MANUFACTURE OF UNSATURATED COMPOUNDS BY ELIMINATION

摘要

1. A process for the preparation of a compound of the formula I R**1 -CH=CH-R**2 I where R**1 is hydrogen or alkyl and R**2 is alkoxy or acylamino and R**1 and R**2 together may form an usubstituted or substituted heterocyclic ring, by elimination of the radical R**3 OH from a compound of the formula II see diagramm : EP0197283,P5,F1 where R**1 and R**2 have the above meanings and R**3 is alkyl, wherein the elimination reaction is carried out by passing the compound of the formula II in a liquid or gaseous state into a high-boiling mineral oil at above the boiling point of the compound I being formed, compound I is taken off in gaseous form, and the high-boiling mineral oil enriched with by-products is removed and replaced with fresh mineral oil.