Industrial & Engineering Chemistry Research, Vol.52, No.25, 8392-8398, 2013
Reaction Kinetics of Transesterification with Titanium Alkoxide-Based Phase-Transforming Catalyst
A catalytic process was developed that uses a phase-transforming catalyst to perform a transesterification reaction. In this process, titanium isopropoxide catalyst is added to the reaction medium as a liquid, and as a result of condensation polymerization, the spent catalyst can be removed as a heterogeneous solid. The kinetics of this system was studied using monoolein as the model monoglyceride and isopropanol as the alcohol. A yield optimization study was also conducted using soybean oil as the triglyceride. The titanium isopropoxide catalyst was able to transesterify monoolein completely, giving >99% ester yields. The kinetic study revealed that the transesterification of monoolein with titanium isopropoxide is second-order with respect to isopropyl alcohol. The rate constant was evaluated to be 0.0002 L mol(-1) min(-1). In studies with soybean oil, a maximum ester yield of 71% was observed using 16% (w/w) catalyst under the conditions tested. This catalyst concept, once fully developed, can be quite useful in a multitude of processes because the initial homogeneous catalyst phase alleviates mass transport issues whereas the latter heterogeneity eases separation of the catalyst from the medium.