Publication Type Journal Article
Title C-scorpionate Au(III) complexes as pre-catalysts for industrially significant toluene oxidation and benzaldehyde esterification reactions
Authors Hugo M. Lapa M. Fátima C. Guedes da Silva Armando J.L. Pombeiro Elisabete C.B.A. Alegria L.M.D.R.S. Martins
Groups CCC
Journal INORGANICA CHIMICA ACTA
Year 2020
Month November
Volume 512
Number
Pages
Abstract The new Au(III) complex [AuCl2(Tpms)] (1) and the previously reported [AuCl2(Tpm)]Cl (2), bearing the potentially tridentate ligands tris(1-pyrazolyl)methanesulfonate (SO3C(C3H3N2)(3)(-), Tpms) or hydrotris(1-pyrazolyl) methane (HC(C3H3N2)(3), Tpm), respectively, were synthesized in water at room temperature and characterized using NMR and IR spectroscopy. The molecular structure of 1 was authenticated by single crystal X-ray diffraction analysis. The catalytic performance of the Au(III) complexes was tested, for the first time, in toluene and benzyl alcohol oxidation reactions. The oxidative esterification of benzaldehyde, by-product of toluene oxidation, was further explored. In order to optimize the catalytic systems, the influence of parameters such as temperature, reaction time, amount of pre-catalyst and the presence of additives was evaluated. In the peroxidative (by H2O2 or t-BuOOH) oxidation reactions, a maximum total yield (benzylic alcohol and benzaldehyde) of 8\% for toluene oxidation with pre-catalyst 1 (6 h, 80 degrees C, H2O2 30\% aq. sol.) and a maximum total yield (benzaldehyde and benzoic acid) of 43\% for benzyl alcohol oxidation with pre-catalyst 2 (24 h, 80 degrees C, t-BuOOH 70\% aq. sol.) with a selectivity of 72\% for benzaldehyde, were obtained. The esterification of benzaldehyde yielded, in the presence of 1, a maximum of 27\% and 48\% of methyl benzoate, at room temperature and 80 degrees C, respectively, and with a selectivity of 78\% for methyl benzoate.
DOI http://dx.doi.org/10.1016/j.ica.2020.119881
ISBN
Publisher ELSEVIER SCIENCE SA
Book Title
ISSN 0020-1693
EISSN 1873-3255
Conference Name
Bibtex ID ISI:000570252800007
Observations
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