PROCESS FOR THE PREPARATION OF METHYL TERT-BUTYL ETHER AND ETHYL TERT-BUTYL ETHER

摘要

A process is described for the preparation of methyl tert-butyl ether and ethyl tert-butyl ether by the selective reaction of methanol and ethanol respectively with isobutylene contained in C4-hydrocarbon fractions, in particular those resulting from processes for the thermal or catalytic pyrolysis of suitable petroleum fractions. The reaction is carried out in the liquid phase, under the influence of acid catalysts, at increased temperatures and pressures and with a molar ratio of the alcohol to the isobutylene equal to or approximately equal to the stoichiometric value. To the reaction medium are added inert aliphatic hydrocarbons which are liquid under the operating conditions in order to dilute the medium to a greater extent than the dilution given by the inert hydrocarbons contained in the C4-fraction of the feed. For this purpose, in the most typical embodiment, the exhausted C4-fraction itself is recycled to the reaction medium. By means of this dilution, the thermodynamic equilibrium conditions of the reaction system are favourably influenced, and improved conversions of the isobutylene to the useful reaction product are achieved. Embodiments are disclosed which are particularly suitable for the preparation of methyl tert-butyl ether and ethyl tert-butyl ether.