Patent ID: 6011182
Filing Date: 2000-01-04
Classification: C07C

Abstract:
A process for preparing 2-cycloalkenones of the formula I ##STR5## which comprises subjecting a 2-alkoxycycloalkanone of the formula II ##STR6## or a 2-hydroxycycloalkanone ketal of the formula III ##STR7## in which n is an integer from 0 to 20,m is 0, 1, 2 or 3,R is alkyl, alkylaryl, aryl, arylalkyl, alkenyl or alkynyl,it being possible for the aryl radicals to have one or two substituents which are selected, independently of one another, from alkyl, hydroxyl or alkoxy,the R' radicals are, independently of one another, alkyl or alkenyl or, in formula III, may together be C.sub.1 -C.sub.5 -alkylene or C.sub.2 -C.sub.5 -alkenylene,or a mixture of the compounds of the formulae II and III to an elimination reaction in the gas phase on an acidic heterogeneous catalyst, whichgeneous catalyseneous catalyst comprises(i) at least one oxide or a mixed oxide of elements of groups 3 to 6 and 13 to 15 of the Periodic Table and is impregnated with one or more mineral acids or metal or ammonium salts of the mineral acids; or(ii)at least one phosphate or a mixture of oxides and phosphates of elements of groups 3 to 6 and 13 to 15 of the Periodic Table and, optionally, is additionally impregnated with one or more mineral acids or metal or ammonium salts of the mineral acids; or(iii) a mixture of (i) and (ii).