Heterogeneous catalyst of the zinc aluminate spinel type surstoichiometric in zinc and use thereof in a process for preparation of alcohol esters from triglycerides and alcohols

摘要

A catalyst with a mixed zinc and aluminum oxide base having a spinel structure surstoichiometric in zinc, in which part of the Zn atoms are in the octahedral position, a process for preparation of the same and use of the same in a process for preparation of a compound of linear monocarboxylic acid alcohol esters with 6-26 carbon atoms from a vegetable or animal oil, neutral or acid, virgin or recycled, with monoalcohols of 1-18 carbon atoms allowing an ester that can be used as a motor fuel or a heating fuel and a pure glycerine to be obtained directly in one or more steps.

主权项

1. A catalyst with a zinc aluminate base, free from ZnO, alumina and ZnAl2O4, the zinc aluminate base of which comprises a single zinc aluminate phase of the spinel type surstoichiometric in zinc in which a portion of the zinc atoms occupy octahedral sites and the Zn/Al atomic ratio is 0.56-0.58, said catalyst prepared by a process comprising:
a) co-precipitation involving the mixing of precursors of zinc II and aluminium III in a Zn/A1 atomic ratio of 0.56-0.58, in the presence of a base, at a pH of 6.1-6.9, and at a temperature of 30-50° C.; b) filtration of precipitate obtained; c) optionally washing to remove residual species; d) drying at a temperature of 80-175° C.; e) calcination in the presence of oxygen at a temperature of 500-800° C.