Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,prov...Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,providing a wide variety of corresponding linear carboxylic esters bearing various functional groups in good yields and>20:1 linear/branch ratios.The reaction is optionally simple and does not need to use CO gas and acid co-catalysts.展开更多
Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The ...Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The effect of reaction temperature, CO pressure, methanol dosage, catalyst dosage and reaction time on catalytic reaction was investigated. The test results revealed that this reaction was greatly affected by reaction temperature, but it was not significantly affected by the CO pressure, the methanol dosage, the catalyst dosage and the reaction time. Under the optimal conditions, the conversion of ethylene oxide was equal to 92.24%, while the selectivity and yield of methyl 3-hydroxypropanoate reached 88.99% and 84.35%, respectively.展开更多
This paper assesses the hydroesterification process for the production of Biodiesel from Monoraphidium contortum (MORF-1) microalgae biomass, as it is a sustainable alternative not only economically, but also environm...This paper assesses the hydroesterification process for the production of Biodiesel from Monoraphidium contortum (MORF-1) microalgae biomass, as it is a sustainable alternative not only economically, but also environmentally and ecologically to replace petroleum diesel fuel. The Biodiesel studied in this work was obtained from fatty acid esterification, a product of microalgae and methanol biomass hydrolysis reaction. CBMM’s (HY-340) niobium oxide powder was used as catalyst. The reactions were carried out in a properly closed autoclave reactor (batch), where the reagents were mixed under constant stirring at 500 rpm for hydrolysis and esterification. The products generated were submitted to gas chromatography and oxidative stability analysis. The hydroesterification process showed itself to be a promising alternative to the conventional biodiesel production process (transesterification) as it favors the use of feedstocks with any acidity and moisture content and may be performed with acid catalyst, which favors high conversions in a small range of time (30 minutes).展开更多
In this paper, sodium cobalt tetracarbonyl （NaCo（CO）4） was synthesized by using sodium dithionite and zinc powder as the reduction system and cobalt hexahydrate acetate as the precursor in the presence of methanol...In this paper, sodium cobalt tetracarbonyl （NaCo（CO）4） was synthesized by using sodium dithionite and zinc powder as the reduction system and cobalt hexahydrate acetate as the precursor in the presence of methanol solvent. Methyl 3-hydroxypropionate was synthesized via hydroesterification of ethylene oxide （EO） catalyzed by NaCo（CO）4. The influencing factors on the reaction results were discussed, including the different ligands, the molar ratio of solvent and ethylene oxide, the reaction temperature, the reaction time, and the reaction pressure. An optimal catalytic system was obtained by using 3-hydroxypyridine as the ligoad under reaction conditions covering a reaction temperature 65 ℃, a reaction time of 7 h, a reaction pressure of 6 MPa, and a methoaol/EO molar ratio of 3：2. Under the optimal conditions, the conversion of ethylene oxide was equal to 97.86%, while the selectivity and yield of methyl 3-hydroxypropionate reached 88.19% and 86.30%, respectively. Finally, the reaction mechanism of hydroesterification of ethylene oxide catalyzed by NaCo（CO）4 was proposed.展开更多
Polymer-supported bimetallic system of PdCl2-4NiCl2-PPH3/PVP [PVP= poly(N-vinyl-2-pyrrolidone)] provided an almost regiospecific conversion of styrene to thebranched methyl 2-propionate at a high conversion. Typical r...Polymer-supported bimetallic system of PdCl2-4NiCl2-PPH3/PVP [PVP= poly(N-vinyl-2-pyrrolidone)] provided an almost regiospecific conversion of styrene to thebranched methyl 2-propionate at a high conversion. Typical reaction conditions are: 353 K,2.1 MPa of CO pressure (gauge pressure), 10h; styrene (1 mmol); methanol (0. 8 mL) ;benzene (10 mL); PdCl2/PVP(0. 04 mmol Pd, N/Pd= 20 in molar ratio); n (Pd): n(Ni): n(PPh3) = 1: 4:1. A remarkable synergic effect of bimetallic catalyst can be observed.Effects of PVP, amount of triphenylphosphine and temperature on the reaction were studied.The system of PdCl2-4NiCl2-PPh3/PVP gave 100% conversion of styrene and 99% selectivityto the branched chain ester under the typical reaction conditions.展开更多
Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Pall...Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Palladium catalytic systems formed with these ligands in situ were used as asymmetric homogenous catalysts for hydroesterification of styrene,giving(R)-2-phenyl propionate in 16.9 and 9.2% ee values,respectively.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.22271024,21632005)Changzhou University.
文摘Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,providing a wide variety of corresponding linear carboxylic esters bearing various functional groups in good yields and>20:1 linear/branch ratios.The reaction is optionally simple and does not need to use CO gas and acid co-catalysts.
基金supported by the Guangdong Province Natural Science Foundation (No. 10152500002000019)the Maoming City Science and Technology Planning Project (NO.2008024)
文摘Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The effect of reaction temperature, CO pressure, methanol dosage, catalyst dosage and reaction time on catalytic reaction was investigated. The test results revealed that this reaction was greatly affected by reaction temperature, but it was not significantly affected by the CO pressure, the methanol dosage, the catalyst dosage and the reaction time. Under the optimal conditions, the conversion of ethylene oxide was equal to 92.24%, while the selectivity and yield of methyl 3-hydroxypropanoate reached 88.99% and 84.35%, respectively.
文摘This paper assesses the hydroesterification process for the production of Biodiesel from Monoraphidium contortum (MORF-1) microalgae biomass, as it is a sustainable alternative not only economically, but also environmentally and ecologically to replace petroleum diesel fuel. The Biodiesel studied in this work was obtained from fatty acid esterification, a product of microalgae and methanol biomass hydrolysis reaction. CBMM’s (HY-340) niobium oxide powder was used as catalyst. The reactions were carried out in a properly closed autoclave reactor (batch), where the reagents were mixed under constant stirring at 500 rpm for hydrolysis and esterification. The products generated were submitted to gas chromatography and oxidative stability analysis. The hydroesterification process showed itself to be a promising alternative to the conventional biodiesel production process (transesterification) as it favors the use of feedstocks with any acidity and moisture content and may be performed with acid catalyst, which favors high conversions in a small range of time (30 minutes).
基金supported by the Guangdong Province Natural Science Foundation (No.10152500002000019)the Maoming City Science and Technology Planning Project(No.2014069)
文摘In this paper, sodium cobalt tetracarbonyl （NaCo（CO）4） was synthesized by using sodium dithionite and zinc powder as the reduction system and cobalt hexahydrate acetate as the precursor in the presence of methanol solvent. Methyl 3-hydroxypropionate was synthesized via hydroesterification of ethylene oxide （EO） catalyzed by NaCo（CO）4. The influencing factors on the reaction results were discussed, including the different ligands, the molar ratio of solvent and ethylene oxide, the reaction temperature, the reaction time, and the reaction pressure. An optimal catalytic system was obtained by using 3-hydroxypyridine as the ligoad under reaction conditions covering a reaction temperature 65 ℃, a reaction time of 7 h, a reaction pressure of 6 MPa, and a methoaol/EO molar ratio of 3：2. Under the optimal conditions, the conversion of ethylene oxide was equal to 97.86%, while the selectivity and yield of methyl 3-hydroxypropionate reached 88.19% and 86.30%, respectively. Finally, the reaction mechanism of hydroesterification of ethylene oxide catalyzed by NaCo（CO）4 was proposed.
文摘Polymer-supported bimetallic system of PdCl2-4NiCl2-PPH3/PVP [PVP= poly(N-vinyl-2-pyrrolidone)] provided an almost regiospecific conversion of styrene to thebranched methyl 2-propionate at a high conversion. Typical reaction conditions are: 353 K,2.1 MPa of CO pressure (gauge pressure), 10h; styrene (1 mmol); methanol (0. 8 mL) ;benzene (10 mL); PdCl2/PVP(0. 04 mmol Pd, N/Pd= 20 in molar ratio); n (Pd): n(Ni): n(PPh3) = 1: 4:1. A remarkable synergic effect of bimetallic catalyst can be observed.Effects of PVP, amount of triphenylphosphine and temperature on the reaction were studied.The system of PdCl2-4NiCl2-PPh3/PVP gave 100% conversion of styrene and 99% selectivityto the branched chain ester under the typical reaction conditions.
文摘Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Palladium catalytic systems formed with these ligands in situ were used as asymmetric homogenous catalysts for hydroesterification of styrene,giving(R)-2-phenyl propionate in 16.9 and 9.2% ee values,respectively.
