Organotin-oxomolybdate coordination polymers as catalysts for the epoxidation of cyclooctene
authors Abrantes, M; Valente, AA; Goncalves, IS; Pillinger, M; Romao, CC
nationality International
journal JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
author keywords molybdenum; tin; coordination polymer; epoxidation; cyclooctene; hydrogen peroxide
keywords UREA-HYDROGEN-PEROXIDE; SELECTIVE EPOXIDATION; OXIDATION; SULFOXIDATION; MECHANISM; KINETICS; ALKENES; SOLVENT; ADDUCT
abstract The organotin-oxomolybdate coordination polymers [(R3Sn)(2)MoO4]-nH(2)O (R=methyl, n-butyl, cyclohexyl, phenyl, benzyl) were tested as catalysts for the liquid-phase epoxidation of cyclooctene with 30% aqueous hydrogen peroxide at 35 degrees C and atmospheric pressure. Water, acetonitrile and dichloromethane were examined as additional co-solvents for the reaction. The catalytic results vary considerably with the nature of the tin-bound R group and the co-solvent. For all systems, cyclooctene oxide was the only observed reaction product. Apart from the trimethyltin derivative, the best results were obtained without additional co-solvent or with CH2Cl2, While addition of water or CH3CN had a detrimental effect on catalytic performance. The highest turnover frequency (46 mol mol(Mo)(-1) h(-1)) was obtained for the system containing the tri-n-butyltin derivative as catalyst and CH2Cl2 as solvent. Complete conversion of the substrate was achieved for this system within 4 h. Using water instead of CH2Cl2 with the n-butyl catalyst reduced the catalytic activity considerably at the beginning of the reaction, although 91% conversion was achieved after 24 h. The behavior of the trimethyltin derivative was atypical in that conversion of cyclooctene was only possible when CH3CN was used as the co-solvent. Experiments were also carried out using a urea/hydrogen peroxide adduct as a water-free source of H2O2. However, the catalytic activities observed were significantly lower than those obtained using aqueous H2O2. (c) 2004 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 1381-1169
year published 2005
volume 238
issue 1-2
beginning page 51
ending page 55
digital object identifier (doi) 10.1016/j.molcata.2005.05.002
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000231018800007
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