A variety of reactions have been reported in open literature with catalysts deposited on monoliths. In this work, an attempt has been made to fill in the gap in the relevant literature of catalytic and kinetic studies of a petrochemical process of industrial importance, namely toluene ethylation. HZSM-5 of Si/Al = 24 with crystal size in the nanorange was wash-coated on a cubic piece of monolith (measuring 2 cm on each side) with a cell density of 400 channels per square inch. The mass of zeolite on a monolith piece was 0.8 g. The effects of reaction temperature (200-375 degrees C) and space time (1.53-4.1 g h/gmol) were studied. Maximum toluene conversion was observed at 300 degrees C. At the temperatures studied in this work, meta-ethyltoluene formed in excess (up to 8%) over thermodynamic equilibrium concentrations. Hydrodynamic analyses showed plug flow to be prevailing within an individual channel of the monolith. Zeolite supported on monolith was found to be more active than that in powder or pellet form. Also, this system exhibited an effectiveness factor of 0.9 at 225 degrees C and 0.46 at 325 degrees C for the main alkylation reaction forming para-ethyl toluene as the primary product. These values were near 0.01 for subsequent isomerization to the meta-isomer. The activation energies for ethylation and isomerization of 64 and 82 kJ/mol, respectively, were observed.