Process for preparing cyclic esters from alpha-hydroxy esters and catalysts used therein KU Leuven
The invention relates to a process for preparing cyclic esters by means of a transesterification reaction in the gas phase, comprising the steps of: (i) vaporizing a liquid solution of alpha-hydroxy esters, (ii) passing the ester vapors through a reaction zone containing a solid catalyst and (iii) recovering the cyclic esters from the gaseous product stream; and wherein the solid catalyst comprises at least one metal of titanium (Ti) and Zirconium (Zr), and a SiO2 support, and wherein said metal is chemically bound to the SiO2 support through M-O-Si chemical bonds.