Synthesis and kinetics of dichloro-methoxybenzenes were studied from 1,2,4-trichlorobenzene and sodium methoxide in a temperature range of 353--383 K. Effects of molar ratio of reactants, solvent and reaction temperat...Synthesis and kinetics of dichloro-methoxybenzenes were studied from 1,2,4-trichlorobenzene and sodium methoxide in a temperature range of 353--383 K. Effects of molar ratio of reactants, solvent and reaction temperature were investigated. Reaction products include three isomers. The order of selectivity for the three isomers was 1,4-dichloro-2-methoxybenzene〉〉2,4-dichoro-1-methoxybenzene〉,2-dichoro-4-methoxybenzene. Kinetic equations for the parallel liquid-solid interface reaction between 1,2,4-trichlorobenzene and sodium methoxide were established in the absence of catalyst. Kinetic parameters such as the pre-exponential factors and the activation energy were deter- mined with the Arrhenius equation.展开更多
The relation of boron trifluoride concentration with conductivity in boron trifluoride methanol solution(BF_3-CH_3OH)was power exponent fitted in low concentration range. The kinetics of the reaction between boron tri...The relation of boron trifluoride concentration with conductivity in boron trifluoride methanol solution(BF_3-CH_3OH)was power exponent fitted in low concentration range. The kinetics of the reaction between boron trifluoride methanol complex and sodium methoxide to produce enriched ^(10)B methylborate was proposed based on a detailed mechanism study, and was verified by acid-base titration method and conductivity method. It was found that this reaction is first order reaction and the rate constant is 0.022 min^(-1) at 338 K(65 ℃), the activity energy is 65 k J/mol. In addition, it was found that the conductivity method is more feasible to measure the kinetic curve than acid-base titration method.展开更多
Reduction of d-alkoxy enal 1 and 4 by sodium borohydride in methanol with a catalytic amount of magnesium methoxide gave unexpected methoxylated poducts 3 and 6 respectively.
(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R...(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R＇=i-Pr and sec-Bu. The crystallographic data of 7 and 8 are herebypresented.展开更多
The photopromoted carbonylation of bromobenzene with carbon monoxide catalyzed by inexpensive commercially available cobalt salts [Co（OAc）2, COCl2] was carried out under ambient conditions. The results revealed that...The photopromoted carbonylation of bromobenzene with carbon monoxide catalyzed by inexpensive commercially available cobalt salts [Co（OAc）2, COCl2] was carried out under ambient conditions. The results revealed that methyl benzoate was produced in the presence of basic additives （CH3ONa, NaOAc or （n-C4H9）3N）. The catalytic activity of Co（OAc）2 was higher than that of COCl2. Furthermore, the activity of the carbonylation was greatly improved by addition of acetophenone, e.g. both the yield and selectivity of the ester were increased from 47% to 91% with Co（OAc）2 as catalyst and CH3ONa as additive, while the yield of byproduct benzene from hydrodehalogenation of bromobenzene decreased from 32% to 8%.展开更多
High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the ...High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the transesterification of dimethyl carbonate(DMC)with ethylene glycol(EG)is provided in this work.However,this reaction is so fast that the reaction kinetics,which is essential for the industrial design,is hard to get by the traditional measuring method.In this work,an easy-to-assemble microreactor was used to precisely determine the reaction kinetics for the fast transesterification of DMC with EG using sodium methoxide as catalyst.The effects of flow rate,microreactor diameter,catalyst concentration,reaction temperature,and reactant molar ratio were investigated.An activity-based pseudohomogeneous kinetic model,which considered the non-ideal properties of reaction system,was established to describe the transesterification of DMC with EG.Detailed kinetics data were collected in the first 5 min.Using these data,the parameters of the kinetic model were correlated with the maximum average error of 11.19%.Using this kinetic model,the kinetic data at different catalyst concentrations and reactant molar ratios were predicted with the maximum average error of 13.68%,suggesting its satisfactory prediction performance.展开更多
A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxy...A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxybenzenes were obtained from the corresponding nitrobenzenes in the presence of NaOH in continuous flow. Compared to batch conditions, the reaction time was significantly shortened, and the chemical waste was reduced obviously.展开更多
文摘Synthesis and kinetics of dichloro-methoxybenzenes were studied from 1,2,4-trichlorobenzene and sodium methoxide in a temperature range of 353--383 K. Effects of molar ratio of reactants, solvent and reaction temperature were investigated. Reaction products include three isomers. The order of selectivity for the three isomers was 1,4-dichloro-2-methoxybenzene〉〉2,4-dichoro-1-methoxybenzene〉,2-dichoro-4-methoxybenzene. Kinetic equations for the parallel liquid-solid interface reaction between 1,2,4-trichlorobenzene and sodium methoxide were established in the absence of catalyst. Kinetic parameters such as the pre-exponential factors and the activation energy were deter- mined with the Arrhenius equation.
基金Supported by the Independent Innovation Fund of Tianjin University(No.1307)
文摘The relation of boron trifluoride concentration with conductivity in boron trifluoride methanol solution(BF_3-CH_3OH)was power exponent fitted in low concentration range. The kinetics of the reaction between boron trifluoride methanol complex and sodium methoxide to produce enriched ^(10)B methylborate was proposed based on a detailed mechanism study, and was verified by acid-base titration method and conductivity method. It was found that this reaction is first order reaction and the rate constant is 0.022 min^(-1) at 338 K(65 ℃), the activity energy is 65 k J/mol. In addition, it was found that the conductivity method is more feasible to measure the kinetic curve than acid-base titration method.
文摘Reduction of d-alkoxy enal 1 and 4 by sodium borohydride in methanol with a catalytic amount of magnesium methoxide gave unexpected methoxylated poducts 3 and 6 respectively.
文摘(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R＇=i-Pr and sec-Bu. The crystallographic data of 7 and 8 are herebypresented.
基金the Science and Technology Research Project for University of Liaoning Province(No.20060038)for the generous financial support.
文摘The photopromoted carbonylation of bromobenzene with carbon monoxide catalyzed by inexpensive commercially available cobalt salts [Co（OAc）2, COCl2] was carried out under ambient conditions. The results revealed that methyl benzoate was produced in the presence of basic additives （CH3ONa, NaOAc or （n-C4H9）3N）. The catalytic activity of Co（OAc）2 was higher than that of COCl2. Furthermore, the activity of the carbonylation was greatly improved by addition of acetophenone, e.g. both the yield and selectivity of the ester were increased from 47% to 91% with Co（OAc）2 as catalyst and CH3ONa as additive, while the yield of byproduct benzene from hydrodehalogenation of bromobenzene decreased from 32% to 8%.
基金support for this work from the National Natural Science Foundation of China(21706034)the Natural Science Foundation of Fujian Province(2021J01645)the Key Program of Qingyuan Innovation Laboratory(00221004).
文摘High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the transesterification of dimethyl carbonate(DMC)with ethylene glycol(EG)is provided in this work.However,this reaction is so fast that the reaction kinetics,which is essential for the industrial design,is hard to get by the traditional measuring method.In this work,an easy-to-assemble microreactor was used to precisely determine the reaction kinetics for the fast transesterification of DMC with EG using sodium methoxide as catalyst.The effects of flow rate,microreactor diameter,catalyst concentration,reaction temperature,and reactant molar ratio were investigated.An activity-based pseudohomogeneous kinetic model,which considered the non-ideal properties of reaction system,was established to describe the transesterification of DMC with EG.Detailed kinetics data were collected in the first 5 min.Using these data,the parameters of the kinetic model were correlated with the maximum average error of 11.19%.Using this kinetic model,the kinetic data at different catalyst concentrations and reactant molar ratios were predicted with the maximum average error of 13.68%,suggesting its satisfactory prediction performance.
基金This Science work was supported by the National Natural Foundation of China （Nos. 21502090, 21522604）, Natural Science Foundation of Jiangsu Province （Nos. BK20150942, BK20150031） and the National Key Basic Research Program of China （No. 2012CB725204）. We also thank the financial support from Top-notch Academic Programs Project of Jiangsu Higher Education Institutions （TAPP）.
文摘A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxybenzenes were obtained from the corresponding nitrobenzenes in the presence of NaOH in continuous flow. Compared to batch conditions, the reaction time was significantly shortened, and the chemical waste was reduced obviously.
