Fatty acid methyl or ethyl ester and glycerol prepn. with min. soap formation

摘要

Liquid phase reaction of oil or fat with MeOH or EtOH and an alkaline catalyst (I) to give the fatty acid (m)ethyl ester and glycerol, which are recovered separately, is carried out in one or more stages. Each stage has a mixer and a separator for sepg. a light, ester-rich phase (II) and a heavy, glycerol-rich phase (III). The first stage is supplied with oil or fat, MeOH or EtOH and (I) and glycerol is sepd. from (III) from the first stage. The novelty is that the glycerol is mixed with alkali hydroxide to give an aq. alkaline soln. with a glycerol:alkali hydroxide molar ratio of 1:5 to 10:1; water is removed, giving mono-alkali glycerate; and the glycerate soln. is passed into mixing zone(s) to cover 50-100% of the total (I) requirement of the reaction.