Transesterification of vegetable oils

摘要

A method for producing diesel grade fuel of plant origin by transesterifying a refined vegetable oil with a charge of a C1-C4 alcohol in the presence of a catalyst and at least 0.2 parts by volume, related to unit volume of refined vegetable oil, of an aliphatic hydrocarbon solvent with a boiling point of −42° C. to 200° C., comprises mixing the oil, alcohol, catalyst and solvent in a single reaction vessel under homogeneous conditions which promote transesterification to 95-98% completion and which suppress reverse glycerolysis, without stopping transesterification to remove by-product polar glycerol, and without subjecting the oil/fuel mixture to a further transesterification step with a fresh charge of alcohol and catalyst.

主权项

1. A biodiesel fuel production method comprising:
(a) charging a single vessel with a charge of:
a refined vegetable oil;a C1-C4 alcohol;a catalyst, andat least 0.2 parts by volume, related to unit volume of refined vegetable oil, of an aliphatic hydrocarbon solvent with a boiling point of −42° C. to 200° C.; (b) mixing the oil, alcohol, catalyst and solvent in said single vessel under homogeneous conditions without stopping transesterification to remove by-product polar glycerol; (c) stopping the mixing and leaving the mixture to stand for a predetermined period of time in said single vessel; (d) allowing the mixture to separate into an upper apolar phase and lower polar phase whilst standing in said single vessel, and (e) allowing the upper apolar phase in said single vessel to undergo continued transesterification, without subjecting the upper apolar phase with additional alcohol and catalyst, the by-product polar glycerol of said continued transesterification passing into the lower polar phase in said single vessel.