Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-I-3We have demonstrated that the use of cation exchange resins such as Amberlite ® isbeneficial because it is resistant toward deactivation, the mass transfer resistance can besuppressed and the activity is similar to sulphuric acid.Based on our experimental data (Figure 1) and information from literature, the polar partρ * σ * of the Taft equation is negligible for the acid-catalyzed systems. The rate constants usedto plot the Figure 1 are the apparent ones. From this Figure, one can see that the steric effectsgovern the perhydrolysis and not the polar effect. However, the values of δ are different forboth series of experiments carried out in similar conditions. In order to explain thisobservation and to have a better comparison between a homogeneous and a heterogeneouscatalyst, kinetic modelling of perhydrolysis over heterogeneous catalysts will be described inthe final presentation.Butanoic acid Propanoic acid Acetic acidEs0.00-0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0-0.10-0.20y = 0.5173x - 0.0006R 2 = 0.9999log(k/ko)-0.30-0.40y = 2.1146x + 0.0095R 2 = 0.9989-0.50-0.60log(k/kacetic) heterogeneous catalystlog(k/kacetic) homogeneous catalystLinear (log(k/kacetic) heterogeneous catalyst)Linear (log(k/kacetic) homogeneous catalyst)-0.70Figure 1. Taft equation for perhydrolysis of different carboxylic acids with H 2 SO 4and Amberlite IR-120 at 45 °CReferences1. A. Finiels, P. Geneste, C. Moreau, J. Mol. Catal. A. Chem. 107 (1996) 385-391.2. J. Lilja, D.Yu. Murzin, T. Salmi, J. Aumo, J. Mol. Catal. A. Chem. 182-183 (2002) 555-563.3. S. Leveneur, T. Salmi, D.Yu. Murzin, L. Estel, J. Warnå, N. Musakka, Ind. Eng. Chem .Res. in press217