The synthesis of methyl chloride from methanol and hydrogen chloride catalysed by zinc chloride was investigated in water and in two room temperature ionic liquids in a CSTR reactor. Both Aliquat336 and BMICI drive to similar rate of reactions as the traditional process albeit at lower temperatures. More importantly, the formation of the side product Me2O is decreased in ionic liquids. From the reactor point of view and on the basis of kinetics and simulations, a new process involving plug flow behaviour using ionic liquids is proposed which would lead to process intensification. i.e. (50x) productivity increase. (c) 2008 Elsevier B.V. All rights reserved.