Influence of toluene-tetramethylbenzene transalkylation on heavy aromatics conversion to xylenes

Transalkylation of toluene-tetramethylbenzene (TeMB) over MOR and BEA was investigated at 250-400 degrees C. Conversion of TeMB was higher than trimethylbenzene (TMB) and toluene. Xylene yield was in the following order: [toluene - TMB - TeMB) > [toluene - TeMB] > [toluene - TMB] [toluene]. Kinetic modeling for reaction network consisting of toluene-TeMB transalkylation; toluene disproportionation; and toluene-TMB transalkylation was carried out. Toluene-TeMB transalkylation rate was >50% higher than the toluene-TMB transalkylation while the toluene disproportionation was an order of magnitude slower than transallcylation reactions. An addition of 5-10 wt.% TeMBs to the heavy reformate caused minor impact on the xylene yield but an improvement in xylene selectivity. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.