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2003 Volume 20 Issue 4
2003, 20(4): 307-311
Abstract:
The ionic sensor properties of the molecular devices based on solid supported bilayer lipid membrane systems were investigated.The results show that the supported bilayer lipid membrane inlayed by each of I2,C60,or C60-I2 mixture is sensitive and special to I-.The detection limit is up to 10-7 mol/L.
The ionic sensor properties of the molecular devices based on solid supported bilayer lipid membrane systems were investigated.The results show that the supported bilayer lipid membrane inlayed by each of I2,C60,or C60-I2 mixture is sensitive and special to I-.The detection limit is up to 10-7 mol/L.
2003, 20(4): 312-317
Abstract:
The thermal behavior of Zn(NH4)3Cl5 have been investigated by non-isothermal TG-DTG at heating rates of 5.0,10.0,15.0 and 20.0℃/min.The results show that its thermal decomposition process can be divided into two steps.The first step,which is very important in ZnSe single crystal growth is controlled by random nucleation and growth mechanism.The most probable kinetic function in differential form,in integral form,the apparent activation energy (E) and the pre-exponential constant (A) of the process are founded to be{1/2(1-α)[-ln(1-α)]-1},[-ln(1-α)]2,162.94 kJ/mol,1011.75 s-1,respectively.The empirical kinetic model equation is dα/dt=1011.75{1/2(1-α)[-ln(1-α)]-1}exp(-(19598.3/T).The results indicate that Zn(NH4)3Cl5 has high thermal stability and is an excellent chemical transport agent for ZnSe single crystal growth from vapor.Two ZnSe bulk crystals were obtained from vapor using Zn(NH4)3Cl5 as a transport agent.
The thermal behavior of Zn(NH4)3Cl5 have been investigated by non-isothermal TG-DTG at heating rates of 5.0,10.0,15.0 and 20.0℃/min.The results show that its thermal decomposition process can be divided into two steps.The first step,which is very important in ZnSe single crystal growth is controlled by random nucleation and growth mechanism.The most probable kinetic function in differential form,in integral form,the apparent activation energy (E) and the pre-exponential constant (A) of the process are founded to be{1/2(1-α)[-ln(1-α)]-1},[-ln(1-α)]2,162.94 kJ/mol,1011.75 s-1,respectively.The empirical kinetic model equation is dα/dt=1011.75{1/2(1-α)[-ln(1-α)]-1}exp(-(19598.3/T).The results indicate that Zn(NH4)3Cl5 has high thermal stability and is an excellent chemical transport agent for ZnSe single crystal growth from vapor.Two ZnSe bulk crystals were obtained from vapor using Zn(NH4)3Cl5 as a transport agent.
2003, 20(4): 318-322
Abstract:
Multiwall carbon nanotubes (MWNT) were treated with nitric acid,followed by filtration,washing,and drying to give the functionalized nanotubes with three chemical groups-COOH,C=O and -OH being introduced on the surface.The photovoltaic properties of the functionalized MWNT thin film were investigated by surface photovoltage spectroscopy,two photovoltaic response bands were observed at 1100 and 1500 nm respectively.The result demonstrates that the functionlized MWNT has a excellent characteristic of photo-induced charge separation.The electrochemical behavior of functionalized MWNT was studied on a glassy carbon (GC) electrode and a borondoped diamond thin film (BDD) electrode by cyclic voltammetry (CV).Three stable redox peak pairs were recorded:one on modified GC electrode with peakpotentials of 0.084V and -0.130V (vs.SCE),respectively;two on modified BBD electrode with peakpotentials of 0.018V,-0.216V (vs,SCE) and 0.214V,0.142V (vs.SCE),respectively.
Multiwall carbon nanotubes (MWNT) were treated with nitric acid,followed by filtration,washing,and drying to give the functionalized nanotubes with three chemical groups-COOH,C=O and -OH being introduced on the surface.The photovoltaic properties of the functionalized MWNT thin film were investigated by surface photovoltage spectroscopy,two photovoltaic response bands were observed at 1100 and 1500 nm respectively.The result demonstrates that the functionlized MWNT has a excellent characteristic of photo-induced charge separation.The electrochemical behavior of functionalized MWNT was studied on a glassy carbon (GC) electrode and a borondoped diamond thin film (BDD) electrode by cyclic voltammetry (CV).Three stable redox peak pairs were recorded:one on modified GC electrode with peakpotentials of 0.084V and -0.130V (vs.SCE),respectively;two on modified BBD electrode with peakpotentials of 0.018V,-0.216V (vs,SCE) and 0.214V,0.142V (vs.SCE),respectively.
2003, 20(4): 323-327
Abstract:
The influence of UV-curable ink on attenuation of colored optical fiber has been examined.The components in the ink affected the attenuation of colored optical fiber in the order of resin >active diluent >dye.The attenuation increment of colored optical fiber was in the following sequence:bisphenol epoxy diacrylate >aromatic urethane diacrylate >aliphatic urethane diacrylate >polyester diacrylate with the other components in ink kept constant.The attenuation increment of colored optical fiber decreases with the increase of line-velocity of coloration of optical fiber.All these effects were found related with the modulus of cured resin system of ink.The greater the modules,shows the greater attenuation increment of colored optical fiber.The cured ink with greater modules probably provides for the colored fiber a greater stress,increase radiation loss,therefore,enhanced attenuation increment.
The influence of UV-curable ink on attenuation of colored optical fiber has been examined.The components in the ink affected the attenuation of colored optical fiber in the order of resin >active diluent >dye.The attenuation increment of colored optical fiber was in the following sequence:bisphenol epoxy diacrylate >aromatic urethane diacrylate >aliphatic urethane diacrylate >polyester diacrylate with the other components in ink kept constant.The attenuation increment of colored optical fiber decreases with the increase of line-velocity of coloration of optical fiber.All these effects were found related with the modulus of cured resin system of ink.The greater the modules,shows the greater attenuation increment of colored optical fiber.The cured ink with greater modules probably provides for the colored fiber a greater stress,increase radiation loss,therefore,enhanced attenuation increment.
2003, 20(4): 328-331
Abstract:
Thermosensitive cationic hydrogels poly (NIPAM-co-DMAPAA-Q) were synthesized by radical copolymerization of N-isopropylacrylamide (NIPAM) with acryloylamino propyl trimethyl ammonium chloride (DMAPAA-Q),and the influences of amount of cationic monomer DMAPAA-Q on the swelling ratio,deswelling/reswelling kinetics have been studied.It is found that the swelling ratio and low critical solution temperature (LCST) of the copolymer hydrogels increased with increase in the content of cationic monomer when the mass fraction of DMAPAA-Q was ≤7.5%.The LCST disappeared when x>(DMAPAA-Q)=37.5%.The greatest reswelling rate occurred in period of first 2 h and the equillibrium state achieved in 5 h.The interaction of the copolymer with surfactants appeared to be a two-step adsorption process,rather than a formation of 1:1 complex between polyelectrolyte and surfactants.
Thermosensitive cationic hydrogels poly (NIPAM-co-DMAPAA-Q) were synthesized by radical copolymerization of N-isopropylacrylamide (NIPAM) with acryloylamino propyl trimethyl ammonium chloride (DMAPAA-Q),and the influences of amount of cationic monomer DMAPAA-Q on the swelling ratio,deswelling/reswelling kinetics have been studied.It is found that the swelling ratio and low critical solution temperature (LCST) of the copolymer hydrogels increased with increase in the content of cationic monomer when the mass fraction of DMAPAA-Q was ≤7.5%.The LCST disappeared when x>(DMAPAA-Q)=37.5%.The greatest reswelling rate occurred in period of first 2 h and the equillibrium state achieved in 5 h.The interaction of the copolymer with surfactants appeared to be a two-step adsorption process,rather than a formation of 1:1 complex between polyelectrolyte and surfactants.
2003, 20(4): 332-335
Abstract:
ZnFe2O4 nanocrystalline has been prepared from Zn powder and FeCl3·5H2O in a mixture of oleic acid and absolute alcohol by a solvothermal process.The product has been characterized by XRD,TEM.The self-controlling synthesis mechanism and gas sensitivity of nanocrystalline ZnFe2O4 have been analyzed.The nanocrystalline ZnFe2O4 product is sized in 30 nm and the fabricated gas sensor therefrom shows a stable electric resistance in air for 120 h.
ZnFe2O4 nanocrystalline has been prepared from Zn powder and FeCl3·5H2O in a mixture of oleic acid and absolute alcohol by a solvothermal process.The product has been characterized by XRD,TEM.The self-controlling synthesis mechanism and gas sensitivity of nanocrystalline ZnFe2O4 have been analyzed.The nanocrystalline ZnFe2O4 product is sized in 30 nm and the fabricated gas sensor therefrom shows a stable electric resistance in air for 120 h.
2003, 20(4): 336-340
Abstract:
Nanosized PbTiO3 powder was prepared by a sol-gel method and characterized by XRD,TEM and CV techniques.PbTiO3 modified MnO2 electrodes were fabricated and their electrochemical behavior were studied by means of galvonostatic charge-discharge and CV experiments.The results indicated that the nano-sized PbTiO3 forms a series of complex oxides with MnO2 of different valency and prevents the formation of Mn3O4 during the course of electrode reaction.The discharge capacity of MnO2 electrodes modified with 5.0% (mass fraction) nanophase PbTiO3 is in average 45% higher than that of I.C.No.1 in 40% (mass fraction) KOH electrolytes,and chargedischarge efficiency is much improved by 10%~40%.
Nanosized PbTiO3 powder was prepared by a sol-gel method and characterized by XRD,TEM and CV techniques.PbTiO3 modified MnO2 electrodes were fabricated and their electrochemical behavior were studied by means of galvonostatic charge-discharge and CV experiments.The results indicated that the nano-sized PbTiO3 forms a series of complex oxides with MnO2 of different valency and prevents the formation of Mn3O4 during the course of electrode reaction.The discharge capacity of MnO2 electrodes modified with 5.0% (mass fraction) nanophase PbTiO3 is in average 45% higher than that of I.C.No.1 in 40% (mass fraction) KOH electrolytes,and chargedischarge efficiency is much improved by 10%~40%.
2003, 20(4): 341-345
Abstract:
An optical chemical sensor has been developed for the determination of iron (Ⅲ) based on reversible fluorescence quenching of N,N'-dibenzyl-3,3',5,5'-tetramethylbenzidine (TMBD) immobilized in a plasticized poly (vinyl chloride)(PVC) membrane.The sensing membrane consisted of 50 mg PVC,100 mg dioctyl sebacate (DOS) and 3.0 mg TMBD.The maximum response of the optode membrane for Iron (Ⅲ) was obtained in HAc-NaAc buffer solution.At optimum conditions the relationship between sensor responce and the concentration of Fe3+ ions was linear from 3.98×10-6 to 1.00×10-3 mol/L,with detection limit of 1.00×10-7 mol/L.The response time was less than 1 min.The sensing membrane has the advantage of high reproducibility,reversibility of the fluorescence signals and good selectivity.Common anions and cations do not interfere the measurements.It was applied for the direct determination of Fe3+ in human hair,green gram and milk powder samples.The results were in good agreement with those obattained by AAS method.
An optical chemical sensor has been developed for the determination of iron (Ⅲ) based on reversible fluorescence quenching of N,N'-dibenzyl-3,3',5,5'-tetramethylbenzidine (TMBD) immobilized in a plasticized poly (vinyl chloride)(PVC) membrane.The sensing membrane consisted of 50 mg PVC,100 mg dioctyl sebacate (DOS) and 3.0 mg TMBD.The maximum response of the optode membrane for Iron (Ⅲ) was obtained in HAc-NaAc buffer solution.At optimum conditions the relationship between sensor responce and the concentration of Fe3+ ions was linear from 3.98×10-6 to 1.00×10-3 mol/L,with detection limit of 1.00×10-7 mol/L.The response time was less than 1 min.The sensing membrane has the advantage of high reproducibility,reversibility of the fluorescence signals and good selectivity.Common anions and cations do not interfere the measurements.It was applied for the direct determination of Fe3+ in human hair,green gram and milk powder samples.The results were in good agreement with those obattained by AAS method.
2003, 20(4): 346-350
Abstract:
The dopamine (DA) electrocatalytical sensor is prepared from a Nafion film coated platinum electrode by immersing it in L-lysine solution,and coated with SiO2 sol-gel layer.The L-lysine is immobilized via electrostatic force between the cation of Lys and the negatively charged sulfonic acid groups in Nafion film.Cyclic voltammetry (CV) is used to investigate the electrochemical characteristics of the sensor.The linearity of DA concentration in the range of 5.0×10-7~5.0×10-4 mol/L with detection limit of 5.0×10-8 mol/L and the correlation coefficient of 0.999 are obtained by differential pulse voltammetry (DPV).No interference was found from ascorbic acid,nitrite,uric acid,glucose and L-arginine in the determination of DA.The sensor is stable for about 4 weeks in a dry state at 4℃.Satisfactory determination results of DA in samples are obtained by this method.
The dopamine (DA) electrocatalytical sensor is prepared from a Nafion film coated platinum electrode by immersing it in L-lysine solution,and coated with SiO2 sol-gel layer.The L-lysine is immobilized via electrostatic force between the cation of Lys and the negatively charged sulfonic acid groups in Nafion film.Cyclic voltammetry (CV) is used to investigate the electrochemical characteristics of the sensor.The linearity of DA concentration in the range of 5.0×10-7~5.0×10-4 mol/L with detection limit of 5.0×10-8 mol/L and the correlation coefficient of 0.999 are obtained by differential pulse voltammetry (DPV).No interference was found from ascorbic acid,nitrite,uric acid,glucose and L-arginine in the determination of DA.The sensor is stable for about 4 weeks in a dry state at 4℃.Satisfactory determination results of DA in samples are obtained by this method.
2003, 20(4): 351-354
Abstract:
In presence of polyacrylamide (PAM) sulfur nanoparticle solutions have a maximum resonance scattering peak at 470 nm,but no absorption peak appears in visible light region.The mass concentration of sulfur particles in the range of 0.05~1.0 mg/L is linear to the resonance scattering intensity at 470 nm.The effects of dyes such as bromophenol blue (BPB),bromomethyl violet (BMV),crystal violet (CV) and brilliant green (BG),and some organic solvents such as acetone,alcohol and methanol on the resonance scattering spectra of S nanoparticle have been studied.It is found that the molecular absorption of the dyes is an important factor to produce scattering peak,and the resonance scattering intensity decreases exponentially with the concentration of the dye.At maximum absorption wavelength of 590 nm,the concentration of BPB is linear to the ΔI590 nm value in the range of 0~1.0×10-5 mol/L.
In presence of polyacrylamide (PAM) sulfur nanoparticle solutions have a maximum resonance scattering peak at 470 nm,but no absorption peak appears in visible light region.The mass concentration of sulfur particles in the range of 0.05~1.0 mg/L is linear to the resonance scattering intensity at 470 nm.The effects of dyes such as bromophenol blue (BPB),bromomethyl violet (BMV),crystal violet (CV) and brilliant green (BG),and some organic solvents such as acetone,alcohol and methanol on the resonance scattering spectra of S nanoparticle have been studied.It is found that the molecular absorption of the dyes is an important factor to produce scattering peak,and the resonance scattering intensity decreases exponentially with the concentration of the dye.At maximum absorption wavelength of 590 nm,the concentration of BPB is linear to the ΔI590 nm value in the range of 0~1.0×10-5 mol/L.
2003, 20(4): 355-359
Abstract:
Mo-doped TiO2/AC immobilized membranes were formed on the surface of active carbon (AC) by a solgel method from ammonium molybdate and tetrabutylorthotitanate and characterized by UV-Vis spectrophotometry,TEM and XRD.The photocatalytic activities of the immobilized membranes were evaluated in photodegradation of methyl orange and omethoate aqueous solutions,respectively.The results show that both the rutile phase and anatase phase are formed in Mo-doped TiO2/AC immobilized membranes,but only rutile phase in the un-doped TiO2/AC immobilized membrane.The band edges in diffuse reflectance UV-Vis spectra of the Mo-doped TiO2/AC immobilized membranes show a red shift as compared with that of the un-doped membrane.The immobilized membrane shows the highest photocatalytic activity when mass fraction of Mo in TiO2 is 1.5%.
Mo-doped TiO2/AC immobilized membranes were formed on the surface of active carbon (AC) by a solgel method from ammonium molybdate and tetrabutylorthotitanate and characterized by UV-Vis spectrophotometry,TEM and XRD.The photocatalytic activities of the immobilized membranes were evaluated in photodegradation of methyl orange and omethoate aqueous solutions,respectively.The results show that both the rutile phase and anatase phase are formed in Mo-doped TiO2/AC immobilized membranes,but only rutile phase in the un-doped TiO2/AC immobilized membrane.The band edges in diffuse reflectance UV-Vis spectra of the Mo-doped TiO2/AC immobilized membranes show a red shift as compared with that of the un-doped membrane.The immobilized membrane shows the highest photocatalytic activity when mass fraction of Mo in TiO2 is 1.5%.
2003, 20(4): 360-364
Abstract:
The spherical Ni(OH)2 was modified with cobalt by three methods:electroless plating with cobalt,coating with Co(OH)2 and mixing with CoO.The difference of three modification methods on the performance of Ni(OH)2 electrode has been investigated.The charge-discharge experiments and cyclic voltammetry results show that coating with Co(OH)2 layer and electroless plating with cobalt greatly improved the charge-discharge efficiency and the reversibility of Ni(OH)2 electrode,significantly improving the utilization of active material and specific capacity of the electrode.The SEM micrograph shows that the Co(OH)2 coated layer and electroless plated Co are uniformly distributed on the surface of the Ni(OH)2 grains.The result from X-ray diffraction patterns shows that the coated Co(OH)2 layer and electroless plated Co can effectively prevent the formation of γ-NiOOH.It is concluded that the method of coating a layer of Co(OH)2 on the spherical Ni(OH)2 is the best among three methods.It is cheaper and simpler in technology.
The spherical Ni(OH)2 was modified with cobalt by three methods:electroless plating with cobalt,coating with Co(OH)2 and mixing with CoO.The difference of three modification methods on the performance of Ni(OH)2 electrode has been investigated.The charge-discharge experiments and cyclic voltammetry results show that coating with Co(OH)2 layer and electroless plating with cobalt greatly improved the charge-discharge efficiency and the reversibility of Ni(OH)2 electrode,significantly improving the utilization of active material and specific capacity of the electrode.The SEM micrograph shows that the Co(OH)2 coated layer and electroless plated Co are uniformly distributed on the surface of the Ni(OH)2 grains.The result from X-ray diffraction patterns shows that the coated Co(OH)2 layer and electroless plated Co can effectively prevent the formation of γ-NiOOH.It is concluded that the method of coating a layer of Co(OH)2 on the spherical Ni(OH)2 is the best among three methods.It is cheaper and simpler in technology.
2003, 20(4): 365-367
Abstract:
Eight derivatives of 1,3-dimethyl-5-methylthio-4-phenylhydrazonocarboxyl pyrazole were synthesized from 1,3-dimethyl-5-methylthio-4-hydrazinocarboxyl pyrazole.All compounds synthesized were identified by 1H NMR and elemental analysis.Some of them exhibited certain growth inhibition action to Phoma asparagi,Alternaria solani,Gibberella zeae,Physalospora piricola,Colletotrichum lagenarium as tested in vitro at dosage of 50 mg/L.
Eight derivatives of 1,3-dimethyl-5-methylthio-4-phenylhydrazonocarboxyl pyrazole were synthesized from 1,3-dimethyl-5-methylthio-4-hydrazinocarboxyl pyrazole.All compounds synthesized were identified by 1H NMR and elemental analysis.Some of them exhibited certain growth inhibition action to Phoma asparagi,Alternaria solani,Gibberella zeae,Physalospora piricola,Colletotrichum lagenarium as tested in vitro at dosage of 50 mg/L.
2003, 20(4): 368-370
Abstract:
Extraction processes of quenching compounds containing Fe2+ from natural mineral luminescent calcite with ammonium chloride,o-phenanthroline and ammonium oxalate were studied.The extraction yield of Fe2+ was 98.50%.Luminescence material-CaS:Mn2+ phosphors were prepared from calcite after Fe2+ had been leached out by sulfurizing flux method.
Extraction processes of quenching compounds containing Fe2+ from natural mineral luminescent calcite with ammonium chloride,o-phenanthroline and ammonium oxalate were studied.The extraction yield of Fe2+ was 98.50%.Luminescence material-CaS:Mn2+ phosphors were prepared from calcite after Fe2+ had been leached out by sulfurizing flux method.
2003, 20(4): 371-372
Abstract:
Benzyl acetate has been synthesized from benzyl alcohol and acetic anhydride using expandable graphite as a catalyst.The result shows that the larger the expanded volume of expandable graphite,the better the catalytic activity.The yield of benzyl acetate was 98.78% over the expandable graphite of 0.18 g when the reaction was carried out at room temperature for 60 min.
Benzyl acetate has been synthesized from benzyl alcohol and acetic anhydride using expandable graphite as a catalyst.The result shows that the larger the expanded volume of expandable graphite,the better the catalytic activity.The yield of benzyl acetate was 98.78% over the expandable graphite of 0.18 g when the reaction was carried out at room temperature for 60 min.
2003, 20(4): 373-375
Abstract:
The extraction of potassium from potash feldspar by NaCl,CaCl2,SrCl2 and BaCl2 has been investigated as function of salt kind and calcination temperature.The phase compositions of potash feldspar and its calcinated,and water insoluble substances of NaCl,CaCl2 co-calcinated potash feldspar were analyzed by XRD.The experiment results showed that the order of ion exchange extraction of potassium was Na+ >Ca2+ >Sr2+ >Ba2+,and at calcination temperature over the melting points of NaCl or CaCl2,the two salts gave potassium ion-exchange degree>90% much greater than that calcinated with other salts.
The extraction of potassium from potash feldspar by NaCl,CaCl2,SrCl2 and BaCl2 has been investigated as function of salt kind and calcination temperature.The phase compositions of potash feldspar and its calcinated,and water insoluble substances of NaCl,CaCl2 co-calcinated potash feldspar were analyzed by XRD.The experiment results showed that the order of ion exchange extraction of potassium was Na+ >Ca2+ >Sr2+ >Ba2+,and at calcination temperature over the melting points of NaCl or CaCl2,the two salts gave potassium ion-exchange degree>90% much greater than that calcinated with other salts.
2003, 20(4): 376-378
Abstract:
Chitosguanidine sulfate was synthesized by reaction of chitosan with aminoiminomethanesufonic acid.The compound has been characterized by IR spectra.It is soluble in water and react with picric acid to form an yellow sediment.Its specific viscosity in aqueous solution is reduced on heating.The chitosguanidine has good hygroscopicity and moisture retention close to hyaluronic acid.
Chitosguanidine sulfate was synthesized by reaction of chitosan with aminoiminomethanesufonic acid.The compound has been characterized by IR spectra.It is soluble in water and react with picric acid to form an yellow sediment.Its specific viscosity in aqueous solution is reduced on heating.The chitosguanidine has good hygroscopicity and moisture retention close to hyaluronic acid.
2003, 20(4): 379-381
Abstract:
A supported amorphous Ru-Co/ZrO2 catalyst was prepared by using formaldehyde as reduetant.The amorphous character of the catalyst was estimated by XRD,TG-DTA and SEM.The amorphous Ru-Co/ZrO2 catalyst has higher selectivity than Ru/ZrO2 in the selective hydrogenation of benzene to cyclohexene when the experiments were run in simulated production conditions.Presence of Co in the catalyst favored the selectivity of Ru-Co/ZrO2 but decreased its activity.
A supported amorphous Ru-Co/ZrO2 catalyst was prepared by using formaldehyde as reduetant.The amorphous character of the catalyst was estimated by XRD,TG-DTA and SEM.The amorphous Ru-Co/ZrO2 catalyst has higher selectivity than Ru/ZrO2 in the selective hydrogenation of benzene to cyclohexene when the experiments were run in simulated production conditions.Presence of Co in the catalyst favored the selectivity of Ru-Co/ZrO2 but decreased its activity.
2003, 20(4): 382-384
Abstract:
PMMA/LDH (layered double hydroxide) composite nanomaterials have been prepared.The relation between the content and dispersion of LDH in PMMA and the thermal stability and transparency of the composite materials has been investigated.The thermal stability of the composite materials was found increased with increase in the content of LDH.Uniform dispersion of LDH in PMMA favored increase of the thermal stability of the PMMA/LDH composite materials with a less loss of their transparency.
PMMA/LDH (layered double hydroxide) composite nanomaterials have been prepared.The relation between the content and dispersion of LDH in PMMA and the thermal stability and transparency of the composite materials has been investigated.The thermal stability of the composite materials was found increased with increase in the content of LDH.Uniform dispersion of LDH in PMMA favored increase of the thermal stability of the PMMA/LDH composite materials with a less loss of their transparency.
2003, 20(4): 385-387
Abstract:
Hexa (2-hydroxyethyl methacrylate) cyclotriphosphazene (HHMP) was synthesized from 2-hydroxyethyl methacrylate and hexachlorocyclotriphosphazene through nucleophilic substitution reaction in the presence of cuprous chloride as a catalyst.Raman,FTIR and NMR techniques were used to characterize and confirm the structure of the product compound.
Hexa (2-hydroxyethyl methacrylate) cyclotriphosphazene (HHMP) was synthesized from 2-hydroxyethyl methacrylate and hexachlorocyclotriphosphazene through nucleophilic substitution reaction in the presence of cuprous chloride as a catalyst.Raman,FTIR and NMR techniques were used to characterize and confirm the structure of the product compound.
2003, 20(4): 388-390
Abstract:
Fluorodenitration reaction was used to synthesis fluoroaromatics.The process has the advantages of mild reaction condition,high yield and little by-reaction when tetraalkylammonium fluoride R4NF was used as a fluorodenitration reagent.
Fluorodenitration reaction was used to synthesis fluoroaromatics.The process has the advantages of mild reaction condition,high yield and little by-reaction when tetraalkylammonium fluoride R4NF was used as a fluorodenitration reagent.
2003, 20(4): 391-393
Abstract:
The kinetics of gellation reaction between amphoteric polyacrylamide (APAM) and water soluble phenolformaldehyde resin has been studied.The whole gelation process could be divided into three periods:induction period,acceleration period and steady period.The accelerative increase period ranged in 3~17 days determines the incremental amount of gelling velocity and gel viscosity,and its gelling kinetics equation is η=η0+kt0.9 (25℃).There are two factors which are the doses of water soluble phenol formaldehyde resin as crosslinker and the molecular weight of APAM affecting the gelling velocity at temperature 40~70℃,the former is the more prominent.The gelling reaction rate constant k could be controlled in 1.57~3.13 Pa·s/d0.9 for reaction of 0.4% APAM solution with 0.2%~0.8% resol as crosslinker at reaction temperature 50℃ and the gel viscosity being reached to the maximum values of 16.2~29.0 Pa·s.
The kinetics of gellation reaction between amphoteric polyacrylamide (APAM) and water soluble phenolformaldehyde resin has been studied.The whole gelation process could be divided into three periods:induction period,acceleration period and steady period.The accelerative increase period ranged in 3~17 days determines the incremental amount of gelling velocity and gel viscosity,and its gelling kinetics equation is η=η0+kt0.9 (25℃).There are two factors which are the doses of water soluble phenol formaldehyde resin as crosslinker and the molecular weight of APAM affecting the gelling velocity at temperature 40~70℃,the former is the more prominent.The gelling reaction rate constant k could be controlled in 1.57~3.13 Pa·s/d0.9 for reaction of 0.4% APAM solution with 0.2%~0.8% resol as crosslinker at reaction temperature 50℃ and the gel viscosity being reached to the maximum values of 16.2~29.0 Pa·s.
2003, 20(4): 394-396
Abstract:
The activities of Ni catalysts with different supports in methane decomposition have been studied.The activity order of the catalysts is Ni/SiO2 >Ni/MgO-Al2O3 >Ni/CaO-Al2O3 >Ni/α-Al2O3 and the interaction between Ni and the support is in the order of Ni/SiO22O3 2O3 2O3.It is thus concluded that the weaker the interaction between Ni and support,the higher the activity of the catalyst.It was also found that the activity of the silica supported Ni-catalyst was increased with increase in its average pore radius and predominance pore radius.
The activities of Ni catalysts with different supports in methane decomposition have been studied.The activity order of the catalysts is Ni/SiO2 >Ni/MgO-Al2O3 >Ni/CaO-Al2O3 >Ni/α-Al2O3 and the interaction between Ni and the support is in the order of Ni/SiO2
2003, 20(4): 397-399
Abstract:
Polyaspartic acid (PASP) was prepared by hydrolysis of the polysuccinimide,which was mechanochemically synthesized from maleic anhydride and ammonium hydroxide in nitrogen atmosphere protection.The scale and corrosion inhibitions of PASP was evaluated and compared with 2-phosphonobutane-1,2,4-tricar-boxylic acid (PBTCA),1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and hydrolyzed polymaleic anhydride (HPMA).The results revealed that the inhibition of the PASP is close to that of PBTCA and HEDP,but much better than that of HPMA.
Polyaspartic acid (PASP) was prepared by hydrolysis of the polysuccinimide,which was mechanochemically synthesized from maleic anhydride and ammonium hydroxide in nitrogen atmosphere protection.The scale and corrosion inhibitions of PASP was evaluated and compared with 2-phosphonobutane-1,2,4-tricar-boxylic acid (PBTCA),1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and hydrolyzed polymaleic anhydride (HPMA).The results revealed that the inhibition of the PASP is close to that of PBTCA and HEDP,but much better than that of HPMA.
2003, 20(4): 400-402
Abstract:
N-p-Hydroxybenzoyl-N'-aryl-ureas (Ⅶ) were prepared in CH2Cl2 or DMF using oxalyl chloride as traceless linker and poly (ethylene glycol) as soluble polymer support with yields of 65%~77%.The reaction process was readily monitored by conventional analytic way.It was easy in work-up.
N-p-Hydroxybenzoyl-N'-aryl-ureas (Ⅶ) were prepared in CH2Cl2 or DMF using oxalyl chloride as traceless linker and poly (ethylene glycol) as soluble polymer support with yields of 65%~77%.The reaction process was readily monitored by conventional analytic way.It was easy in work-up.
2003, 20(4): 403-405
Abstract:
The titanium sulfate catalyst was prepared by calcination at 400~500℃.IR spectra of pyridine adsorption showed the presence of Brönsted acid sites on its surface.The catalysts had good activity in ketalization between cyclohexanone and 1,2-propanediol with yield being 89% in reaction conditions:molar ratio of cyclohexanone to 1,2-propanediol 1:1.3,catalyst amount 4% based on the mass of cyclohexanone,140℃ and 50~75 min.In esterification of succinic acid with butanol the yield of dibutyl succinate was 97%.The catalyst could be reused through regeneration.
The titanium sulfate catalyst was prepared by calcination at 400~500℃.IR spectra of pyridine adsorption showed the presence of Brönsted acid sites on its surface.The catalysts had good activity in ketalization between cyclohexanone and 1,2-propanediol with yield being 89% in reaction conditions:molar ratio of cyclohexanone to 1,2-propanediol 1:1.3,catalyst amount 4% based on the mass of cyclohexanone,140℃ and 50~75 min.In esterification of succinic acid with butanol the yield of dibutyl succinate was 97%.The catalyst could be reused through regeneration.
2003, 20(4): 406-408
Abstract:
Two hexaarylbisimidazoles were prepared from benzil,arylacetates and ammonium acetate after cyclization and oxidation.Their structures were identified by IR spectra and elemental analysis.The photochromic properties of the hexaarylbisimidazoles were studied.The absorption spectra of hexaarylbisimidazole in solvents were measured.The decolouration kinetics of the bisimidazoles in dark circumstance was found to be followed through the second order reaction.
Two hexaarylbisimidazoles were prepared from benzil,arylacetates and ammonium acetate after cyclization and oxidation.Their structures were identified by IR spectra and elemental analysis.The photochromic properties of the hexaarylbisimidazoles were studied.The absorption spectra of hexaarylbisimidazole in solvents were measured.The decolouration kinetics of the bisimidazoles in dark circumstance was found to be followed through the second order reaction.
