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2003 Volume 20 Issue 7
2003, 20(7): 613-617
Abstract:
A brief introduction is present on progresses in researches of inhibitors of pyruvate dehydrogenase complex(PDH) and the characteristic and function of PDH. Authors ongoing research works in this field are also introduced:an approach to design an inhibitor of pyruvate dehydrogenase with a novel structure by biochemical reasoning, α-(substituted phenoxy acetoxy) alkyl phosphonates with good herbicidal activities and a new kind of inhibitors of pyruvate dehydrogenase complex.
A brief introduction is present on progresses in researches of inhibitors of pyruvate dehydrogenase complex(PDH) and the characteristic and function of PDH. Authors ongoing research works in this field are also introduced:an approach to design an inhibitor of pyruvate dehydrogenase with a novel structure by biochemical reasoning, α-(substituted phenoxy acetoxy) alkyl phosphonates with good herbicidal activities and a new kind of inhibitors of pyruvate dehydrogenase complex.
2003, 20(7): 618-623
Abstract:
The synthesis of 1,1'-binaphthyl derivatives from 2-naphthol and analogues by direct oxidative coupling reaction using copper-amine complexes, copper sulfate, ferric salt and oxovanadium complexes as oxidants is reviewed. Some correlative mechanisms are discussed.
The synthesis of 1,1'-binaphthyl derivatives from 2-naphthol and analogues by direct oxidative coupling reaction using copper-amine complexes, copper sulfate, ferric salt and oxovanadium complexes as oxidants is reviewed. Some correlative mechanisms are discussed.
2003, 20(7): 624-628
Abstract:
2-Methylthio-5-pyrazolyl-1,3,4-oxadizole 1 was oxidized by KMnO4/HAc to give 2-methylsulfonyl-5-pyrazolyl-1,3,4-oxadiazole 2. Nucleophilic reaction of 2 with arylamines afforded the title compounds 2-arylamino-5-pyrazolyl-1,3,4-oxadiazoles 3. Structures of 2 and 3 were determined by elemental analysis, 1H NMR and mass spectrometry. The MS fragmentation patterns of compounds 2A and 2B were discussed. Bioassay showed that at a mass fraction of 0.005%, 2A and 2B inhibited Phoma asparagi by 40% and 60%. Compound 3A-5 and 3B-1 also have certain fungicidal activity.
2-Methylthio-5-pyrazolyl-1,3,4-oxadizole 1 was oxidized by KMnO4/HAc to give 2-methylsulfonyl-5-pyrazolyl-1,3,4-oxadiazole 2. Nucleophilic reaction of 2 with arylamines afforded the title compounds 2-arylamino-5-pyrazolyl-1,3,4-oxadiazoles 3. Structures of 2 and 3 were determined by elemental analysis, 1H NMR and mass spectrometry. The MS fragmentation patterns of compounds 2A and 2B were discussed. Bioassay showed that at a mass fraction of 0.005%, 2A and 2B inhibited Phoma asparagi by 40% and 60%. Compound 3A-5 and 3B-1 also have certain fungicidal activity.
2003, 20(7): 629-632
Abstract:
The reaction of Li(1-C5H9C9H6) and anhydrous YCl3 in 2:1 molar ratio in THF gave the anionic complex (C5H9C9H6)2-Y(μ-Cl)2Li(THF)2, which was characterized by elemental analysis, IR and X-ray crystal structural analysis. The crystal is orthorhombic with space group Pna2(1), a=1.648 2(7) nm, b=1.877 2(8) nm, c=1.131 7(5) nm, V=3.501(3) nm3, Z=4, Dc=1.285 Mg/m3, Mr=677.48, R=0.068 3 and Rw=0.114 3.
The reaction of Li(1-C5H9C9H6) and anhydrous YCl3 in 2:1 molar ratio in THF gave the anionic complex (C5H9C9H6)2-Y(μ-Cl)2Li(THF)2, which was characterized by elemental analysis, IR and X-ray crystal structural analysis. The crystal is orthorhombic with space group Pna2(1), a=1.648 2(7) nm, b=1.877 2(8) nm, c=1.131 7(5) nm, V=3.501(3) nm3, Z=4, Dc=1.285 Mg/m3, Mr=677.48, R=0.068 3 and Rw=0.114 3.
2003, 20(7): 633-637
Abstract:
The influence of ionic strength, kind of salt, concentration of extractant and initial pH value of water phase on the distribution coefficient of tryptophane(Trp) in the extraction process carried out in tri-n-octylmethylammonium chloride(TOMAC) system have been investigated. The results indicate that the distribution coefficient changes little with the increase of the ionic strength, when the latter is large enough. The difference in distribution coefficient obtained from experiments and theretical calculation has been analyzed, and an equation describing the relation between ionic strength and activity coefficient is obtained. The distribution coefficient of the Trp increases with increase of TOMAC concentration and initial pH value of water phase, but it is less affected when pH0 is>11. For salts of the same cation Na+, DCl->DBr-, and for salts of the same anion Cl-, DNa+>DK+.
The influence of ionic strength, kind of salt, concentration of extractant and initial pH value of water phase on the distribution coefficient of tryptophane(Trp) in the extraction process carried out in tri-n-octylmethylammonium chloride(TOMAC) system have been investigated. The results indicate that the distribution coefficient changes little with the increase of the ionic strength, when the latter is large enough. The difference in distribution coefficient obtained from experiments and theretical calculation has been analyzed, and an equation describing the relation between ionic strength and activity coefficient is obtained. The distribution coefficient of the Trp increases with increase of TOMAC concentration and initial pH value of water phase, but it is less affected when pH0 is>11. For salts of the same cation Na+, DCl->DBr-, and for salts of the same anion Cl-, DNa+>DK+.
2003, 20(7): 638-642
Abstract:
An agricultural film composed of LLDPE and nano-silica has been prepared and characterized by FTIR, UV-Vis spectrophotometry and haze value measurement. The film shows good ability to absorb infrared light ranged from 7 μm to 11 μm and ultraviolet below 300 nm. For example, the IR absorptivity of film containing 9.1%(mass fraction) nano-silica was 58%, nearly 3 times that of the pure LLDPE film. Increase of the content of nano-silica powder significantly led to the increase of the haze value of the film,but little changed the visible light transmittance. The surface-treatment method of nano-SiO2 has great influence on the optical properties of the composites film.
An agricultural film composed of LLDPE and nano-silica has been prepared and characterized by FTIR, UV-Vis spectrophotometry and haze value measurement. The film shows good ability to absorb infrared light ranged from 7 μm to 11 μm and ultraviolet below 300 nm. For example, the IR absorptivity of film containing 9.1%(mass fraction) nano-silica was 58%, nearly 3 times that of the pure LLDPE film. Increase of the content of nano-silica powder significantly led to the increase of the haze value of the film,but little changed the visible light transmittance. The surface-treatment method of nano-SiO2 has great influence on the optical properties of the composites film.
2003, 20(7): 643-646
Abstract:
Nine 3-(2-chloro-4-trifluoromethyl phenoxy)-N-heterocycle benzamides were synthesized and characterized by IR, 1H NMR, MS and elemental analysis. Their plant growth regulation activities were examined on wheat and cucumber seedling. The compound 4e exhibited high growth stimulating activity towards cucumber at dosage of 10 μg/g.
Nine 3-(2-chloro-4-trifluoromethyl phenoxy)-N-heterocycle benzamides were synthesized and characterized by IR, 1H NMR, MS and elemental analysis. Their plant growth regulation activities were examined on wheat and cucumber seedling. The compound 4e exhibited high growth stimulating activity towards cucumber at dosage of 10 μg/g.
2003, 20(7): 647-650
Abstract:
The titanate solution has been prepared by dissolving ilmenite in sulfuric acid. A composite crystal seed was obtained from titanate solution and stannous dichloride in the course of hydrolysis of titanate solution under atmosphere pressure, using stannic oxide(7.0% in mass fraction) as an accelerant. Thus the temperature of crystal phase transition from anatase to rutile titania was decreased to 870℃, the time for complete phase transition was shortened evidently. It was also found that introducing 0.5%(mass fraction) zinc ions in the salt treatment process could further shorten the phase transition time.
The titanate solution has been prepared by dissolving ilmenite in sulfuric acid. A composite crystal seed was obtained from titanate solution and stannous dichloride in the course of hydrolysis of titanate solution under atmosphere pressure, using stannic oxide(7.0% in mass fraction) as an accelerant. Thus the temperature of crystal phase transition from anatase to rutile titania was decreased to 870℃, the time for complete phase transition was shortened evidently. It was also found that introducing 0.5%(mass fraction) zinc ions in the salt treatment process could further shorten the phase transition time.
2003, 20(7): 651-654
Abstract:
The appropriate conditions of the hydrolysis of polysuccinimide determined by means of an orthogonal experimental design were 2 mol/L NaOH(in water), 0.45~0.48 g NaOH/g polysuccinimide, 50~90℃ and 30 min. The effects of temperature, time, concentration and amount of NaOH on the scale inhibition capacity and molecular weight(Mw) of the hydrolysis products were investigated. The polymers were characterized by IR, 13C NMR, 1H NMR and TG-DTA. The reaction temperature is all important affecting the molecular weight of the product and the kinetics of hydrolysis reaction is deduced to be a 2nd order cascade type reaction.
The appropriate conditions of the hydrolysis of polysuccinimide determined by means of an orthogonal experimental design were 2 mol/L NaOH(in water), 0.45~0.48 g NaOH/g polysuccinimide, 50~90℃ and 30 min. The effects of temperature, time, concentration and amount of NaOH on the scale inhibition capacity and molecular weight(Mw) of the hydrolysis products were investigated. The polymers were characterized by IR, 13C NMR, 1H NMR and TG-DTA. The reaction temperature is all important affecting the molecular weight of the product and the kinetics of hydrolysis reaction is deduced to be a 2nd order cascade type reaction.
2003, 20(7): 655-659
Abstract:
A series of initiator systems have been selected in order to realize the stable polymerization of acrylates in inverse or bicontinuous microemulsions. The micro-structures of transparent polymer prepared were analyzed. The results showed that transparent polymer gels with close-cell structure could be obtained by inverse microemulsion polymerization initiated with AIBN. Another transparent gels with open-cell structure could be obtained by bicontinuous microemulsion polymerization using potassium permanganate-oxalic acid redox system as initiator. The polymerization was fast and considerably stable using the redox initiator. The ESEM micrographs showed a certain relationship between the original structure of microemulsions and the structure of the polymer gels obtained. The mechanism of initiation reaction was discussed briefly.
A series of initiator systems have been selected in order to realize the stable polymerization of acrylates in inverse or bicontinuous microemulsions. The micro-structures of transparent polymer prepared were analyzed. The results showed that transparent polymer gels with close-cell structure could be obtained by inverse microemulsion polymerization initiated with AIBN. Another transparent gels with open-cell structure could be obtained by bicontinuous microemulsion polymerization using potassium permanganate-oxalic acid redox system as initiator. The polymerization was fast and considerably stable using the redox initiator. The ESEM micrographs showed a certain relationship between the original structure of microemulsions and the structure of the polymer gels obtained. The mechanism of initiation reaction was discussed briefly.
2003, 20(7): 660-663
Abstract:
The fluorescence and resonance scattering spectra of Tris-HCl-acetone (or ethanol)-HSA(human serum albumin) system(pH=7.4) were studied by a double-cell method. The results demonstrate the fluorescence quenching effect of acetone on the HSA system at 325 nm primarily due to the molecular absorption of acetone. The fluorescence intensity of HSA system at 325 nm was observerved enhanced by addition of ethanol. It could be explained in term of the destruction of high structures of HSA by ethanol and the formation of H-bondings from Trp exposed on the HSA surface. The destructed HSA species could be congregated in NaAC-HAC buffer solution of pH=4.8, when the concentration of acetone is >30% or that of ethanol is>40%. The congregation of HSA hurriedly enhances the resonance scattering intensity of the system at 470 nm.
The fluorescence and resonance scattering spectra of Tris-HCl-acetone (or ethanol)-HSA(human serum albumin) system(pH=7.4) were studied by a double-cell method. The results demonstrate the fluorescence quenching effect of acetone on the HSA system at 325 nm primarily due to the molecular absorption of acetone. The fluorescence intensity of HSA system at 325 nm was observerved enhanced by addition of ethanol. It could be explained in term of the destruction of high structures of HSA by ethanol and the formation of H-bondings from Trp exposed on the HSA surface. The destructed HSA species could be congregated in NaAC-HAC buffer solution of pH=4.8, when the concentration of acetone is >30% or that of ethanol is>40%. The congregation of HSA hurriedly enhances the resonance scattering intensity of the system at 470 nm.
2003, 20(7): 664-667
Abstract:
Five solid complexes of phenyl-phenacyl sulfoxide(L) with light rare earth perchlorate have been synthesized and characterized. Elemental analysis and TG-DTA results suggested the complexes have a composition of RE(ClO4)3·L5·2H2O(RE=La,Pr,Nd,Sm,Eu). IR and 1H NMR spectra results indicated that the ligand is bonded with RE(Ⅲ) ions through one oxygen atom of carbonyl group and one oxygen atom of sulfoxyl group. The molar conductivies and IR data indicated that only two anions ClO4- are in coordination. The ligand in Eu3+ complex showed a sensitization effect on the fluorescence of RE3+.
Five solid complexes of phenyl-phenacyl sulfoxide(L) with light rare earth perchlorate have been synthesized and characterized. Elemental analysis and TG-DTA results suggested the complexes have a composition of RE(ClO4)3·L5·2H2O(RE=La,Pr,Nd,Sm,Eu). IR and 1H NMR spectra results indicated that the ligand is bonded with RE(Ⅲ) ions through one oxygen atom of carbonyl group and one oxygen atom of sulfoxyl group. The molar conductivies and IR data indicated that only two anions ClO4- are in coordination. The ligand in Eu3+ complex showed a sensitization effect on the fluorescence of RE3+.
2003, 20(7): 668-671
Abstract:
Nanosized SO42-/Ce-TiO2 particles have been prepared from Ti(OBu)4、Ce(NO3)3 and H2SO4 by a sol-gel method followed by calcination at 500℃ and characterized by XRD、IR、BET、XPS and TG-DTA technologies. The SO42-/Ce-TiO2 obtained mainly comsisted of anatase TiO2 with a solid superacid character. The catalytic activity of SO42-/Ce-TiO2(ratio of Ce to TiO2 was 0.5% and impregnated with H2SO4 solution(0.5 mol/L)) in photodegradation on dimethyl dichlorovinyl phosphate(DDVP) was much higher than that of Ce-TiO2 under the same reaction conditions.
Nanosized SO42-/Ce-TiO2 particles have been prepared from Ti(OBu)4、Ce(NO3)3 and H2SO4 by a sol-gel method followed by calcination at 500℃ and characterized by XRD、IR、BET、XPS and TG-DTA technologies. The SO42-/Ce-TiO2 obtained mainly comsisted of anatase TiO2 with a solid superacid character. The catalytic activity of SO42-/Ce-TiO2(ratio of Ce to TiO2 was 0.5% and impregnated with H2SO4 solution(0.5 mol/L)) in photodegradation on dimethyl dichlorovinyl phosphate(DDVP) was much higher than that of Ce-TiO2 under the same reaction conditions.
2003, 20(7): 672-675
Abstract:
A charge-transfer complex, [(CH3)2NH2]3[HSiMo12O40]·2DMF·4H2O, has been synthesized and characterized. The crystal structure of the complex obtained in mixed solvent of acetonitrile and water has been determined by single crystal X-ray diffractometry. It is triclinic lattice, space group Pī, with a=1.210 1(2) nm, b=1.498 6(3) nm, c=1.499 2(3) nm, α=83.59(3)°, β=86.88(3)°, γ=87.09(3)°, V=2.694 9(9) nm3, Dc=2.683 9 g/cm3, Z=2 and R=0.031 0.
A charge-transfer complex, [(CH3)2NH2]3[HSiMo12O40]·2DMF·4H2O, has been synthesized and characterized. The crystal structure of the complex obtained in mixed solvent of acetonitrile and water has been determined by single crystal X-ray diffractometry. It is triclinic lattice, space group Pī, with a=1.210 1(2) nm, b=1.498 6(3) nm, c=1.499 2(3) nm, α=83.59(3)°, β=86.88(3)°, γ=87.09(3)°, V=2.694 9(9) nm3, Dc=2.683 9 g/cm3, Z=2 and R=0.031 0.
2003, 20(7): 676-679
Abstract:
An epoxy silane, a new kind of ambient temperature crosslinker for acrylate copolymer soap-free hydrosol is introduced. Some factors affecting the stability of the microemulsion such as kind and content of emulsifiers, content of KH-560 have been studied. When ω(OP-10)=5% and ω(KH-560)=40%, a stable microemulsion is obtained. The shelf stability of curable emulsion comprising of hydrosol is longer than 6 months at room temperature(content of microemulsion is 5%), crosslinking degree of the film is 93% and the film has good resistance to water(swelling ratio decreases by 83%) swelling ratio of 115% in toluene.
An epoxy silane, a new kind of ambient temperature crosslinker for acrylate copolymer soap-free hydrosol is introduced. Some factors affecting the stability of the microemulsion such as kind and content of emulsifiers, content of KH-560 have been studied. When ω(OP-10)=5% and ω(KH-560)=40%, a stable microemulsion is obtained. The shelf stability of curable emulsion comprising of hydrosol is longer than 6 months at room temperature(content of microemulsion is 5%), crosslinking degree of the film is 93% and the film has good resistance to water(swelling ratio decreases by 83%) swelling ratio of 115% in toluene.
2003, 20(7): 680-683
Abstract:
The solubilization of n-butanol, n-pentanol, n-hexanol, benzyl alcohol, n-hexane, benzene, toluene and carbon tetrachloride in the aqueous solutions of 3-alkoxyl-2-hydroxylpropyltrimethyl ammonium chloride(RnTAC), sodium dodecyl sulfate(SDS) and their mixtures have been studied by microtitration method. The experimental results show that the solubilizing ability of the mixture system for polar substances is lower than that of the single surfactant aqueous solution. "V"-shaped solubilization curves for polar substances have been observed, and the minimum solubilized amount occurs in the mixture with molar ratio of R14TAC/SDS=1:1. However, the solubilization curves of R14TAC/SDS for non-polar substances show a saddle shape and the maximum solubilized amount occurs when their molar ratio is of 1:1. The phase transfer free energy for organic compounds from aqueous phase to micelle phase is found dependent on their polarity and chain length of RnTAC and the less the polarity of organic compound, the easier for it to transfer from aqueous phase to micelle phase.
The solubilization of n-butanol, n-pentanol, n-hexanol, benzyl alcohol, n-hexane, benzene, toluene and carbon tetrachloride in the aqueous solutions of 3-alkoxyl-2-hydroxylpropyltrimethyl ammonium chloride(RnTAC), sodium dodecyl sulfate(SDS) and their mixtures have been studied by microtitration method. The experimental results show that the solubilizing ability of the mixture system for polar substances is lower than that of the single surfactant aqueous solution. "V"-shaped solubilization curves for polar substances have been observed, and the minimum solubilized amount occurs in the mixture with molar ratio of R14TAC/SDS=1:1. However, the solubilization curves of R14TAC/SDS for non-polar substances show a saddle shape and the maximum solubilized amount occurs when their molar ratio is of 1:1. The phase transfer free energy for organic compounds from aqueous phase to micelle phase is found dependent on their polarity and chain length of RnTAC and the less the polarity of organic compound, the easier for it to transfer from aqueous phase to micelle phase.
2003, 20(7): 684-686
Abstract:
2-Mercapto benzoxazole reacted with alkyl halide or N-substituted-2-chloroacetamides gave corresponding 2-alkylthiobenzoxazoles(2a~2h) and benzoxazole-2-ylthio-acetanilides (3a~3g) respectively. The structures of all the above compounds were confirmed by 1H NMR, IR and elemental analysis. Results showed that only compound 2g exhibited favorable fungicidal activity against Puccinia triticina(90%) in vivo at dosage of 500 mg/L; compounds 3a~3g exhibited inhibitory activity to Echinochloa oryzicola V and Brassica campestris L at the dosage of 150 mg/m2.
2-Mercapto benzoxazole reacted with alkyl halide or N-substituted-2-chloroacetamides gave corresponding 2-alkylthiobenzoxazoles(2a~2h) and benzoxazole-2-ylthio-acetanilides (3a~3g) respectively. The structures of all the above compounds were confirmed by 1H NMR, IR and elemental analysis. Results showed that only compound 2g exhibited favorable fungicidal activity against Puccinia triticina(90%) in vivo at dosage of 500 mg/L; compounds 3a~3g exhibited inhibitory activity to Echinochloa oryzicola V and Brassica campestris L at the dosage of 150 mg/m2.
2003, 20(7): 687-689
Abstract:
The acid-alkali titration method of determination of degree of substitution(DS) for starch acetates has been improved by using acetone as solvent instead of ethanol. The saponification time could be reduced from 48 h or 72 h(using ethanol as solvent) to 1 h with acetone as solvent, and the RSD also decreased. The method has advantages of rapidity and high accuracy.
The acid-alkali titration method of determination of degree of substitution(DS) for starch acetates has been improved by using acetone as solvent instead of ethanol. The saponification time could be reduced from 48 h or 72 h(using ethanol as solvent) to 1 h with acetone as solvent, and the RSD also decreased. The method has advantages of rapidity and high accuracy.
2003, 20(7): 690-692
Abstract:
C12-6-C12·2Br violently interacts with sodium dodecyl sulfate(SDS) leading to the formation of mixed micelles. When molar fraction(x2) of C12-6-C12·2Br in the bulk solution was 10.0%, the total critical micelle concentration(cmcT) of the mixed solution was found to be 0.043 7 mmol/L, and the micelle aggregation number NT and the molar fraction(x2M) of C12-6-C12·2Br in the mixed micelle were 17.4 and 49.0%, respectively. With x2 increased to 16.7%, cmcT further decreased and NT gradually increased, but x2M almost remained unchanged. The average value of the interaction parameter(βM) calculated by the theory of regular solution equals to -33.3.
C12-6-C12·2Br violently interacts with sodium dodecyl sulfate(SDS) leading to the formation of mixed micelles. When molar fraction(x2) of C12-6-C12·2Br in the bulk solution was 10.0%, the total critical micelle concentration(cmcT) of the mixed solution was found to be 0.043 7 mmol/L, and the micelle aggregation number NT and the molar fraction(x2M) of C12-6-C12·2Br in the mixed micelle were 17.4 and 49.0%, respectively. With x2 increased to 16.7%, cmcT further decreased and NT gradually increased, but x2M almost remained unchanged. The average value of the interaction parameter(βM) calculated by the theory of regular solution equals to -33.3.
2003, 20(7): 693-695
Abstract:
Salicylaldehyde thiodiacylhydrazone(STZ), 5-bromosalicylaldehyde thiodiacyl hydrazone(BSTZ) and their Cu(Ⅱ) complexes:STZ(Cu)2 and BSTZ(Cu)2 were synthesized. The structures of the ligands and complexes were characterized by elemental analysis, IR, 1H NMR and UV spectroscopy. The bacteriostatic test showed that the ligands were more bioactive than the complexes.
Salicylaldehyde thiodiacylhydrazone(STZ), 5-bromosalicylaldehyde thiodiacyl hydrazone(BSTZ) and their Cu(Ⅱ) complexes:STZ(Cu)2 and BSTZ(Cu)2 were synthesized. The structures of the ligands and complexes were characterized by elemental analysis, IR, 1H NMR and UV spectroscopy. The bacteriostatic test showed that the ligands were more bioactive than the complexes.
2003, 20(7): 696-698
Abstract:
The key intermediates of the sex pheromone of the pine sawfly 2-methyl-octanol and 2-methyl-decanol were synthesized from n-octanol and n-decanol sucessively via the oxidation with pyridinium chlorochromate(PCC), Mannich reaction, catalytic transferhydrogenation over Pd/C and reduction by LiAlH4 in the total yield of 23.4% and 38.8%, respectively. Using acetic acid as solvent of pH=7, the yield of α-hexyl-acrolein in Mannich reaction was up to 70.1% in the optimized condition. 2-Methyl-dodecanol was similarly synthesized with the same procedure in the total yield of 48.2%.
The key intermediates of the sex pheromone of the pine sawfly 2-methyl-octanol and 2-methyl-decanol were synthesized from n-octanol and n-decanol sucessively via the oxidation with pyridinium chlorochromate(PCC), Mannich reaction, catalytic transferhydrogenation over Pd/C and reduction by LiAlH4 in the total yield of 23.4% and 38.8%, respectively. Using acetic acid as solvent of pH=7, the yield of α-hexyl-acrolein in Mannich reaction was up to 70.1% in the optimized condition. 2-Methyl-dodecanol was similarly synthesized with the same procedure in the total yield of 48.2%.
2003, 20(7): 699-701
Abstract:
A simultaneously potentiometric titration method for determinating benzaldehyde and benzoic acid in electrosynthesis product is reported. The interferences from benzyl alcohol and toluene were examined. The determination method has advantages of high precision, good reproducibility, easiness in operation and rapidity. The RSD and recovery of benzaldehyde and benzoic acid in synthesis sample is 0.33%, 1.30% and 97.76%, 101.27%, repectively.
A simultaneously potentiometric titration method for determinating benzaldehyde and benzoic acid in electrosynthesis product is reported. The interferences from benzyl alcohol and toluene were examined. The determination method has advantages of high precision, good reproducibility, easiness in operation and rapidity. The RSD and recovery of benzaldehyde and benzoic acid in synthesis sample is 0.33%, 1.30% and 97.76%, 101.27%, repectively.
2003, 20(7): 702-703
Abstract:
The selective bromination of paeonol (4-methoxy-2-hydroxyacetophenone) has been studied as function of solvents(methanol, ethanol, chloroform-ethyl acetate), reaction time, temperature and the mole ratio of reagents. The higher yield was obtained in polar solvents than in non-polar ones. The best solvent appeared methanol, and the mixtures of polar solvents were better than any single of them, except methanol. Paeonol and cupric bromide in mole ratio of 1:2 in methanol under reflux temperature for five hours gave a bromination product in yield of 63.3%.
The selective bromination of paeonol (4-methoxy-2-hydroxyacetophenone) has been studied as function of solvents(methanol, ethanol, chloroform-ethyl acetate), reaction time, temperature and the mole ratio of reagents. The higher yield was obtained in polar solvents than in non-polar ones. The best solvent appeared methanol, and the mixtures of polar solvents were better than any single of them, except methanol. Paeonol and cupric bromide in mole ratio of 1:2 in methanol under reflux temperature for five hours gave a bromination product in yield of 63.3%.
2003, 20(7): 704-705
Abstract:
Eight 4-arylidene-2-phenyloxazol-5-ones were synthesized by reaction of aromatic aldehydes and hippuric acid under ultrasonic irradiation in the absence of catalyst. The reaction was completed in 30~40 min in high yield. The structures of the products were characterized by IR and 1H NMR.
Eight 4-arylidene-2-phenyloxazol-5-ones were synthesized by reaction of aromatic aldehydes and hippuric acid under ultrasonic irradiation in the absence of catalyst. The reaction was completed in 30~40 min in high yield. The structures of the products were characterized by IR and 1H NMR.
2003, 20(7): 706-708
Abstract:
The preparation procedure of benzylpenicillin sulfoxide p-methoxybenzyl ester by esterificating penicillin G potassium salt and following oxidizing the corresponding benzylpenicillin ester is described. The method using the only reactive solvent minimizes the kinds of solvents and decreases the volume of solvents, which facilitates technical procedures and reduces the cost.
The preparation procedure of benzylpenicillin sulfoxide p-methoxybenzyl ester by esterificating penicillin G potassium salt and following oxidizing the corresponding benzylpenicillin ester is described. The method using the only reactive solvent minimizes the kinds of solvents and decreases the volume of solvents, which facilitates technical procedures and reduces the cost.
2003, 20(7): 709-711
Abstract:
The vermiculite(VMT) was treated at high temperature or by microwave and modified by treatment with different intercalaling agents:reagent A, which was synthesised in our lab, hexadecyl trimethyl ammonium chloride and octadecylamine to give organo-vermiculite(OVMT). The polyethylene terephthalate(PET)/vermiculite composite was obtained from OVMT with in situ polymerized PET. The cation exchange capacity of VMT was found increased apparently after chemical treatments. The spacing of layers in VMT was increased to 4.65 nm after intercalation with different organic reagents. The structure of PET/VMT nanocomposites synthesized was studied by FTIR、XRD and TEM. The DSC results showed that the PET/VMT nanocomposite has Tg of 137.16℃ and melting point of 235.76℃.
The vermiculite(VMT) was treated at high temperature or by microwave and modified by treatment with different intercalaling agents:reagent A, which was synthesised in our lab, hexadecyl trimethyl ammonium chloride and octadecylamine to give organo-vermiculite(OVMT). The polyethylene terephthalate(PET)/vermiculite composite was obtained from OVMT with in situ polymerized PET. The cation exchange capacity of VMT was found increased apparently after chemical treatments. The spacing of layers in VMT was increased to 4.65 nm after intercalation with different organic reagents. The structure of PET/VMT nanocomposites synthesized was studied by FTIR、XRD and TEM. The DSC results showed that the PET/VMT nanocomposite has Tg of 137.16℃ and melting point of 235.76℃.
2003, 20(7): 712-714
Abstract:
In the presence of solid base catalyst KF-Al2O3, 2-methylbenzothiazole was condensated with aromatic aldehydes in DMF to give 2-styrylbenzothiazoles in yields of 80% to 92%. The maxinum absorption frequencies of the ultraviolet spectra in sixteen organic solvents finely correlate with the Hammett's substituent coefficients.
In the presence of solid base catalyst KF-Al2O3, 2-methylbenzothiazole was condensated with aromatic aldehydes in DMF to give 2-styrylbenzothiazoles in yields of 80% to 92%. The maxinum absorption frequencies of the ultraviolet spectra in sixteen organic solvents finely correlate with the Hammett's substituent coefficients.
