Optimization of glycerol ketalization to produce solketal as biodiesel additive in a continuous reactor with subcritical acetone using Purolite® PD206 as catalyst

This paper represents a continuous, easy to scale up, high yield, 100% selective ketalization of glycerol to solketal (4-hydroxy methyl-2,2-dimethyl-1,3-dioxolane) over Purolite® PD206 in subcritical acetone. A central composite design was used to obtain the optimum conditions for five effective parameters of temperature, pressure, acetone to glycerol mole ratio, feed flow rate, and the catalyst mass. At a temperature of 20 °C, a pressure of 120 bar, acetone to glycerol mole ratio of 5, feed flow rate of 0.1 mL·min− 1, and the catalyst mass of 0.77 g, a 95% yield was achieved experimentally which is close to the model yield prediction of 100%. This agreement showed that the central composite design model could ideally make an acceptable estimation of the process.