Stable free nitroxyl radicals as oxidation catalysts and process for oxidation

摘要

The instant invention relates to stable free nitroxyl radicals of formula (I) at least one of the substituents R is -O. and the others are hydrogen or OH; X is -NR1R2, wherein R1 and R2 are independently hydrogen, C1-C18alkyl or together with the nitrogen atom to which they are bound from a 5 or 6 membered ring which may be further interrupted by an O atom. Further subjects of the invention are an oxidation process for alcohols to aldehydes or ketones or to carboxylic acids in the presence of a compound of formula (I) and the use of stable free nitroxyl radicals of formula (I) as oxidation catalysts.