After impregnation the catalysts were dried at 80°C overnight and then calcined at 500 °C for 3h at heating rate of 0.5 °C/min.KOH/ZSM5 catalysts with different active phase loadings (15,25 and 35 wt.% ) were labeled 15KOH/ZSM5, 25KOH/ZSM5 and 35KOH/ZSM5, respectively