Patent ID: 8269050

Claim:
A process for preparing ethyl tert-butyl ether (ETBE) from a technical mixture of C 4 hydrocarbons I which comprises at least 1-butene, isobutene, n-butane and 2-butenes, comprising a) reacting a portion of the isobutene present in the technical mixture with ethanol in the presence of an acidic catalyst to give ETBE and unconverted C 4 hydrocarbons III, b) removing the unconverted C 4 hydrocarbons III from the effluent of a) by a thermal separating process to obtain a fraction II comprising ETBE, c) distillatively separating the C 4 hydrocarbons III into a fraction IV comprising at least 1-butene and isobutene, and a virtually isobutene-free fraction V comprising at least 2-butenes and n-butane, d) feeding fraction IV of c) directly into a reactor and with ethanol VI in the presence of an acidic catalyst to give ETBE and unconverted C 4 hydrocarbons VIII, and e) removing the unconverted C 4 hydrocarbons VIII from the effluent of d) to obtain a fraction VII comprising ETBE.