Selective formation of C-10-C-13 range fuel precursors by gas-phase alkylation of m-cresol (a bio-oil product from lignin/lignocellulosic biomass) with iso-propanol (light oxygenates) over highly efficient metal ion-exchanged zeolite catalysts is reported. Zn-HY zeolite exhibited higher catalytic activity as compared to Zn-HZSM5, Zn-HBEA, Zn-HMCM22, and other metal ion-exchanged HY zeolites. The catalytic activity was observed to increase with zinc content in HY, which is attributed to its high Lewis acidity. A comprehensive investigation of important process parameters like reaction temperature (200 -300 degrees C), WHSV (1.68-3.92 h(-1)), iso-propanol:m-cresol mole ratio (1:1-3:1), and catalyst loading (0.5 -1.5 g) is reported and optimized using Design of Experiment (DoE) through Response Surface Methodology (RSM). Experimental data was fitted to a second-order polynomial equation using multiple regression analysis with high determination coefficient (R-2) value of 98.65% for conversion of m-cresol and 98.37% for selectivity to thymol. An m-cresol conversion of similar to 92% with similar to 71% selectivity to thymol was obtained over Zn-HY-III containing 0.99 mmol g(-1) zinc at optimal conditions of 250 degrees C temperature, 2.8 h(-1) WHSV, 2:1 reactant mole ratio, and 1 g catalyst loading. This work demonstrates the prevention of carbon fraction loss during hydrodeoxygenation by efficient alkylation of phenolics with oxygenates obtained as major fractions in bio-oil. (C) 2019 Elsevier Ltd. All rights reserved.