosene have been studied. The pseudo-first order apparent rate constants, k1d and k2a, of interfacial reactions in membrane-feed solution interface or membrane-stripping solution interface have been determined with bulk liquid membrane on various carrier concentration and Span-80 content.The zinc(Ⅱ)transport kinetics has been evaluated by two consecutive irreversible first order reactions.
The effects of H2SO4 concentration in stripping phase, H+ concentration in feed phase and temperature on the transport of zinc(Ⅱ) ions through a bulk liquid membrane containing di(2-ethylhexyl) phosphoric acid in kerosene have been studied. The pseudo-first order apparent rate constants, k1d and k2a, of interfacial reactions in membrane-feed solution interface or membrane-stripping solution interface have been determined with bulk liquid membrane on various carrier concentration and Span-80 content.The zinc(Ⅱ)transport kinetics has been evaluated by two consecutive irreversible first order reactions.
2000, 17(1): 51-53
Abstract:
The study on separation of bilirubin by liquid membrane showed that ethylacetate is an appropriate carrier for bilirubin, its clearance efficiency for bilirubin is 99.9% in 0.1 mol/L aqueous phosphate buffer and 83% in simulated human serum albumin solution. In comparison with the adsorption of bilirubin by macroporous resins, liquid membrane possesses the merits of more rapid separation rate and higher clearance efficiency.
The study on separation of bilirubin by liquid membrane showed that ethylacetate is an appropriate carrier for bilirubin, its clearance efficiency for bilirubin is 99.9% in 0.1 mol/L aqueous phosphate buffer and 83% in simulated human serum albumin solution. In comparison with the adsorption of bilirubin by macroporous resins, liquid membrane possesses the merits of more rapid separation rate and higher clearance efficiency.
2000, 17(1): 54-56
Abstract:
The ordered two-dimensional arrays of uniform copolymer microspheres had been fabricated on a substrate by the liquid capillary meniscus attraction force method. Thin aluminium film was deposited on the latex monolayer through vacuum evaporation. After ultrasonic etching and dissolving of polymer spheres a surface with features remained. Different patterings of net, islands and separate spots can be obtained by controlling the ultrasonic treatment time. The interaction among the metal, microspheres and the substrate as well as its effect on the micropatternings has been discussed.
The ordered two-dimensional arrays of uniform copolymer microspheres had been fabricated on a substrate by the liquid capillary meniscus attraction force method. Thin aluminium film was deposited on the latex monolayer through vacuum evaporation. After ultrasonic etching and dissolving of polymer spheres a surface with features remained. Different patterings of net, islands and separate spots can be obtained by controlling the ultrasonic treatment time. The interaction among the metal, microspheres and the substrate as well as its effect on the micropatternings has been discussed.
2000, 17(1): 57-59
Abstract:
The bisphenol A type epoxy resin has been modified by p-aminobenzoic acid, that leads to the formation of a product with both hy drophillic and lipophillic properties. DSC records indicated good compatibility of the modified resin with unmodified ones. The waterborne coating film sobtained from the modified resin and the mixture showed good properties in luster, impact strength, hardness, adhesion, flexibility, and also excellent performance on water-resistance and chemical resistance.
The bisphenol A type epoxy resin has been modified by p-aminobenzoic acid, that leads to the formation of a product with both hy drophillic and lipophillic properties. DSC records indicated good compatibility of the modified resin with unmodified ones. The waterborne coating film sobtained from the modified resin and the mixture showed good properties in luster, impact strength, hardness, adhesion, flexibility, and also excellent performance on water-resistance and chemical resistance.
2000, 17(1): 60-62
Abstract:
The cathode material Li1+xMn2O4 was prepared by a modified citric acid complexation method. The influences of temperature, sintering time and n(Li)/n(Mn) ratio on the structure of the products have been explored, characterized and tested by XRD, TEM, BET measurements. The sample sintered at 750℃ for 12 h had greater charge/discharge capacity, better cyclic stability under electric current charge/discharge cycle. The initial capacity reached 120 mA·h/g with the charge/discharge efficieney of 98% and maintained 115 mA·h/g after 50 cycles.
The cathode material Li1+xMn2O4 was prepared by a modified citric acid complexation method. The influences of temperature, sintering time and n(Li)/n(Mn) ratio on the structure of the products have been explored, characterized and tested by XRD, TEM, BET measurements. The sample sintered at 750℃ for 12 h had greater charge/discharge capacity, better cyclic stability under electric current charge/discharge cycle. The initial capacity reached 120 mA·h/g with the charge/discharge efficieney of 98% and maintained 115 mA·h/g after 50 cycles.
2000, 17(1): 63-65
Abstract:
Five corrosion inhibitors have been evaluated in high-temperature naphthenic acid environment: triethyl phosphate(A), dioctylphosphoric acid (B), tripheny lphosphate (C), tetraethylenepentamine(D)and 1-aminoethyl-2-dodecylimidazoline(E). It is found that A, B and C have good inhibitory property and the corrosion inhibitory efficiency increases linearly with the hydrophilicity of inhibitor molecule; poly amine compound, being a corrosion inhibitor, reacts also with naphthenic acid to produce azole or amide compounds, which also behave as inhibitors.
Five corrosion inhibitors have been evaluated in high-temperature naphthenic acid environment: triethyl phosphate(A), dioctylphosphoric acid (B), tripheny lphosphate (C), tetraethylenepentamine(D)and 1-aminoethyl-2-dodecylimidazoline(E). It is found that A, B and C have good inhibitory property and the corrosion inhibitory efficiency increases linearly with the hydrophilicity of inhibitor molecule; poly amine compound, being a corrosion inhibitor, reacts also with naphthenic acid to produce azole or amide compounds, which also behave as inhibitors.
2000, 17(1): 66-68
Abstract:
The N-alkyl chitosans were prepared from chitosan through Schiff-base formation and hydrogenation. The adsorption properties of N-alkyl chitosans, bearing the same substitution degree but different carbon chain length and vice versa for Cu(Ⅱ), Hg(Ⅱ)and Pb(Ⅱ) have been investigated. It is found that chitosan derivatives of the same carbon chain length show the highest adsorption capacity for testedions, when their substitution degree is ranged in 0.35~0.39. And among the chitosan derivatives bearing the same substitution degree, N-pentyl chitosan shows the highest adso rption capacity towards mentioned ions.
The N-alkyl chitosans were prepared from chitosan through Schiff-base formation and hydrogenation. The adsorption properties of N-alkyl chitosans, bearing the same substitution degree but different carbon chain length and vice versa for Cu(Ⅱ), Hg(Ⅱ)and Pb(Ⅱ) have been investigated. It is found that chitosan derivatives of the same carbon chain length show the highest adsorption capacity for testedions, when their substitution degree is ranged in 0.35~0.39. And among the chitosan derivatives bearing the same substitution degree, N-pentyl chitosan shows the highest adso rption capacity towards mentioned ions.
2000, 17(1): 69-71
Abstract:
A study on liquid-liquid extraction of cadmium based on KI-ethanol in the presence of ammonium sulphate has been performed.It shows that the charged complex compound CdI42- could be easily extracted into the ethanol phase. Commonions such as Fe3+, Co2+, Ni2+, Mn2+, Zn2+, Al3+ and Cr3+ would not be extracted into the ethanol phase and Cd2+ could be separated completely from them by mixture of 3.0 g (NH4)2SO4 and 0.2 g KI in 10.0 mL 30% (volume fraction) ethanol solution at pH=1~5.
A study on liquid-liquid extraction of cadmium based on KI-ethanol in the presence of ammonium sulphate has been performed.It shows that the charged complex compound CdI42- could be easily extracted into the ethanol phase. Commonions such as Fe3+, Co2+, Ni2+, Mn2+, Zn2+, Al3+ and Cr3+ would not be extracted into the ethanol phase and Cd2+ could be separated completely from them by mixture of 3.0 g (NH4)2SO4 and 0.2 g KI in 10.0 mL 30% (volume fraction) ethanol solution at pH=1~5.
2000, 17(1): 72-74
Abstract:
The rheological properties of partially hydrolyzed polyacrylamide (PHP) aqueous solutions at low shear rates have been studied by using a concentric cylinder rotational rheometer. Some rheological parameters: non-New tonian index(n), consistency coefficient (K), apparent viscosity (ηa) and yield stress (τy) have been determined at conditions of different PHP concentration, temperature and salinity. The results show ed that at shear rates of 1~5 s-1 a yield stress occurred, PHP aqueous solution behaved as a Bingham fluid and a linear relationship between τy and PHP concentration(c) was obtained:τy=kc.
The rheological properties of partially hydrolyzed polyacrylamide (PHP) aqueous solutions at low shear rates have been studied by using a concentric cylinder rotational rheometer. Some rheological parameters: non-New tonian index(n), consistency coefficient (K), apparent viscosity (ηa) and yield stress (τy) have been determined at conditions of different PHP concentration, temperature and salinity. The results show ed that at shear rates of 1~5 s-1 a yield stress occurred, PHP aqueous solution behaved as a Bingham fluid and a linear relationship between τy and PHP concentration(c) was obtained:τy=kc.
2000, 17(1): 75-77
Abstract:
A series of pH-sensitive cationic polyelectrolyte gel beads were prepared by suspension copolymerization of styrene or methyl methacrylate with diethylaminoethyl methacry late and divinylbenzene. The study on the swelling behavior of the gels showed that the hydrophobic/hydrophilic composition of the gels had a great influence on the phase transition pH value and the swelling ability of the gels. Both the equilibrium swelling capacity and the swelling rate were pH dependent. The drug release behavior of the gels were well correlated with the swelling behavior of the gels.
A series of pH-sensitive cationic polyelectrolyte gel beads were prepared by suspension copolymerization of styrene or methyl methacrylate with diethylaminoethyl methacry late and divinylbenzene. The study on the swelling behavior of the gels showed that the hydrophobic/hydrophilic composition of the gels had a great influence on the phase transition pH value and the swelling ability of the gels. Both the equilibrium swelling capacity and the swelling rate were pH dependent. The drug release behavior of the gels were well correlated with the swelling behavior of the gels.
2000, 17(1): 78-80
Abstract:
Ten ferrocenylformyl-1, 1'-dialkylferrocenes were sy thesized by Friedel-Crafts acylation of 1, 1'-dialkylferrocenes and the respective isomers were isolated by column chromatog raphy. The relations between the properties of the compounds to their structures and α-/β-isomer ratios have been studied by elemental analysis, IR and 1H NMR.
Ten ferrocenylformyl-1, 1'-dialkylferrocenes were sy thesized by Friedel-Crafts acylation of 1, 1'-dialkylferrocenes and the respective isomers were isolated by column chromatog raphy. The relations between the properties of the compounds to their structures and α-/β-isomer ratios have been studied by elemental analysis, IR and 1H NMR.
2000, 17(1): 81-83
Abstract:
Four alkoxo complexes [Cp2Mo(PMe3) OR]+OTs-(R=Me, Et, Prn, Pri) were synthesized and characterized by IR, 1H NMR and elemental analysis.The β-hydrogen elimination of these complexes in dimethyl sulfoxide gave monohydrido complex [Cp2Mo(PMe3)H]+OTs- and a ketone or aldehyde.
Four alkoxo complexes [Cp2Mo(PMe3) OR]+OTs-(R=Me, Et, Prn, Pri) were synthesized and characterized by IR, 1H NMR and elemental analysis.The β-hydrogen elimination of these complexes in dimethyl sulfoxide gave monohydrido complex [Cp2Mo(PMe3)H]+OTs- and a ketone or aldehyde.
2000, 17(1): 84-86
Abstract:
Nanocrystalline BaTiO3 powder was prepared by sol-gel process from tetrabuty ltitanium and hydrated barium hydroxide.The thermal decomposition reaction of the obtained gel has been studied by TG-DTA and FTIR techniques.The nano-powder had particle size of about 50 nm and was of cubic perovskite structure.The ceramics made from BaTiO3 nano-powder still maintained nano-scale microstructure with size of about 80~150 nm after sintering at 1190~1330℃.
Nanocrystalline BaTiO3 powder was prepared by sol-gel process from tetrabuty ltitanium and hydrated barium hydroxide.The thermal decomposition reaction of the obtained gel has been studied by TG-DTA and FTIR techniques.The nano-powder had particle size of about 50 nm and was of cubic perovskite structure.The ceramics made from BaTiO3 nano-powder still maintained nano-scale microstructure with size of about 80~150 nm after sintering at 1190~1330℃.
2000, 17(1): 87-89
Abstract:
The azo-chromophore anchored polyurethanes were synthesized by azo coupling of 4-nitrobenzenediazonium tetrafluoroborate and reacting the obtained 6-nitrobenzothiazole-2-diazoniun tetrafluoroborate with polyurethane in dimethylforamide in the presence of HAc and its sodium salt. The polyurethanes were characterized by IR, UV-Vis and 1H NMR spectra.The method has the advantages of simplicity and facility in preparing polyurethane NLO materials with different chromophores.
The azo-chromophore anchored polyurethanes were synthesized by azo coupling of 4-nitrobenzenediazonium tetrafluoroborate and reacting the obtained 6-nitrobenzothiazole-2-diazoniun tetrafluoroborate with polyurethane in dimethylforamide in the presence of HAc and its sodium salt. The polyurethanes were characterized by IR, UV-Vis and 1H NMR spectra.The method has the advantages of simplicity and facility in preparing polyurethane NLO materials with different chromophores.
2000, 17(1): 90-92
Abstract:
6-Methoxy-2-acetyl-naphthalene and 6-methoxy-2-propionylnaphthalene were selectively brominated by cupric bromide in methanol to give 6-methoxy-2-(2'-bromoacety l) naphthalene and 6-methoxy-2-(2'-bromopropiony l) naphthalene in yield of 94%~97% and 2-methoxy-1-bromo-naphthalene in yield of 98%, respectively.
6-Methoxy-2-acetyl-naphthalene and 6-methoxy-2-propionylnaphthalene were selectively brominated by cupric bromide in methanol to give 6-methoxy-2-(2'-bromoacety l) naphthalene and 6-methoxy-2-(2'-bromopropiony l) naphthalene in yield of 94%~97% and 2-methoxy-1-bromo-naphthalene in yield of 98%, respectively.
2000, 17(1): 93-95
Abstract:
A new technology including semisolid phase maceration for preparation of low surphur expandable graphite is presented, in which potassium permanganate and concentrated sulphuric acid are adopted as blended oxidants and ferric trichlo ride as an inserting agent. The optimum conditions of the process are as follows: mass ratio of graphite to sulfuric acid, potassium permang anate and ferric trichlo ride=1.0:3.0:0.8:0.2; reaction tem perature and time: 50℃ and 1 h. The expandable graphite has an expanded volume of 230 mL/g and S content of 0.48%. By treating the product with sucrose bo rate solution and heating the flexible graphite plates also have been obtained with tensile strength of 7.5 MPa and oxidation loss of 11%. It is a green technology.
A new technology including semisolid phase maceration for preparation of low surphur expandable graphite is presented, in which potassium permanganate and concentrated sulphuric acid are adopted as blended oxidants and ferric trichlo ride as an inserting agent. The optimum conditions of the process are as follows: mass ratio of graphite to sulfuric acid, potassium permang anate and ferric trichlo ride=1.0:3.0:0.8:0.2; reaction tem perature and time: 50℃ and 1 h. The expandable graphite has an expanded volume of 230 mL/g and S content of 0.48%. By treating the product with sucrose bo rate solution and heating the flexible graphite plates also have been obtained with tensile strength of 7.5 MPa and oxidation loss of 11%. It is a green technology.
2000, 17(1): 96-98
Abstract:
Compounds Ind2Zr(OC6H4-p-Me)2, Ind2Zr(OC6H5)2, Ind2ZrCl2 and Cp2Zr(OC6H4-p-Me)2 have been synthesized and formed respective catalysts A、B、C、D with Et2AlCl. The effects of polymerization temperature, time and catalyst aging temperature on the catalytic activities and selectivities of the catalysts in ethy lene oligomerization have been investigated. The order of the catalytic activity of the catalysts was A > B > C > D. Under optimal reaction conditions the activity of catalyst A was 1666 g/g·h (oligomer mass obtained by one gram Zr in cataly st per an hour) with selectivity of 92.7% for C4=~C10= olefins and 86.0% for C4=~C10= linear α-olefins.
Compounds Ind2Zr(OC6H4-p-Me)2, Ind2Zr(OC6H5)2, Ind2ZrCl2 and Cp2Zr(OC6H4-p-Me)2 have been synthesized and formed respective catalysts A、B、C、D with Et2AlCl. The effects of polymerization temperature, time and catalyst aging temperature on the catalytic activities and selectivities of the catalysts in ethy lene oligomerization have been investigated. The order of the catalytic activity of the catalysts was A > B > C > D. Under optimal reaction conditions the activity of catalyst A was 1666 g/g·h (oligomer mass obtained by one gram Zr in cataly st per an hour) with selectivity of 92.7% for C4=~C10= olefins and 86.0% for C4=~C10= linear α-olefins.
2000, 17(1): 99-101
Abstract:
The composite nanocrystallites with mullite as the main crystalline phase was prepared from kaolin by hydrothermal method after a series of treatments. The influences of feed composition, heat treatment of kaolin, crystallization time and calcination on the particle size and shape have been investigated.
The composite nanocrystallites with mullite as the main crystalline phase was prepared from kaolin by hydrothermal method after a series of treatments. The influences of feed composition, heat treatment of kaolin, crystallization time and calcination on the particle size and shape have been investigated.
2000, 17(1): 102-104
Abstract:
The molecular weight of acrylonitrile/itaconic acid copolymer can be calculated from the intrinsic viscosities of the dilute reaction solutions directly, when the conversion was higher than 90% during the solution polymerization. Because of the sample treatment processes such as film preparing, washing, drying and redissolving were simplified, the analysis time was reduced substantially. The proposed method is more suitable for rapid analysis.The measurement error compared with common method of determination for the copolymer in DMSO by single point method was about 1%.
The molecular weight of acrylonitrile/itaconic acid copolymer can be calculated from the intrinsic viscosities of the dilute reaction solutions directly, when the conversion was higher than 90% during the solution polymerization. Because of the sample treatment processes such as film preparing, washing, drying and redissolving were simplified, the analysis time was reduced substantially. The proposed method is more suitable for rapid analysis.The measurement error compared with common method of determination for the copolymer in DMSO by single point method was about 1%.
2000, 17(1): 105-106
Abstract:
L-Alanine crystal with the same optical purity ([α]D25=+1.98)as that of the seed L-alanine cry stal has been obtained from saturated solution of DL-α-alanine by seed crystal resolution method. Addition of surfactant (OP series) in culture fluid accelerated the crystallization of L-alanine.
L-Alanine crystal with the same optical purity ([α]D25=+1.98)as that of the seed L-alanine cry stal has been obtained from saturated solution of DL-α-alanine by seed crystal resolution method. Addition of surfactant (OP series) in culture fluid accelerated the crystallization of L-alanine.
2000, 17(1): 107-109
Abstract:
The lanthanium modified lead titanite (PLT) nanocrystals were prepared by sol-gel method. The effects of calcination temperature on the crystal size, lattice parameters and c/a ratios of the products have been investigated by XRD technique. The relation between the crystal size and c/a ratio in terms of lanthanium contents in the modified titanite has been discussed.
The lanthanium modified lead titanite (PLT) nanocrystals were prepared by sol-gel method. The effects of calcination temperature on the crystal size, lattice parameters and c/a ratios of the products have been investigated by XRD technique. The relation between the crystal size and c/a ratio in terms of lanthanium contents in the modified titanite has been discussed.
2000, 17(1): 110-112
Abstract:
Modified NiS nano-particles were prepared by mixing MTTF (dimethy lthiotetrathiafulvalenyldithiolato) with NiS nanoparticles in alcoholic solution.IR and ESR results show the radical properties of the modified NiS. Material with m(NiS):m(MTTF)=200:20 has a conductivity of 4.3×10-2 S/cm.
Modified NiS nano-particles were prepared by mixing MTTF (dimethy lthiotetrathiafulvalenyldithiolato) with NiS nanoparticles in alcoholic solution.IR and ESR results show the radical properties of the modified NiS. Material with m(NiS):m(MTTF)=200:20 has a conductivity of 4.3×10-2 S/cm.
2000, 17(1): 113-114
Abstract:
A new route to diastereoselective synthesis of (±)-trans-cognac lactone in five steps is described. The key intermediate methyl 3-formylbutanoate (4) was prepared from methy lcro tonate (1) in high yield.Addition of n-amylmagnesium bromide/cuprous iodide to the fo rmyl of (4), through fo rmation of seven-membered ring chelate which involved both carbonyl function groups of (4) and MgX or Cu as a central metal, afforded (±)-trans-cognac lactone (5) in 52% yield with high diastereoselectivity: ratio of trans to cisisomers was 97:3 by GC. The procedure had advantages of simplicity, high stereoselectivity of products and mild reaction conditions.
A new route to diastereoselective synthesis of (±)-trans-cognac lactone in five steps is described. The key intermediate methyl 3-formylbutanoate (4) was prepared from methy lcro tonate (1) in high yield.Addition of n-amylmagnesium bromide/cuprous iodide to the fo rmyl of (4), through fo rmation of seven-membered ring chelate which involved both carbonyl function groups of (4) and MgX or Cu as a central metal, afforded (±)-trans-cognac lactone (5) in 52% yield with high diastereoselectivity: ratio of trans to cisisomers was 97:3 by GC. The procedure had advantages of simplicity, high stereoselectivity of products and mild reaction conditions.
2000, 17(1): 115-116
Abstract:
The compositions and bonding energies of elements C, O and N in the surfaces of chitosan and Cu2+-chitosan chelate have been investigated by XPS. An adsorption mechanism is proposed by which the adsorption occurs through a chelating reaction betw een Cu2+ and -NH2 on the surface of chitosan.
The compositions and bonding energies of elements C, O and N in the surfaces of chitosan and Cu2+-chitosan chelate have been investigated by XPS. An adsorption mechanism is proposed by which the adsorption occurs through a chelating reaction betw een Cu2+ and -NH2 on the surface of chitosan.
