Patent ID: 8633345
Filing Date: 2014-01-21
Classification: C07C

Abstract:
1. A process for preparing isobutene from a MTBE-comprising mixture, the process comprising: A) in a reactor R, cleaving a mixture obtained from an MTBE-comprising feedstock and/or a first MTBE-comprising stream, affording a first product stream of reaction products comprising isobutene, isoprene, methanol, dimethoxymethane, MTBE, and by-products, the by-products consisting of a1) high boilers having a boiling range above 55° C. at a pressure of 0.1 MPa; a2) medium boilers having a boiling range of 12 to 55° C. at a pressure of 0.1 MPa; and a3) low boilers having a boiling range below 12° C. at a pressure of 0.1 MPa; B) distillatively separating the first product stream into a second product stream which comprises the isobutene and low boilers, and a third product stream which comprises MTBE, methanol, medium boilers, and high boilers; C) distillatively separating the third product stream to obtain a second MTBE-comprising stream and a first methanol-comprising high boiler stream; D) recycling the second MTBE-comprising stream into the cleaving A), the medium boilers being removed completely or partially before the recycling D) from the second MTBE-comprising stream; wherein at least one of dimethoxymethane and isoprene are removed from a the second MTBE comprising stream recycled to the cleaving.