Process for producing esters of fatty substances and the high purity esters produced

A process for simultaneously producing a composition of esters of linear monocarboxylic acids containing 6 to 26 carbon atoms and glycerine with a high degree of purity, characterized in that it comprises:

• a step a) in which a plant or animal oil, which may or may not be acidic, is reacted with an excess of at least one aliphatic mono-alcohol containing 1 to 4 carbon atoms, in the presence of a heterogeneous catalyst, eliminating the excess mono-alcohol and separating the glycerine, this step producing a crude ester containing fatty acid esters and residual monoglycerides and depleted of mono-alcohol;
• a step b) in which the crude ester obtained undergoes transesterification or esterification of the residual monoglycerides to di- and optionally triglycerides, in the presence of a heterogeneous catalyst using the fatty acid esters or by at least one fatty acid containing 6 to 26 carbon atoms which is added;
• and
• a step c) in which the resultant ester composition from step b) is evaporated under reduced pressure to obtain an overhead ester product of said at least one aliphatic mono-alcohol of 1 to 4 carbon atom, and depleted of said mono-glycerides and an evaporation residue of di- and optionally tri-glycerides and, recycling the evaporation residue containing the di- and optionally tri-glycerides to the starting oil of step a).