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Carbon supports for the oxidative cleavage of oleic acid: Influence of textural properties

Abstract:

Microporous oxidized activated carbon (ACO) and macroporous oxidized carbon black (CBO) were assessed in the complexation of Ru for the oxidative cleavage of oleic acid. This reaction breaks carbon-carbon double bond to produce azelaic and pelargonic acids (highly demanded in pharmacology). Both carbon materials were treated with HNO<inf>3</inf> prior Ru deposition by wet impregnation method. Carbon supports were characterized by FTIR, Boehm's titration and N<inf>2</inf> physisorption, while Ru complexation was determined by ICP and XPS spectroscopy. Activated carbon catalyst displayed a low conversion (∼53%) in comparison to carbon black catalyst (>99%). The reason is related to the molecular length of oleic acid (2.2 nm), estimated by ab initio Hartree-Fock calculation, which is larger than micropores from activated carbon (∼0.7 nm). Despite Ru losses during the catalytic tests, CBO was more active and stable than ACO, confirming that a macroporous support is more suitable to perform the oxidative cleavage of oleic acid.