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Heterogeneous Oxidation of Pyrimidine and Alkyl Thioethers in Ionic Liquids over Mesoporous Ti or Ti/Ge Catalysts
Author(s) -
Cimpeanu Valentin,
Parvulescu Vasile I.,
Amorós Pedro,
Beltrán Daniel,
Thompson Jillian M.,
Hardacre Christopher
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400105
Subject(s) - ionic liquid , catalysis , chemistry , inorganic chemistry , selectivity , mesoporous material , hydrogen peroxide , trifluoromethanesulfonate , anhydrous , alkyl , imide , bromide , organic chemistry
Heterogeneous catalytic oxidation of a series of thioethers (2‐thiomethylpyrimidine, 2‐thiomethyl‐4,6‐dimethyl‐pyrimidine, 2‐thiobenzylpyrimidine, 2‐thiobenzyl‐4,6‐dimethylpyrimidine, thioanisole, and n ‐heptyl methyl sulfide) was performed in ionic liquids by using MCM‐41 and UVM‐type mesoporous catalysts containing Ti, or Ti and Ge. A range of triflate, tetrafluoroborate, trifluoroacetate, lactate and bis(trifluoromethanesulfonyl)imide‐based ionic liquids were used. The oxidations were carried out by using anhydrous hydrogen peroxide or the urea–hydrogen peroxide adduct and showed that ionic liquids are very effective solvents, achieving greater reactivity and selectivity than reactions performed in dioxane. The effects of halide and acid impurities on the reactions were also investigated. Recycling experiments on catalysts were carried out in order to evaluate Ti leaching and its effect on activity and selectivity.