Patent ID: 7297809

Claim:
A continuous process for the preparation of ethyl lactate (I) by esterification of lactic acid or of a lactic acid composition using ethanol, according to the reaction (1): which comprises reacting said lactic acid or lactic acid composition with ethanol at an ethanol/lactic acid initial molar ratio at least equal to 2.5, in the presence of a catalyst, at reflux of the reaction medium, at approximately 100° C., and under an absolute pressure ranging from 1.5 to 3 bar; said process being characterized in that a water/ethanol gas mixture close to the azeotrope is continuously extracted from the esterification reaction medium, in that this gas mixture is then dehydrated directly using molecular sieves, in that an ethanol gas stream, which can be recycled to the esterification reaction medium, and a stream composed of water and of ethanol are then recovered from said dehydration, which stream composed of water and of ethanol is subjected to a distillation, from which water and a water/ethanol azeotrope are obtained, which water/ethanol azeotrope is injected at the top of the column for the distillation of the gas mixture extracted from the esterification reaction medium, and in that crude ethyl lactate is then continuously extracted, which crude ethyl lactate is subjected to purification, from which an ethyl lactate of high purity and heavy products are obtained.