Gas Chromatographic Study of Solvent Effect of Vinyl Acetate in Asymmetric Hydroformylation
用气相色谱法研究乙酸乙烯酯不对称氢甲酰化反应中溶剂的影响

Optical 2-acetoxypropanal was the main product in the asymmetric hydroformylation of vinyl acetate with catalyst containing chiral phosphate. The products of asymmetric hydroformylation in polar and non-polar solvents were separated and characterized by use of capillary gas chromatography, gas chromatography/mass spectrometry, optical rotators dispersion and circular dichroism.According to the experiments using SE-52 glass capillary column,6 components,in which 2-acetoxypropanal was 43%,were found in the catalytic reaction with non-polar solvent toluene; whereas 24 components with 24.6 % of 2-acetoxypropanal in polar solvent methanol. It is quite evident that there are more secondary reactions occurred in polar solvent (methanol) than in non-polar solvent(toluene). The main product 2-acetoxypropanal was synthesized to give yield up to 83.1 mol% with selectivity 98.7 mol% and e.e.value7.2% in solvent toluene;but in polar solvent methanol and without solvent(vinyl acetate as the reaction solvent itself).The main product 2-acetoxypropanal was synthesized to give yield,59. 2mol% and 67.4 mol% with selectivity 60.2 mol% and 98. 3 mol% ,e. e. value 1. 9% and 2. 8% respectively. There are indications that in the asymmetric hydroformylation the yield,selectivity and.e.e.value of reaction in solvent toluene is higher than those of the reactions in solvent methanol and without solvent.That shows the notable effect of solvent in the asymmetric hydroformylation of vinyl acetate.In the catalysis,using non-polar solvent is advantageous to its yield,selectivity and e.e. value.