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2007 Volume 24 Issue 6
2007, 24(6): 605-609
Abstract:
A novel fluorinated acrylic polymer with core-shell structure,which was obtained by semi-continuous seed emulsion polymerization with butyl acrylate (BA) as the core and methyl methylacrylate (MMA) and methyl dodecafluorinacrylate (DFMA,C11H8O2F12) as the shell in the presence of mixed emulsifier of sodium lauryl sulfate (SDS) and octyl-phenyl poly-oxyethylene (TX-10),was modified by hydrolysis of tetraethyloxysilane (TEOS) and coupling of long-chain alkyl trimethoxysilane (WD-10).Silicon dioxide produced by the hydrolysis of TEOS was detected by X-ray diffraction (XRD).FTIR,scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX),transmission electron microscopy (TEM),stretch tester (RGD),differential scanning calorimetry (DSC),and NMR were used for characterizing the morphology structure,particle size,and the effect of TEOS and WD-10 content on the coating properties.The modified fluorinated acrylic polymer displayed improved performance in hydrophobicity,mechanical and optical properties.The optimal content of TEOS was 3.1%~3.8% and that of WD-10 was between 0.9% and 0.95% of TEOS.
A novel fluorinated acrylic polymer with core-shell structure,which was obtained by semi-continuous seed emulsion polymerization with butyl acrylate (BA) as the core and methyl methylacrylate (MMA) and methyl dodecafluorinacrylate (DFMA,C11H8O2F12) as the shell in the presence of mixed emulsifier of sodium lauryl sulfate (SDS) and octyl-phenyl poly-oxyethylene (TX-10),was modified by hydrolysis of tetraethyloxysilane (TEOS) and coupling of long-chain alkyl trimethoxysilane (WD-10).Silicon dioxide produced by the hydrolysis of TEOS was detected by X-ray diffraction (XRD).FTIR,scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX),transmission electron microscopy (TEM),stretch tester (RGD),differential scanning calorimetry (DSC),and NMR were used for characterizing the morphology structure,particle size,and the effect of TEOS and WD-10 content on the coating properties.The modified fluorinated acrylic polymer displayed improved performance in hydrophobicity,mechanical and optical properties.The optimal content of TEOS was 3.1%~3.8% and that of WD-10 was between 0.9% and 0.95% of TEOS.
2007, 24(6): 610-614
Abstract:
Using ammonium persulphate as the initiator and industrial grade dimethyldiallylammonium chloride (DMDAAC) as the monomer,PDMDAAC with high molecular mass was obtained by adding all the initiator in one shot and raising the polymerization temperature in steps.The maximum intrinsic viscosity of the product PDMDAAC could reach 3.17 dL/g,and the monomer conversion rate was 94.8%.The product structure was characterized by FTIR and NMR.The effect of process conditions,such as the concentration of DMDAAC,the mass ratio of APS to DMDAAC,the mass ratio of Na4EDTA to DMDAAC,initiating temperature T1 and reaction temperature T3 on the intrinsic viscosity of the product and monomer conversion were investigated respectively.The results showed that the optimum process conditions were mass concentration of DMDAAC 65.0%,mass ratio of APS to DMDAAC 0.35:100,mass ratio of Na4EDTA to DMDAAC 0.007 1:100,T1=46℃,T2=50℃ and T3=70℃,with 3 h reaction time at each temperature.
Using ammonium persulphate as the initiator and industrial grade dimethyldiallylammonium chloride (DMDAAC) as the monomer,PDMDAAC with high molecular mass was obtained by adding all the initiator in one shot and raising the polymerization temperature in steps.The maximum intrinsic viscosity of the product PDMDAAC could reach 3.17 dL/g,and the monomer conversion rate was 94.8%.The product structure was characterized by FTIR and NMR.The effect of process conditions,such as the concentration of DMDAAC,the mass ratio of APS to DMDAAC,the mass ratio of Na4EDTA to DMDAAC,initiating temperature T1 and reaction temperature T3 on the intrinsic viscosity of the product and monomer conversion were investigated respectively.The results showed that the optimum process conditions were mass concentration of DMDAAC 65.0%,mass ratio of APS to DMDAAC 0.35:100,mass ratio of Na4EDTA to DMDAAC 0.007 1:100,T1=46℃,T2=50℃ and T3=70℃,with 3 h reaction time at each temperature.
2007, 24(6): 615-618
Abstract:
TiO2/SiO2 composite porous material was prepared with the activated carbon as the template and silicic acid tetraethyl ester and tetrabutyl titanate as the precursors in supercritical carbon dioxide (SC-CO2).The effects of coating pressure and temperature on the coating ratio under the supercritical CO2 were studied.The results show that at 40℃,the optimal coating pressure is 22 MPa;at the same coating pressure,the optimal coating T is 70℃.The X-ray diffraction (XRD) result shows that the product is composite of anatase TiO2,rutile TiO2 and crystal SiO2.BET surface area calculated from the nitrogen adsorption isotherms of the product is up to 144.44 m2/g and the average pore diameter is about 7 nm.SEM experimental results indicate the activated carbon template is well replicated by the porous product and TEM results show the nano-particles are well dispersed in the product.
TiO2/SiO2 composite porous material was prepared with the activated carbon as the template and silicic acid tetraethyl ester and tetrabutyl titanate as the precursors in supercritical carbon dioxide (SC-CO2).The effects of coating pressure and temperature on the coating ratio under the supercritical CO2 were studied.The results show that at 40℃,the optimal coating pressure is 22 MPa;at the same coating pressure,the optimal coating T is 70℃.The X-ray diffraction (XRD) result shows that the product is composite of anatase TiO2,rutile TiO2 and crystal SiO2.BET surface area calculated from the nitrogen adsorption isotherms of the product is up to 144.44 m2/g and the average pore diameter is about 7 nm.SEM experimental results indicate the activated carbon template is well replicated by the porous product and TEM results show the nano-particles are well dispersed in the product.
2007, 24(6): 619-622
Abstract:
This article describes the synthesis of 9,9'-(1,4-phenylene)-2H,2'H,3H,3'H,4H,4'H,5H,5'H,6H,6'H,7H,7'H,9H,9'H-tetradecahydro-dixanthene-1,1',8,8'-tetra-one (compound Ⅰ) from 1,3-cyclohexedione and 1,4-benzenedicarboaldehyde through condensation and dehydration in acidic medium.The reaction mechanism was proposed.And then,the cyclization reaction between Ⅰ and pentaerythritol gave 9,9'-(1,4-phenylene)-2H,2H,2'H,2'H,3H,3H,3'H,3'H,4H,4H,4'H,4'H,5H,5H,5'H,5'H,6H,6H,6'H,6'H,7H,7H,7'H,7'H,9H,9'H-tetradecahydro dixanthene-1,1',8,8'-tetraone ketal di-pentaerythritol (compound Ⅱ) using I2 as a catalyst,and the yield was 40%.The structures of Ⅰ and Ⅱ were confirmed by IR,1H NMR,and MS.In 1H NMR spectra,the peaks for the eight hydrogen atoms of the methylene groups in compound Ⅱ containing spiro-structure split into four doublets due to the presence of chiral axis and benzene ring.The reaction parameters and the formation of by-products were discussed.
This article describes the synthesis of 9,9'-(1,4-phenylene)-2H,2'H,3H,3'H,4H,4'H,5H,5'H,6H,6'H,7H,7'H,9H,9'H-tetradecahydro-dixanthene-1,1',8,8'-tetra-one (compound Ⅰ) from 1,3-cyclohexedione and 1,4-benzenedicarboaldehyde through condensation and dehydration in acidic medium.The reaction mechanism was proposed.And then,the cyclization reaction between Ⅰ and pentaerythritol gave 9,9'-(1,4-phenylene)-2H,2H,2'H,2'H,3H,3H,3'H,3'H,4H,4H,4'H,4'H,5H,5H,5'H,5'H,6H,6H,6'H,6'H,7H,7H,7'H,7'H,9H,9'H-tetradecahydro dixanthene-1,1',8,8'-tetraone ketal di-pentaerythritol (compound Ⅱ) using I2 as a catalyst,and the yield was 40%.The structures of Ⅰ and Ⅱ were confirmed by IR,1H NMR,and MS.In 1H NMR spectra,the peaks for the eight hydrogen atoms of the methylene groups in compound Ⅱ containing spiro-structure split into four doublets due to the presence of chiral axis and benzene ring.The reaction parameters and the formation of by-products were discussed.
2007, 24(6): 623-627
Abstract:
The effects of interfacial film's strength and Zeta potential on the stability of O/W emulsion have been investigated by measuring the interfacial shear viscosity,zeta potential and emulsion stability of a system with surfactant,polymer and kerosene.In the system of kerosene and OPE-100 with polymer 3530S or its degradation polymer,the maximum of interfacial shear viscosity is more than 0.1 mN/m;the zeta potential is -18.4 mV.The stability of the emulsion is high.The results show that the stability of the O/W emulsion is mainly affected by both the strength of the interfacial film and the zeta potential of the oil droplets.The higher the interfacial film's strength and the zeta potential are,the higher the stability of the O/W emulsion is.At the same level of interfacial film's strength,the stability of the emulsion is dominated by the zeta potential.In this case,the stability of the O/W emulsion is enhanced by electric double layer.On the other hand,interfacial film's strength plays an important role in keeping the stability of the emulsion at the same level of zeta potential.The study also shows that the interfacial shear viscosity,zeta potential and stability of the emulsion are decreased after the polymer have been degradated both mechniacally and thermochamically.
The effects of interfacial film's strength and Zeta potential on the stability of O/W emulsion have been investigated by measuring the interfacial shear viscosity,zeta potential and emulsion stability of a system with surfactant,polymer and kerosene.In the system of kerosene and OPE-100 with polymer 3530S or its degradation polymer,the maximum of interfacial shear viscosity is more than 0.1 mN/m;the zeta potential is -18.4 mV.The stability of the emulsion is high.The results show that the stability of the O/W emulsion is mainly affected by both the strength of the interfacial film and the zeta potential of the oil droplets.The higher the interfacial film's strength and the zeta potential are,the higher the stability of the O/W emulsion is.At the same level of interfacial film's strength,the stability of the emulsion is dominated by the zeta potential.In this case,the stability of the O/W emulsion is enhanced by electric double layer.On the other hand,interfacial film's strength plays an important role in keeping the stability of the emulsion at the same level of zeta potential.The study also shows that the interfacial shear viscosity,zeta potential and stability of the emulsion are decreased after the polymer have been degradated both mechniacally and thermochamically.
2007, 24(6): 628-631
Abstract:
Cyclic voltammetric oxidation of pyrocatechin,hydroquinone and resorcinol in aqueous HClO4 was investigated for examination of the possible formation of charge-transfer complex (CTC) via electrochemical quartz crystal microbalance (EQCM) technique.CTC deposition occurred in HClO4 solutions containing pyrocatechin or hydroquinone of high concentrations,while resorcinol only polymerized under the same conditions.With the pyrocatechin system as an example,the effects of potential-sweep rate and concentrations of pyrocatechin and HClO4 were examined.FTIR data also supported the CTC formation of the pyrocatechin system.We also found that the addition of large-sized heparin sodium influenced significantly the CTC deposition.With the increase of heparin mass concentration,the CTC deposition was first enhanced significantly and then inhibited,and the turning point was at 0.05 g/L heparin.The EQCM as a fast,convenient and sensitive tool is highly recommended for CTC-deposition investigations including the monitoring and screening during CTC syntheses.
Cyclic voltammetric oxidation of pyrocatechin,hydroquinone and resorcinol in aqueous HClO4 was investigated for examination of the possible formation of charge-transfer complex (CTC) via electrochemical quartz crystal microbalance (EQCM) technique.CTC deposition occurred in HClO4 solutions containing pyrocatechin or hydroquinone of high concentrations,while resorcinol only polymerized under the same conditions.With the pyrocatechin system as an example,the effects of potential-sweep rate and concentrations of pyrocatechin and HClO4 were examined.FTIR data also supported the CTC formation of the pyrocatechin system.We also found that the addition of large-sized heparin sodium influenced significantly the CTC deposition.With the increase of heparin mass concentration,the CTC deposition was first enhanced significantly and then inhibited,and the turning point was at 0.05 g/L heparin.The EQCM as a fast,convenient and sensitive tool is highly recommended for CTC-deposition investigations including the monitoring and screening during CTC syntheses.
2007, 24(6): 632-637
Abstract:
A novel supramolecular compound[Mo6O19]2-/PAMAM assembled via ionic bonding was synthesized with poly (amide amine) dendrimer (PAMAM) and[Mo6O19]2- polyanion.It was characterized by elemental analysis,FTIR,UV-Vis absorption,TG/DTA,fluorescence spectrum.The electrochemical behavior of the carbon paste electrode (CPE) modified by the title compound was studied in 1 mol/L H2SO4 aqueous solution by means of cyclic voltammetry.The results show that the title compound exhibits good fluorescence and reversible photochromism;one more pair of redox peaks was observed in a potential range of -0.2 V to 0.2 V with CPE modified by the title compound compared with the redox peaks of CPE modified by [Mo6O19][N(C4H9)2]2;when the scan rate was varied from 20 to 100 mV/s,the redox process of the CPE is surface controlled,however,when the scan rate was varied from 100 to 200 mV/s,the redox process of the CPE is diffusion-controlled;the CPE modified by title compound also exhibits a remarkable electro-chemical stability.
A novel supramolecular compound[Mo6O19]2-/PAMAM assembled via ionic bonding was synthesized with poly (amide amine) dendrimer (PAMAM) and[Mo6O19]2- polyanion.It was characterized by elemental analysis,FTIR,UV-Vis absorption,TG/DTA,fluorescence spectrum.The electrochemical behavior of the carbon paste electrode (CPE) modified by the title compound was studied in 1 mol/L H2SO4 aqueous solution by means of cyclic voltammetry.The results show that the title compound exhibits good fluorescence and reversible photochromism;one more pair of redox peaks was observed in a potential range of -0.2 V to 0.2 V with CPE modified by the title compound compared with the redox peaks of CPE modified by [Mo6O19][N(C4H9)2]2;when the scan rate was varied from 20 to 100 mV/s,the redox process of the CPE is surface controlled,however,when the scan rate was varied from 100 to 200 mV/s,the redox process of the CPE is diffusion-controlled;the CPE modified by title compound also exhibits a remarkable electro-chemical stability.
2007, 24(6): 638-643
Abstract:
Capsulated calcium hydroxide was synthesized by in situ capsulation of calcium hydroxide with phenol-formaldehyde resin formed from phenol and formaldehyde during slaking of calcium oxide.The samples were prepared through adjusting the concentration of prepolymer,reaction time and temperature,and were characterized by means of TEM,FTIR,XRD.Experimental results demonstrate that samples obtained at 20% reactant and 2 h reaction time at 80℃ showed the best properties.The properties of PVC containing capsulated calcium hydroxide were analyzed with DSC-TG,Congo Red test and SEM.Results show that the thermal stability was enhanced more than twice with 1% capsule calcium hydroxide contained in PVC,and the compatibility was improved,too.
Capsulated calcium hydroxide was synthesized by in situ capsulation of calcium hydroxide with phenol-formaldehyde resin formed from phenol and formaldehyde during slaking of calcium oxide.The samples were prepared through adjusting the concentration of prepolymer,reaction time and temperature,and were characterized by means of TEM,FTIR,XRD.Experimental results demonstrate that samples obtained at 20% reactant and 2 h reaction time at 80℃ showed the best properties.The properties of PVC containing capsulated calcium hydroxide were analyzed with DSC-TG,Congo Red test and SEM.Results show that the thermal stability was enhanced more than twice with 1% capsule calcium hydroxide contained in PVC,and the compatibility was improved,too.
2007, 24(6): 644-647
Abstract:
High yield and purity flame retardant bis-(4-allyloxy-3,5-dibromophenyl) sulfone (ATBS) was obtained by allyl-etherizing bis-(4-hydrxy-3,5-dibromophenyl) sulfone (TBS) with dropping allyl chloride in aqueous NaOH in the presence of cetyltrimethylammonium bromide (CTAB) or other surfactants.The catalyst amount,dropwise time,i-propanol amount,water amount influencing the yield and purity of ATBS were particularly discussed.When V (allyl chloride)=15 mL,m(TBS)=28.3 g,reaction temperature 65~75℃,reaction time 4 h,m(CTAB)=0.1~0.18 g,ATBS was prepared in a yield of 95.5%~97.5% and a purity of 95.5%~98.0%.When n(allyl chloride):n(TBS)=1:2.5,reaction temperature 80~90℃,reaction time 8 h,and the used surfactant was m(DBS)=0.8~1.0 g,m(OP-10)=0.5 g or m(OS-15)=0.8 g,respectively,ATBS was synthesized in a yield of 95.2%,97.3% or 95.5% and the purity of 94.0%,92.7% or 90.1%,respectively.
High yield and purity flame retardant bis-(4-allyloxy-3,5-dibromophenyl) sulfone (ATBS) was obtained by allyl-etherizing bis-(4-hydrxy-3,5-dibromophenyl) sulfone (TBS) with dropping allyl chloride in aqueous NaOH in the presence of cetyltrimethylammonium bromide (CTAB) or other surfactants.The catalyst amount,dropwise time,i-propanol amount,water amount influencing the yield and purity of ATBS were particularly discussed.When V (allyl chloride)=15 mL,m(TBS)=28.3 g,reaction temperature 65~75℃,reaction time 4 h,m(CTAB)=0.1~0.18 g,ATBS was prepared in a yield of 95.5%~97.5% and a purity of 95.5%~98.0%.When n(allyl chloride):n(TBS)=1:2.5,reaction temperature 80~90℃,reaction time 8 h,and the used surfactant was m(DBS)=0.8~1.0 g,m(OP-10)=0.5 g or m(OS-15)=0.8 g,respectively,ATBS was synthesized in a yield of 95.2%,97.3% or 95.5% and the purity of 94.0%,92.7% or 90.1%,respectively.
2007, 24(6): 648-651
Abstract:
2-Aryl-3-methyl-5-phenylmorpholine compounds were synthesized via the reactions of 2-amino-2-phenyl-1-alcohol with 2-bromo-3-chloropropiophenone,2-bromopropiophenone,6-methoxy-2-(2-bromopropionyl) naphthalene or 2-bromo-4-methoxypropiophenone respectively,followed by their reactions with 2-aryl-3-methyl-5-phenyl-2-morpholine and hydrochloride to obtain the hydrochloride salts with yields of 52.4%,55.3%,47.6%,and 51.2%,respectively.The structures of the target compounds were confirmed by means of IR,1H NMR and MS spectra.Their antidepressant activities were tested with mice forced swimming test.The results showed that the mice that were administered with the intermediate 4a had shorter immobility time than the blank control mice in forced swimming test.
2-Aryl-3-methyl-5-phenylmorpholine compounds were synthesized via the reactions of 2-amino-2-phenyl-1-alcohol with 2-bromo-3-chloropropiophenone,2-bromopropiophenone,6-methoxy-2-(2-bromopropionyl) naphthalene or 2-bromo-4-methoxypropiophenone respectively,followed by their reactions with 2-aryl-3-methyl-5-phenyl-2-morpholine and hydrochloride to obtain the hydrochloride salts with yields of 52.4%,55.3%,47.6%,and 51.2%,respectively.The structures of the target compounds were confirmed by means of IR,1H NMR and MS spectra.Their antidepressant activities were tested with mice forced swimming test.The results showed that the mice that were administered with the intermediate 4a had shorter immobility time than the blank control mice in forced swimming test.
2007, 24(6): 652-655
Abstract:
A solid-solid phase change material with cross-linking polyurethane structure (C-PUPCM) was prepared via a two-step process with polyethylene glycol (PEG),4,4'-diphenylmethane diisocyanate (MDI),and pentaerythritol (PETA) as raw materials.The morphology and phase transition behaviors of these C-PUPCM films were investigated by means of differential scanning calorimetry (DSC),thermo-gravimetric analysis (TGA),wide-angle X-ray diffraction (WAXD),polarizing optical microscopy (POM).The results indicate that the C-PUPCM showed typical solid-solid phase transition between amorphous and crystalline of the soft segment PEG.The results also show that C-PUPCMs' with different crystallinities,different latent heats,different phase transition temperatures,and different thermal stable properties can be obtained by means of modifying the weight percentage of PEG.
A solid-solid phase change material with cross-linking polyurethane structure (C-PUPCM) was prepared via a two-step process with polyethylene glycol (PEG),4,4'-diphenylmethane diisocyanate (MDI),and pentaerythritol (PETA) as raw materials.The morphology and phase transition behaviors of these C-PUPCM films were investigated by means of differential scanning calorimetry (DSC),thermo-gravimetric analysis (TGA),wide-angle X-ray diffraction (WAXD),polarizing optical microscopy (POM).The results indicate that the C-PUPCM showed typical solid-solid phase transition between amorphous and crystalline of the soft segment PEG.The results also show that C-PUPCMs' with different crystallinities,different latent heats,different phase transition temperatures,and different thermal stable properties can be obtained by means of modifying the weight percentage of PEG.
2007, 24(6): 656-659
Abstract:
The structure of silane grafted High Density Polyethylene (HDPE) was characterized by FT-IR and Laser Raman spectroscopy.The characteristic peaks of silane at 1 170,1 110,1 090 and 960 cm-1 were rather stronger in the FT-IR spectrum,while the characteristic peak of silane at near 1 091 cm-1 was quite weaker in the Raman spectrum.With the increase of the silane content,the ratio of peaks (R1) calculated from FT-IR and R2 calculated from Raman increased respectively from 0.43 to 1.44 and from 0.028 to 0.099.Both R1 and R2 could be used to estimate the grafting ratio of silane and have the same concentration depen-dence trend.The crystallization of silane grafted HDPE was also characterized by Raman spectroscopy.With the increase of the silane content,Raman data showed that the mass fractions of the crystalline phase and the amorphous decreased respectively from 69.8% to 67.5% and from 12.9% to 5.5%,while the mesophase increased from 17.3% to 27%.DSC data showed that the crystallinity of silane grafted polyethylene and the melting point decreased respectively from 71.8% to 61.1% and from 134.4℃ to 131.1℃.
The structure of silane grafted High Density Polyethylene (HDPE) was characterized by FT-IR and Laser Raman spectroscopy.The characteristic peaks of silane at 1 170,1 110,1 090 and 960 cm-1 were rather stronger in the FT-IR spectrum,while the characteristic peak of silane at near 1 091 cm-1 was quite weaker in the Raman spectrum.With the increase of the silane content,the ratio of peaks (R1) calculated from FT-IR and R2 calculated from Raman increased respectively from 0.43 to 1.44 and from 0.028 to 0.099.Both R1 and R2 could be used to estimate the grafting ratio of silane and have the same concentration depen-dence trend.The crystallization of silane grafted HDPE was also characterized by Raman spectroscopy.With the increase of the silane content,Raman data showed that the mass fractions of the crystalline phase and the amorphous decreased respectively from 69.8% to 67.5% and from 12.9% to 5.5%,while the mesophase increased from 17.3% to 27%.DSC data showed that the crystallinity of silane grafted polyethylene and the melting point decreased respectively from 71.8% to 61.1% and from 134.4℃ to 131.1℃.
2007, 24(6): 660-664
Abstract:
Di-n-butyltin di-2-(2-formylphenoxy) acetic ester (1) was synthesized by the reaction of di-n-butyl tin oxide with 2-(2-formylphenoxy) acetic acid and azeotropic removal of water with benzene.The compound was characterized by elemental analysis,1H NMR,FT-IR,and single crystal X-ray diffraction analysis.The crystal belongs to space group C2/c,and the cell parameter are:a=3.324 6(7) nm,b=0.484 54(10) nm,c=2.214 7(5) nm,β=131.373(2)°,V=2.677 3(9) m3,Z=4,F(000)=1 208,Dc=1.467 g/cm4,μ=0.999 nm-1,R1=0.048 and wR2=0.104 8.There is one molecule in the unit cell,which adopts a skew-trapezoidal bipyramidal arrangement around the tin atom with hexa-coordination;in addition,there are weak bridging intermolecular SnO-(0.346 8 nm) interactions,and the endocyclic Sn atom is octa-coordinated and exists in distorted hexagonal bipyramidal geometry in a one-dimensional chain.The complex (1) exhibits good antibacterial properties,while the antibacterial activity decreased in the order of compound (1Z) >di-n-butyltin oxide >2-(2-formylphenoxy) acetic acid.
Di-n-butyltin di-2-(2-formylphenoxy) acetic ester (1) was synthesized by the reaction of di-n-butyl tin oxide with 2-(2-formylphenoxy) acetic acid and azeotropic removal of water with benzene.The compound was characterized by elemental analysis,1H NMR,FT-IR,and single crystal X-ray diffraction analysis.The crystal belongs to space group C2/c,and the cell parameter are:a=3.324 6(7) nm,b=0.484 54(10) nm,c=2.214 7(5) nm,β=131.373(2)°,V=2.677 3(9) m3,Z=4,F(000)=1 208,Dc=1.467 g/cm4,μ=0.999 nm-1,R1=0.048 and wR2=0.104 8.There is one molecule in the unit cell,which adopts a skew-trapezoidal bipyramidal arrangement around the tin atom with hexa-coordination;in addition,there are weak bridging intermolecular SnO-(0.346 8 nm) interactions,and the endocyclic Sn atom is octa-coordinated and exists in distorted hexagonal bipyramidal geometry in a one-dimensional chain.The complex (1) exhibits good antibacterial properties,while the antibacterial activity decreased in the order of compound (1Z) >di-n-butyltin oxide >2-(2-formylphenoxy) acetic acid.
2007, 24(6): 665-669
Abstract:
In view of the reservoir characters of severe heterogeneity,wide pore radius distribution,unpredictability of pore radius,and unrealized protection for whole hole section and bad protection effect by conventional shielding temporary plugging technology,we designed a broad spectrum oil film temporary plugging drilling and completion fluid system for reservoir protection.The in-house system evaluation and field application showed that an excellent oil film for shielding temporary plugging could be formed near borehole wall and both plugging and recovering rates of permeability reached more than 90% when the added amount of the broad spectrum oil film temporary plugging agent GPJ reached 3%;skin factor decreased by 7.4 to 10 times and production increased by 1.82 to 2.96 times compared with conventional technology.
In view of the reservoir characters of severe heterogeneity,wide pore radius distribution,unpredictability of pore radius,and unrealized protection for whole hole section and bad protection effect by conventional shielding temporary plugging technology,we designed a broad spectrum oil film temporary plugging drilling and completion fluid system for reservoir protection.The in-house system evaluation and field application showed that an excellent oil film for shielding temporary plugging could be formed near borehole wall and both plugging and recovering rates of permeability reached more than 90% when the added amount of the broad spectrum oil film temporary plugging agent GPJ reached 3%;skin factor decreased by 7.4 to 10 times and production increased by 1.82 to 2.96 times compared with conventional technology.
2007, 24(6): 670-674
Abstract:
Hyperbranched polyesters were synthesized by reacting the centronuclei of pentaerythritol with 1,2,4-benzenetricarboxylic anhydride and epichlorohydrin.Then the base-soluble photo-sensitive polymers containing photo-sensitizer units were prepared by further reaction of the above synthesized polymers with 1-hydroxy cyclohexyl-phenyl-ketone and glycidyl methacrylate.Under the optimum conditions,the monomer conversion could reach over 80% during 1 h of reaction.The glass transition temperature of the product was 200℃.TGA showed no mass loss at below 200℃ for the polymer,and a small mass loss was observed between 200℃ and 300℃.It viscosity performance was characteristic of hyperbranched polymers.Additionally,they show excellent solubilities in aqueous alkali.They could be photocured by UV irradiation without additional photoinitiators.Moreover,these resins have such merits as little exposing energy (E0=1×10-3~1×10-2 J/cm2) and satisfactory photo sensitivity.
Hyperbranched polyesters were synthesized by reacting the centronuclei of pentaerythritol with 1,2,4-benzenetricarboxylic anhydride and epichlorohydrin.Then the base-soluble photo-sensitive polymers containing photo-sensitizer units were prepared by further reaction of the above synthesized polymers with 1-hydroxy cyclohexyl-phenyl-ketone and glycidyl methacrylate.Under the optimum conditions,the monomer conversion could reach over 80% during 1 h of reaction.The glass transition temperature of the product was 200℃.TGA showed no mass loss at below 200℃ for the polymer,and a small mass loss was observed between 200℃ and 300℃.It viscosity performance was characteristic of hyperbranched polymers.Additionally,they show excellent solubilities in aqueous alkali.They could be photocured by UV irradiation without additional photoinitiators.Moreover,these resins have such merits as little exposing energy (E0=1×10-3~1×10-2 J/cm2) and satisfactory photo sensitivity.
2007, 24(6): 675-679
Abstract:
ZnO nanoparticles were prepared by thermal decomposition of [Zn4CO3(OH)6]CMC precursor,which was synthesized by sol-gel process in aqueous solution of carboxymethyl cellulose (CMC) polymer.The reaction precursor and the nanoparticles obtained were characterized by means of XRD,SEM,TEM,TG-DSC and FT-IR.The influence of the CMC polymer on the precursor morphology and the nanoparticle size were also investigated.The size of the ZnO nanoparticles was less than 20 nm and uniform.The agglomeration tendency of the ZnO nanoparticles was decreased due to the steric hindrance by the adsorbed polymer.The ZnO nano-particles exhibited an extremely strong absorption at 200~400 nm wavelength.
ZnO nanoparticles were prepared by thermal decomposition of [Zn4CO3(OH)6]CMC precursor,which was synthesized by sol-gel process in aqueous solution of carboxymethyl cellulose (CMC) polymer.The reaction precursor and the nanoparticles obtained were characterized by means of XRD,SEM,TEM,TG-DSC and FT-IR.The influence of the CMC polymer on the precursor morphology and the nanoparticle size were also investigated.The size of the ZnO nanoparticles was less than 20 nm and uniform.The agglomeration tendency of the ZnO nanoparticles was decreased due to the steric hindrance by the adsorbed polymer.The ZnO nano-particles exhibited an extremely strong absorption at 200~400 nm wavelength.
2007, 24(6): 680-683
Abstract:
Heavily diesel-contaminated soil was oxidized with hydrogen peroxide.The effect of pH value of the soil with super-saturated water on the reaction were investigated.The results show that more than 96% of the diesel was degraded within 24 h when pH was about 5~8 for the soil with 5% initial oil content.The pH of the soil solutions reduced from 7.34,6.74,5.78 to 7.02,6.58,5.49 respectively throughout the reaction,which could be attributed mainly to the generation of acid species such as CO2,H+,carboxylic,and β-keto acids.The H2O2 concentration in the soil solution decreased greatly from 0.05 mol/L to close to 0 after 1 h.The diesel content in the surface layer varied but decreased in general,while the diesel content in the underlayer declined greatly,showing that the decomposition,volatilization and movement from bottom to top of diesel components occurred during the oxidation reaction.
Heavily diesel-contaminated soil was oxidized with hydrogen peroxide.The effect of pH value of the soil with super-saturated water on the reaction were investigated.The results show that more than 96% of the diesel was degraded within 24 h when pH was about 5~8 for the soil with 5% initial oil content.The pH of the soil solutions reduced from 7.34,6.74,5.78 to 7.02,6.58,5.49 respectively throughout the reaction,which could be attributed mainly to the generation of acid species such as CO2,H+,carboxylic,and β-keto acids.The H2O2 concentration in the soil solution decreased greatly from 0.05 mol/L to close to 0 after 1 h.The diesel content in the surface layer varied but decreased in general,while the diesel content in the underlayer declined greatly,showing that the decomposition,volatilization and movement from bottom to top of diesel components occurred during the oxidation reaction.
2007, 24(6): 684-687
Abstract:
Fluorosilicone polymers have many excellent properties,such as high and low temperature resistance,weather resistance,corrosion resistance,chemical stability,water and oil resistance.Acrylate copolymer latexes containing fluorosilicone units were prepared via core-shell emulsion copolymerization of methacrylate (MMA),butyl acrylate (BA) and fluorosilcone monomer which was prepared by fluorinated alcohol and vinyltriethoxyl silane.Results show that latexes had good storage stability,and high and low temperature stability.The structure of the fluorosilcone monomer and the acrylate copolymer containing the fluorosilicone were characterized by FT-IR.The morphology of the latex particles was studied with TEM,which confirmed the core-shell structure of the particles,and the particle diameter was 125 nm or so.Compared to that of the copolymer films,the water absorption of the latex films containing fluorosilicone units reduced to 8.32%,and the thermal decomposition temperature increased by 23℃.The latex films could be dissolved in THF and toluene,and could be swollen in methanal and ethanol.
Fluorosilicone polymers have many excellent properties,such as high and low temperature resistance,weather resistance,corrosion resistance,chemical stability,water and oil resistance.Acrylate copolymer latexes containing fluorosilicone units were prepared via core-shell emulsion copolymerization of methacrylate (MMA),butyl acrylate (BA) and fluorosilcone monomer which was prepared by fluorinated alcohol and vinyltriethoxyl silane.Results show that latexes had good storage stability,and high and low temperature stability.The structure of the fluorosilcone monomer and the acrylate copolymer containing the fluorosilicone were characterized by FT-IR.The morphology of the latex particles was studied with TEM,which confirmed the core-shell structure of the particles,and the particle diameter was 125 nm or so.Compared to that of the copolymer films,the water absorption of the latex films containing fluorosilicone units reduced to 8.32%,and the thermal decomposition temperature increased by 23℃.The latex films could be dissolved in THF and toluene,and could be swollen in methanal and ethanol.
2007, 24(6): 688-692
Abstract:
The semi-conductive properties of the passive film formed on N80 tube steel in 0.5 mol/L NaHCO3 solution were investigated via capacitance measurement.Based on Mott-Schottky equation,the factors,such as measuring frequency,formation potential and Cl- concentration,which affect the semi-conductive performance of the passive films,were analyzed.The results show that the passive film exhibited n-type semi-conductive character.The donor density of the passive film decreased with the increase of the measurement frequency,the formation potential,and Cl- concentration.The photo-electrochemical experiments revealed that the photo-current increased with the increase of the formation potential and the formation time,which was attributed to the increasing mobility of the photo-generated holes or electrons.
The semi-conductive properties of the passive film formed on N80 tube steel in 0.5 mol/L NaHCO3 solution were investigated via capacitance measurement.Based on Mott-Schottky equation,the factors,such as measuring frequency,formation potential and Cl- concentration,which affect the semi-conductive performance of the passive films,were analyzed.The results show that the passive film exhibited n-type semi-conductive character.The donor density of the passive film decreased with the increase of the measurement frequency,the formation potential,and Cl- concentration.The photo-electrochemical experiments revealed that the photo-current increased with the increase of the formation potential and the formation time,which was attributed to the increasing mobility of the photo-generated holes or electrons.
2007, 24(6): 693-697
Abstract:
Microcapsules containing initiator for anaerobic adhesive by in situ polymerization in which urea-formaldehyde resin was used as the wall material and benzoyl peroxide was used as the core material.The influences of different kinds of emulsifiers such as sodium dodecylben-zenesulfonate,tween-80,gum arabic and styrene-maleic anhydride and other process conditions on the preparation of microcapsulation were investigated,and IR,TG and SEM were used to analyse the microcapsules.When the microencapsulation was conducted in a system modified by multiple emulsifiers,i.e.,the mixture of styrene-maleic anhydride copolymer and gum arabic,the end point pH value was at around 1.5,the reaction temperature was 70℃,the reaction time was 4 h,and the agitation rate was of 1 000 r/min,the microcapsules were dispersed moderately in size,with good shape and appearance,and the diameter was about 100 μm.The performance of the precoating type adhesive made up of the microcapsules prepared in this article could match that of the ones made by Loctite Company in America.
Microcapsules containing initiator for anaerobic adhesive by in situ polymerization in which urea-formaldehyde resin was used as the wall material and benzoyl peroxide was used as the core material.The influences of different kinds of emulsifiers such as sodium dodecylben-zenesulfonate,tween-80,gum arabic and styrene-maleic anhydride and other process conditions on the preparation of microcapsulation were investigated,and IR,TG and SEM were used to analyse the microcapsules.When the microencapsulation was conducted in a system modified by multiple emulsifiers,i.e.,the mixture of styrene-maleic anhydride copolymer and gum arabic,the end point pH value was at around 1.5,the reaction temperature was 70℃,the reaction time was 4 h,and the agitation rate was of 1 000 r/min,the microcapsules were dispersed moderately in size,with good shape and appearance,and the diameter was about 100 μm.The performance of the precoating type adhesive made up of the microcapsules prepared in this article could match that of the ones made by Loctite Company in America.
2007, 24(6): 698-702
Abstract:
A series of monoacetylated and diacetylated derivatives of trans-3-hydroxy-4-aminobenzopyran was synthesized from 3-acetyl-4-hydroxylbenzonitrile via condensation,reduction,epoxidation,amino addition and acetylation reaction.Their structures were confirmed by spectral data and elemental analysis.The preliminary bioassay suggested that synthesized compounds (7a~7d and 8a~8d) exhibited some K+ channel opening activity against contraction induced by 30 mmol/L KCl on rat aorta in vitro at a concentration of 1.0 μmol/L.The derivatives with monoacetyled at C-4 position showed higher vasorelaxant activity than the derivatives with diacetyled at C-3 and C-4 position.
A series of monoacetylated and diacetylated derivatives of trans-3-hydroxy-4-aminobenzopyran was synthesized from 3-acetyl-4-hydroxylbenzonitrile via condensation,reduction,epoxidation,amino addition and acetylation reaction.Their structures were confirmed by spectral data and elemental analysis.The preliminary bioassay suggested that synthesized compounds (7a~7d and 8a~8d) exhibited some K+ channel opening activity against contraction induced by 30 mmol/L KCl on rat aorta in vitro at a concentration of 1.0 μmol/L.The derivatives with monoacetyled at C-4 position showed higher vasorelaxant activity than the derivatives with diacetyled at C-3 and C-4 position.
2007, 24(6): 703-706
Abstract:
The competitive UV-Vis spectrophotometric method was performed in aqueous sodium carbonate and sodium bicarbonate buffer solution (pH=10.50,c=0.025 mol/L) at 30.0℃ to determine the inclusion of various mercaptan molecules by β-CD with phenolphthalein as a spectral probe.The results obtained indicate that β-CD could include different mercaptans to form the inclusion compounds.The inclusion stability constants of β-CD encapsulating 1-propanethiol,1-butanethiol,1-pentanethiol,1-hexanethiol,and 1-octanethiol were 28.71,66.39,127.8,186.2,and 651.1 L/mol,respectively,and the inclusion stability constants of β-CD encapsulating 2-methyl-1-propanethiol and 2-methyl-2-propanethiol were 364.6 and 641.9 L/mol,respectively.It was found that the inclusion ability of β-CD encapsulating normal mercaptans increases with the increase of the number of the carbon atom,and the inclusion ability of β-CD encapsulating isomercaptans increase with the increasing of the isomerization of mercaptans.The size matching between the host and the guest and the polarity of the guest have important effect on the inclusion.
The competitive UV-Vis spectrophotometric method was performed in aqueous sodium carbonate and sodium bicarbonate buffer solution (pH=10.50,c=0.025 mol/L) at 30.0℃ to determine the inclusion of various mercaptan molecules by β-CD with phenolphthalein as a spectral probe.The results obtained indicate that β-CD could include different mercaptans to form the inclusion compounds.The inclusion stability constants of β-CD encapsulating 1-propanethiol,1-butanethiol,1-pentanethiol,1-hexanethiol,and 1-octanethiol were 28.71,66.39,127.8,186.2,and 651.1 L/mol,respectively,and the inclusion stability constants of β-CD encapsulating 2-methyl-1-propanethiol and 2-methyl-2-propanethiol were 364.6 and 641.9 L/mol,respectively.It was found that the inclusion ability of β-CD encapsulating normal mercaptans increases with the increase of the number of the carbon atom,and the inclusion ability of β-CD encapsulating isomercaptans increase with the increasing of the isomerization of mercaptans.The size matching between the host and the guest and the polarity of the guest have important effect on the inclusion.
2007, 24(6): 707-711
Abstract:
A cyclic amino acid,N,N'-isopropylidene Asparagine[cAsn(acetone)],was synthesized via the reaction of L-asparagine with acetone in methanol in the presence of potassium hydroxide.Fmoc protected amino acids,Fmoc-Tyr (Bzl)-OH,Fmoc-Phe-OH,and Fmoc-Ala-OH were then allowed to react with cAsn(acetone) in DMF/CH2>Cl2 in the presence of 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide hydrochloride (EDCI) and 1-hydroxybenztriazole (HOBt) to give dipeptides Fmoc-Tyr (Bzl)-cAsn(acetone)-OH,Fmoc-Phe-cAsn(acetone)-OH and Fmoc-Ala-cAsn(acetone)-OH in yields of 35%,30% and 30% respectively.Further coupling of the dipeptide Fmoc-Tyr (Bzl)-cAsn(acetone)-OH with H-Phe-Phe-NH2 in the presence of EDCI and HOBt led to the formation of a tetrapeptide Fmoc-Tyr (Bzl)-cAsn(acetone)-Phe-Phe-NH2 in a yield of 70%.Deprotection of the Fmoc and Bzl groups on the tyrosine residue in the tetrapeptide with H2/Pd-C in acetic acid gave a novel analogue of endomorphin-2(H-Tyr-cAsn(acetone)-Phe-Phe-NH2) in a yield of 60%.1H NMR,IR,MS and HRMS were used to characterize the structures of the titled product and the intermediates.Antinociceptive activity of the tetrapeptide was assessed in acetic acid-induced abdominal constriction tests after i.p.injected in mouse with an inhibition rate of 45% at a dose of 2.4×10-5 g/Kg.
A cyclic amino acid,N,N'-isopropylidene Asparagine[cAsn(acetone)],was synthesized via the reaction of L-asparagine with acetone in methanol in the presence of potassium hydroxide.Fmoc protected amino acids,Fmoc-Tyr (Bzl)-OH,Fmoc-Phe-OH,and Fmoc-Ala-OH were then allowed to react with cAsn(acetone) in DMF/CH2>Cl2 in the presence of 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide hydrochloride (EDCI) and 1-hydroxybenztriazole (HOBt) to give dipeptides Fmoc-Tyr (Bzl)-cAsn(acetone)-OH,Fmoc-Phe-cAsn(acetone)-OH and Fmoc-Ala-cAsn(acetone)-OH in yields of 35%,30% and 30% respectively.Further coupling of the dipeptide Fmoc-Tyr (Bzl)-cAsn(acetone)-OH with H-Phe-Phe-NH2 in the presence of EDCI and HOBt led to the formation of a tetrapeptide Fmoc-Tyr (Bzl)-cAsn(acetone)-Phe-Phe-NH2 in a yield of 70%.Deprotection of the Fmoc and Bzl groups on the tyrosine residue in the tetrapeptide with H2/Pd-C in acetic acid gave a novel analogue of endomorphin-2(H-Tyr-cAsn(acetone)-Phe-Phe-NH2) in a yield of 60%.1H NMR,IR,MS and HRMS were used to characterize the structures of the titled product and the intermediates.Antinociceptive activity of the tetrapeptide was assessed in acetic acid-induced abdominal constriction tests after i.p.injected in mouse with an inhibition rate of 45% at a dose of 2.4×10-5 g/Kg.
2007, 24(6): 712-715
Abstract:
Conductive composite materials of polyaniline/PMMA were prepared via in situ Chemical-oxidative polymerization of aniline in the solution of PMMA dissolved in dimethyl benzene.The free-standing films of them were made through the evaporation of dimethyl benzene solvent.The electric conductivities of the films reached to 12 S/cm measured by the standard four-probe method.The factors affecting the polymerization were studied,and proper polymerization conditions were obtained.Some properties of the films were measured.
Conductive composite materials of polyaniline/PMMA were prepared via in situ Chemical-oxidative polymerization of aniline in the solution of PMMA dissolved in dimethyl benzene.The free-standing films of them were made through the evaporation of dimethyl benzene solvent.The electric conductivities of the films reached to 12 S/cm measured by the standard four-probe method.The factors affecting the polymerization were studied,and proper polymerization conditions were obtained.Some properties of the films were measured.
2007, 24(6): 716-719
Abstract:
A chelating starch containing multiple amidocyanogen and acyl groups was synthsized from starch grafted with methyl acrylate and ethylene diamine.The grafting degree and grafting efficiency for the grafted starch (SMA) were 44.14% and 18.42% respectively.The nitrogen content of the chelating starch determined by micro-Kjeldahl method was 2.86%.The structure of the chelating starch was determined by FTIR.This chelating starch was used to chelate copper (Ⅱ) and argentum (Ⅰ) ions,and thermal gravity analysis was used to determine the mass loss of the chelated starch before and after adsorption of the metal ions to estimate the adsorption capacities,which were 3.328 mmol/g and 1.667 mmol/g for Cu2+ and Ag+,respectively.
A chelating starch containing multiple amidocyanogen and acyl groups was synthsized from starch grafted with methyl acrylate and ethylene diamine.The grafting degree and grafting efficiency for the grafted starch (SMA) were 44.14% and 18.42% respectively.The nitrogen content of the chelating starch determined by micro-Kjeldahl method was 2.86%.The structure of the chelating starch was determined by FTIR.This chelating starch was used to chelate copper (Ⅱ) and argentum (Ⅰ) ions,and thermal gravity analysis was used to determine the mass loss of the chelated starch before and after adsorption of the metal ions to estimate the adsorption capacities,which were 3.328 mmol/g and 1.667 mmol/g for Cu2+ and Ag+,respectively.
2007, 24(6): 720-722
Abstract:
The extraction process of lappaconitine from the root of Aconitum sinomontanum Nakai,which is a special plant in GanSu province China,using 75% ethanol with a yield of 0.61% was described.The lappaconitine hydrobromide was synthesized in a new way,with a yield of 84%.The structures of extracted lappaconitine and the lappaconitine hydrobromide were characterized by IR,elemental analysis,1H NMR,13C NMR and MS.The results show that using 75% ethanol to extract lappaconitine gets over the problem which was brought by adding alkali traditionally.And in the lappaconitine hydrobromide preparation,the outgrowth and long reaction time were overcome by dibromine alkyl instead of hydrobromic acid.
The extraction process of lappaconitine from the root of Aconitum sinomontanum Nakai,which is a special plant in GanSu province China,using 75% ethanol with a yield of 0.61% was described.The lappaconitine hydrobromide was synthesized in a new way,with a yield of 84%.The structures of extracted lappaconitine and the lappaconitine hydrobromide were characterized by IR,elemental analysis,1H NMR,13C NMR and MS.The results show that using 75% ethanol to extract lappaconitine gets over the problem which was brought by adding alkali traditionally.And in the lappaconitine hydrobromide preparation,the outgrowth and long reaction time were overcome by dibromine alkyl instead of hydrobromic acid.
2007, 24(6): 723-725
Abstract:
A new cathode structure with two layers and small channels for air-breathing micro H2/air proton exchange membrane fuel cell (μPEMFC) was designed and fabricated with the microelectromechanical system (MEMS) technique.The use of such a new cathode not only reduces the volume and mass of the μPEMFC but also promotes the air distribution in cathode,thus making the maximum power density,volume power density and mass power density increased by 35.8%,53.3% and 76.5%,respectively.Moreover,the steady voltage of a μPEMFC with a new cathode at a discharge current density of 0.2 A/cm2 is higher than that with an old cathode at a discharge current density of 0.14 A/cm2.This investigation provides better insights into the development of air-breathing micro H2/air proton exchange membrane fuel cells with high performance.
A new cathode structure with two layers and small channels for air-breathing micro H2/air proton exchange membrane fuel cell (μPEMFC) was designed and fabricated with the microelectromechanical system (MEMS) technique.The use of such a new cathode not only reduces the volume and mass of the μPEMFC but also promotes the air distribution in cathode,thus making the maximum power density,volume power density and mass power density increased by 35.8%,53.3% and 76.5%,respectively.Moreover,the steady voltage of a μPEMFC with a new cathode at a discharge current density of 0.2 A/cm2 is higher than that with an old cathode at a discharge current density of 0.14 A/cm2.This investigation provides better insights into the development of air-breathing micro H2/air proton exchange membrane fuel cells with high performance.
2007, 24(6): 726-728
Abstract:
NiO-MgO nano-particles were successfully prepared by the hydrothermal method with NiSO4 and MgSO4 as raw material.Microstructure and morphology of the product were characterized by means of scan electron microscopy,X-ray diffraction and energy dispersive X-ray spectroscopy.The results show the particle has a sphere-like apparent structure,and the diameter of the particle is in a range of 10~40 nm.Compared with the particles prepared by the hydrothermal method,the microstructure and morphology of the sample sintered at 380℃ remain unchanged.When the sample is sintered at 690℃,the crystallization degree is improved,and the particles are well dispersed.The particles exhibited a high stability when used as catalyst.
NiO-MgO nano-particles were successfully prepared by the hydrothermal method with NiSO4 and MgSO4 as raw material.Microstructure and morphology of the product were characterized by means of scan electron microscopy,X-ray diffraction and energy dispersive X-ray spectroscopy.The results show the particle has a sphere-like apparent structure,and the diameter of the particle is in a range of 10~40 nm.Compared with the particles prepared by the hydrothermal method,the microstructure and morphology of the sample sintered at 380℃ remain unchanged.When the sample is sintered at 690℃,the crystallization degree is improved,and the particles are well dispersed.The particles exhibited a high stability when used as catalyst.
