Process for the continuous production of lower alkyl esters of higher fatty acids

In a process for the continuous production of lower alkyl esters of higher fatty acids wherein lower alcohol and an oil phase of fatty triglycerides or natural oils or fats containing free fatty acids is subjected to catalytic transesterification at reaction temperatures of up to 100.degree. C. in the presence of an alkaline catalyst, and glycerine, catalyst residue alcohol reactant are removed, the improvement which comprises, in sequence,

• a) introducing a reaction mixture which is pre-mixed combination of oil phase, alcohol and catalyst at reaction temperature into the top of a reactor column such that the rate of flow is less than the sinking rate of the glycerine which separates from the reaction mixture and separating free glycerine from the column transesterification product,
• b) transferring the column transesterification product which contains dissolved and dispersed glycerine, lower alkyl esters, alcohol, catalyst, oil and partially transformed oil, to a second reactor which is at reaction temperatures and conducting a further transesterification,
• c) washing the thus obtained reaction mixture with an aqueous extractant in a first separator,
• d) introducing the thus washed reaction mixture, additional alcohol and catalyst into a third reactor at reaction temperature and at a flow speed conforming to the stage a) of the process,
• e) introducing the resulting mixture into a fourth reactor and maintaining the mixture under stirring for a further transesterification, forming a reaction product have a degree of transesterification of at least 99.2%,
• f) introducing the resulting transesterification product and hot, aqueous extractant solution into a second separator and separating alcohol, glycerine, soaps formed and catalyst from the transesterification product, and
• g) drying the transesterification product.