Ring and Side Chain Alkylation of Toluene with Methanol over Modified Zeolite Beta

Abstract

Kinetic study for toluene alkylation with methanol over Fe and K modified beta zeolite has been investigated in the present study. The reaction has been carried out in a fixed bed down-flow reactor. The influences of various process parameters such as temperature (613K - 673K) and space-time (0.009 - 0.057 kgh/kmol) on methanol conversion and xylene selectivity were studied. Maximum methanol conversion of 99.86% was achieved at a temperature 673K, reactant ratio 5:1, space time 0.023 kgh/kmol. However maximum toluene conversion of 32.63% was found at temperature 673K, reactant ratio 5:1, space time 0.057 kgh/kmol. The kinetic runs have been carried out to choose the zone in which the mass transfer effects are negligible. Based on product distribution, a mechanism for the formation of xylene over the Fe modified catalyst was proposed along with a rate expression. The kinetic and adsorption constants of the rate equations were estimated by non-linear regression. The activation energy was found to be 10.36 kJ/mol. Highest xylene selectivity of 58.58% at 0.0231 kgh/kmol space-time was noted. The second investigation has also been carried out to determine the catalytic performance of Fe and K exchanged zeolite beta for the synthesis of styrene. A series of K modified zeolite beta was prepared. The experimental runs were taken to optimize the different parameters like temperature, reactant mole-ratio, and spacetime. The catalyst is characterized by XRD, SEM and EDS.