Patent ID: 6878837
Filing Date: 2005-04-12
Classification: C07C,C11C

Abstract:
1. In a process for producing alkyl esters of fatty acids, and high purity glycerin, comprising conducting a set of transesterification reactions between a vegetable or animal oil and an aliphatic monoalcohol in the presence of a catalyst, said process comprising a) providing a dried oil to be treated; b) at least one step of transesterifying the dried vegetable or animal oil with an excess of said aliphatic monoalcohol, the proportion being of 20% to 80% by weight of the oil, to form an alkyl ester; c) at least one step of separating at least part of the excess of aliphatic monoalcohol in the form of vapor and removing glycerin; d) at least one step of transesterifying the alkyl ester resulting from step (b) with an excess amount of aliphatic monoalcohol, the proportion being of 20% to 80% by weight of the alkyl ester to form transesterified alkyl ester and a final excess of the aliphatic monoalcohol; e) and separating the final excess of the aliphatic monoalcohol to form the transesterified alkyl, the improvement comprising separating water from at least part of the methanol vapor separated (in step (c)) and passing at least part of the resultant water-depleted methanol to at least one of steps (b) and (d), so as to control the water content in the transesterification reaction medium to a value of less than 1500 ppm.