Subsequently, the pilot reactor was used to investigate the effects of the reaction conditions on catalysis. As shown in Table 2, with the change of reaction temperature, the methanol conversion rate fluctuated slightly and the selectivity for DMM and byproducts FA and methyl formate (MF) changed considerably. At 360 °C and 380 °C, far from equilibrium, the oxidative dehydrogenation of FA from methanol was thermodynamically favorable20. The higher temperature was conducive to the activation of the C-H bond of FA by methanol, and the reaction of methanol with FA converted DMM and DME intermediates into FA, methanol and MF11. The increase in temperature led to lower DMM selectivity and higher FA and MF selectivity.
Table 2 . Catalytic activity of Fe-Mo/HZSM-5 catalyst in circulating fluidized bed pilot reactor with different temperatures and methanol/air ratios.