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Oxidation of Polycyclic Aromatic Hydrocarbons with Hydrogen Peroxide in the Presence of Transition Metal Mono‐Substituted Keggin‐Type Polyoxometalates
Author(s) -
Estrada Ana C.,
Simões Mário M. Q.,
Santos Isabel C. M. S.,
Neves M. Graça P. M. S.,
Cavaleiro José A. S.,
Cavaleiro Ana M. V.
Publication year - 2011
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201000264
Subject(s) - chemistry , anthracene , naphthalene , hydrogen peroxide , catalysis , acetonitrile , cycloalkane , substituent , transition metal , benzothiophene , alkyl , photochemistry , medicinal chemistry , inorganic chemistry , organic chemistry , thiophene
The oxidation of anthracene, naphthalene, 1‐ethylnaphthalene, and 2‐ethylnaphthalene with environmentally benign hydrogen peroxide has been studied in the presence of the tetrabutylammonium salts of iron and manganese mono‐substituted Keggin‐type polyoxometalates [XW 11 M(H 2 O)O 39 ] n − (X=P, Si, or B, M=Mn III or Fe III ). The reactions were performed under homogeneous conditions at 80 °C, using acetonitrile as the solvent. For all the catalysts studied, anthracene was selectively oxidized to 9,10‐anthraquinone at 100 % conversion in the presence of [BW 11 Mn(H 2 O)O 39 ] 6− . The oxidation of 1‐ethylnaphthalene and 2‐ethylnaphthalene occurs mainly at the alkyl substituent, along with the formation of phthalic anhydrides, which resulted from aromatic ring oxidation, with iron substituted anions. Naphthalene could not be oxidized with the conditions used. To understand the reaction pathways, the oxidation of several products was performed in the presence of [PW 11 Fe(H 2 O)O 39 ] 4− . Under the conditions used, the oxidation of vinylnaphthalene derivatives gave rise to mainly carbon–carbon double‐bond cleavage, affording the corresponding naphthaldehydes in high yields (>67 %). Possible reaction pathways are presented and the role of different catalysts is discussed.