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1999 Volume 16 Issue 5
1999, 16(5): 1-4
Abstract:
The organic/inorganic complex support was prepared by impregnating SiO2 with poly(styrene co acrylamide)(PSAm) and metallocene was then supported on it. The support and ca talyst obtained have been examined by XPS, SEM, TGA and IR and its catalytic activity for ethylene polymerization has been studied.
The organic/inorganic complex support was prepared by impregnating SiO2 with poly(styrene co acrylamide)(PSAm) and metallocene was then supported on it. The support and ca talyst obtained have been examined by XPS, SEM, TGA and IR and its catalytic activity for ethylene polymerization has been studied.
1999, 16(5): 5-8
Abstract:
The electropolymerization of o-phenylenediamine(OPD) on gold electrode and the redox behavior of poly(o-phenylenediamine)(POPD) films in sulfuric acid solutions have been studied by cyclic voltammetry and electrochemical quartz crystal microbalance(EQCM). The decrease in the resonant frequency of the quartz crystal during electropolymerization of OPD demonstrated that the deposition of the polymer films occurrs mainly in the potential range>0.5 V, at which the monomers are anodically oxidized. It is revealed that the protonation and deprotonation play an important role in the redox process of POPD films. The protonation during the reduction of POPD film induces the intercalation of anions, whereas the deprotonation in the oxidation of POPD film makes the escape of anions from the film. The quantity of anions intercalated into POPD film has been calculated according Sauerbry equation from the frequency decrease of EQCM electrode. Its values are in the range of 10-9 to 10-8 mol/cm2 and varies with the mass of POPD film as well as with the scan rate of electrode potential.
The electropolymerization of o-phenylenediamine(OPD) on gold electrode and the redox behavior of poly(o-phenylenediamine)(POPD) films in sulfuric acid solutions have been studied by cyclic voltammetry and electrochemical quartz crystal microbalance(EQCM). The decrease in the resonant frequency of the quartz crystal during electropolymerization of OPD demonstrated that the deposition of the polymer films occurrs mainly in the potential range>0.5 V, at which the monomers are anodically oxidized. It is revealed that the protonation and deprotonation play an important role in the redox process of POPD films. The protonation during the reduction of POPD film induces the intercalation of anions, whereas the deprotonation in the oxidation of POPD film makes the escape of anions from the film. The quantity of anions intercalated into POPD film has been calculated according Sauerbry equation from the frequency decrease of EQCM electrode. Its values are in the range of 10-9 to 10-8 mol/cm2 and varies with the mass of POPD film as well as with the scan rate of electrode potential.
1999, 16(5): 9-12
Abstract:
The effects of HCl acid concentration and treatment time on the removed magnesium ratio, surface and pore structures of sepiolite have been investigated. The results show that with removed magnesium ratio of 36%, the treated sepiolite has a maximum surface area of 554 4 m2/g, therfore a better adsorability towards Pb2+ and Cd2+. The adsorptive behavior can be related to the Langmuir isothermal adsorption equation.
The effects of HCl acid concentration and treatment time on the removed magnesium ratio, surface and pore structures of sepiolite have been investigated. The results show that with removed magnesium ratio of 36%, the treated sepiolite has a maximum surface area of 554 4 m2/g, therfore a better adsorability towards Pb2+ and Cd2+. The adsorptive behavior can be related to the Langmuir isothermal adsorption equation.
1999, 16(5): 13-16
Abstract:
A series of aromatic poly(ester imide)s containing 1,1'-binaphthyl 2,2' diyl units in main chain were prepared by polycondensation of 2,2'-bis(3,4 dicarboxybenzoyloxy)-1,1'-binaphthyl dianhydride with various diamines. The poly(ester amide)s obtained show good solubility, thermal property and film transparency.
A series of aromatic poly(ester imide)s containing 1,1'-binaphthyl 2,2' diyl units in main chain were prepared by polycondensation of 2,2'-bis(3,4 dicarboxybenzoyloxy)-1,1'-binaphthyl dianhydride with various diamines. The poly(ester amide)s obtained show good solubility, thermal property and film transparency.
1999, 16(5): 17-20
Abstract:
The oxygen electroreduction on the glassy carbon electrode coated by polypyrrole film with ferriporphyrin(FeTPPS) has been investigated by RRDE technique, TPPS standing for meso-terakis(p-sulfonatophenyl)porphyrin. The results show that the presence of the modified layer decreases the overpotential of oxygen reduction and the reduction product is H2O2, which may be used to destroy organic compounds in waste water. Carbon is a better electrode substrate for the peroxide formation, as compared with Au or Pt. The rate of oxygen reduction on the modified electrode in acidic media is higher than that in neutral media. The apparent rate constant for the reaction of oxygen molecule with FeTPPS in the polypyrrole film has been estimated according to Koutecky Levich relationship. The process is explained in terms of the heterogeneous redox cata lysis i.e. EC mechanism.
The oxygen electroreduction on the glassy carbon electrode coated by polypyrrole film with ferriporphyrin(FeTPPS) has been investigated by RRDE technique, TPPS standing for meso-terakis(p-sulfonatophenyl)porphyrin. The results show that the presence of the modified layer decreases the overpotential of oxygen reduction and the reduction product is H2O2, which may be used to destroy organic compounds in waste water. Carbon is a better electrode substrate for the peroxide formation, as compared with Au or Pt. The rate of oxygen reduction on the modified electrode in acidic media is higher than that in neutral media. The apparent rate constant for the reaction of oxygen molecule with FeTPPS in the polypyrrole film has been estimated according to Koutecky Levich relationship. The process is explained in terms of the heterogeneous redox cata lysis i.e. EC mechanism.
1999, 16(5): 21-24
Abstract:
TX-100 reverse microemulsion systems in which pentanol and octanol were used as cosurfactants have been studied by FT-IR and ESR techniques. The results showed that alcohol with long carbon chain had stronger surface activity and joined in the hydration process; alcohol with short carbon chain owing to its stronger polarity mainly functioned as a polarity regulator of the reverse microemusion. The flexibility of the surfactant chains could be enhanced by hydration process in octanol reverse microemulsion system.
TX-100 reverse microemulsion systems in which pentanol and octanol were used as cosurfactants have been studied by FT-IR and ESR techniques. The results showed that alcohol with long carbon chain had stronger surface activity and joined in the hydration process; alcohol with short carbon chain owing to its stronger polarity mainly functioned as a polarity regulator of the reverse microemusion. The flexibility of the surfactant chains could be enhanced by hydration process in octanol reverse microemulsion system.
1999, 16(5): 25-28
Abstract:
Twelve water soluble photoinitiators of thioxanthone were prepared. The compounds were identified by IR, NMR, MS and elemental analysis. The relationship between the structures of the compounds and their UV absorption wavelengths, molar absorption coefficients and fluorescent quantum yields have been discussed.
Twelve water soluble photoinitiators of thioxanthone were prepared. The compounds were identified by IR, NMR, MS and elemental analysis. The relationship between the structures of the compounds and their UV absorption wavelengths, molar absorption coefficients and fluorescent quantum yields have been discussed.
1999, 16(5): 29-32
Abstract:
The hydrolysis kinetics of 2,4 dinitrochlorobenzene in microemulsion system of cetyltrimethylammonium bromide/n butanol/25% n-octane/water has been studied. The results show that the hydrolysis in W/O microemulsion decreases rapidly with increase of the water content in it, it also true in O/W microemulsion; whereas in B.C. the hydrolysis increases with water con tent. The transition points of the hydrolysis rates occur at the structural transition points from W/O to B C, and B C to O/W. This is considered to be caused by the change of polarity in interfacial films and the size of the particles. The effects of hydrocarbons, alcohols, temperature and NaOH concentration on the hydrolysis rate also have been investigated.
The hydrolysis kinetics of 2,4 dinitrochlorobenzene in microemulsion system of cetyltrimethylammonium bromide/n butanol/25% n-octane/water has been studied. The results show that the hydrolysis in W/O microemulsion decreases rapidly with increase of the water content in it, it also true in O/W microemulsion; whereas in B.C. the hydrolysis increases with water con tent. The transition points of the hydrolysis rates occur at the structural transition points from W/O to B C, and B C to O/W. This is considered to be caused by the change of polarity in interfacial films and the size of the particles. The effects of hydrocarbons, alcohols, temperature and NaOH concentration on the hydrolysis rate also have been investigated.
1999, 16(5): 33-36
Abstract:
The effects of plasticizer, curing agent, antioxidant as well as glycol structure on the thermooxidation of EO/THF copolyether urethane have been investigated by FT-IR and NMR techniques. It is found that plasticizer dibutyl phthalate(DBP) has some stabilizing effect on the polyether urethane, but not on the degradation mechanism. Dibutyltin dilaurate(DBTDL) and triphenyl bismuth(TPB) show striking different behavior towords the thermooxidatin of polyurethane. Being plasticized with DBP, polyurethane with PEG as soft segments is more susceptible to thermooxidation than that with EO/THF copolymer, whereas the polyurethane plasticized with nitrate esters is less sensitive to thermooxidation.
The effects of plasticizer, curing agent, antioxidant as well as glycol structure on the thermooxidation of EO/THF copolyether urethane have been investigated by FT-IR and NMR techniques. It is found that plasticizer dibutyl phthalate(DBP) has some stabilizing effect on the polyether urethane, but not on the degradation mechanism. Dibutyltin dilaurate(DBTDL) and triphenyl bismuth(TPB) show striking different behavior towords the thermooxidatin of polyurethane. Being plasticized with DBP, polyurethane with PEG as soft segments is more susceptible to thermooxidation than that with EO/THF copolymer, whereas the polyurethane plasticized with nitrate esters is less sensitive to thermooxidation.
1999, 16(5): 37-40
Abstract:
Title ternary complex was prepared from EuCl3·6H2O, L-tryptophane and benzimidazole in ethanol. It has a constitution of[Eu(Trp)3BIM]Cl3·3H2O as a result of elemental analysis, molar conductivity, IR, UV and XPS measurements. Cyclic voltammetry study of the complex showed that it had quasireversible electrochemical behavior on glass carbon electrode. The diffusion coefficient and rate constant of the complex have been calculated.
Title ternary complex was prepared from EuCl3·6H2O, L-tryptophane and benzimidazole in ethanol. It has a constitution of[Eu(Trp)3BIM]Cl3·3H2O as a result of elemental analysis, molar conductivity, IR, UV and XPS measurements. Cyclic voltammetry study of the complex showed that it had quasireversible electrochemical behavior on glass carbon electrode. The diffusion coefficient and rate constant of the complex have been calculated.
1999, 16(5): 41-44
Abstract:
The title compound, a bidentate ligand was prepared via two routes from 2 bromobenzoic acid in 31% yield and its rhodium complex has been tested to catalyze the hydroformylation of styrene and p-isobutylstyrene.
The title compound, a bidentate ligand was prepared via two routes from 2 bromobenzoic acid in 31% yield and its rhodium complex has been tested to catalyze the hydroformylation of styrene and p-isobutylstyrene.
1999, 16(5): 45-48
Abstract:
The electroless Ni-Sn-P composite films on steel surface have been formed in the presence of lead acetate and multi ligands:butane dioic acid+malic acid+1 hydroxyethylene-1,1-diphosphonic acid. The influences of the bath composition and deposition conditions on the films and their corrosion resistance have been investigated by SEM, AES and XPS techniques. The film obtained has a thickness of 21μm with a metallic luster and low porosity and good corrosion resistance. The relative atomic percent contents of the films are Ni 67.03%, Sn 0.50%, P 30.40% and Fe 2.04%.
The electroless Ni-Sn-P composite films on steel surface have been formed in the presence of lead acetate and multi ligands:butane dioic acid+malic acid+1 hydroxyethylene-1,1-diphosphonic acid. The influences of the bath composition and deposition conditions on the films and their corrosion resistance have been investigated by SEM, AES and XPS techniques. The film obtained has a thickness of 21μm with a metallic luster and low porosity and good corrosion resistance. The relative atomic percent contents of the films are Ni 67.03%, Sn 0.50%, P 30.40% and Fe 2.04%.
1999, 16(5): 49-52
Abstract:
Ten 1-substituted arylaminopropyl silatranes were synthesized in yield of 43%~82% by the functional group transformation reaction on silatranes. Their structures were identified by elemental analysis, IR, 1H NMR and MS measurements. Some of the compounds were found to have a good antibacterial activity.
Ten 1-substituted arylaminopropyl silatranes were synthesized in yield of 43%~82% by the functional group transformation reaction on silatranes. Their structures were identified by elemental analysis, IR, 1H NMR and MS measurements. Some of the compounds were found to have a good antibacterial activity.
1999, 16(5): 53-56
Abstract:
Seventeen novel fused heterocyclic compounds have been synthesized by the reaction of 3-p-nitrophenyl/m-nitrophenyl/-4-amino-5-mercapto 1,2,4 triazoles with aldehydes in the pre sence of hydrochloric acid at 80℃ for 10 h. The reaction conditions and catalysts have been in vestigated. The structures of the compounds have been confirmed by elemental analysis, IR, 1H NMR and MS measurements. The preliminary tests showed they display some antibaterial ac tivities.
Seventeen novel fused heterocyclic compounds have been synthesized by the reaction of 3-p-nitrophenyl/m-nitrophenyl/-4-amino-5-mercapto 1,2,4 triazoles with aldehydes in the pre sence of hydrochloric acid at 80℃ for 10 h. The reaction conditions and catalysts have been in vestigated. The structures of the compounds have been confirmed by elemental analysis, IR, 1H NMR and MS measurements. The preliminary tests showed they display some antibaterial ac tivities.
1999, 16(5): 57-60
Abstract:
The hydrated Ti(Ⅳ) oxide was electrodeposited on SnO2 conducting glass from TiCl3 solution and converted into TiO2 films containing anatase and rutile by annealing. The mass ratio of the two crystalloids depended on the annealing temperature. Photocatalytic degradation experiments of aniline indicated that about 93% aniline was degraded with PbS sensitied TiO2 film consisted of 70% anatase and 30% rutile under 1h illumination.
The hydrated Ti(Ⅳ) oxide was electrodeposited on SnO2 conducting glass from TiCl3 solution and converted into TiO2 films containing anatase and rutile by annealing. The mass ratio of the two crystalloids depended on the annealing temperature. Photocatalytic degradation experiments of aniline indicated that about 93% aniline was degraded with PbS sensitied TiO2 film consisted of 70% anatase and 30% rutile under 1h illumination.
1999, 16(5): 61-64
Abstract:
Six pentamethine pyrylium dyes have been synthesized and characterized by IR, 1H NMR and elemental analysis. Their electronic absorption spectra and characteristics of mode locking have been studied. The λmax of the dye solutions are found to be in the range of 1052~1095 nm and the pulse widths within 28~36 ps. They were also found to be useful as collide pulse mode locking(CPM) dye for Nd3+:YAG laser and mode locking dyes for Nd3+:YAG, better than BDN.
Six pentamethine pyrylium dyes have been synthesized and characterized by IR, 1H NMR and elemental analysis. Their electronic absorption spectra and characteristics of mode locking have been studied. The λmax of the dye solutions are found to be in the range of 1052~1095 nm and the pulse widths within 28~36 ps. They were also found to be useful as collide pulse mode locking(CPM) dye for Nd3+:YAG laser and mode locking dyes for Nd3+:YAG, better than BDN.
1999, 16(5): 65-68
Abstract:
The in situ regenerated catalysts in different positions of the hydrotreating reactor for hydrodesulfurization and hydrodenitrogenation of diesel fuel oil have been studied using EDS, DTA and BET techniques. The results show that the temperature runaway occurred easily near the top of the hydrotreating reactor on the oxidation regeneration and the catalysts in this area were sintered easily due to the deposition of ferrous sulfide on the surface of the catalysts. The properties of the regenerated catalysts in the middle or bottom part of the reactor were changed relatively less.
The in situ regenerated catalysts in different positions of the hydrotreating reactor for hydrodesulfurization and hydrodenitrogenation of diesel fuel oil have been studied using EDS, DTA and BET techniques. The results show that the temperature runaway occurred easily near the top of the hydrotreating reactor on the oxidation regeneration and the catalysts in this area were sintered easily due to the deposition of ferrous sulfide on the surface of the catalysts. The properties of the regenerated catalysts in the middle or bottom part of the reactor were changed relatively less.
1999, 16(5): 69-72
Abstract:
Biodegradable triblock copolymers were prepared from d,l lactide and poly(ethylene glycol) by bulk ring opening polymerization. The compositions and molecular weights of the copolymers were determined by 1H NMR. Keeping the molecular weight of PLA segment constant, the water adsorption capacity of the copolymer films increased with the increase of the molecular weight and content of PEG segment in copolymer. The PLA/PEG/PLA triblock copolymer could be degraded in phosphate buffer solution(pH=7.4) at 37℃ in 60 days. The spherical copolymer nanospheres with narrow unimodal size distribution 103 6~141 6 nm were prepared by one step emulsion method. Their sizes were influenced by PLA chain length and PEG chain length.
Biodegradable triblock copolymers were prepared from d,l lactide and poly(ethylene glycol) by bulk ring opening polymerization. The compositions and molecular weights of the copolymers were determined by 1H NMR. Keeping the molecular weight of PLA segment constant, the water adsorption capacity of the copolymer films increased with the increase of the molecular weight and content of PEG segment in copolymer. The PLA/PEG/PLA triblock copolymer could be degraded in phosphate buffer solution(pH=7.4) at 37℃ in 60 days. The spherical copolymer nanospheres with narrow unimodal size distribution 103 6~141 6 nm were prepared by one step emulsion method. Their sizes were influenced by PLA chain length and PEG chain length.
1999, 16(5): 73-75
Abstract:
1-Aza-2-azoniaallene cations 3(denoted also as azo carbenium ions) were generated in situ as reactive intermediates by chlorination of pinakolone hydrazones 1 with tert-butyl hypochlorite and treatment of the resulted(1-choroalkyl)azo compounds 2 with a Lewis acid (SbCl5). The allene like cations 3 were trapped by cycloaddition to the triple bond of nitriles giving 3H 1,2,4-triazolium salts 4. The initially formed heterocycles 4 couldn't be isolated but underwent smooth 1,2-tert butyl shift accompanied by elimination of isobutene to afford 1H-1,2,4 triazolium salts 5, from which 1,3,5-trisubstituted-1H 1,2,4 triazoles 6 have been obtained in moderate to high yields after basic work-up. Heterocycles 6 are characterized by elemental analysis and IR, 1H NMR measurements.
1-Aza-2-azoniaallene cations 3(denoted also as azo carbenium ions) were generated in situ as reactive intermediates by chlorination of pinakolone hydrazones 1 with tert-butyl hypochlorite and treatment of the resulted(1-choroalkyl)azo compounds 2 with a Lewis acid (SbCl5). The allene like cations 3 were trapped by cycloaddition to the triple bond of nitriles giving 3H 1,2,4-triazolium salts 4. The initially formed heterocycles 4 couldn't be isolated but underwent smooth 1,2-tert butyl shift accompanied by elimination of isobutene to afford 1H-1,2,4 triazolium salts 5, from which 1,3,5-trisubstituted-1H 1,2,4 triazoles 6 have been obtained in moderate to high yields after basic work-up. Heterocycles 6 are characterized by elemental analysis and IR, 1H NMR measurements.
1999, 16(5): 76-78
Abstract:
The doping reaction of pristine polyaniline(udpan) with camphor sulfonic acid in N-methyl 2 pyrrolidone(NMP) and N,N-dimethylformamide(DMF) has been studied by UV-Vis spectrometry. The results showed that the polaron band of the compound doped in NMP at 800 nm shifted to short wavelength with time and that of doped in DMF at 725 nm to long wavelength. The results are discussed in terms of the solubility behavior of the doped compounds in different solvents.
The doping reaction of pristine polyaniline(udpan) with camphor sulfonic acid in N-methyl 2 pyrrolidone(NMP) and N,N-dimethylformamide(DMF) has been studied by UV-Vis spectrometry. The results showed that the polaron band of the compound doped in NMP at 800 nm shifted to short wavelength with time and that of doped in DMF at 725 nm to long wavelength. The results are discussed in terms of the solubility behavior of the doped compounds in different solvents.
1999, 16(5): 79-81
Abstract:
An automatic analytical method by HPLC for vapor and particle polycyclic aromatic hydrocarbons(PAHs) in ambient air is proposed. The PAHs were sampled simutaneously by a little volume and low noise sampling pump and extracted by a mixture of dichloromethane and methyl cyanide, concentrated by nitrogen sweeping, injected automatically and detected by a fluorometric detector with programmed excitation and emmission wavelength pairs. The mobile phase is a linear gradient mixture of methanol and water. The relative standard deviations of the retention time and peak height were 0.05%~0.39% and 0.68%~1.29%, respectively at PAHs concentration levels of 14.14~2360.0 μg/L with the linearly regressive factors being over 0.999. The detection limits were 5.30 ng/L for fluorene and 291.30 ng/L for fluoranthene.
An automatic analytical method by HPLC for vapor and particle polycyclic aromatic hydrocarbons(PAHs) in ambient air is proposed. The PAHs were sampled simutaneously by a little volume and low noise sampling pump and extracted by a mixture of dichloromethane and methyl cyanide, concentrated by nitrogen sweeping, injected automatically and detected by a fluorometric detector with programmed excitation and emmission wavelength pairs. The mobile phase is a linear gradient mixture of methanol and water. The relative standard deviations of the retention time and peak height were 0.05%~0.39% and 0.68%~1.29%, respectively at PAHs concentration levels of 14.14~2360.0 μg/L with the linearly regressive factors being over 0.999. The detection limits were 5.30 ng/L for fluorene and 291.30 ng/L for fluoranthene.
1999, 16(5): 82-84
Abstract:
Five title complexes:FcCO2SnPh3, (FcCO2)2SnBu2, {[(FcCO2)SnBu2]2O}2, FcC(CH3)=CHCO2SnPh3, {[(FcC(CH3)=CHCO2)SnBu2]2O}2, (Fc=(η5-C5H 5)Fe(η5-C5H4-)) have been synthesized via reactions of ferrocenecarboxylic acid or 3-ferrocenyl 2-crotonic acid with triphenyltin hydroxide or di-n-butyltin oxide. All of the compounds have been characterized by elemental analysis, IR, 1H NMR and MS.
Five title complexes:FcCO2SnPh3, (FcCO2)2SnBu2, {[(FcCO2)SnBu2]2O}2, FcC(CH3)=CHCO2SnPh3, {[(FcC(CH3)=CHCO2)SnBu2]2O}2, (Fc=(η5-C5H 5)Fe(η5-C5H4-)) have been synthesized via reactions of ferrocenecarboxylic acid or 3-ferrocenyl 2-crotonic acid with triphenyltin hydroxide or di-n-butyltin oxide. All of the compounds have been characterized by elemental analysis, IR, 1H NMR and MS.
1999, 16(5): 85-87
Abstract:
A micellar electrokinetic capillary chromatographic method was used for quantitative determination of benzene, toluene and xylene in the groundwater at different depth. A fused silica capillary of 57 cm×50 μm(50 cm to detector) was used. Running buffer was a 2.0 mmol/L aqueous tetraborate solution containing 50 mmol/L sodium dodecyl sulfate(pH 9 16) and 20% methanol as an organic modifier. The voltage used was 25 kV. Detection wavelength was 200 nm. Benzene, toluene and xylene were separated well within 20 min. The calibration curves were linear over 4.3~52.8 mg/L. The minimum detectable concentrations were 2.3, 1.3 and 0.8 mg/L for three compounds respectively. The determination results showed that at the same well benzene concentration increased linearly with the increase of the well depth.
A micellar electrokinetic capillary chromatographic method was used for quantitative determination of benzene, toluene and xylene in the groundwater at different depth. A fused silica capillary of 57 cm×50 μm(50 cm to detector) was used. Running buffer was a 2.0 mmol/L aqueous tetraborate solution containing 50 mmol/L sodium dodecyl sulfate(pH 9 16) and 20% methanol as an organic modifier. The voltage used was 25 kV. Detection wavelength was 200 nm. Benzene, toluene and xylene were separated well within 20 min. The calibration curves were linear over 4.3~52.8 mg/L. The minimum detectable concentrations were 2.3, 1.3 and 0.8 mg/L for three compounds respectively. The determination results showed that at the same well benzene concentration increased linearly with the increase of the well depth.
1999, 16(5): 88-90
Abstract:
The acylation reactions of L-α-Lysophosphatidylcholine(Lyso PC) or L-α-Glycerophosphorylcholine.CdCl2(GPC-CdCl2) with fatty acid bearing bulky aromatic group or corresponding anhydride have been investigated. The acylation of Lyso PC with fatty acid bearing bulky aromatic group in the presence of condensing reagent N,N'-dicyclohexylcarbodiimide(DCC) and catalyst 4-(N,N'-dimethylamino) pyridine(DMAP) was found to be more convenient and more efficient than that of Lyso PC with the corresponding fatty acid anhydride prepared prior to acylation(yield 85% to 45%). The poor formation of anhydride from fatty acid is responsible largely for the low yield. It was found that the acylation reaction of Lyso PC or GPC CdCl 2 with fatty acid bearing bulky aromatic group could be accomplished in 85% and 74% yield respectively by using a fatty acid/Lyso PC(or GPC CdCl2) molar ratio of 4, DMAP/Lyso PC(or GPC CdCl2) molar ratio of 4 and DCC/fatty acid molar ratio of 0.6 (1 for the acylation of GPC CdCl2). The procedures described provide significant improvements in yield over methods repor ted
The acylation reactions of L-α-Lysophosphatidylcholine(Lyso PC) or L-α-Glycerophosphorylcholine.CdCl2(GPC-CdCl2) with fatty acid bearing bulky aromatic group or corresponding anhydride have been investigated. The acylation of Lyso PC with fatty acid bearing bulky aromatic group in the presence of condensing reagent N,N'-dicyclohexylcarbodiimide(DCC) and catalyst 4-(N,N'-dimethylamino) pyridine(DMAP) was found to be more convenient and more efficient than that of Lyso PC with the corresponding fatty acid anhydride prepared prior to acylation(yield 85% to 45%). The poor formation of anhydride from fatty acid is responsible largely for the low yield. It was found that the acylation reaction of Lyso PC or GPC CdCl 2 with fatty acid bearing bulky aromatic group could be accomplished in 85% and 74% yield respectively by using a fatty acid/Lyso PC(or GPC CdCl2) molar ratio of 4, DMAP/Lyso PC(or GPC CdCl2) molar ratio of 4 and DCC/fatty acid molar ratio of 0.6 (1 for the acylation of GPC CdCl2). The procedures described provide significant improvements in yield over methods repor ted
1999, 16(5): 91-93
Abstract:
An amorphous silica product of high brightness is prepared by calcination of kaolin with ammonium bisulphate at 560℃ for 1 hour
An amorphous silica product of high brightness is prepared by calcination of kaolin with ammonium bisulphate at 560℃ for 1 hour
1999, 16(5): 94-96
Abstract:
A methematical pattern on computation of molecular simularity is proposed and used to compute the molecular simularity of three organic hetero compounds. The results are relatively identical with those obtained from codes for chemical environment.
A methematical pattern on computation of molecular simularity is proposed and used to compute the molecular simularity of three organic hetero compounds. The results are relatively identical with those obtained from codes for chemical environment.
1999, 16(5): 97-99
Abstract:
Nanocrystalline BaCO3 was synthesized at ambient temperature by solid state reactions. Phase, particle size and morphology of the prepared nanocrystallite were characterized by XRD and TEM. The crystallite product has a size about 30 nm. The effects of a series of reaction conditions on the synthesis of BaCO3 are studied.
Nanocrystalline BaCO3 was synthesized at ambient temperature by solid state reactions. Phase, particle size and morphology of the prepared nanocrystallite were characterized by XRD and TEM. The crystallite product has a size about 30 nm. The effects of a series of reaction conditions on the synthesis of BaCO3 are studied.
1999, 16(5): 100-102
Abstract:
A novel dioxime, N,N-bis[2-(2-iminohydroxyphenoxy)ethyl]-toluenesulfonamide(BIHET), was synthesized and characterized, and a carbon paste electrode modified with BIHET was employed for electroanalysis of iron(Ⅲ) from aqueous solutions. The electrochemical redox reaction of the dioxime with the modified CPE and the electrochemical behavior of iron(Ⅲ) on the CPE were investigated.
A novel dioxime, N,N-bis[2-(2-iminohydroxyphenoxy)ethyl]-toluenesulfonamide(BIHET), was synthesized and characterized, and a carbon paste electrode modified with BIHET was employed for electroanalysis of iron(Ⅲ) from aqueous solutions. The electrochemical redox reaction of the dioxime with the modified CPE and the electrochemical behavior of iron(Ⅲ) on the CPE were investigated.
1999, 16(5): 103-105
Abstract:
The effect of tungsten content on the structure of Ni-W coating has been studied by XRD and SEM techniques. It is found that the increase of W content in alloy coating results in the increase of crystal lattice distortion which is the main factor in formation of amorphous structure of the coating. With the tungsten content greater than 44% an amorphous structure consisted of long range disorder and short range order has been observed.
The effect of tungsten content on the structure of Ni-W coating has been studied by XRD and SEM techniques. It is found that the increase of W content in alloy coating results in the increase of crystal lattice distortion which is the main factor in formation of amorphous structure of the coating. With the tungsten content greater than 44% an amorphous structure consisted of long range disorder and short range order has been observed.
1999, 16(5): 106-108
Abstract:
The XRD patterns of different calcined layered double hydroxides(CLDH) and their ultraviolet absorbing and screening properties have been investigated. It has been found that a calcined layered double hydroxide(CLDH) containing zinc is very effective in absorbing and screening ultraviolet radiation. The crystal structure of a CLDH containing zinc is similar to that of ZnO and is not related to the crystal structure of Al2O3. It is not a simple combination of zinc oxide and aluminium oxide but a calcined layered double hydroxide in which part of the Zn3+ cations is replaced by Al3+ cations.
The XRD patterns of different calcined layered double hydroxides(CLDH) and their ultraviolet absorbing and screening properties have been investigated. It has been found that a calcined layered double hydroxide(CLDH) containing zinc is very effective in absorbing and screening ultraviolet radiation. The crystal structure of a CLDH containing zinc is similar to that of ZnO and is not related to the crystal structure of Al2O3. It is not a simple combination of zinc oxide and aluminium oxide but a calcined layered double hydroxide in which part of the Zn3+ cations is replaced by Al3+ cations.
1999, 16(5): 109-110
Abstract:
Poly(ether ketone ether ketone ketone) containing meta phenylene linkage(PEKEKmK) was synthesized from 4,4' diphenoxybenzophenone and isophthaolyl chloride by electrophilic polycondensation and characterized by IR, DSC, TGA and WAXD. The crystallization of the PEKEKmK has been carried out under different conditions:melt crystallization, cold crystallization and solvent induced crystallization and the following order of crystallinity was obtained: Wcx,melt > Wcx,cold > Wcx,sic.
Poly(ether ketone ether ketone ketone) containing meta phenylene linkage(PEKEKmK) was synthesized from 4,4' diphenoxybenzophenone and isophthaolyl chloride by electrophilic polycondensation and characterized by IR, DSC, TGA and WAXD. The crystallization of the PEKEKmK has been carried out under different conditions:melt crystallization, cold crystallization and solvent induced crystallization and the following order of crystallinity was obtained: Wcx,melt > Wcx,cold > Wcx,sic.
1999, 16(5): 111-112
Abstract:
Title compound has been synthesized successfully from biphenyl in four steps:nitration, iodination, cyanation and reduction with total yield of 33%.
Title compound has been synthesized successfully from biphenyl in four steps:nitration, iodination, cyanation and reduction with total yield of 33%.
1999, 16(5): 113-114
Abstract:
The general revolving combination design has been used to optimize the palladium purification process with cation exchanger, particularly for Fe, Cu and Ni removing. The method has advantages of simplicity, better isolation efficiency and low cost. Satisfactory results are obtained.
The general revolving combination design has been used to optimize the palladium purification process with cation exchanger, particularly for Fe, Cu and Ni removing. The method has advantages of simplicity, better isolation efficiency and low cost. Satisfactory results are obtained.
1999, 16(5): 115-116
Abstract:
The effects of reaction conditions on the direct synthesis of dimethylcarbonate(DMC) from carbon dioxide and methanol in the presence of magnesium methoxide have been studied. The results indicate that the introduction of iodomethane increases the yield of DMC efficiently and lowers the reaction temperature. The addition of water absorption agents also brings about the increase of DMC yield. The reaction conversion can be enhanced under the nitrogen atmosphere.
The effects of reaction conditions on the direct synthesis of dimethylcarbonate(DMC) from carbon dioxide and methanol in the presence of magnesium methoxide have been studied. The results indicate that the introduction of iodomethane increases the yield of DMC efficiently and lowers the reaction temperature. The addition of water absorption agents also brings about the increase of DMC yield. The reaction conversion can be enhanced under the nitrogen atmosphere.
