PREPARATION OF NOVEL HETEROGENEOUS CATALYSTS OF ZINC SILICATES FOR THE SYNTHESIS OF BIODIESEL RESULTING FROM VEGETABLE OILS.

摘要

The invention provides porous catalysts based on silica and zinc, which effectively promote transesterification reactions, the catalysts being easily recycled, stable even after a repeated use. These catalysts have surface areas ranging from 4.42 to 20.524 m2 and may convert vegetable oil and animal fat, in a quick manner and under soft conditions, into alkyl (C10-C30), alkyl ester and glycerin, which are mechanically separated in an easy manner. The invention refers but it is no limited to a method for the transesterification of an ester, a mono or diglyceride or vegetable oil or animal fat, for preparing an alkyl ester (C1-C4) consisting in: combining the ester, an alcohol (C1-C4) and the catalyst of the invention under conditions where said catalyst promotes the formation of the alkyl ester (C1-C4). The invention also provides a method for preparing mesoporous silicate obtained from zinc, which consists in the combination of silica gel and deionized water and sodium hydroxide, for forming a first mixture at not more than 40°C; and then obtain a zinc silicate by the addition of a solution of a zinc halide, the resulting mixture being heated at 70-95°C, which may be isolated by filtration.