Effect of water presence on methyl tert-butyl ether and ethyl tert-butyl ether liquid-phase syntheses

Abstract

Equilibrium constants for the liquid-phase synthesis of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) were determined experimentally in the temperature range 40-80 C, using an initial water percentage range in the alcohol of 1.4-5 wt%. The initial molar alcohol-isobutylene ratio varied from 0.8 to 1.44. Both systems behave nonideally, and the equilibrium constants found agree with those determined without initial water quoted in the literature. In experimental kinetic runs performed at 40 C, ETBE and MTBE production rates are strongly lowered by the initial water presence. This inhibitor effect disappears as water is converted into tert-butyl alcohol (TBA). The TBA equilibrium is reached faster than those of the ethers, and the residual water is rather small.