Kinetics of the nopol synthesis by the Prins reaction over tin impregnated MCM-41 catalyst

The kinetics of the nopol synthesis by Prins condensation of beta-pinene and paraformaldehyde over Sn-MCM-41 synthesized by impregnation was evaluated using the initial reaction rate method. The reaction rate equation obtained from a kinetic model based on the Langmuir-Hinshelwood formalism with the surface reaction of adsorbed reactants on catalytic sites of the same nature as the limiting step, gave a good prediction of the experimental data. The effect of temperature on the kinetics of nopol synthesis over Sn-MCM-41 obtained by impregnation was studied between 75 and 100 degrees C. The robustness analysis of the kinetic model showed that the surface reaction constant, k(sr), should be about 0.185 mol g(-1) h(-1) at 90 degrees C, while the ratio between the adsorption equilibrium constant of beta-pinene, K-A, and formaldehyde species, K-B, is approximately 1.2:1 (K-A:K-B). The obtained apparent activation energy and pre-exponential factor are 78 kJ/mol and 2.3 x 10(10) mol g(-1) h(-1), respectively, but compensation effect analysis using both experimental and simulated data gave strong evidence of the dependency in temperature of the apparent Arrhenius parameters. (C) 2012 Elsevier B.V. All rights reserved.