Process for preparing an epoxide from an oxygenate

A process for preparing an epoxide from an oxygenate, the process comprising the following steps:

• a) contacting the oxygenate with a molecular sieve-comprising catalyst, at a temperature in the range of from 350 to 1000° C. to obtain an olefinic product stream comprising ethylene, propylene and a C4+ hydrocarbon fraction comprising C4+ paraffins and C4+ olefins including isobutene;
• b) supplying at least part of the C4+ hydrocarbon fraction and methanol to an etherification reaction zone comprising an etherification catalyst and reacting, in the etherification reaction zone, at least part of the isobutene with an alcohol selected from the group consisting of methanol, ethanol and a mixture thereof to obtain an etherification product stream comprising an alkyl tert-butyl ether;
• c) separating at least part of the etherification product stream into an alkyl tert-butyl ether-enriched stream and an isobutene-depleted C4+ hydrocarbon stream;
• d) converting at least part of the alkyl tert-butyl ether in the alkyl tert-butyl ether-enriched stream into the alcohol and isobutane;
• e) oxidizing isobutane obtained in step d) into tert-butyl hydroperoxide;
• and
• f) reacting tert-butyl hydroperoxide obtained in step e) with ethylene and/or propylene separated from the olefinic product stream obtained in step a) to obtain the epoxide and tertiary-butanol.