Process for preparation of isoprene

US3972955A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Kurt Halcour · Leverkusen, DE
• Paul Losacker · Leichlingen, DE
• Wulf Schwerdtel
• Wolfgang Swodenk

Key dates

• Filing date: Sep 13, 1974
• Grant date: Aug 3, 1976
• Expiry date: Sep 13, 1994

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D319/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In the preparation of isoprene by reacting isobutene with formaldehyde to produce 4,4-dimethyl-m-dioxane in a first stage, and decomposing the dioxane to isoprene and formaldehyde in a second stage, formaldehyde in the effluent streams of either or both of said stages is recovered. The formaldehyde-containing liquids are distilled to separate high boilers; the overhead, which is formaldehyde-rich, is extracted with isobutene feed to the process, whereby the isobutene extracts low boilers from the formaldehyde-containing liquid; and the formaldehyde-containing liquid, having at some point after said distillation been treated with an alkaline material, is subjected to rectification to produce as head product, the recovered formaldehyde.