Patent ID: 7906663

Claim:
A process for producing both an olefinic fraction and a composition of diesters or diacids from unsaturated fats, characterized in that it comprises a succession of steps including: a) a step for bringing into contact, under methathesis conditions, at least one unsaturated fat comprising at least one carboxylic monoacid containing 12 to 22 carbon atoms and comprising at least one ethylenically unsaturated bond or a monoester of said monoacid, with excess ethylene, in the presence of a catalyst and in the presence of at least one non-aqueous ionic liquid, jointly producing an olefinic fraction and a fraction of monoesters or monoacids of unsaturated fats; b) a step for separating and recycling ionic liquid containing the catalyst used in step a); c) a step for separating the olefinic fraction (fraction A) and the unsaturated fat monoester or monoacid fraction (fraction B) produced in step a); d) a step for homometathesis of fraction B of unsaturated fat monoesters or monoacids separated in step c), said homometathesis being carried out in the liquid phase in the presence of at least one catalyst.