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2006 Volume 23 Issue 6
2006, 23(6): 581-585
Abstract:
Thermo-sensitive poly(N-isopropylacrylamide)(PNIPA) hydrogel with a fast response rate was prepared by polymerization in aqueous solution of hydroxypropyl-methyl cellulose.The volume phase transition temperature of the PNIPA hydrogels was characterized by differential scanning calorimetry.The surface morphology of the PNIPA hydrogels was studied by scanning electron microscopy.The swelling ratios of the hydrogels at different temperatures were measured.Furthermore,the deswelling kinetics of the hydrogels was studied.In comparision with a conventional PNIPA hydrogel prepared in water,the hydrogel synthesized in hydroxypropyl-methyl cellulose aqueous solution has higher swelling ratios at temperatures below the lower critical solution temperature and exhibits a much faster response rate to temperature changes.For example,the hydrogel prepared in hydroxypropyl-methyl cellulose aqueous solution loses 89% water within 1min and about 93% water within 4 min,whereas the conventional hydrogel loses only about 66% water within 15 min.
Thermo-sensitive poly(N-isopropylacrylamide)(PNIPA) hydrogel with a fast response rate was prepared by polymerization in aqueous solution of hydroxypropyl-methyl cellulose.The volume phase transition temperature of the PNIPA hydrogels was characterized by differential scanning calorimetry.The surface morphology of the PNIPA hydrogels was studied by scanning electron microscopy.The swelling ratios of the hydrogels at different temperatures were measured.Furthermore,the deswelling kinetics of the hydrogels was studied.In comparision with a conventional PNIPA hydrogel prepared in water,the hydrogel synthesized in hydroxypropyl-methyl cellulose aqueous solution has higher swelling ratios at temperatures below the lower critical solution temperature and exhibits a much faster response rate to temperature changes.For example,the hydrogel prepared in hydroxypropyl-methyl cellulose aqueous solution loses 89% water within 1min and about 93% water within 4 min,whereas the conventional hydrogel loses only about 66% water within 15 min.
2006, 23(6): 586-590
Abstract:
Photocatalyst Cu/Fe2O3-TiO2 was prepared with sol-gel method.The surface structure,photon absorption and photocatalysis properties of the solid materials were assessed by XRD,Raman,TPR,IR,TEM,UV-Vis DRS and photocatalytic reaction experiments,respectively.The results showed that Fe2O3 was dispersed on the surface of TiO2 support as a monolayer at 10% content.Blue shift of the photon absorption edge of TiO2 was observed after the addition of Fe2O3.When the amount of Fe2O3 exceeded 10%,crystalline Fe2O3 appeared and the photon absorption decreased.The formation of the Fe-O-Ti bond strengthened the interaction between the semiconductors and promoted the transfer of photoexcited electron-hole pairs.Metal Cu broadened the photon absorption edge of the coupled materials toward visible region.The photocatalysis activity of the materials was related with photon absorption property closely.In the photocatalysis of reaction between CO2 and CH2NH2 to produce glycine directly,10% of Fe2O3 showed the best photocatalysis perfor-mance.Under the conditions of 120℃,normal pressure,space velocity 200 h-1 ,n(CO2):n(CH3NH2)=1:1 and UV light intensity 6.5×10-4 W/cm2,the conversion of CH3NH2 was 1.35% and the selectivity to glycine reached 92.0%.
Photocatalyst Cu/Fe2O3-TiO2 was prepared with sol-gel method.The surface structure,photon absorption and photocatalysis properties of the solid materials were assessed by XRD,Raman,TPR,IR,TEM,UV-Vis DRS and photocatalytic reaction experiments,respectively.The results showed that Fe2O3 was dispersed on the surface of TiO2 support as a monolayer at 10% content.Blue shift of the photon absorption edge of TiO2 was observed after the addition of Fe2O3.When the amount of Fe2O3 exceeded 10%,crystalline Fe2O3 appeared and the photon absorption decreased.The formation of the Fe-O-Ti bond strengthened the interaction between the semiconductors and promoted the transfer of photoexcited electron-hole pairs.Metal Cu broadened the photon absorption edge of the coupled materials toward visible region.The photocatalysis activity of the materials was related with photon absorption property closely.In the photocatalysis of reaction between CO2 and CH2NH2 to produce glycine directly,10% of Fe2O3 showed the best photocatalysis perfor-mance.Under the conditions of 120℃,normal pressure,space velocity 200 h-1 ,n(CO2):n(CH3NH2)=1:1 and UV light intensity 6.5×10-4 W/cm2,the conversion of CH3NH2 was 1.35% and the selectivity to glycine reached 92.0%.
2006, 23(6): 591-596
Abstract:
(NH4)4[PMo11VO40]·4H2O nanometer powders were prepared by solid state reaction between H4PMo11VO40·13H2O and(NH4)2C2O4·H2O at room temperature and characterized by elemental analysis,FTIR,XRD,TEM,TG-DTA and BET techniques.The experimental results indicate that the nanometer powders remain Keggin structure and have a mean grain size of 25 nm and BET specific surface area of 157.82 m2/g.The heteropolyanion shows good thermal stability up to 390℃.Using so-obtained nanomaterial as catalyst for the dehydration of cyclohexanol,the yield of cyclohexene could reach 77.98%,which is higher than those of currently widely used catalyst as well as its bulk counterpart.The yield was achived under optimized catalytic reaction conditions with the mass ratio (catalyst/cyclohexanol) of 8.31%,0.5 h reaction duration and 160℃ reaction temperature.
(NH4)4[PMo11VO40]·4H2O nanometer powders were prepared by solid state reaction between H4PMo11VO40·13H2O and(NH4)2C2O4·H2O at room temperature and characterized by elemental analysis,FTIR,XRD,TEM,TG-DTA and BET techniques.The experimental results indicate that the nanometer powders remain Keggin structure and have a mean grain size of 25 nm and BET specific surface area of 157.82 m2/g.The heteropolyanion shows good thermal stability up to 390℃.Using so-obtained nanomaterial as catalyst for the dehydration of cyclohexanol,the yield of cyclohexene could reach 77.98%,which is higher than those of currently widely used catalyst as well as its bulk counterpart.The yield was achived under optimized catalytic reaction conditions with the mass ratio (catalyst/cyclohexanol) of 8.31%,0.5 h reaction duration and 160℃ reaction temperature.
2006, 23(6): 597-601
Abstract:
Six Quaternary Ammonium tetraphenyl borates salt photobase generators were synthesized with the use of p-methoxy phenacylmethylene or 2-naphthoymethylene as chromophore,and triethylene diamine, pyridine or 3-methyl pyridine as tertiary amine.Their fluorescence emission properties were studied and their photolysis kinetics was investigated in different media by means of steady state photolysis method.The results show that their photolysis kinetics follows the first order reaction.
Six Quaternary Ammonium tetraphenyl borates salt photobase generators were synthesized with the use of p-methoxy phenacylmethylene or 2-naphthoymethylene as chromophore,and triethylene diamine, pyridine or 3-methyl pyridine as tertiary amine.Their fluorescence emission properties were studied and their photolysis kinetics was investigated in different media by means of steady state photolysis method.The results show that their photolysis kinetics follows the first order reaction.
2006, 23(6): 602-606
Abstract:
The preparation of supported liquid-phase platinum catalyst,and its catalytic property for hydro-silylation reaction of 3-chloropropene were studied.The catalyst displays a high activity and stability under atmospheric pressure for hydrosilylation of 3-chloropropene.The effects of temperature,feeding rate of reactants,and quantity of catalyst used on the hydrosilylation reaction were investigated.At 90℃,the single conversion of 3-chloropropene can be 96.2%,while the selectivity and yield of (3-chloropropyl)methyldichlorosilane can reach 86.9% and 83.6% respectively.The catalyst can be used for 15 h without too loss in term of catalytic activity.The catalytic activity for the hydrosilylation can be improved when modified by Gd.
The preparation of supported liquid-phase platinum catalyst,and its catalytic property for hydro-silylation reaction of 3-chloropropene were studied.The catalyst displays a high activity and stability under atmospheric pressure for hydrosilylation of 3-chloropropene.The effects of temperature,feeding rate of reactants,and quantity of catalyst used on the hydrosilylation reaction were investigated.At 90℃,the single conversion of 3-chloropropene can be 96.2%,while the selectivity and yield of (3-chloropropyl)methyldichlorosilane can reach 86.9% and 83.6% respectively.The catalyst can be used for 15 h without too loss in term of catalytic activity.The catalytic activity for the hydrosilylation can be improved when modified by Gd.
2006, 23(6): 607-611
Abstract:
With the presence of KI,Cd(Ⅱ) can react with I- to form metal complex anions CdI3- and CdI42- at pH 1.0~6.0,which can be well adsorbed on microcrystalline phenolphthalein modified by ethyl violet.Cd(Ⅱ) can be completely separated from Zn(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ),Cr(Ⅲ) and Al(Ⅲ) under optimized conditions.This method was successfully applied to the concentration and determination of trace cadmium in environmental aqueous samples.The preconcentration factor can reach 100~200 times.Cadmium in natural water samples was concentrated prior to determination by FAAS.The recovery is above 96%.The detection limit is 0.018 μg/L.
With the presence of KI,Cd(Ⅱ) can react with I- to form metal complex anions CdI3- and CdI42- at pH 1.0~6.0,which can be well adsorbed on microcrystalline phenolphthalein modified by ethyl violet.Cd(Ⅱ) can be completely separated from Zn(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ),Cr(Ⅲ) and Al(Ⅲ) under optimized conditions.This method was successfully applied to the concentration and determination of trace cadmium in environmental aqueous samples.The preconcentration factor can reach 100~200 times.Cadmium in natural water samples was concentrated prior to determination by FAAS.The recovery is above 96%.The detection limit is 0.018 μg/L.
2006, 23(6): 612-616
Abstract:
HA/ZrO2 composite coatings were successfully prepared on titanium electrode by means of the hydrothermal electrodeposition method via adding ZrO2 powder in the electrolyte in an autoclave.The bonding strength,bioactivity and thermal stability of the coatings were investigated.The results obtained show that the bonding strength of HA/ZrO2 composite coating is obviously higher than that of pure HA coating.HA/ZrO2 composite coating surfaces are covered by carbonate-apatite coating after immersion in simulate body fluid for 7 d,which indicates that the bonding strength of the coating is improved without the decrease of the bioactivity by the addition of the ZrO2 in HA coating.Tetragonal phase ZrO2(t-ZrO2) underwent a martensitic transformation to monoclinic phase ZrO2(m-ZrO2) after sintering treatment.At sintering temperature above 700℃,HA partially decomposed which causes the ZrO2 transformation to β-calcium phosphate(β-TCP).when sintering at 1 200℃,HA decomposed to α-calcium phosphate(α-TCP) and gave CaO,cubic phases ZrO2 (c-ZrO2) and yields CaZrO3.
HA/ZrO2 composite coatings were successfully prepared on titanium electrode by means of the hydrothermal electrodeposition method via adding ZrO2 powder in the electrolyte in an autoclave.The bonding strength,bioactivity and thermal stability of the coatings were investigated.The results obtained show that the bonding strength of HA/ZrO2 composite coating is obviously higher than that of pure HA coating.HA/ZrO2 composite coating surfaces are covered by carbonate-apatite coating after immersion in simulate body fluid for 7 d,which indicates that the bonding strength of the coating is improved without the decrease of the bioactivity by the addition of the ZrO2 in HA coating.Tetragonal phase ZrO2(t-ZrO2) underwent a martensitic transformation to monoclinic phase ZrO2(m-ZrO2) after sintering treatment.At sintering temperature above 700℃,HA partially decomposed which causes the ZrO2 transformation to β-calcium phosphate(β-TCP).when sintering at 1 200℃,HA decomposed to α-calcium phosphate(α-TCP) and gave CaO,cubic phases ZrO2 (c-ZrO2) and yields CaZrO3.
2006, 23(6): 617-621
Abstract:
A new crosslinking agent containing silicon-hydrogen atoms and trimethoxylsilicon groups was synthesized by controlling the molar ratio of 2,4,6,8-tetramethylcyclotetrasiloxane to vinyltrimethoxyl-siloxane to be 1:2.A PMDS hybrid membrane was also prepared by using the crosslinking agent,a silicone rubber containing vinyl groups of 10% (molar fraction) and tetraethoxysilicone(TEOS) were chosen as the matrix materials.There were three types of the crosslinking reactions involved in the membrane-forming process.These included an addition reaction between the silicon-hydrogen atom and the vinyl group,hydrolyzation and condensation between trimethoxylsiloxane and TEOS and their self hydrolyzation and condensation.The chemical structures and morphologies of the hybrid membranes were characterized by using FTIR and SEM.The mechanical properties were also measured.The hybrid membrane containing a mass fraction of 25.0% of TEOS showed a good membrane-forming property,better optimal mechanical performance and oxygen-enriching property.For example,at 30℃ and 0.05 MPa,PO2 and αO2/N2 were 3.7×107 Pa Barrer and 3.45,respectively,which are higher than the target of modified silicone rubber membranes at present: PO2 >1.0×107 Pa,αO2/N2 >3.0.
A new crosslinking agent containing silicon-hydrogen atoms and trimethoxylsilicon groups was synthesized by controlling the molar ratio of 2,4,6,8-tetramethylcyclotetrasiloxane to vinyltrimethoxyl-siloxane to be 1:2.A PMDS hybrid membrane was also prepared by using the crosslinking agent,a silicone rubber containing vinyl groups of 10% (molar fraction) and tetraethoxysilicone(TEOS) were chosen as the matrix materials.There were three types of the crosslinking reactions involved in the membrane-forming process.These included an addition reaction between the silicon-hydrogen atom and the vinyl group,hydrolyzation and condensation between trimethoxylsiloxane and TEOS and their self hydrolyzation and condensation.The chemical structures and morphologies of the hybrid membranes were characterized by using FTIR and SEM.The mechanical properties were also measured.The hybrid membrane containing a mass fraction of 25.0% of TEOS showed a good membrane-forming property,better optimal mechanical performance and oxygen-enriching property.For example,at 30℃ and 0.05 MPa,PO2 and αO2/N2 were 3.7×107 Pa Barrer and 3.45,respectively,which are higher than the target of modified silicone rubber membranes at present: PO2 >1.0×107 Pa,αO2/N2 >3.0.
2006, 23(6): 622-625
Abstract:
CeO2 nano-powders were synthesized by coupling homogeneous precipitation and carbon adsorption method. The effect of the amount of added carbon on the nano-powder size was investigated. The optimal carbon to Ce(NO3)3 mole ratio is 3. The phase,particle shape,particle size and specific surface area of CeO2 particles were characterized by XRD,TEM and BET. CeO2 powder calcined at 700℃ is cubic fluorite and has a surface area of 53.6 m2/g. The average particle size is about 18 nm. The structures of the products calcined at 800~900℃ remain stable and no agglomeration could be observed.
CeO2 nano-powders were synthesized by coupling homogeneous precipitation and carbon adsorption method. The effect of the amount of added carbon on the nano-powder size was investigated. The optimal carbon to Ce(NO3)3 mole ratio is 3. The phase,particle shape,particle size and specific surface area of CeO2 particles were characterized by XRD,TEM and BET. CeO2 powder calcined at 700℃ is cubic fluorite and has a surface area of 53.6 m2/g. The average particle size is about 18 nm. The structures of the products calcined at 800~900℃ remain stable and no agglomeration could be observed.
2006, 23(6): 626-631
Abstract:
Sodium alginate and anion polyacrylamide were crossed by HCHO.The effects of the viscosity of the preparation solution,water ratio,total ion exchange capacity,temperature and acid-base concentration on the swelling ratio of membrane SA-APMA were investigated.SA-APAM membrane was characterized by means of FTIR and SEM and applied in electro-generated ferrate.The experiment results show that SA-APAM membrane of 1%PAM-3%SA could prevent FeO42- diffusion to cathode chamber and the OH- consumed in the anode chamber could be continuously feeded from cathode chamber.
Sodium alginate and anion polyacrylamide were crossed by HCHO.The effects of the viscosity of the preparation solution,water ratio,total ion exchange capacity,temperature and acid-base concentration on the swelling ratio of membrane SA-APMA were investigated.SA-APAM membrane was characterized by means of FTIR and SEM and applied in electro-generated ferrate.The experiment results show that SA-APAM membrane of 1%PAM-3%SA could prevent FeO42- diffusion to cathode chamber and the OH- consumed in the anode chamber could be continuously feeded from cathode chamber.
2006, 23(6): 632-636
Abstract:
The performances of MEG,including shale inhibition,water activity,toxicity and its effect on shale membrane efficiency and high density drilling fluid rheological and filtrating properties,were studied in laboratory.With the addition of 25% MEG,the inhibiting expansion ratio of shale is just about 10.55%,the water activity can be lowered to below 0.85 and the shale membrane efficiency can be increased by 202%.The major anti-collapse mechanism of MEG is believed to be originated from decreasing drilling fluid loss through osmosis.Using MEG to prepare drilling fluids possesses virtues,besides nontoxic and improvement in terms of rheological properties,suchas simple components,high temperature stability and good resistance to clay and gypsum.
The performances of MEG,including shale inhibition,water activity,toxicity and its effect on shale membrane efficiency and high density drilling fluid rheological and filtrating properties,were studied in laboratory.With the addition of 25% MEG,the inhibiting expansion ratio of shale is just about 10.55%,the water activity can be lowered to below 0.85 and the shale membrane efficiency can be increased by 202%.The major anti-collapse mechanism of MEG is believed to be originated from decreasing drilling fluid loss through osmosis.Using MEG to prepare drilling fluids possesses virtues,besides nontoxic and improvement in terms of rheological properties,suchas simple components,high temperature stability and good resistance to clay and gypsum.
2006, 23(6): 637-640
Abstract:
11 1,4-dioxide quinoxaline formaldehyde semicarbazones and imines were synthesized by the reactions of 1,4-dioxide quinoxaline formaldehyde with aminourea or substituted anilines.The structures were characterized by IR,MS,H NMR and elemental analysis.The bacteriostatic activities of the new compounds were assessed by 5 fungies.The results are as follow: the bacteriostatic effects of semicarbazones and formaldehyde imines are below 20% and in the range of 30%~40% at a dosage of 80 mg/L,di-aldehydethe imines have no effect,while those of formaldehyde imines g and h having o-electron donating group substituted anilines can reach 50% or higher.
11 1,4-dioxide quinoxaline formaldehyde semicarbazones and imines were synthesized by the reactions of 1,4-dioxide quinoxaline formaldehyde with aminourea or substituted anilines.The structures were characterized by IR,MS,H NMR and elemental analysis.The bacteriostatic activities of the new compounds were assessed by 5 fungies.The results are as follow: the bacteriostatic effects of semicarbazones and formaldehyde imines are below 20% and in the range of 30%~40% at a dosage of 80 mg/L,di-aldehydethe imines have no effect,while those of formaldehyde imines g and h having o-electron donating group substituted anilines can reach 50% or higher.
2006, 23(6): 641-645
Abstract:
The precursor of bismuth stannate(Bi2Sn2O7) was prepared by precipitation reaction in the nanodroplets of water/TX100/n-hexanol/cyclohexane microemulsion system.Some factors that affected the size and shape of the precursor were investigated.Spherical bismuth stannate particles with single pyrochlore structure were obtained when the precursor was calcined at a temperature as low as 500℃.The particle size was in the range of 10~20 nm with a mean size close to 10 nm.The IR bands were broadened when calcined at 500℃.
The precursor of bismuth stannate(Bi2Sn2O7) was prepared by precipitation reaction in the nanodroplets of water/TX100/n-hexanol/cyclohexane microemulsion system.Some factors that affected the size and shape of the precursor were investigated.Spherical bismuth stannate particles with single pyrochlore structure were obtained when the precursor was calcined at a temperature as low as 500℃.The particle size was in the range of 10~20 nm with a mean size close to 10 nm.The IR bands were broadened when calcined at 500℃.
2006, 23(6): 646-650
Abstract:
Here we report a novel preparation method of Mn(Salen)/Al-HMS catalysts through host-guest interaction between Mn(Salen) complex and mesoporous Al-HMS under microwave irradiation(MWI).FT-IR,DR UV-Vis and TG measurement results indicate that Mn(Salen) complex could be successfully immobilized on mesoporous Al-HMS.Styrene epoxidation with PhIO as oxidant was carried out to test the effect of the catalyst prepared with different preparation methods on the catalytic activity and selectivity.It was found that the catalyst of Mn(Salen)/Al-HMS-IP1 shows a good conversion of styrene(74.6%) and the best selectivity for phenyloxirane(94.8%).Moreover,radiation time,quantity of oxidant and recycle times were investigated to investigate their effects on the catalytic performance.
Here we report a novel preparation method of Mn(Salen)/Al-HMS catalysts through host-guest interaction between Mn(Salen) complex and mesoporous Al-HMS under microwave irradiation(MWI).FT-IR,DR UV-Vis and TG measurement results indicate that Mn(Salen) complex could be successfully immobilized on mesoporous Al-HMS.Styrene epoxidation with PhIO as oxidant was carried out to test the effect of the catalyst prepared with different preparation methods on the catalytic activity and selectivity.It was found that the catalyst of Mn(Salen)/Al-HMS-IP1 shows a good conversion of styrene(74.6%) and the best selectivity for phenyloxirane(94.8%).Moreover,radiation time,quantity of oxidant and recycle times were investigated to investigate their effects on the catalytic performance.
2006, 23(6): 651-654
Abstract:
With TiCl4 and urea as the raw materials,the mix-crystals of rutile and anatase TiO2 were prepared at 100℃ by means of microwave irradiation method.The effect of pH on the ratio of the nanometer TiO2 mix- crystal was discussed.The crystal structure was determined by XRD.TEM indicated that the TiO2 was spherical particles,and the average diameter of the particles was 15 nm.The photocatalytic experiment showed that the mix-crystal material had better photocatalytic activity than the singleness TiO2.The compound could completely degrade the blue dye in 50 min under the sunlight.
With TiCl4 and urea as the raw materials,the mix-crystals of rutile and anatase TiO2 were prepared at 100℃ by means of microwave irradiation method.The effect of pH on the ratio of the nanometer TiO2 mix- crystal was discussed.The crystal structure was determined by XRD.TEM indicated that the TiO2 was spherical particles,and the average diameter of the particles was 15 nm.The photocatalytic experiment showed that the mix-crystal material had better photocatalytic activity than the singleness TiO2.The compound could completely degrade the blue dye in 50 min under the sunlight.
2006, 23(6): 655-658
Abstract:
Nine N1-furanidin-2'-yl-N3-alkylsulphonylalkyl-5-fluorouracils were synthesized via the oxidations of N1-furanidin-2'-yl-N3-alkylthioalkyl-5-fluorouracils 2.The intermediates 2 were prepared by the reactions of N1-furanidin-2'-yl-N3-bromoalkyl-5-fluorouracil 1 with sodium alkylsulfide.The structures of the products were confirmed by means of 1H NMR,IR,MS and elemental analysis.The inhibitory activities of compounds 3 to A549,HCT-8 and Bel-7402 cancer cells were tested in vitro.
Nine N1-furanidin-2'-yl-N3-alkylsulphonylalkyl-5-fluorouracils were synthesized via the oxidations of N1-furanidin-2'-yl-N3-alkylthioalkyl-5-fluorouracils 2.The intermediates 2 were prepared by the reactions of N1-furanidin-2'-yl-N3-bromoalkyl-5-fluorouracil 1 with sodium alkylsulfide.The structures of the products were confirmed by means of 1H NMR,IR,MS and elemental analysis.The inhibitory activities of compounds 3 to A549,HCT-8 and Bel-7402 cancer cells were tested in vitro.
2006, 23(6): 659-662
Abstract:
In the solid-phase synthesis of oligosaccharides,1,2-isopropyl-5,6-dehydrate-α,d-furan glucose was linked to the carriers styrene-diphenyl ethylene with sizes of 100~200 nm by dimethyldichlorosilane coupling agent.The saccharide chains were prolonged by the linkage of 1,2-isopropyl-5,6-dehydrate-α,d-furan glucose.In principle,the epoxy of the glucose unit on the carrier could react with the hydroxyl of another 1,2-isopropyl-5,6-dehydrate-α,d-furan glucose to make the target oligosaccharide.The resulant oligosaccharides were deattached from the carrier by tetrabutylammonium fluoride(TBAF) buffered with acetic acid and their structure was confirmed based on the results of UV,FT-IR,NMR and MS.
In the solid-phase synthesis of oligosaccharides,1,2-isopropyl-5,6-dehydrate-α,d-furan glucose was linked to the carriers styrene-diphenyl ethylene with sizes of 100~200 nm by dimethyldichlorosilane coupling agent.The saccharide chains were prolonged by the linkage of 1,2-isopropyl-5,6-dehydrate-α,d-furan glucose.In principle,the epoxy of the glucose unit on the carrier could react with the hydroxyl of another 1,2-isopropyl-5,6-dehydrate-α,d-furan glucose to make the target oligosaccharide.The resulant oligosaccharides were deattached from the carrier by tetrabutylammonium fluoride(TBAF) buffered with acetic acid and their structure was confirmed based on the results of UV,FT-IR,NMR and MS.
2006, 23(6): 663-667
Abstract:
(PEO)8LiClO4-modified SiO2 composite polymer electrolyte was prepared by the reaction of Si(OC2H5)4 in (PEO)8LiClO4) matrix and simultaneous modification of SiO2 by silane-coupling agent KH560.The morphology and ionic conductivity of the polymer electrolytes were investigated by means of SEM,AFM,DSC and A.C.impedance spectroscopy.The results showed that the modified SiO2 particles with the sizes of 35 nm were dispered uniformly in PEO matrix.Compared with unmodified SiO2,the addition of modified SiO2 in (PEO)8LiClO4 polymer electrolyte effectively leads to higher enhancement in ionic conductivity.When mass ratio of SiO2 reaches 10%,a maximum conductivity of 4.8×10-5 S/cm could be achieved.
(PEO)8LiClO4-modified SiO2 composite polymer electrolyte was prepared by the reaction of Si(OC2H5)4 in (PEO)8LiClO4) matrix and simultaneous modification of SiO2 by silane-coupling agent KH560.The morphology and ionic conductivity of the polymer electrolytes were investigated by means of SEM,AFM,DSC and A.C.impedance spectroscopy.The results showed that the modified SiO2 particles with the sizes of 35 nm were dispered uniformly in PEO matrix.Compared with unmodified SiO2,the addition of modified SiO2 in (PEO)8LiClO4 polymer electrolyte effectively leads to higher enhancement in ionic conductivity.When mass ratio of SiO2 reaches 10%,a maximum conductivity of 4.8×10-5 S/cm could be achieved.
2006, 23(6): 668-671
Abstract:
DL-tryptophan was synthesizd by condensing gramine with hydantoin and subsequent hydrolyzation of 5-(3-indole-methyl)hydantoin intermediate.The yield of DL-tryptophan to gramine was up to 41.6%.The optimum conditions of condensation were: 10 h reaction time,1.2:0.8:1 molar ratio of CH3I to C2H5ONa to gramine,0.9:1 molar ratio of gramine to hydantoin.The optimum conditions of hydrolysis were: 1.5 mol/L NaOH,10 h hydrolysis time,0.2 mol/L 5-(3-indolemethyl)hydantoin,and 100℃ reaction temperature.
DL-tryptophan was synthesizd by condensing gramine with hydantoin and subsequent hydrolyzation of 5-(3-indole-methyl)hydantoin intermediate.The yield of DL-tryptophan to gramine was up to 41.6%.The optimum conditions of condensation were: 10 h reaction time,1.2:0.8:1 molar ratio of CH3I to C2H5ONa to gramine,0.9:1 molar ratio of gramine to hydantoin.The optimum conditions of hydrolysis were: 1.5 mol/L NaOH,10 h hydrolysis time,0.2 mol/L 5-(3-indolemethyl)hydantoin,and 100℃ reaction temperature.
2006, 23(6): 672-675
Abstract:
Vinylbenzene sulfonate(VBS) pillared hydrotalcite(VBS-HT) was obtained by the ion-exchange reaction of VBS with nitrate anion pillared HT(NO3-HT),which was previously prepared by a co-precipitation method.The polymerization of pillaring VBS was conducted.The structure of VBS pillared HT and its polymerization product were characterized by means of X-ray diffraction,infrared spectrum and elemental analysis.It was found that well pillaring of VBS in HT could be achieved via ion-exchange reaction,and the interlayer spacing increased from 0.90 nm for NO3-HT to 1.83 nm for VBS pillared HT.The interlayer spacing was further increased to 1.94 nm after VBS was polymerized in the interspace of HT.
Vinylbenzene sulfonate(VBS) pillared hydrotalcite(VBS-HT) was obtained by the ion-exchange reaction of VBS with nitrate anion pillared HT(NO3-HT),which was previously prepared by a co-precipitation method.The polymerization of pillaring VBS was conducted.The structure of VBS pillared HT and its polymerization product were characterized by means of X-ray diffraction,infrared spectrum and elemental analysis.It was found that well pillaring of VBS in HT could be achieved via ion-exchange reaction,and the interlayer spacing increased from 0.90 nm for NO3-HT to 1.83 nm for VBS pillared HT.The interlayer spacing was further increased to 1.94 nm after VBS was polymerized in the interspace of HT.
2006, 23(6): 676-681
Abstract:
The inhibition corrosion behavior of 2-amido(1-phenyl-3-butyl)-5-methyl-thiadiazole and 2-amido(1,4-diphenyl-3-butyl)-5-methyl-thiadiazole on A3 steel in 1 mol/L HCl solution was investigated by means of mass loss and AC impedance.It has been shown that the two inhibitors have good inhibition performance for A3 steel in 1 mol/L HCl solution with optimal concentration of 400 mg/L.And inhibition efficiency of 2-amido(1,4-diphenyl-3-butyl)-5-methyl-thiadiazole is better than that of 2-amido(1-phenyl-3-butyl)-5-methyl-thiadiazole.The adsorption processes are exothermic reactions and belongs to the physical adsorptions and the Langmuir isotherm is followed.
The inhibition corrosion behavior of 2-amido(1-phenyl-3-butyl)-5-methyl-thiadiazole and 2-amido(1,4-diphenyl-3-butyl)-5-methyl-thiadiazole on A3 steel in 1 mol/L HCl solution was investigated by means of mass loss and AC impedance.It has been shown that the two inhibitors have good inhibition performance for A3 steel in 1 mol/L HCl solution with optimal concentration of 400 mg/L.And inhibition efficiency of 2-amido(1,4-diphenyl-3-butyl)-5-methyl-thiadiazole is better than that of 2-amido(1-phenyl-3-butyl)-5-methyl-thiadiazole.The adsorption processes are exothermic reactions and belongs to the physical adsorptions and the Langmuir isotherm is followed.
2006, 23(6): 682-684
Abstract:
NiO nanoparticles were successfully prepared by solid state thermal decomposition of NiCO3 (10 nm) precursor,which was synthesized by solid state reaction at room temperature.The crystal structure,particle-size and properties of the nanoparticles were characterized by means of XRD,TEM TG-DTA and BET.The results show that the NiO had an average particle size of 5.8 nm and highest BET specific surface area of 116.6 m2/g after annealling the precursor at 300℃ for 2 h.The formation mechanism of the nanoparticles were also discussed.
NiO nanoparticles were successfully prepared by solid state thermal decomposition of NiCO3 (10 nm) precursor,which was synthesized by solid state reaction at room temperature.The crystal structure,particle-size and properties of the nanoparticles were characterized by means of XRD,TEM TG-DTA and BET.The results show that the NiO had an average particle size of 5.8 nm and highest BET specific surface area of 116.6 m2/g after annealling the precursor at 300℃ for 2 h.The formation mechanism of the nanoparticles were also discussed.
2006, 23(6): 685-687
Abstract:
Based on the one-carbon unit transfer reaction of tetrahydrofolate coenzymes,α-naphthyl cyclo-hexyl ketone was synthesized successfully with benzoimidazolium salt as the tetrahydrofolate coenzyme model at formic acid oxidation level and Grignard reagent as a nucleophile to which one carbon unit was transferred via addition-hydrolysis reaction.This provides a new convenient biomimetic synthesis method to the title compound.The α-naphthyl cyclohexyl ketone was characterized by means of IR spectra,MS and 1H NMR.The reaction mechanism and the effects of reaction conditions on the yield were investigated.
Based on the one-carbon unit transfer reaction of tetrahydrofolate coenzymes,α-naphthyl cyclo-hexyl ketone was synthesized successfully with benzoimidazolium salt as the tetrahydrofolate coenzyme model at formic acid oxidation level and Grignard reagent as a nucleophile to which one carbon unit was transferred via addition-hydrolysis reaction.This provides a new convenient biomimetic synthesis method to the title compound.The α-naphthyl cyclohexyl ketone was characterized by means of IR spectra,MS and 1H NMR.The reaction mechanism and the effects of reaction conditions on the yield were investigated.
Catalytic Asymmetric Epoxidation of Styrene with Chiral Mn(Ⅲ) Salen as Catalyst and NaOCl as Oxidant
2006, 23(6): 688-690
Abstract:
A new chiral Mn(Ⅲ) Salen complex was synthesized and characterized by FT-IR and elemental analysis.The complex was used as catalyst for enantioselective epoxidation of styrene with NaOCl as oxidant in the presence of axial base.The effects of pH value,solvents and axial bases on the asymmetric epoxidation of styrene were investigated.Conversion of styrene and ee of the epoxides could reach 100% and 42% respectively when the reaction was run at 0℃,the catalyst loading is 0.1 mmol,and pH value of 1.0 mmol 4-PPNO in buffered CH2Cl2 is 11.30.
A new chiral Mn(Ⅲ) Salen complex was synthesized and characterized by FT-IR and elemental analysis.The complex was used as catalyst for enantioselective epoxidation of styrene with NaOCl as oxidant in the presence of axial base.The effects of pH value,solvents and axial bases on the asymmetric epoxidation of styrene were investigated.Conversion of styrene and ee of the epoxides could reach 100% and 42% respectively when the reaction was run at 0℃,the catalyst loading is 0.1 mmol,and pH value of 1.0 mmol 4-PPNO in buffered CH2Cl2 is 11.30.
2006, 23(6): 691-693
Abstract:
New calix[4]arene poly(aza) derivatives 3,4 and bis-calix[4]arene 5 containing azo-groups,amido groups and Schiff-base groups were synthesized in yields of 87%,89%,84%,respectively.Their structures were confirmed by 1H NMR,ESI-MS and elemental analysis.Liquid-liquid extraction experiments showed they possessed excellent extraction capabilities for cations and their extraction percentages were higher than those of similar calix[4]arene derivatives containing amido and Schiff-base groups.
New calix[4]arene poly(aza) derivatives 3,4 and bis-calix[4]arene 5 containing azo-groups,amido groups and Schiff-base groups were synthesized in yields of 87%,89%,84%,respectively.Their structures were confirmed by 1H NMR,ESI-MS and elemental analysis.Liquid-liquid extraction experiments showed they possessed excellent extraction capabilities for cations and their extraction percentages were higher than those of similar calix[4]arene derivatives containing amido and Schiff-base groups.
2006, 23(6): 694-696
Abstract:
A narrow distribution low molecular weight chitosan(LMWCTS) was prepared by the oxide degradation system adjusted with trace amount of zinc sulfate.Fluorescence probe was used to investigate the polarity of micro-area of this degradation system,IR and GPC were utilized for measuring the physic-chemical properties of these LMWCTS samples.The system with 3.8 mmol ZnSO4 had a narrow distribution of LMWCTS (Mw=973,d=1.1) and the yield of LMWCTS was 85%.Those primary structure units of the chitosan have not been altered after degradation.
A narrow distribution low molecular weight chitosan(LMWCTS) was prepared by the oxide degradation system adjusted with trace amount of zinc sulfate.Fluorescence probe was used to investigate the polarity of micro-area of this degradation system,IR and GPC were utilized for measuring the physic-chemical properties of these LMWCTS samples.The system with 3.8 mmol ZnSO4 had a narrow distribution of LMWCTS (Mw=973,d=1.1) and the yield of LMWCTS was 85%.Those primary structure units of the chitosan have not been altered after degradation.
