TRIPHASE CATALYSIS - A NEW ROTATING-DISK CONTACTOR FOR MEASURING MASS-TRANSFER COEFFICIENTS

Triphase catalysis (TPC) is a practically attractive way of carrying o ut phase transfer catalyzed reactions. The analysis of triphase cataly tic systems requires a knowledge of mass transfer coefficients, but no correlations for estimating these are available. Therefore, a new rot ating disk contactor (RDC) for measuring the external mass transfer co efficients of TPC systems has been designed and operated. Details of t he design and construction of the contactor are discussed. In order to test the apparatus, experiments were carried out on a test system: sy nthesis of benzyl acetate from benzyl chloride and sodium acetate with polymer supported tributylmethylammonium chloride as the immobilized phase transfer catalyst. This reaction was found to be mass transfer c ontrolled at low agitation speeds, and it was therefore possible to de termine the external mass transfer coefficient as a function of the bu lk agitation speed. The values ranged from 1.4 x 10(-3) to 2.0 x 10(-3 ) cm/min. (C) 1998 Elsevier Science Ltd. All rights reserved.