中国科技论文在线

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2006年01月25日

【期刊论文】One-pot synthesis of dimethyl carbonate catalyzed by n-Bu4NBr/n-Bu3N from methanol, epoxides, and supercritical CO2

何良年， Jie-Sheng Tian a， Jin-Quan Wang a， Jian-Yu Chen b， Jian-Guo Fan a， Fei Cai b， Liang-Nian He a， *

J.-S. Tian et al./Applied Catalysis A: General xxx (2006) xxx-xxx，-0001，（）：

-1年11月30日

摘要

A homogenous binary catalyst system, n-Bu4NBr/n-Bu3N, was found to be active for the synthesis of dimethyl carbonate from styrene oxide (SO), methanol, and supercritical CO2. Under the optimized conditions, the dimethyl carbonate yield could reach 84% at SO conversion of 98%. Several parameters were studied, i.e. catalyst precursors, reaction time and temperature, methanol/epoxide feed ratio in moles, and CO2 pressure. The best compromise for the one-pot synthesis was achieved with an equimolar amount of n-Bu4NBr/n-Bu3N. A possible mechanism for the present n-Bu4NBr/n-Bu3N-catalyzed one-pot synthesis of dimethyl carbonate was proposed.

Supercritical carbon dioxide， Epoxide， Dimethyl carbonate， Methanol， Binary catalyst system (， n-Bu4NBr/， n-Bu3N)，， Homogeneous catalysis

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2006年01月25日

【期刊论文】Hydrosilation of polyfluoroolefin in dense carbon dioxide

何良年， Liang-Nian He， Jun-Chul Choi and Toshiyasu Sakakura*

Tetrahedron Letters 42 (2001) 2169-2171，-0001，（）：

-1年11月30日

摘要

Ruthenium and rhodium phosphine complexes catalyze the hydrosilation of olefins in dense carbon dioxide. The incorporation of polyfluorinated phosphine ligands in the conventional hydrosilation catalysts provides enhanced solubility in dense carbon dioxide resulting in a higher catalytic activity and selectivity; the best result was obtained using RuCl2[P(C6H4-p-CF3)3]3. The reaction is applicable to the synthesis of a fluorous silane coupling agent.

hydrosilation， olefin， carbon dioxide， ruthenium， rhodium.，

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2006年01月25日

【期刊论文】Cyclic Carbonate Synthesis from Supercritical Carbon Dioxide and Epoxide over Lanthanide Oxychloride

何良年， Hiroyuki Yasuda， Liang-Nian He， and Toshiyasu Sakakura

Journal of Catalysis 209, 547-550 (2002)，-0001，（）：

-1年11月30日

摘要

Lanthanide oxychloride, especially SmOCl, is an efficient solid catalyst for propylene carbonate synthesis from supercritical CO2 and propylene oxide. The process requires no additional organic solvents and the product is automatically separated out from the CO2 phase.

propylene carbonate， propylene oxide， supercritical carbon dioxide， lanthanide oxychloride.，

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2006年01月25日

【期刊论文】A poly (ethylene glycol)-supported quaternary ammonium salt for highly efficient and environmentally friendly chemical fixation of CO2 with epoxides under supercritical conditions

何良年， Ya Du， a， Jin-Quan Wang， Jian-Yu Chen， Fei Cai， b， Jie-Sheng Tian， De-Lin Konga and Liang-Nian He a， *

Y. Du et al./Tetrahedron Letters xxx (2006) xxx-xxx，-0001，（）：

-1年11月30日

摘要

A PEG-supported quaternary ammonium salt is proved to be an efficient and recyclable homogeneous catalyst for solvent-free synthesis of cyclic carbonates from carbon dioxide and epoxides under supercritical conditions. Supporting Bu4NBr onsoluble polymer PEG6000 enhances the catalytic activity. The workup procedure is straightforward, and the catalyst can be reused over five times with no appreciable loss of catalytic activity and selectivity.

Supported catalyst， Cyclic carbonate， Supercritical CO2， Polyethylene glycol， Homogeneous catalyst recycling.，

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2006年01月25日

【期刊论文】Selective and high yield synthesis of dimethyl carbonate directly from carbon dioxide and methanol

何良年， Jun-Chul Choi， Liang-Nian He， Hiroyuki Yasuda and Toshiyasu Sakakura*

Green Chemistry, 2002, 4, 230-234，-0001，（）：

-1年11月30日

摘要

Supercritical carbon dioxide is efficiently converted to dimethyl carbonate (DMC) via the reaction with methanol in the presence of a catalytic amount of dialkyltin oxide or its derivatives. The removal of water is the key to accomplishing the high conversion by shifting the equilibrium to dimethyl carbonate. Dehydration is successfully carried out by circulating the reaction mixture through a dehydrating tube packed with molecular sieve 3A. Under the effective dehydration conditions, the DMC yield is almost linearly dependent on the reaction time, catalyst amount, methanol concentration, and CO2 pressure.

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