Studies on the Decomposition of Alkyl Hydroperoxides by different catalysts

Abstract

Abstract The catalytic decomposition of cumene, 1‐methylcyclohexyl and cyclohexyl hydroperoxides was studied in cyclohexane, cis‐ and trans‐1,4‐dimethylcyclohexane and cis‐pinane as the solvents. The stearates and the acetylacetonates of manganese, cobalt and chromium, the acetylacetonates of molybdenum and vanadium, n‐butyl orthoborate and n‐butyl metaborate were used as the catalysts. The chromium‐, vanadium‐, molybdenum‐ and boron‐containing catalysts brought about some Hock‐type decomposition of cumene hydroperoxide and thus proved to be acidic. Of these more of less acidic catalysts only molybdenyl acetylacetonate effected a partially stereospecific hydroxylation of the tertiary CH‐bonds in cis‐ and trans‐1,4‐dimethylcyclohexane. The well‐known selectivity of chromium catalysts for the ketone formation during the decomposition of secondary hydroperoxides is caused by the catalytic oxidatio of secondary alcohols by hydroperoxides in the presence of chromium compounds. In the presence of all the catalysts used the free‐radical pathways of the hydroperoxide decomposition predominated, and the attack of the intermediate radicals on the starting hydroperoxide was more important than the attack on the solvent molecules.