Login In
2005 Volume 22 Issue 4
2005, 22(4): 349-354
Abstract:
Coupled semiconductor ZnO-TiO2 was prepared by the sol-gel method,and its crystal structure,surface composition,chemisorption properties,absorptivity of ultraviolet and visible light,and photocatalytic behavior were investigated by virtue of thermal analysis (DTA-TG),X-ray diffraction (XRD),transmission electron microscopy (TEM),BET surface area (BET),temperature programmed reduction (TPR),infrared spectrometry (IR),UV-Visible diffuse reflectance spectrometry (UV-Vis),and photo stimulated surface catalytic reaction.The results show that the main crystal structure of the coupled-semiconductor was anatase TiO2 with the particle size in the range of 10~20 nm,and the BET surface area was about 72.5 m2/g.In the sol-gel process,Zn2+ cations take the places of the O-tetrahedral and O-octahedral centers to form Zn2 TiO4,and the coupling effects enhance the absorptivity of the semiconductor in the wavelength region of 250~400 nm.Acrylic acid was successfully synthesized from CO2 and C2H4 with a selectivity of above 70% under the photoreaction conditions of 0.1 MPa and 100℃.
Coupled semiconductor ZnO-TiO2 was prepared by the sol-gel method,and its crystal structure,surface composition,chemisorption properties,absorptivity of ultraviolet and visible light,and photocatalytic behavior were investigated by virtue of thermal analysis (DTA-TG),X-ray diffraction (XRD),transmission electron microscopy (TEM),BET surface area (BET),temperature programmed reduction (TPR),infrared spectrometry (IR),UV-Visible diffuse reflectance spectrometry (UV-Vis),and photo stimulated surface catalytic reaction.The results show that the main crystal structure of the coupled-semiconductor was anatase TiO2 with the particle size in the range of 10~20 nm,and the BET surface area was about 72.5 m2/g.In the sol-gel process,Zn2+ cations take the places of the O-tetrahedral and O-octahedral centers to form Zn2 TiO4,and the coupling effects enhance the absorptivity of the semiconductor in the wavelength region of 250~400 nm.Acrylic acid was successfully synthesized from CO2 and C2H4 with a selectivity of above 70% under the photoreaction conditions of 0.1 MPa and 100℃.
2005, 22(4): 355-360
Abstract:
The electrooxidation of 3,3',5,5'-tetramethylbenzidine (TMB) was investigated at a platinum minigrid electrode by means of UV-Vis optically transparent thin-layer electrochemistry technique.In the (B-R) buffer solution,TMB (underwent) a one-step two-electron electrooxidation in the pH range from 2.0 to <4.0 with a product quinonediimine,and two successive one-electron electrooxidation processes in the pH range from 4.0 to <7.0,to yield a mediate product TMB-free radical first,and then the complete oxidative product quinonediimine.At pH 8.4,the electrooxidation of TMB was also a quasi-reversible two-electron-transfer process to yield an azo compound.Several spectroelectrochemical techniques,such as thin-layer cyclic voltammetry,thin-layer cyclic voltabsorptometry,thin-layer potential-controlled electrolysis absorptometry,thin-layer single-potential-step chronoabsorptometry,and thin-layer double-potential-step chronoabsorptometry were applied to this investigation.The formal potential E0' and the electron transfer number corresponding to the electrooxidation of TMB in the B-R buffer solution at different pH values were determined.
The electrooxidation of 3,3',5,5'-tetramethylbenzidine (TMB) was investigated at a platinum minigrid electrode by means of UV-Vis optically transparent thin-layer electrochemistry technique.In the (B-R) buffer solution,TMB (underwent) a one-step two-electron electrooxidation in the pH range from 2.0 to <4.0 with a product quinonediimine,and two successive one-electron electrooxidation processes in the pH range from 4.0 to <7.0,to yield a mediate product TMB-free radical first,and then the complete oxidative product quinonediimine.At pH 8.4,the electrooxidation of TMB was also a quasi-reversible two-electron-transfer process to yield an azo compound.Several spectroelectrochemical techniques,such as thin-layer cyclic voltammetry,thin-layer cyclic voltabsorptometry,thin-layer potential-controlled electrolysis absorptometry,thin-layer single-potential-step chronoabsorptometry,and thin-layer double-potential-step chronoabsorptometry were applied to this investigation.The formal potential E0' and the electron transfer number corresponding to the electrooxidation of TMB in the B-R buffer solution at different pH values were determined.
2005, 22(4): 361-366
Abstract:
The microcapsular cores were prepared by dispersing low molecular weight heparin (LMWH) in emulsion,which were encapsulated with chitosan (CS) and then with alginate (ALG) by means of macromolecular self-assembly to form complex microcapsules with a multi-layer structure.The IR results indicated that there were strong electrostatic interactions between LMWH and CS and between CS and ALG.The SEM images showed the LMWH/CS/ALG microcapsules were spherical with an average diameter of (6.9±0.85)μm.The degree of encapsulation of the LMWH was as high as 93.5%.The results of the release kinetics experiments of the microcapsules show that the half-life of LMWH in the microcapsules reached 72 h.With the increase of the concentration of CS or ALG,the LMWH-releasing rate decreases;the higher the mass ratio of LMWH to CS,the faster the drug-release rate of the microcapsules;higher cross-linking degree results in a better drug-release performance;and the drug releases slightly faster in acid media than in alkali ones.
The microcapsular cores were prepared by dispersing low molecular weight heparin (LMWH) in emulsion,which were encapsulated with chitosan (CS) and then with alginate (ALG) by means of macromolecular self-assembly to form complex microcapsules with a multi-layer structure.The IR results indicated that there were strong electrostatic interactions between LMWH and CS and between CS and ALG.The SEM images showed the LMWH/CS/ALG microcapsules were spherical with an average diameter of (6.9±0.85)μm.The degree of encapsulation of the LMWH was as high as 93.5%.The results of the release kinetics experiments of the microcapsules show that the half-life of LMWH in the microcapsules reached 72 h.With the increase of the concentration of CS or ALG,the LMWH-releasing rate decreases;the higher the mass ratio of LMWH to CS,the faster the drug-release rate of the microcapsules;higher cross-linking degree results in a better drug-release performance;and the drug releases slightly faster in acid media than in alkali ones.
2005, 22(4): 367-371
Abstract:
The cathode material of lithium/sulfur rechargeable batteries,sulfur,exhibits poor conductivity,and its dischange product is partially soluble,leading to capacity decay during cycling.To mitigate these problems,we proposed to design the cathode material with a conducting skeleton and energy-storing side chains,and prepared a novel material carbyne polysulfide.The products obtained by co-heating carbon containing carbyne moieties and element sulfur were characterized by elemental analysis,13C NMR,Raman,and DSC/TG,and the product obtained at 300℃ was proved to have a sp2 hybride carbon skeleton with polysulfide attached on it,which resembles the theoretical structure of carbyne polysulfide.This material exhibits a high capacity of 773 mA·h/g at 400 mA/g and a stable reversible capacity of 350 mA·h/g after 50 cycles.The good performance of this cathode material under swift discharge condition and its good cycling properties indicate the success of our new design principle.
The cathode material of lithium/sulfur rechargeable batteries,sulfur,exhibits poor conductivity,and its dischange product is partially soluble,leading to capacity decay during cycling.To mitigate these problems,we proposed to design the cathode material with a conducting skeleton and energy-storing side chains,and prepared a novel material carbyne polysulfide.The products obtained by co-heating carbon containing carbyne moieties and element sulfur were characterized by elemental analysis,13C NMR,Raman,and DSC/TG,and the product obtained at 300℃ was proved to have a sp2 hybride carbon skeleton with polysulfide attached on it,which resembles the theoretical structure of carbyne polysulfide.This material exhibits a high capacity of 773 mA·h/g at 400 mA/g and a stable reversible capacity of 350 mA·h/g after 50 cycles.The good performance of this cathode material under swift discharge condition and its good cycling properties indicate the success of our new design principle.
2005, 22(4): 372-376
Abstract:
Several Cu(Ⅱ) complexes were synthesized by solid-state reaction and liquid-state reaction of pyrazolone derivatives with cupric acetate,respectively,and characterized by elemental analysis,IR,TG-DTA and XRD techniques.The results show that the solid-state reaction and liquid-state reaction leadto different products.The molecular formulae of the liquid-state reaction products are M2L2·nH2O(n=0,1) or M(HL)2H2O,and those of the solid-state reaction products are M(H2L)·2OAc·nH2O(n=1,2).
Several Cu(Ⅱ) complexes were synthesized by solid-state reaction and liquid-state reaction of pyrazolone derivatives with cupric acetate,respectively,and characterized by elemental analysis,IR,TG-DTA and XRD techniques.The results show that the solid-state reaction and liquid-state reaction leadto different products.The molecular formulae of the liquid-state reaction products are M2L2·nH2O(n=0,1) or M(HL)2H2O,and those of the solid-state reaction products are M(H2L)·2OAc·nH2O(n=1,2).
2005, 22(4): 377-381
Abstract:
Stable silver nanoparticles were synthesized via chemical reduction,and silver oxide nanoparticles were synthesized by means of mechanical stirring or sonicating,and both were characterized by TEM.The Ag and Ag2O nanoparticles can significantly increase the reductive peak current of Pb(Ⅱ)/Pb(Ⅳ) at the Pb electrode which indicates that these nanoparticles have high electrocatalytic activities for the reduction of Pb(Ⅳ) to Pb(Ⅱ).The appearance of an extra reduction peak in the presence of Ag2O nanoparticles indicates that they also exhibit Ag+ electrochemistry besides the electrocatalysis behavior due to the small amount of Ag+ adsorbed.The electrochemical behavior and the SEM images of the electrodes prove that the silver and silver oxide nanoparticles adsorbed and congregated on the surface of the lead electrode.In the indirected oxidation of Mn2+,the yield of the oxidative product Mn3+ increased by 11.11% or 18.51% respectively in the presence of Ag or Ag2O nanoparticles.
Stable silver nanoparticles were synthesized via chemical reduction,and silver oxide nanoparticles were synthesized by means of mechanical stirring or sonicating,and both were characterized by TEM.The Ag and Ag2O nanoparticles can significantly increase the reductive peak current of Pb(Ⅱ)/Pb(Ⅳ) at the Pb electrode which indicates that these nanoparticles have high electrocatalytic activities for the reduction of Pb(Ⅳ) to Pb(Ⅱ).The appearance of an extra reduction peak in the presence of Ag2O nanoparticles indicates that they also exhibit Ag+ electrochemistry besides the electrocatalysis behavior due to the small amount of Ag+ adsorbed.The electrochemical behavior and the SEM images of the electrodes prove that the silver and silver oxide nanoparticles adsorbed and congregated on the surface of the lead electrode.In the indirected oxidation of Mn2+,the yield of the oxidative product Mn3+ increased by 11.11% or 18.51% respectively in the presence of Ag or Ag2O nanoparticles.
2005, 22(4): 382-386
Abstract:
The damping functional zone of chlorinated butyl rubber (CⅡR) was successfully extended to higher temperature zone by means of forming interpenetration networks (IPNs) where poly (meth) acrylate was employed as the second network.The results from DMA show that in the IPNs,the content of crosslinking agent in the first network of CⅡR,the ratio between the two components,the type of (meth) acrylate composing the second network as well as the type and content of the crosslinking agent in the second network all have significant influence on the damping properties of the IPN.When m(CⅡR):m(PMAc) was (80~60):(20~40),at 10 Hz,CⅡR/PEA IPNs exhibited a high damping value with tanδmax≥1.24,while CⅡR/PBMA IPNs exhibited a wide damping zone of -45℃ to +57℃(tanδ≥0.3),and a tanδmax of 0.65.The (morphologies) and structures of the IPNs were characterized by means of TEM,and it was found that the CⅡR/PBMA IPNs had smaller phase domain size of 100~320 nm,and exhibited a good compatibility between its components.
The damping functional zone of chlorinated butyl rubber (CⅡR) was successfully extended to higher temperature zone by means of forming interpenetration networks (IPNs) where poly (meth) acrylate was employed as the second network.The results from DMA show that in the IPNs,the content of crosslinking agent in the first network of CⅡR,the ratio between the two components,the type of (meth) acrylate composing the second network as well as the type and content of the crosslinking agent in the second network all have significant influence on the damping properties of the IPN.When m(CⅡR):m(PMAc) was (80~60):(20~40),at 10 Hz,CⅡR/PEA IPNs exhibited a high damping value with tanδmax≥1.24,while CⅡR/PBMA IPNs exhibited a wide damping zone of -45℃ to +57℃(tanδ≥0.3),and a tanδmax of 0.65.The (morphologies) and structures of the IPNs were characterized by means of TEM,and it was found that the CⅡR/PBMA IPNs had smaller phase domain size of 100~320 nm,and exhibited a good compatibility between its components.
2005, 22(4): 387-390
Abstract:
Tetrachloroterephthaloyl chloride (TCTPC) was synthesized via chlorination of terephthaloyl chloride (TPC) catalyzed by ferric chloride at 175~180℃ for 10 h,and confirmed by means of FTIR,MS and elemental analysis.A series of novel polychloro substituted poly (aryl ether ketone sulfone)(PESEKK/(C-PESEKK)) copolymers with high molecular weights were prepared by low-temperature solution polycondensation of TCTPC,4,4-diphenoxydiphenyl sulfone (DPODPS) and TPC in 1,2-dichloroethane in the presence of AlCl3 and NMP.The copolymers were characterized by FT-IR,DSC and WAXD,etc.The results show that the copolymers are non-crystalline,exhibit high Tg's (168~232℃),which are higher than that of commercial PEEK and PEKK,and increase with increasing C-PESEKK content.But the decomposition onset temperatures (Td)(5% mass loss) of the copolymers were a little lower than that of commercial PEEK and PEKK.The (copolymers) are soluble in CHCl3,and especially in strong aprotogenic organic solvents such as DMF,DMSO and NMP at room temperature.
Tetrachloroterephthaloyl chloride (TCTPC) was synthesized via chlorination of terephthaloyl chloride (TPC) catalyzed by ferric chloride at 175~180℃ for 10 h,and confirmed by means of FTIR,MS and elemental analysis.A series of novel polychloro substituted poly (aryl ether ketone sulfone)(PESEKK/(C-PESEKK)) copolymers with high molecular weights were prepared by low-temperature solution polycondensation of TCTPC,4,4-diphenoxydiphenyl sulfone (DPODPS) and TPC in 1,2-dichloroethane in the presence of AlCl3 and NMP.The copolymers were characterized by FT-IR,DSC and WAXD,etc.The results show that the copolymers are non-crystalline,exhibit high Tg's (168~232℃),which are higher than that of commercial PEEK and PEKK,and increase with increasing C-PESEKK content.But the decomposition onset temperatures (Td)(5% mass loss) of the copolymers were a little lower than that of commercial PEEK and PEKK.The (copolymers) are soluble in CHCl3,and especially in strong aprotogenic organic solvents such as DMF,DMSO and NMP at room temperature.
2005, 22(4): 391-394
Abstract:
Eleven novel N-acylpyrazole derivatives were synthesized via acylation reaction of intermediate 1H-pyrazole derivatives with acyl chloride.All the compounds synthesized were identified by means of 1H NMR,IR and MS.These compounds show certain insecticidal activity against aphid in a dosage of 250 mg/L,and exhibit certain fungicidal activity at 50 mg/L.
Eleven novel N-acylpyrazole derivatives were synthesized via acylation reaction of intermediate 1H-pyrazole derivatives with acyl chloride.All the compounds synthesized were identified by means of 1H NMR,IR and MS.These compounds show certain insecticidal activity against aphid in a dosage of 250 mg/L,and exhibit certain fungicidal activity at 50 mg/L.
2005, 22(4): 395-398
Abstract:
The host-guest interaction between N,N'-bis (ferrocenoyl) diaminoethane and β-cyclodextrin (β-CD) was studied.The absorption intensity of the solution containing N,N'-bis (ferrocenoyl) diaminoethane and β-CD increased with the increase of the β-CD concentration.The introduction of N,N'-bis (ferrocenoyl) diaminoethane altered the fluorescence emission spectrum of the β-CD and pyrene system.Only one oxidative peak was found in the cyclic voltammogram of the mixture of N,N'-bis (ferrocenoyl) diaminoethane with β-CD,and the oxidation potential was significantly greater than that of the electro-active compound N,N'-bis (ferrocenoyl) diaminoethane in free state.These results show that as a guest,the two ferrocene groups in N,N'-bis (ferrocenoyl) diaminoethane can combine with β-CD simultaneously.
The host-guest interaction between N,N'-bis (ferrocenoyl) diaminoethane and β-cyclodextrin (β-CD) was studied.The absorption intensity of the solution containing N,N'-bis (ferrocenoyl) diaminoethane and β-CD increased with the increase of the β-CD concentration.The introduction of N,N'-bis (ferrocenoyl) diaminoethane altered the fluorescence emission spectrum of the β-CD and pyrene system.Only one oxidative peak was found in the cyclic voltammogram of the mixture of N,N'-bis (ferrocenoyl) diaminoethane with β-CD,and the oxidation potential was significantly greater than that of the electro-active compound N,N'-bis (ferrocenoyl) diaminoethane in free state.These results show that as a guest,the two ferrocene groups in N,N'-bis (ferrocenoyl) diaminoethane can combine with β-CD simultaneously.
Composition and Microstructure of the Fisheyes in a Metallocene Linear Low Density Polyethylene Film
2005, 22(4): 399-402
Abstract:
The fisheyes in the blown film of a metallocene linear low density polyethylene (mLLDPE) were isolated by the dissolution method,and the solubility,the molecular weight,and the crystallinity of the separated parts were characterized by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC).The results show that the fisheyes are composed of (92.6±1.1)% of soluble mLLDPE and (7.4±1.1)% of insoluble,slightly crosslinked high density polyethylene gel.
The fisheyes in the blown film of a metallocene linear low density polyethylene (mLLDPE) were isolated by the dissolution method,and the solubility,the molecular weight,and the crystallinity of the separated parts were characterized by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC).The results show that the fisheyes are composed of (92.6±1.1)% of soluble mLLDPE and (7.4±1.1)% of insoluble,slightly crosslinked high density polyethylene gel.
2005, 22(4): 403-406
Abstract:
An amphiphilic block copolymer poly (D,L-lactide-b-ethylene glycol)(PLA-mPEG) was synthesized via copolymerization of monomethoxypoly (ethylene glycol) with lactide prepared by the catalyst-free method.The copolymer PLA-mPEG750 shows the characteristic structures of both PLA and mPEG750 determined by FT-IR,and its molecular weight was determined by GPC.The surface tension of the aqueous solutions of the amphiphilic copolymer was measured and the critical micelle concentration (CMC) was calculated to be in the range of 3.5×10-5~5.8×10-5 mol/L,showing that the surface activity of these di-block copolymers is similar to that of typical surfactants.The copolymer can self-associate in aqueous solution to form micelle,and different micelle could be prepared by changing the conditions.
An amphiphilic block copolymer poly (D,L-lactide-b-ethylene glycol)(PLA-mPEG) was synthesized via copolymerization of monomethoxypoly (ethylene glycol) with lactide prepared by the catalyst-free method.The copolymer PLA-mPEG750 shows the characteristic structures of both PLA and mPEG750 determined by FT-IR,and its molecular weight was determined by GPC.The surface tension of the aqueous solutions of the amphiphilic copolymer was measured and the critical micelle concentration (CMC) was calculated to be in the range of 3.5×10-5~5.8×10-5 mol/L,showing that the surface activity of these di-block copolymers is similar to that of typical surfactants.The copolymer can self-associate in aqueous solution to form micelle,and different micelle could be prepared by changing the conditions.
2005, 22(4): 407-411
Abstract:
Pure silica mesoporous molecular sieve MCM-41 and those containing aluminum (Al-MCM-41) or lanthanum (La-MCM-41) with Si/Al (Si/La) mole ratios of 30:1 and 80:1 were synthesized under hydrothermal conditions with cetylpyridinium chloride (CPCl) as the surfactant and nonylphenolpolyoxyethylene ether (TX-100) as the composite template and ethyl silicate (TEOS) as the silica source in hydrochloric acid.The mesoporous materials,pure silica MCM-41,Al-MCM-41 and La-MCM-41,were characterized by means of XRD,BET,TG-DTA,FT-IR,TEM,and NH3 adsorption-desorption (NH3-TPD).The XRD and BET studies indicate that the calcined materials have the standard MCM-41 structure and ordered pore structure and high specific surface area.The NH3-TPD and TG-DTA spectra indicate that all the samples prepared are rich in surface strong acid sites and of high thermal stability.Pure silica MCM-41,Al-MCM-41 and La-MCM-41 were used as catalysts in the ethyloxylation.The results show that Al-MCM-41 has higher catalytic activity than the others.Orthogonal experiment indicated that when octanol was heated with 3 equivalance of ethylene oxide (EO) at 120℃ in the presence of 5% catalyst (Al-MCM-41),the yield was 88%.The catalyst can be recycled.The reaction rate only changed a little after the catalyst was recycled three times.
Pure silica mesoporous molecular sieve MCM-41 and those containing aluminum (Al-MCM-41) or lanthanum (La-MCM-41) with Si/Al (Si/La) mole ratios of 30:1 and 80:1 were synthesized under hydrothermal conditions with cetylpyridinium chloride (CPCl) as the surfactant and nonylphenolpolyoxyethylene ether (TX-100) as the composite template and ethyl silicate (TEOS) as the silica source in hydrochloric acid.The mesoporous materials,pure silica MCM-41,Al-MCM-41 and La-MCM-41,were characterized by means of XRD,BET,TG-DTA,FT-IR,TEM,and NH3 adsorption-desorption (NH3-TPD).The XRD and BET studies indicate that the calcined materials have the standard MCM-41 structure and ordered pore structure and high specific surface area.The NH3-TPD and TG-DTA spectra indicate that all the samples prepared are rich in surface strong acid sites and of high thermal stability.Pure silica MCM-41,Al-MCM-41 and La-MCM-41 were used as catalysts in the ethyloxylation.The results show that Al-MCM-41 has higher catalytic activity than the others.Orthogonal experiment indicated that when octanol was heated with 3 equivalance of ethylene oxide (EO) at 120℃ in the presence of 5% catalyst (Al-MCM-41),the yield was 88%.The catalyst can be recycled.The reaction rate only changed a little after the catalyst was recycled three times.
2005, 22(4): 412-416
Abstract:
Nanostructured TiO2 thin films were fabricated on glass substrates by soaking the substrates in and lifting the substrates from TiO2 colloids prepared via the hydrolysis of TiCl4.The thin films were investigated by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),and energy dispersion spectroscopy (EDS) to characterize the particle size and surface properties.UV absorption spectroscopy and the visible light transmission rate were employed to investigate the optical characteristics of the thin films.The photo-catalytic activity was determined by degrading acetic acid in aqueous solution.The results show that the mass of thin film was in good linear relationship with the number of coated layers,and the thin film with 4 coated layers and 0.192 μm in thickness with the diameter of TiO2 particles being 0.5 nm can strongly absorb ultraviolet radiation,and the absorption band exhibited a red shift.The photocatalytic degradation rate of 500 mL of 20 mg/L acetic acid on the thin films was 75.9%,27.9% higher than the degradation rate of the same reaction catalyzed by the same amount of TiO2 powder produced from the Sol-gel solution within 350 min,which demonstrates the higher photocatalytic activity of the thin films.
Nanostructured TiO2 thin films were fabricated on glass substrates by soaking the substrates in and lifting the substrates from TiO2 colloids prepared via the hydrolysis of TiCl4.The thin films were investigated by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),and energy dispersion spectroscopy (EDS) to characterize the particle size and surface properties.UV absorption spectroscopy and the visible light transmission rate were employed to investigate the optical characteristics of the thin films.The photo-catalytic activity was determined by degrading acetic acid in aqueous solution.The results show that the mass of thin film was in good linear relationship with the number of coated layers,and the thin film with 4 coated layers and 0.192 μm in thickness with the diameter of TiO2 particles being 0.5 nm can strongly absorb ultraviolet radiation,and the absorption band exhibited a red shift.The photocatalytic degradation rate of 500 mL of 20 mg/L acetic acid on the thin films was 75.9%,27.9% higher than the degradation rate of the same reaction catalyzed by the same amount of TiO2 powder produced from the Sol-gel solution within 350 min,which demonstrates the higher photocatalytic activity of the thin films.
2005, 22(4): 417-421
Abstract:
The photocatalytic degradation of 1-naphthylamine by TiO2/C photocatalyst was studied.Based on the characterization of TiO2/C photocatalyst with XRD,SEM,specific surface area,adsorption valves of methylene blue and the amount of TiO2 supported on active carbon,the effects of the amount of TiO2/C photocatalyst,the solution pH,the initial concentration of 1-naphthylamine and illumination time on the photocatalytic degradation of 1-naphthylamine were studied.It was found that when the solution pH was 7.10,the amount of TiO2/C photocatalyst was 1.0 g,the concentration of 1-naphthylamine solution was 1.40×10-3 mol/L and the illumination time was 2.5 h,the photocatalytic degradation rate of 1-naphthylamine reached 80%.
The photocatalytic degradation of 1-naphthylamine by TiO2/C photocatalyst was studied.Based on the characterization of TiO2/C photocatalyst with XRD,SEM,specific surface area,adsorption valves of methylene blue and the amount of TiO2 supported on active carbon,the effects of the amount of TiO2/C photocatalyst,the solution pH,the initial concentration of 1-naphthylamine and illumination time on the photocatalytic degradation of 1-naphthylamine were studied.It was found that when the solution pH was 7.10,the amount of TiO2/C photocatalyst was 1.0 g,the concentration of 1-naphthylamine solution was 1.40×10-3 mol/L and the illumination time was 2.5 h,the photocatalytic degradation rate of 1-naphthylamine reached 80%.
2005, 22(4): 422-426
Abstract:
Acetylacetone chelate of isopropoxy titanium was used to modify a ternary carboxy copolymer (MBA) and two tetracopolymers with additional hydroxyl and hydroxylamine groups (MBAH and MBAN).The addition of the chelate increased both the hydrosol viscosity and average particle size,and decreased the hydrosol surface tension;the Tg of the film and the activation energy for the thermal decomposition were higher,and the water resistance of the film was improved.The chelate brought the biggest change for MBA hydrosol in average particle size,which increased from 70 nm to 123 nm,and its surface tension decreaced to 25.20 mN/m,and the decomposition activation energy reached 138.3 kJ/mol.The water resistance of MBAN was improved saliently,with a water up-take of less than 1.5%.Thus it is suitable for use as water-based ink.All the three heated hydrosols with the chelate showed a new absorption peak in UV analysis,indicating that a new product was formed in the heating course.DSC results also show that there was an exothermic reaction in heating the chelate/MBA blend.
Acetylacetone chelate of isopropoxy titanium was used to modify a ternary carboxy copolymer (MBA) and two tetracopolymers with additional hydroxyl and hydroxylamine groups (MBAH and MBAN).The addition of the chelate increased both the hydrosol viscosity and average particle size,and decreased the hydrosol surface tension;the Tg of the film and the activation energy for the thermal decomposition were higher,and the water resistance of the film was improved.The chelate brought the biggest change for MBA hydrosol in average particle size,which increased from 70 nm to 123 nm,and its surface tension decreaced to 25.20 mN/m,and the decomposition activation energy reached 138.3 kJ/mol.The water resistance of MBAN was improved saliently,with a water up-take of less than 1.5%.Thus it is suitable for use as water-based ink.All the three heated hydrosols with the chelate showed a new absorption peak in UV analysis,indicating that a new product was formed in the heating course.DSC results also show that there was an exothermic reaction in heating the chelate/MBA blend.
2005, 22(4): 427-430
Abstract:
The interaction between sodium dodecyl sulfate (SDS) and 3-alkoxyl-2-hydroxypropyl trimethyl ammonium chloride (CnNCl) in aqueous systems was investigated by means of microcalorimetric titration.The pseudo-critical micellar concentration (pcmc) and thermodynamic parameters for the formation of the micelle of each mixture surfactant system were estimated from the calorimetric data and the titration curve.The formation enthalpy and entropy of the mixture micelle are discussed based on the structure of the surfactant using the iceberg model.The results show that the interaction between the hydrophobic chains of the SDS and the CnNCl is more important than the mutual electrostatic attraction between the negatively charged end group of SDS and the positively charged end of CnNCl in the synergistic interaction between the anionic and cationic surfactants.
The interaction between sodium dodecyl sulfate (SDS) and 3-alkoxyl-2-hydroxypropyl trimethyl ammonium chloride (CnNCl) in aqueous systems was investigated by means of microcalorimetric titration.The pseudo-critical micellar concentration (pcmc) and thermodynamic parameters for the formation of the micelle of each mixture surfactant system were estimated from the calorimetric data and the titration curve.The formation enthalpy and entropy of the mixture micelle are discussed based on the structure of the surfactant using the iceberg model.The results show that the interaction between the hydrophobic chains of the SDS and the CnNCl is more important than the mutual electrostatic attraction between the negatively charged end group of SDS and the positively charged end of CnNCl in the synergistic interaction between the anionic and cationic surfactants.
2005, 22(4): 431-434
Abstract:
The composition and chain structures of two solution polymerized styrene-butadiene rubbers (S-SBR) were studied by means of 1H NMR and 13C NMR.The copolymer composition of the S-SBR from Yanshan (SSBR1) was similar to that of the S-SBR from Bayer (SSBR2).The contents of styrene units in the two S-SBRs are all about 14% (mole fraction).SSBR1 has a higher content of trans-1,4 polybutadiene (PB) structure (about 49.7% (mole fraction)).The cis-1,4 polybutadiene content in SSBR2 is very high (49.4% (mole fraction)) and segmented cis-1,4 PB was found in SSBR2.The content of 1,2-add PB in SSBR2 is lower than that in SSBR1.The chain structure of SSBR2 induces good compatibility between SSBR2 and (natural) rubbers,and SSBR2 has a lower glass transition temperature than SSBR1.
The composition and chain structures of two solution polymerized styrene-butadiene rubbers (S-SBR) were studied by means of 1H NMR and 13C NMR.The copolymer composition of the S-SBR from Yanshan (SSBR1) was similar to that of the S-SBR from Bayer (SSBR2).The contents of styrene units in the two S-SBRs are all about 14% (mole fraction).SSBR1 has a higher content of trans-1,4 polybutadiene (PB) structure (about 49.7% (mole fraction)).The cis-1,4 polybutadiene content in SSBR2 is very high (49.4% (mole fraction)) and segmented cis-1,4 PB was found in SSBR2.The content of 1,2-add PB in SSBR2 is lower than that in SSBR1.The chain structure of SSBR2 induces good compatibility between SSBR2 and (natural) rubbers,and SSBR2 has a lower glass transition temperature than SSBR1.
2005, 22(4): 435-439
Abstract:
A pH sensor was fabricated from polypyrrole (PPy) on Pt wire.PPy was prepared electrochemically in a 0.1 mol/L Py aqueous solution with or without addition of 0.1 mol/L NaHCO3 and characterized by means of infrared absorption spectroscopy (IR) and electrochemical impedance spectroscopy (EIS).The Nyquist plots for non-doped PPy in an acid solution (pH=4.01),a neutral solution (pH=6.85),and an alkali solution (pH=9.14) were composed of two semicircles in the high and mid frequency regions and a Warburg response arisen by H+ diffusion process in the low frequency region.The Nyquist plots for HCO3--doped PPy in corresponding pH buffer solutions were composed of two semicircles in the tested frequency region and did not show the Warburg response.In the latter case,the charge transfer resistance and the film resistance of PPy were increased apparently.The electrochemically synthesized non-doped PPy as a pH-indicator electrode had satisfactory potentiometric properties:sub-Nernstian response with a slope of 49.32 mV/pH at buffer solutions of pH 3 to 10,excellent linearity,r=-0.997 1,and relatively short response time and small selectivity coefficient to conventional positive ions such as K+ and Na+.
A pH sensor was fabricated from polypyrrole (PPy) on Pt wire.PPy was prepared electrochemically in a 0.1 mol/L Py aqueous solution with or without addition of 0.1 mol/L NaHCO3 and characterized by means of infrared absorption spectroscopy (IR) and electrochemical impedance spectroscopy (EIS).The Nyquist plots for non-doped PPy in an acid solution (pH=4.01),a neutral solution (pH=6.85),and an alkali solution (pH=9.14) were composed of two semicircles in the high and mid frequency regions and a Warburg response arisen by H+ diffusion process in the low frequency region.The Nyquist plots for HCO3--doped PPy in corresponding pH buffer solutions were composed of two semicircles in the tested frequency region and did not show the Warburg response.In the latter case,the charge transfer resistance and the film resistance of PPy were increased apparently.The electrochemically synthesized non-doped PPy as a pH-indicator electrode had satisfactory potentiometric properties:sub-Nernstian response with a slope of 49.32 mV/pH at buffer solutions of pH 3 to 10,excellent linearity,r=-0.997 1,and relatively short response time and small selectivity coefficient to conventional positive ions such as K+ and Na+.
2005, 22(4): 440-444
Abstract:
A starch supported palladium catalyst was synthesized and characterized by means of XPS,TG,DTA,TEM etc.The thermal analysis result showed that the catalyst was stable at up to 220℃.TEM confirmed that the Pd particles were spherical and uniformly distributed,and the average size was 10 nm.The starch supported palladium was an efficient catalyst for Heck arylation of acrylic acid and styrene with iodoarenes.In the presence of a small amount of the catalyst,the substituted trans-cinnamic acid or trans-stilbene was obtained in air.In the presence of the starch supported palladium,Heck arylation of acrylic acid with iodobenzene can be carried out efficiently at a low temperature (80℃) and the yield was 81%,indicating the high catalytic activity of the starch supported palladium (0).The Pd content decreased to 3.5%,2.6% and 2.0% respectively when the catalyst was repeatedly used three times.This was perhaps the reason why the catalytic activity of the catalyst decreased when used repeatedly.
A starch supported palladium catalyst was synthesized and characterized by means of XPS,TG,DTA,TEM etc.The thermal analysis result showed that the catalyst was stable at up to 220℃.TEM confirmed that the Pd particles were spherical and uniformly distributed,and the average size was 10 nm.The starch supported palladium was an efficient catalyst for Heck arylation of acrylic acid and styrene with iodoarenes.In the presence of a small amount of the catalyst,the substituted trans-cinnamic acid or trans-stilbene was obtained in air.In the presence of the starch supported palladium,Heck arylation of acrylic acid with iodobenzene can be carried out efficiently at a low temperature (80℃) and the yield was 81%,indicating the high catalytic activity of the starch supported palladium (0).The Pd content decreased to 3.5%,2.6% and 2.0% respectively when the catalyst was repeatedly used three times.This was perhaps the reason why the catalytic activity of the catalyst decreased when used repeatedly.
2005, 22(4): 445-447
Abstract:
The two enantiomers of flutriafol were resolved by means of high-performance liquid chromato-graphy with a cellulose derivative chiral stationary phase.The mobile phase was n-hexane,and five alkane alcohols were used as the polar modifier.The effects of the modifier and its concentration on the resolution were studied,and the influence of the temperature was also investigated.The results show that the separation factor could reach 1.41 at room temperature with 5% (volume fraction) isopropanol in the mobile phase.Lower column temperature resulted in a higher separation factor.The separation mechanism was primarily discussed.
The two enantiomers of flutriafol were resolved by means of high-performance liquid chromato-graphy with a cellulose derivative chiral stationary phase.The mobile phase was n-hexane,and five alkane alcohols were used as the polar modifier.The effects of the modifier and its concentration on the resolution were studied,and the influence of the temperature was also investigated.The results show that the separation factor could reach 1.41 at room temperature with 5% (volume fraction) isopropanol in the mobile phase.Lower column temperature resulted in a higher separation factor.The separation mechanism was primarily discussed.
2005, 22(4): 448-450
Abstract:
Seven 2-tert-butyl-4-chloro-5-(3'-aryl-2'-oxo-5'-oxazolidinylmethoxy)-3(2H) pyridazinones were synthesized via the reaction of aryl isocyanates and 2-tert-butyl-4-chloro-5-(2,3-epoxypropyloxy)-3(2H)(pyridazinones) prepared by the reaction of 2-tert-butyl-4-chloro-5-hydroxy-3(2H) pyridazinones with epichlorohydrin.The structures of the title compounds were confirmed by 1H NMR,HR MS and IR.The bioassay tests showed the inhibition of compound 2b and that of compound 2c against Colletotrichum lagenarium under 500 mg/L were 33% and 50%,respectively.
Seven 2-tert-butyl-4-chloro-5-(3'-aryl-2'-oxo-5'-oxazolidinylmethoxy)-3(2H) pyridazinones were synthesized via the reaction of aryl isocyanates and 2-tert-butyl-4-chloro-5-(2,3-epoxypropyloxy)-3(2H)(pyridazinones) prepared by the reaction of 2-tert-butyl-4-chloro-5-hydroxy-3(2H) pyridazinones with epichlorohydrin.The structures of the title compounds were confirmed by 1H NMR,HR MS and IR.The bioassay tests showed the inhibition of compound 2b and that of compound 2c against Colletotrichum lagenarium under 500 mg/L were 33% and 50%,respectively.
2005, 22(4): 451-453
Abstract:
Collagen and chitosan was dissolved acetic acid in a concentration of 4 g/L (w/v),respec-tively.The mixtures of collagen and chitosan with the mass ratios of 1:3,1:1,3:1(collagen:chitosan) were cast into blend films and examined by AFM.The results suggest that an interpenetrating polymeric network was formed in collagen and chitosan blend films,which differed from the tight network of collagen fiber (100~400 nm) in pure collagen film,or the linear pure chitosan film in structure.With the increase of chitosan content the collagen fiber bunches loosened and the holes were filled by chitosan particles.
Collagen and chitosan was dissolved acetic acid in a concentration of 4 g/L (w/v),respec-tively.The mixtures of collagen and chitosan with the mass ratios of 1:3,1:1,3:1(collagen:chitosan) were cast into blend films and examined by AFM.The results suggest that an interpenetrating polymeric network was formed in collagen and chitosan blend films,which differed from the tight network of collagen fiber (100~400 nm) in pure collagen film,or the linear pure chitosan film in structure.With the increase of chitosan content the collagen fiber bunches loosened and the holes were filled by chitosan particles.
2005, 22(4): 454-456
Abstract:
Intermediate 6-cyanoindole was obtained from 4-methylbenzonitrile as a raw material via nitration with the mixed acid,condensation with N,N-dimethylformamide dimethyl acetal and cyclic reaction with Raney nickel-hydrazine.6-Cyanoindole-3-carboxyaldehyde was synthesized via the Vilsmeier reaction of 6-(cyanoindole) with N,N-diemthylformamide and phosphorus oxychloride.The structure of the target compound was confirmed by 1H NMR,IR and elemental analysis.The total yield was 57% and the purity of the final product reached 99.4%.
Intermediate 6-cyanoindole was obtained from 4-methylbenzonitrile as a raw material via nitration with the mixed acid,condensation with N,N-dimethylformamide dimethyl acetal and cyclic reaction with Raney nickel-hydrazine.6-Cyanoindole-3-carboxyaldehyde was synthesized via the Vilsmeier reaction of 6-(cyanoindole) with N,N-diemthylformamide and phosphorus oxychloride.The structure of the target compound was confirmed by 1H NMR,IR and elemental analysis.The total yield was 57% and the purity of the final product reached 99.4%.
2005, 22(4): 457-459
Abstract:
The natural alkaloid isoanabasine was prepared by catalytic hydrogenation of tetrahydrobipyridines with (S)-BINAP-Rh complex.The tetrahydrobipyridines bearing bigger N-substituted group displayed high stereoselectivity and low reaction rate.Moreover,the position of the double bond on piperidinene also displayed a great effect on the stereoselectivity that made the ee value of hydrogenation of 1'-benzyl-1',4',5',6'-tetrahydro-2,3'-bipyridine being up to 21.5% but that of 1'-benzyl-1',2',5',6'-tetrahydro-2,3'-bipyridine only being up to 10.0%.
The natural alkaloid isoanabasine was prepared by catalytic hydrogenation of tetrahydrobipyridines with (S)-BINAP-Rh complex.The tetrahydrobipyridines bearing bigger N-substituted group displayed high stereoselectivity and low reaction rate.Moreover,the position of the double bond on piperidinene also displayed a great effect on the stereoselectivity that made the ee value of hydrogenation of 1'-benzyl-1',4',5',6'-tetrahydro-2,3'-bipyridine being up to 21.5% but that of 1'-benzyl-1',2',5',6'-tetrahydro-2,3'-bipyridine only being up to 10.0%.
2005, 22(4): 460-461
Abstract:
The optical active fork glycerinol (2,2-dimethyl-1,3-dioxolane-4-methanol)(1) was synthesized with L-serine (2) as the starting material.L-glyceric acid (3) was synthesized via the nitrosation of (2).With TsOH as the catalyst and 4A molecular sieve as the dehydration agent,LM-2,3-O-isopropylidene-glycerate (5) was directly prepared from (3),2,2'-dimethoxypropane and methanol without isolating the intermediate.Instead of LiAlH4,NaBH4 was used to reduce (5) to the final compound (1).The total yield of was 47%.
The optical active fork glycerinol (2,2-dimethyl-1,3-dioxolane-4-methanol)(1) was synthesized with L-serine (2) as the starting material.L-glyceric acid (3) was synthesized via the nitrosation of (2).With TsOH as the catalyst and 4A molecular sieve as the dehydration agent,LM-2,3-O-isopropylidene-glycerate (5) was directly prepared from (3),2,2'-dimethoxypropane and methanol without isolating the intermediate.Instead of LiAlH4,NaBH4 was used to reduce (5) to the final compound (1).The total yield of was 47%.
2005, 22(4): 462-464
Abstract:
5-Aryl-2,2'-bipyridine was obtained by means of the annulation reaction of ammonia and the addition product of each of β-arylvinamidinium salts with 2-acetyl pyridine.The annulation reaction was dependent on the nature of the substituent at the β-position of the vinamidinium species.
5-Aryl-2,2'-bipyridine was obtained by means of the annulation reaction of ammonia and the addition product of each of β-arylvinamidinium salts with 2-acetyl pyridine.The annulation reaction was dependent on the nature of the substituent at the β-position of the vinamidinium species.
