Enantiomerically pure syn-4,5-dihydroxy carboxylic acid lactones were prepared by microbial reduction of acyl lactones with resting cell of Aspergillus niger.
Enantiomerically pure a-substituted bamino esters were prepared from natural L-a-amino acids through Arndt-Eistert homologation and diastereoselective aalkylation.
In this study, the kinetics of isopropyl palmitate synthesis including the reaction mechanism was studied based on the two-step noncatalytic method. The liquid-phase diffusion effect on the reaction process was elimin...In this study, the kinetics of isopropyl palmitate synthesis including the reaction mechanism was studied based on the two-step noncatalytic method. The liquid-phase diffusion effect on the reaction process was eliminated by adjusting the stirring rate. The results showed that the two-step reaction followed a tetrahedral mechanism and conformed to second-order reaction kinetics. Nucleophilic attack on the carbonyl carbon afforded an intermediate, containing a tetrahedral carbon center. The intermediate ultimately decomposed by elimination of the leaving group, affording isopropyl palmitate. The experimental data were analyzed at different temperatures by the integral method. The kinetic equations of the each step were deduced, and the activation energy and frequency factor were obtained. Experiments were performed to verify the feasibility of kinetic equations, and the result showed that the kinetic equations were reliable. This study could be very signi ficant to both industrial application and determining the continuous production of isopropyl palmitate.展开更多
A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coat...A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coated on ceramic tiles and fired at 900 ℃ to fabricate photocatalytic ceramic. Experimental results show that anatase TiO2 in the composite powder has high thermal stability until 1 200 ℃. ZrSiO4 matrix prevents the mass transfer of anatase TiO2 at high temperature and greatly retards the phase transition of anatase to rutile. Besides, the photocatalytic ceramic shows apparent activities for the degradation of methyl orange under ultra-violet irradiation.展开更多
Oxidation of perfluoroalkanesulfinate usually resulted in the formation of the correspon-ding sulfonyl derivatives,thus reaction with hydrogen peroxide or halogen（Cl,Br,I）gavesulfonic acid or sulfonyl halides.Howeve...Oxidation of perfluoroalkanesulfinate usually resulted in the formation of the correspon-ding sulfonyl derivatives,thus reaction with hydrogen peroxide or halogen（Cl,Br,I）gavesulfonic acid or sulfonyl halides.However in comparison with alkanesulfinate the perfluo-ro analog was shown to be relatively inert toward oxidizing agents.展开更多
Chemical or electrochemical oxidation of N-benzylaniline in perehloric acid solution yields a highly colored polymer——poly-N-benzylaniline (PBAn).The polymer has good solubility in a num- ber of organic solvents in ...Chemical or electrochemical oxidation of N-benzylaniline in perehloric acid solution yields a highly colored polymer——poly-N-benzylaniline (PBAn).The polymer has good solubility in a num- ber of organic solvents in either acid or base form.At room temperature,conductivity measurements on pressed pellets of the acid form PBAn give a conductivity of 9.3×10^(-6) S·cm^(-1).The soluble polymer was analyzed using a variety of common experimental techniques including UV-vis,IR,NMR,ESR spectroscopy,elemental analysis and electrochemieal analysis.All experimental results showed that PBAn has a structure similar to polyaniline with the elimination of some benzyl groups.展开更多
文摘Enantiomerically pure syn-4,5-dihydroxy carboxylic acid lactones were prepared by microbial reduction of acyl lactones with resting cell of Aspergillus niger.
基金The project is generously supported by the National Natural Science Foundation of China (Grant No. 29972002 20172002)+1 种基金 the Trans-Century Training Programme Foundation for the Talents by Ministry of Education and Bayer Co. Ltd (Germany). We thank Dr
文摘Enantiomerically pure a-substituted bamino esters were prepared from natural L-a-amino acids through Arndt-Eistert homologation and diastereoselective aalkylation.
文摘In this study, the kinetics of isopropyl palmitate synthesis including the reaction mechanism was studied based on the two-step noncatalytic method. The liquid-phase diffusion effect on the reaction process was eliminated by adjusting the stirring rate. The results showed that the two-step reaction followed a tetrahedral mechanism and conformed to second-order reaction kinetics. Nucleophilic attack on the carbonyl carbon afforded an intermediate, containing a tetrahedral carbon center. The intermediate ultimately decomposed by elimination of the leaving group, affording isopropyl palmitate. The experimental data were analyzed at different temperatures by the integral method. The kinetic equations of the each step were deduced, and the activation energy and frequency factor were obtained. Experiments were performed to verify the feasibility of kinetic equations, and the result showed that the kinetic equations were reliable. This study could be very signi ficant to both industrial application and determining the continuous production of isopropyl palmitate.
基金Funded by the Guangdong Provincial Science and technology project(2010A090200040)the Foundation for Distinguished Young Talents in Higher Education of Guangdong Province(LYM10017)
文摘A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coated on ceramic tiles and fired at 900 ℃ to fabricate photocatalytic ceramic. Experimental results show that anatase TiO2 in the composite powder has high thermal stability until 1 200 ℃. ZrSiO4 matrix prevents the mass transfer of anatase TiO2 at high temperature and greatly retards the phase transition of anatase to rutile. Besides, the photocatalytic ceramic shows apparent activities for the degradation of methyl orange under ultra-violet irradiation.
文摘Oxidation of perfluoroalkanesulfinate usually resulted in the formation of the correspon-ding sulfonyl derivatives,thus reaction with hydrogen peroxide or halogen（Cl,Br,I）gavesulfonic acid or sulfonyl halides.However in comparison with alkanesulfinate the perfluo-ro analog was shown to be relatively inert toward oxidizing agents.
基金the National Natural Science Foundation of China
文摘Chemical or electrochemical oxidation of N-benzylaniline in perehloric acid solution yields a highly colored polymer——poly-N-benzylaniline (PBAn).The polymer has good solubility in a num- ber of organic solvents in either acid or base form.At room temperature,conductivity measurements on pressed pellets of the acid form PBAn give a conductivity of 9.3×10^(-6) S·cm^(-1).The soluble polymer was analyzed using a variety of common experimental techniques including UV-vis,IR,NMR,ESR spectroscopy,elemental analysis and electrochemieal analysis.All experimental results showed that PBAn has a structure similar to polyaniline with the elimination of some benzyl groups.
