Liquid phase catalytic oxidation of isophorone with tert-butylhydroperoxide over Cu/Co/Fe-MgAl ternary hydrotalcites

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Dasari Kishore (Author) FEUP; Alírio E. Rodrigues (Author) FEUP

Journal

Title: Applied Catalysis A: General

Vol. 345 No. 1

Pages: 104-111

ISSN: 0926-860X

Publisher: Elsevier

Indexing

ISI Proceedings

ISI Web of Knowledge - 16 Citations

ISI Web of Science

Scopus - 12 Citations

COMPENDEX

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Technological sciences > Engineering > Chemical engineering

Other information

Authenticus ID: P-003-XNC

DOI: 10.1016/j.apcata.2008.04.029

Abstract (EN): Liquid phase catalytic oxidation of isophorone was carried out over M-MgAl ternary hydrotalcites, where M is Cu, Co or Fe, using tert-butylhydroperoxide (TBHP) as an oxidant. The influence of various reaction parameters, namely, substrate/catalyst mass ratio, substrate: oxidant mole ratio, nature of oxidant, solvent, reaction temperature and reaction time on the activity and selectivity for the desired reaction, were studied. The catalysts were synthesized by the coprecipitation technique using metal nitrates and a NaOH/Na2CO3 mixture. Powder X-ray diffraction and thermal analysis of these samples confirmed the presence of hydrotalcite like layered network. Oxidation of isophorone over these catalysts resulted mainly in the formation of ketoisophorone (KIP). A maximum isophorone conversion of 74% with 100% selectivity to KIP was observed over CuMgAl-13 at 333 K up to 48 h using acetonitrile as a solvent, followed by CoMgAl-13 (36%) and FeMgAl-13 (25%). The redox properties of transition metal ions played an important role in driving the reaction and a reaction mechanism involving predominantly free radicals were proposed. An increase in the conversion of isophorone was observed with decreasing substrate/ catalyst mass ratio down to 20. With respect to the influence of reaction temperature, the conversion increased up to 333 K and decreased when the temperature was further increased. Among the solvents studied acetonitrile showed maximum conversion and selectivity to KIP, where as methanol showed minimum conversion. An increase in the conversion of isophorone was observed with decreasing molar ratio of isophorone to TBHP. A gradual increase in the conversion of isophorone was observed with reaction time and the maximum conversion was observed at 48 h. Reusable studies showed that the catalysts were stable and reusable up to three cycles without substantial loss of activity. (C) 2008 Elsevier B.V. All rights reserved.

Language: English

Type (Professor's evaluation): Scientific