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2004 Volume 21 Issue 7
2004, 21(7): 649-654
Abstract:
Allyl salicylaldimine (6) was prepared and reacted with trans-[NiCl(Ph)(PPh3)2]to give the salicylaldiminato nickel (Ⅱ) complex (7)([O-(3-Allyl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3-Ni (Ph3-P)(Ph)).These compounds are characterized by MS,1H NMR,13C NMR,IR and elemental analysis.The complex (7) activated by 1,5-cyclooctadiene nickel (Ni(COD)2) is able to catalyze ethylene polymerization effectively.At pressure of 8.08×105 Pa,the polymerization activity achieved 2.86×105g/(mol·h)(calculated on the basis of Ni in the catalyst),the Mη of polyethylene ranged in 0.86×104~3.17×104.Effects of THF,ethyl acetate,MMA and ethyl ether on the catalyst have been studied.
Allyl salicylaldimine (6) was prepared and reacted with trans-[NiCl(Ph)(PPh3)2]to give the salicylaldiminato nickel (Ⅱ) complex (7)([O-(3-Allyl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3-Ni (Ph3-P)(Ph)).These compounds are characterized by MS,1H NMR,13C NMR,IR and elemental analysis.The complex (7) activated by 1,5-cyclooctadiene nickel (Ni(COD)2) is able to catalyze ethylene polymerization effectively.At pressure of 8.08×105 Pa,the polymerization activity achieved 2.86×105g/(mol·h)(calculated on the basis of Ni in the catalyst),the Mη of polyethylene ranged in 0.86×104~3.17×104.Effects of THF,ethyl acetate,MMA and ethyl ether on the catalyst have been studied.
2004, 21(7): 655-659
Abstract:
The technique of hydrothermal stripping was applied to prepare nanosized α-Fe2O3 powders from iron-loaded organic phase composed of naphthenic acid,isooctyl alcohol and kerosene.Infrared spectra indicated that the naphthenic acid used in the experiments is stable and TEM images showed that the particles of the α-Fe2O3 powders are quasi-elliptical sphere in shape and have average diameter ranges from 2 nm to 30 nm.The technique is environmental friend.The investigation showed that the granularity of Fe2O3 powders could be controlled by changing iron concentration,reaction temperature,pH of the aqueous phase and stripping time,as well as by addition of surfactants.
The technique of hydrothermal stripping was applied to prepare nanosized α-Fe2O3 powders from iron-loaded organic phase composed of naphthenic acid,isooctyl alcohol and kerosene.Infrared spectra indicated that the naphthenic acid used in the experiments is stable and TEM images showed that the particles of the α-Fe2O3 powders are quasi-elliptical sphere in shape and have average diameter ranges from 2 nm to 30 nm.The technique is environmental friend.The investigation showed that the granularity of Fe2O3 powders could be controlled by changing iron concentration,reaction temperature,pH of the aqueous phase and stripping time,as well as by addition of surfactants.
2004, 21(7): 660-663
Abstract:
Soap-free emulsion polymerization of methyl methacrylate (MMA),ethyl acrylate (EA) and acrylic acid (AA) has been carried out.The effects of technology and the mass ratio of MMA to EA on the polymerization and latex properties were investigated.The distribution of-COOH in the latex was determined by conductometric titration.The results showed that the monomer conversion and the amount (Sa) and density (Sd) of surface-COOH increased,and particle diameter (Dp) and the amount of embedded-COOH (Ea) decreased with the increase of temperature.With stirring rate being increased,the monomer conversion,Sa,Ea and Ea decreased,and Dp and Fa(amount of-COOH in water phase) increased;Sa and Sd increased and Ea decreased with m(MMA)/m(EA) decreased.When polymerization was carried out at 80℃,300 r/min and m(MMA)/m(EA) was 19,the properties of resulted latex was best:monomer conversion was 97.51%,Dp was 306 nm and in the narrowest distribution,the Sd was 1.01×1015/cm2.
Soap-free emulsion polymerization of methyl methacrylate (MMA),ethyl acrylate (EA) and acrylic acid (AA) has been carried out.The effects of technology and the mass ratio of MMA to EA on the polymerization and latex properties were investigated.The distribution of-COOH in the latex was determined by conductometric titration.The results showed that the monomer conversion and the amount (Sa) and density (Sd) of surface-COOH increased,and particle diameter (Dp) and the amount of embedded-COOH (Ea) decreased with the increase of temperature.With stirring rate being increased,the monomer conversion,Sa,Ea and Ea decreased,and Dp and Fa(amount of-COOH in water phase) increased;Sa and Sd increased and Ea decreased with m(MMA)/m(EA) decreased.When polymerization was carried out at 80℃,300 r/min and m(MMA)/m(EA) was 19,the properties of resulted latex was best:monomer conversion was 97.51%,Dp was 306 nm and in the narrowest distribution,the Sd was 1.01×1015/cm2.
2004, 21(7): 664-668
Abstract:
ZnCl2 modified NaY solid L-acid catalysts were prepared by solid-state reaction and characterized by XRD and NH3-TPD.The Zn content in the catalysts was determined by ICP-AES.The catalytic properties of the catalysts in the etherification of cathechol with methanol were examined in a fixed bed micro-reactor.The results indicated that ZnCl2 modified NaY showed higher catalytic activity than HY with B acid sites in etherification.In the optimum reaction conditions,the conversion of catechol and the selectivity for guaiacol over ZnCl2(10%)/NaY were up to 86.7% and 99.3% respectively.
ZnCl2 modified NaY solid L-acid catalysts were prepared by solid-state reaction and characterized by XRD and NH3-TPD.The Zn content in the catalysts was determined by ICP-AES.The catalytic properties of the catalysts in the etherification of cathechol with methanol were examined in a fixed bed micro-reactor.The results indicated that ZnCl2 modified NaY showed higher catalytic activity than HY with B acid sites in etherification.In the optimum reaction conditions,the conversion of catechol and the selectivity for guaiacol over ZnCl2(10%)/NaY were up to 86.7% and 99.3% respectively.
2004, 21(7): 669-672
Abstract:
A series of multiblock copolymers composed of polyether ketone ketone (PEKK) and 4,4'-diphenoxydiphenylsulfone (DPODPS) were synthesized by polycondensation of acyl chloride-terminated PEKK oligomers and 4,4'-diphenoxydiphenylsulfone.The properties of the copolymers were characterized by DSC and TGA.The results indicated that the Tg of the copolymers increases with increase in DPODPS content and the Tm of the copolymers decreases with increase in DPODPS content.When the ω(DPODPS) of the copolymers ranged from 32.63% to 40.73%,the Tg of the copolymers were in range from 185℃ to 193℃,20~28℃ higher than that of para-linked pure PEKK and the Tm of the copolymers were from 322℃ to 346℃,35~59℃ lower than that of para-linked pure PEKK.The copolymers showed both good thermal property and melting-processing property.The tensile strengths of the copolymers containing 32.63%~40.73% DPODPS are 86.6~84.2 MPa,the tensile modulus 3.1~3.4 GPa and the breaking elongation 18.5%~20.3%.
A series of multiblock copolymers composed of polyether ketone ketone (PEKK) and 4,4'-diphenoxydiphenylsulfone (DPODPS) were synthesized by polycondensation of acyl chloride-terminated PEKK oligomers and 4,4'-diphenoxydiphenylsulfone.The properties of the copolymers were characterized by DSC and TGA.The results indicated that the Tg of the copolymers increases with increase in DPODPS content and the Tm of the copolymers decreases with increase in DPODPS content.When the ω(DPODPS) of the copolymers ranged from 32.63% to 40.73%,the Tg of the copolymers were in range from 185℃ to 193℃,20~28℃ higher than that of para-linked pure PEKK and the Tm of the copolymers were from 322℃ to 346℃,35~59℃ lower than that of para-linked pure PEKK.The copolymers showed both good thermal property and melting-processing property.The tensile strengths of the copolymers containing 32.63%~40.73% DPODPS are 86.6~84.2 MPa,the tensile modulus 3.1~3.4 GPa and the breaking elongation 18.5%~20.3%.
2004, 21(7): 673-677
Abstract:
A chlorphenamine maleate (CPM) electrode of potentiometric type has been prepared by drip-coating the surface of disk platinum electrode with SiO2 sol-gel containing chlorphenamine tetraphenylborate ion-pair complex as sensing agent.Experimental results indicate the good electrode performances.The range of linear response is 5.2×10-7~8.0×10-4 mol/L with detection limit of 2.8×10-7 mol/L,the slope is 5.78×10-2 V/pC and the correlation coefficient 0.999.The electrode can be used at pH range of 3.0~8.5 and exhibits an excellent stability and reproducibility.The determination of chlorphenamine maleate in pharmaceuticals also gives satisfactory results.The electrode shows good properties when it is applied to urine sample and gives a good excretion curve of chlorphenamine maleate.
A chlorphenamine maleate (CPM) electrode of potentiometric type has been prepared by drip-coating the surface of disk platinum electrode with SiO2 sol-gel containing chlorphenamine tetraphenylborate ion-pair complex as sensing agent.Experimental results indicate the good electrode performances.The range of linear response is 5.2×10-7~8.0×10-4 mol/L with detection limit of 2.8×10-7 mol/L,the slope is 5.78×10-2 V/pC and the correlation coefficient 0.999.The electrode can be used at pH range of 3.0~8.5 and exhibits an excellent stability and reproducibility.The determination of chlorphenamine maleate in pharmaceuticals also gives satisfactory results.The electrode shows good properties when it is applied to urine sample and gives a good excretion curve of chlorphenamine maleate.
2004, 21(7): 678-682
Abstract:
LiCoO2/LiMn2O4 thin film electrode was prepared by an electrostatic spray deposition (ESD) technique.The XRD results indicated the formation of a single spinel phase in all LiMn2O4 films.AES analysis revealed that LiCoO2/LiMn2O4 film prepared by one-step deposition changed to Co-doping LiMn2O4 film due to the diffusion of Co,and LiCoO2 remained on the surface of LiMn2O4 in LiCoO2/LiMn2O4 film prepared by multi-step deposition.The electrochemical experiement results showed improved cycling stability of LiCoO2/LiMn2O4 film at 55℃.The LiCoO2/LiMn2O4 film prepared by multi-step deposition exhibited more superior performance at 55℃ than the sample prepared by one-step deposition and improved rate capability.The mechanism of the improvement of the performance of LiMn2O4 film by coating with LiCoO2 was discussed.
LiCoO2/LiMn2O4 thin film electrode was prepared by an electrostatic spray deposition (ESD) technique.The XRD results indicated the formation of a single spinel phase in all LiMn2O4 films.AES analysis revealed that LiCoO2/LiMn2O4 film prepared by one-step deposition changed to Co-doping LiMn2O4 film due to the diffusion of Co,and LiCoO2 remained on the surface of LiMn2O4 in LiCoO2/LiMn2O4 film prepared by multi-step deposition.The electrochemical experiement results showed improved cycling stability of LiCoO2/LiMn2O4 film at 55℃.The LiCoO2/LiMn2O4 film prepared by multi-step deposition exhibited more superior performance at 55℃ than the sample prepared by one-step deposition and improved rate capability.The mechanism of the improvement of the performance of LiMn2O4 film by coating with LiCoO2 was discussed.
2004, 21(7): 683-686
Abstract:
A non-liquid junction cell (A) represented by In|HCl (cA),In2(SO4)3(cB),H2O|AgCl-Ag has been designed and realized.The electrical po tentials of the cell have been determined in condition of constant total ionic strength of solution,I,and ionic strength fraction of In2(SO4)3 in solution.The standard polentials of In3+/In electrode have been calculated based on the electrical potentials obtained in experiments with cell.They are identical with those reported in literatures.
A non-liquid junction cell (A) represented by In|HCl (cA),In2(SO4)3(cB),H2O|AgCl-Ag has been designed and realized.The electrical po tentials of the cell have been determined in condition of constant total ionic strength of solution,I,and ionic strength fraction of In2(SO4)3 in solution.The standard polentials of In3+/In electrode have been calculated based on the electrical potentials obtained in experiments with cell.They are identical with those reported in literatures.
2004, 21(7): 687-691
Abstract:
Hydroxyapatite/titania (HA/TiO2) composite coatings were obtained via electrodeposition.The influence of process technology on the content of TiO2 in the coating and the influence of the content of TiO2 in the coating on the bonding strength of the coating were investigated.The results revealed that the content of TiO2 in the coating increased with reduction of the current density and prolonging of the deposition time and increase in the concentration of TiO2 in the electrolyte,but increased first and decreased afterwards with increase in the electrolyte concentration.Calcination could improve the bonding strength up to 18.7 MPa,when the mass fraction of TiO2 in the coating was 72.2%.The composite coatings have a fairly good chemical stability,erosive endurance and dissolvation resistibility.HA in the composite coatings is partly decomposed to β-Ca3(PO4)2 and CaO when the calcination temperature in preparation above 800℃.
Hydroxyapatite/titania (HA/TiO2) composite coatings were obtained via electrodeposition.The influence of process technology on the content of TiO2 in the coating and the influence of the content of TiO2 in the coating on the bonding strength of the coating were investigated.The results revealed that the content of TiO2 in the coating increased with reduction of the current density and prolonging of the deposition time and increase in the concentration of TiO2 in the electrolyte,but increased first and decreased afterwards with increase in the electrolyte concentration.Calcination could improve the bonding strength up to 18.7 MPa,when the mass fraction of TiO2 in the coating was 72.2%.The composite coatings have a fairly good chemical stability,erosive endurance and dissolvation resistibility.HA in the composite coatings is partly decomposed to β-Ca3(PO4)2 and CaO when the calcination temperature in preparation above 800℃.
2004, 21(7): 692-695
Abstract:
o-Nitrobenzaldehyde was prepared by oxidation of o-nitrotoluene by ammonium metavanadate in sulfuric acid solution.The maximum yield of o-nitrobenzaldehyde was 44.6% under the conditions:H2SO410 mol/L,mole ratio of ammonium metavanadate to o-Nitrobenzalde 1:11,reaction temperature 80℃,reaction time 6 h,in the presence of cetyltrimethylammonium bromide:1.3%(mass fraction).The used aqueous solution could be separated and oxidized on graphite electrode for regeneration of V5+ ion at 60℃ and anodic current density 1.0×10-3 A/cm2.
o-Nitrobenzaldehyde was prepared by oxidation of o-nitrotoluene by ammonium metavanadate in sulfuric acid solution.The maximum yield of o-nitrobenzaldehyde was 44.6% under the conditions:H2SO410 mol/L,mole ratio of ammonium metavanadate to o-Nitrobenzalde 1:11,reaction temperature 80℃,reaction time 6 h,in the presence of cetyltrimethylammonium bromide:1.3%(mass fraction).The used aqueous solution could be separated and oxidized on graphite electrode for regeneration of V5+ ion at 60℃ and anodic current density 1.0×10-3 A/cm2.
2004, 21(7): 696-701
Abstract:
The microemulsion system for the copolymerization of acrylamide (AM) and styrene (St) was prepared using copolymer (PAM-b-PSt) of small molecular weight and good surface activity as macromolecular surfactant.The phase diagram of three components was drawn up,from which a suitable copolymerization system was selected and an amphiphilic block copolymer PAM-b-PSt with high molecular weight was synthesized by self-emulsifying microemulsion copolymerization.The composition of the copolymer was analyzed by FTIR and UV method,the block architecture was characterized by DSC,and the hydrophobic association behaviour of the copolymer was investigated by fluorescence probe technique and apparent viscosity measurement.The results show that the microemulsion copolymerization system of O/W type can also be prepared using macromolecular surfactant.Only 3 g of the macromolecular surfactant was enough to disperse 0.25 g St into water.The method has advantages of having high emulsification efficiency and avoiding purification processes of polymers to remove the surfactant.The pure copolymer PAM-b-PSt could be obtained in one step process.The product has excellent hydrophobic association behaviour and thickening property,and the viscosity of its aqueous solution is about 5 times higher than that of PAM aqueous solution under the same concentration (ω(p)=0.5%).
The microemulsion system for the copolymerization of acrylamide (AM) and styrene (St) was prepared using copolymer (PAM-b-PSt) of small molecular weight and good surface activity as macromolecular surfactant.The phase diagram of three components was drawn up,from which a suitable copolymerization system was selected and an amphiphilic block copolymer PAM-b-PSt with high molecular weight was synthesized by self-emulsifying microemulsion copolymerization.The composition of the copolymer was analyzed by FTIR and UV method,the block architecture was characterized by DSC,and the hydrophobic association behaviour of the copolymer was investigated by fluorescence probe technique and apparent viscosity measurement.The results show that the microemulsion copolymerization system of O/W type can also be prepared using macromolecular surfactant.Only 3 g of the macromolecular surfactant was enough to disperse 0.25 g St into water.The method has advantages of having high emulsification efficiency and avoiding purification processes of polymers to remove the surfactant.The pure copolymer PAM-b-PSt could be obtained in one step process.The product has excellent hydrophobic association behaviour and thickening property,and the viscosity of its aqueous solution is about 5 times higher than that of PAM aqueous solution under the same concentration (ω(p)=0.5%).
2004, 21(7): 702-707
Abstract:
The transesterification of dimethyl carbonate (DMC) with phenol was carried out in the presence of Mg-Al-hydrotalcites with different Mg to Al molar ratio.The Mg-Al hydrotalcite with Mg to Al molar ratio 2:1 showed the highest catalytic activity,and it was more efficient than solid catalysts TiO2/SiO2,MoO3/SiO2 and CaO.When the reaction was run at 150~185℃ for 12 h at n(PhOH):n(DMC)=2:1 and catalyst concentration (mass fraction)1.5%,the yield of diphenyl carbonate (DPC),methyl phenyl carbonate (MPC) and anisole were 25.8%,11.2% and 12.8%,respectively,and total selectivity for DPC and MPC reached 74.3%.In addition,78% of hydrotalcite could be regenerated after 5 times usage of transesterification without significant loss of its catalytic activity.
The transesterification of dimethyl carbonate (DMC) with phenol was carried out in the presence of Mg-Al-hydrotalcites with different Mg to Al molar ratio.The Mg-Al hydrotalcite with Mg to Al molar ratio 2:1 showed the highest catalytic activity,and it was more efficient than solid catalysts TiO2/SiO2,MoO3/SiO2 and CaO.When the reaction was run at 150~185℃ for 12 h at n(PhOH):n(DMC)=2:1 and catalyst concentration (mass fraction)1.5%,the yield of diphenyl carbonate (DPC),methyl phenyl carbonate (MPC) and anisole were 25.8%,11.2% and 12.8%,respectively,and total selectivity for DPC and MPC reached 74.3%.In addition,78% of hydrotalcite could be regenerated after 5 times usage of transesterification without significant loss of its catalytic activity.
2004, 21(7): 708-712
Abstract:
Dendrimer[G1.5(NH2)]with peripheral multiamimogroups was synthesized from dendrimer[G1.0(=)]and ethylene diamine (EDA) by Michael addition reaction.The optimum conditions were:n[G1.0(=)]:n(EDA)=1:360,CH3OH as solvent and catalyst,reaction temperature 30℃ and reaction time 24 h.Yield and mass fraction of G1.5(NH2) were 93.6% and 98.4% respectively.The structure of G1.5(NH2) was identified by IR,NMR and elemental analysis.G1.5(NH2) was less volatile,little poisonous,well compatible with epoxide and could be used as its hardener.The pot life and gelation time of the G1.5(NH2)/epoxide systems were 5.0 and 2.1 times that of the EDA/epoxide systems respectively,while the curing speed was 2.9,5.8,12.0 and 17.1 times that of EDA systems,when cured at 50℃,95℃,120℃ and 150℃ respectively.DSC analysis showed that G1.5(NH2) systems gradually liberated heat in two stages during the curing process,and the total heat liberated was less than that of EDA systems.
Dendrimer[G1.5(NH2)]with peripheral multiamimogroups was synthesized from dendrimer[G1.0(=)]and ethylene diamine (EDA) by Michael addition reaction.The optimum conditions were:n[G1.0(=)]:n(EDA)=1:360,CH3OH as solvent and catalyst,reaction temperature 30℃ and reaction time 24 h.Yield and mass fraction of G1.5(NH2) were 93.6% and 98.4% respectively.The structure of G1.5(NH2) was identified by IR,NMR and elemental analysis.G1.5(NH2) was less volatile,little poisonous,well compatible with epoxide and could be used as its hardener.The pot life and gelation time of the G1.5(NH2)/epoxide systems were 5.0 and 2.1 times that of the EDA/epoxide systems respectively,while the curing speed was 2.9,5.8,12.0 and 17.1 times that of EDA systems,when cured at 50℃,95℃,120℃ and 150℃ respectively.DSC analysis showed that G1.5(NH2) systems gradually liberated heat in two stages during the curing process,and the total heat liberated was less than that of EDA systems.
2004, 21(7): 713-716
Abstract:
CO2 laser-induced local deposition of silver from aqueous solution was explored.It was showed that the width and thickness of deposited silver lines were related to laser power (P),scan rate (v),thickness of solution level (T),and concentration of Ag salt solution (c),and the effects of P,v and T on the width and thickness of silver lines were more remarkable than that of c.There existed a maximum thickness of silver lines in a definite range of P,v and T.The larger the P and c,the wider the silver lines.But the change of the silver line width in relation with v and T was just opposite to this.The adoptedP,v,T,and c values were as follows:P(4.0~6.0 W),v(1.3~2.4 cm/s),T(10~50 μm),c(0.5~1.0 mol/L).Three optimal experiment groups were obtained from orthogonal experiments.
CO2 laser-induced local deposition of silver from aqueous solution was explored.It was showed that the width and thickness of deposited silver lines were related to laser power (P),scan rate (v),thickness of solution level (T),and concentration of Ag salt solution (c),and the effects of P,v and T on the width and thickness of silver lines were more remarkable than that of c.There existed a maximum thickness of silver lines in a definite range of P,v and T.The larger the P and c,the wider the silver lines.But the change of the silver line width in relation with v and T was just opposite to this.The adoptedP,v,T,and c values were as follows:P(4.0~6.0 W),v(1.3~2.4 cm/s),T(10~50 μm),c(0.5~1.0 mol/L).Three optimal experiment groups were obtained from orthogonal experiments.
2004, 21(7): 717-721
Abstract:
The quaternary ammonium cationic sesbania gum (QACSG) with high substitution degree was prepared from sesbania gum (SG) and 3-chloro-2-hydroxypropyl-trimethyl-ammonium chloride (CHPAC).The effects of reaction conditions on substitution degree of primary hydroxyl group of SG and flocculating properties of QACSG were studied.At n(PHG):n(CHPAC)=1:1,reaction temperature 50℃,pH 9~10,V(CH3CH2OH):V(H2O)=1:10,reaction time 6 h,the substitution degree was 0.68.When it was treated by QACSG,removal rate of COD Cr of domestic wastewater achieved 90%.Absorbance of Yellow-rever water treated by QACSG as flocculant was below 0.1.
The quaternary ammonium cationic sesbania gum (QACSG) with high substitution degree was prepared from sesbania gum (SG) and 3-chloro-2-hydroxypropyl-trimethyl-ammonium chloride (CHPAC).The effects of reaction conditions on substitution degree of primary hydroxyl group of SG and flocculating properties of QACSG were studied.At n(PHG):n(CHPAC)=1:1,reaction temperature 50℃,pH 9~10,V(CH3CH2OH):V(H2O)=1:10,reaction time 6 h,the substitution degree was 0.68.When it was treated by QACSG,removal rate of COD Cr of domestic wastewater achieved 90%.Absorbance of Yellow-rever water treated by QACSG as flocculant was below 0.1.
2004, 21(7): 722-726
Abstract:
The fluorescence spectra and visible spectra of a cationic fluorescent dye,phenosafranine (PF),in the solution of anionic surfactants has been studied.A non-fluorescent dye dimer with a new characteristic peak at 515 nm was formed when the concentration of anionic surfactant was in the range of 8.0×10-4~2.0×10 -3 mol/L.The studies on the possibility of using the in situ dimmer of dye as a fluorescence probe showed that the fluorescence intensities increased significantly and varied linearly with the concentration of nucleic acid when appropriate amounts of nucleic acid was added,thus a new method for the determination of nucleic acid was realized.Upon optimal conditions,the linear range for ct-DNA,fs-DNA,and yeast-RNA was 0.06~18 mg/L,0.04~20 mg/L and 0.12~20 mg/L,respectively;with detect limit being 21 μg/L,17 μg/L and 36 μg/L,respectively.
The fluorescence spectra and visible spectra of a cationic fluorescent dye,phenosafranine (PF),in the solution of anionic surfactants has been studied.A non-fluorescent dye dimer with a new characteristic peak at 515 nm was formed when the concentration of anionic surfactant was in the range of 8.0×10-4~2.0×10 -3 mol/L.The studies on the possibility of using the in situ dimmer of dye as a fluorescence probe showed that the fluorescence intensities increased significantly and varied linearly with the concentration of nucleic acid when appropriate amounts of nucleic acid was added,thus a new method for the determination of nucleic acid was realized.Upon optimal conditions,the linear range for ct-DNA,fs-DNA,and yeast-RNA was 0.06~18 mg/L,0.04~20 mg/L and 0.12~20 mg/L,respectively;with detect limit being 21 μg/L,17 μg/L and 36 μg/L,respectively.
2004, 21(7): 727-730
Abstract:
The resting cells were used to produce acrylamide from acrylonitrile by enzyme hydration in semi-continuous process.The result indicated that the enzyme Nocardia sp was deactivated at temperature more than 20℃,it was also intensely inhibited when the volume fraction of acrylonitrile was above 4% and product concentration above 30%.The enzyme activity could be kept in considerable level when acrylonitrile and enzyme were added in stream-form and at low temperature.When volume fraction of enzyme was 10% and at 20℃ by this addition mode acrylamide could be obtained in mass concentration of 23% more than that by batch-mode addition process
The resting cells were used to produce acrylamide from acrylonitrile by enzyme hydration in semi-continuous process.The result indicated that the enzyme Nocardia sp was deactivated at temperature more than 20℃,it was also intensely inhibited when the volume fraction of acrylonitrile was above 4% and product concentration above 30%.The enzyme activity could be kept in considerable level when acrylonitrile and enzyme were added in stream-form and at low temperature.When volume fraction of enzyme was 10% and at 20℃ by this addition mode acrylamide could be obtained in mass concentration of 23% more than that by batch-mode addition process
2004, 21(7): 731-733
Abstract:
The preparation method of precursor for SiC was improved.Polyborazine-polymethylsilane (PBN-PMS) was obtained by reaction of PMS with 1%(mass fraction) PBN;and then soluble polymeric precursor PBN-PCS-PMS was prepared by hybridization of the PBN-PMS with a suitable amount of PCS (polycarbosilane).Silicon carbide material was obtained by pyrolysis of the PBN-PCS-PMS in inert atmosphere at 1 400℃.XRD,elemental analysis,29Si and 13CMAS NMR indicated it is a near-stoichiometric β-SiC when the mass ratio of PCS to PBN-PMS is 0.25:1.00.
The preparation method of precursor for SiC was improved.Polyborazine-polymethylsilane (PBN-PMS) was obtained by reaction of PMS with 1%(mass fraction) PBN;and then soluble polymeric precursor PBN-PCS-PMS was prepared by hybridization of the PBN-PMS with a suitable amount of PCS (polycarbosilane).Silicon carbide material was obtained by pyrolysis of the PBN-PCS-PMS in inert atmosphere at 1 400℃.XRD,elemental analysis,29Si and 13CMAS NMR indicated it is a near-stoichiometric β-SiC when the mass ratio of PCS to PBN-PMS is 0.25:1.00.
2004, 21(7): 734-736
Abstract:
The title copolymer was synthesized by grafting dimethyldiallylammonium chloride onto chitosan with ammonium cerium nitrate as initiator.The effects of reaction temperature,pH and concentration of initiator on product yield were examined.The optimum conditions were as follows:90℃,concentration of initiator 5×10-4 mol/L,pH=6.The flocculation experiments on the fermentation wastewater showed that flocculabi-lity of the chitosan graft copolymer was better than the chitosan itself and the flocculation treatment could be carried out at lower dosage and wider pH range.
The title copolymer was synthesized by grafting dimethyldiallylammonium chloride onto chitosan with ammonium cerium nitrate as initiator.The effects of reaction temperature,pH and concentration of initiator on product yield were examined.The optimum conditions were as follows:90℃,concentration of initiator 5×10-4 mol/L,pH=6.The flocculation experiments on the fermentation wastewater showed that flocculabi-lity of the chitosan graft copolymer was better than the chitosan itself and the flocculation treatment could be carried out at lower dosage and wider pH range.
2004, 21(7): 737-739
Abstract:
The adsorption of aniline on the as-grown and purified carbon nanotubes has been investigated.The initial concentration of aniline solution,time,temperature and pH values of aniline solution have great influence on the adsorption capacity.The adsorption capacity of the as-grown carbon nanotubes towards aniline was 4.8 mg/g at pH=5.For that treated with nitric acid,it increased to 15.4 mg/g.The adsorption capacity decreased with increase of temperature in the range of 283 to 303 K.The adsorption isotherms can be described by Freundlich equation.
The adsorption of aniline on the as-grown and purified carbon nanotubes has been investigated.The initial concentration of aniline solution,time,temperature and pH values of aniline solution have great influence on the adsorption capacity.The adsorption capacity of the as-grown carbon nanotubes towards aniline was 4.8 mg/g at pH=5.For that treated with nitric acid,it increased to 15.4 mg/g.The adsorption capacity decreased with increase of temperature in the range of 283 to 303 K.The adsorption isotherms can be described by Freundlich equation.
2004, 21(7): 740-741
Abstract:
A high reactive penta-coordinated organic silicon compound (KSi (OCH2CH2O)2(OCH2CH2OH)) was prepared,by the reaction of silica with ethylene glycol and potassium hydroxide,and di-hydroxy tetra coordinated silicon (OCH2CH2O)2(OCH2CH2OH)(OCH2CH2OCH2CH2OH)(DHTS) was prepared by reacting penta-coordinated silicon complex with ClCH2CH2OH.Composite film of DHTS/polyvinyl butyral (PVB) was prepared by a sol-gel method.The thermal property,including glass-transition temperature of the composite film were examined.When the mass ratio of PVB to tetra coordinated silicon was 1:1.7,the on set mass loss temperature of the composite film was increased by 27℃ in comparison with PVB.The transparency and tenacity of the composite film were all increased.But increase of the mass fraction of DHTS could decrease the decomposition temperature of the film.
A high reactive penta-coordinated organic silicon compound (KSi (OCH2CH2O)2(OCH2CH2OH)) was prepared,by the reaction of silica with ethylene glycol and potassium hydroxide,and di-hydroxy tetra coordinated silicon (OCH2CH2O)2(OCH2CH2OH)(OCH2CH2OCH2CH2OH)(DHTS) was prepared by reacting penta-coordinated silicon complex with ClCH2CH2OH.Composite film of DHTS/polyvinyl butyral (PVB) was prepared by a sol-gel method.The thermal property,including glass-transition temperature of the composite film were examined.When the mass ratio of PVB to tetra coordinated silicon was 1:1.7,the on set mass loss temperature of the composite film was increased by 27℃ in comparison with PVB.The transparency and tenacity of the composite film were all increased.But increase of the mass fraction of DHTS could decrease the decomposition temperature of the film.
2004, 21(7): 742-744
Abstract:
The sulphonation of polyethersulphone (PES) with oleums gave sulphonated polyethersulphone (SPES) with high sulphonation degree and solubility in water.Results show that the acid strengths of SPES are in 8.2≤-H0≤11.9 and the catalytic activity and selectivety of SPES are proportional to the sulphonation degree of SPES.The SPES is deactivated rather slowly under experimental conditions.
The sulphonation of polyethersulphone (PES) with oleums gave sulphonated polyethersulphone (SPES) with high sulphonation degree and solubility in water.Results show that the acid strengths of SPES are in 8.2≤-H0≤11.9 and the catalytic activity and selectivety of SPES are proportional to the sulphonation degree of SPES.The SPES is deactivated rather slowly under experimental conditions.
2004, 21(7): 745-747
Abstract:
1-(4-aminophenyl)-2-(1-piperidino)-1-propanone hydrochloride,a sort of water-soluble photoinitiator,was synthesized from acetanilide in three steps,i.e.Friedel-Crafts acylation,α-bromination,amination and hydrochlorination,and its structure was analyzed by IR,MS,UV,elemental analysis,1H NMR.During the 3rd step,water acted as solvent and piperidine was dripped in at ambient temperature.After reaction at 40℃ for 2 h,the mixture was treated with 15%(volume fraction) HCl.The yield was 60.7%.The product has good solubility and photoinitiability.In the air with the distance of 20 cm,the curing time of photosensitive prepolymer was 10s only.
1-(4-aminophenyl)-2-(1-piperidino)-1-propanone hydrochloride,a sort of water-soluble photoinitiator,was synthesized from acetanilide in three steps,i.e.Friedel-Crafts acylation,α-bromination,amination and hydrochlorination,and its structure was analyzed by IR,MS,UV,elemental analysis,1H NMR.During the 3rd step,water acted as solvent and piperidine was dripped in at ambient temperature.After reaction at 40℃ for 2 h,the mixture was treated with 15%(volume fraction) HCl.The yield was 60.7%.The product has good solubility and photoinitiability.In the air with the distance of 20 cm,the curing time of photosensitive prepolymer was 10s only.
2004, 21(7): 748-750
Abstract:
The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene (St) with hydroxyethyl methacrylate (HEMA).The nucleation mechanism and growth process of polymer latex particles were investigated.The effects of HEMA on diameter of the latex particles and monomer conversion were discussed.The elemental analysis and XRD results showed that HEMA was dispersed mainly on the surface of the latex particles,it could stabilize the latex particles and lead the nucleation.The nucleation of particles occurs likely by homogeneous nucleation mechanism.The diameter of the latex particles decreased and the conversion increased,as HEMA's dosage increased.
The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene (St) with hydroxyethyl methacrylate (HEMA).The nucleation mechanism and growth process of polymer latex particles were investigated.The effects of HEMA on diameter of the latex particles and monomer conversion were discussed.The elemental analysis and XRD results showed that HEMA was dispersed mainly on the surface of the latex particles,it could stabilize the latex particles and lead the nucleation.The nucleation of particles occurs likely by homogeneous nucleation mechanism.The diameter of the latex particles decreased and the conversion increased,as HEMA's dosage increased.
2004, 21(7): 751-753
Abstract:
Salicylic acid as a drug carrying agent was intercalated into microporous poly (ε-caprolactone)(PCL) and PCL resin particles using supercritical CO2 as solvent.The drug releasing currves in 95% ethanol solution for open-hole PCL and close-hole PCL particles have been obtained and the releasing half-life (t1/2) for both systems were calculated to be 35 h and 57 h,respectively.The latter appears more preferable.
Salicylic acid as a drug carrying agent was intercalated into microporous poly (ε-caprolactone)(PCL) and PCL resin particles using supercritical CO2 as solvent.The drug releasing currves in 95% ethanol solution for open-hole PCL and close-hole PCL particles have been obtained and the releasing half-life (t1/2) for both systems were calculated to be 35 h and 57 h,respectively.The latter appears more preferable.
2004, 21(7): 754-756
Abstract:
The isolation and characterization of vanadium porphyrins in Tahe crude oil has been carried out.The vanadium porphyrins were at first isolated by methanol extraction and then purified by column chromatography and thin layer chromatography.Ultraviolet-visible spectrophotometry and laser desorption ionization-time of flight mass spectrometry were employed to characterize the vanadium porphyrins.The vanadium porphyrins in Tahe crude oil are chiefly ETIO homologues (C26~C39) with a small amount of DPEP homologues (C29~C39) and RHODO-ETIO homologues (C29~C39).
The isolation and characterization of vanadium porphyrins in Tahe crude oil has been carried out.The vanadium porphyrins were at first isolated by methanol extraction and then purified by column chromatography and thin layer chromatography.Ultraviolet-visible spectrophotometry and laser desorption ionization-time of flight mass spectrometry were employed to characterize the vanadium porphyrins.The vanadium porphyrins in Tahe crude oil are chiefly ETIO homologues (C26~C39) with a small amount of DPEP homologues (C29~C39) and RHODO-ETIO homologues (C29~C39).
