Benzene Hydroxylation Reaction Research Articles

Selective hydroxylation of benzene using dioxygen activated by vanadium–copper oxide catalysts supported on SBA-15

Phenol was synthesized through directly hydroxylation reaction of benzene over VO x /CuSBA-15 catalyst using molecular dioxygen as an oxidant in the presence of ascorbic acid. A high yield of phenol was achieved at ca. 27% with the selectivity of nearly 100%. The vanadium and copper oxide species supported catalyst, VO x /CuSBA-15, was synthesized to catalyze the hydroxylation reaction of benzene to form phenol using molecular dioxygen in the presence of ascorbic acid. A high yield of phenol was achieved at ca. 27% with the selectivity of nearly 100%. The VO x /CuSBA-15 has two characteristics that it can selectively activate dioxygen molecules rather than H 2 O 2 , and it can selectively catalyze benzene hydroxylation to form phenol, but can hardly catalyze phenol for further oxidation under the same reaction conditions. Both copper and vanadium oxide species supported on a mesoporous silicate has a prominent catalytic performance toward the benzene hydroxylation reaction comparing to the other bi-transition metal oxides or monometallic catalysts on the same support. The results suggest that there might be a synergy between copper and vanadium oxide species on the support. It is believed that benzene hydroxylation over the VO x /CuSBA-15 catalyst occurs through the hydroxyl radical pathway, and the catalytic activation of molecular oxygen to form hydroxyl radical would be a rate determining step.

Mono (V, Nb) or bimetallic (V–Ti, Nb–Ti) ions modified MCM-41 catalysts: synthesis, characterization and catalysis in oxidation of hydrocarbons (aromatics and alcohols)

Mesoporous MCM-41 molecular sieves modified by single (V and Nb) or bimetal (Nb–Ti and V–Ti) ions with highly ordered hexagonal arrangement of their cylindrical channels were prepared by direct synthesis with two different silica sources (sodium silicate and TEOS) and characterized (as-synthesized samples and those used after reaction) by XRD, N 2 adsorption–desorption, TEM, SEM and FTIR techniques. Niobium and titanium were stabilized in the autoclavized gel by complexation with a ligand (acetylacetone and oxalic acid, respectively). V modified MCM-41 catalysts gave a very high activity in hydroxylation reaction of benzene and toluene and a low conversion in oxidation of styrene while Nb-modified MCM-41 samples showed very high conversion in oxidation of styrene but low oxidation conversion of benzene and toluene. Further introduction of titanium in V- and Nb-modified MCM-41 materials conducted to the less well-ordered hexagonal arrangement and gave very different effect on activity in oxidation of aromatics. Introduction of Ti into V-MCM-41 solids led to an increase in activity in oxidation of styrene and benzene but a decrease in conversion in oxidation of toluene. While the addition of Ti in Nb-MCM-41 resulted in a slight increase in conversion of styrene oxidation but a significant decrease in activity of benzene and toluene oxidation. It reveals that the introduction mode of oxidant in the reactors can also influence the activity and selectivity of reaction. An increase in reaction rate of oxidation, in the first 20 h, was obtained by introduction of H 2O 2 step by step during the reaction. The present paper evidenced that the side chain oxidation is main reaction of styrene oxidation while the hydroxylation is main reaction of benzene and toluene. That is why these two reactions need different catalytic centers as revealed by this paper. The oxidation of alcohols using V-modified MCM-41 as catalysts has also been explored and these catalysts showed a very low catalytic activity which increases in the order: hexanol<cyclohexanol<hexanediol.

Pd/SiO2 catalyst for oxidation of benzene to phenol

Usefulness of silica supported palladium catalysts applied for the hydroxylation reaction of benzene under ambient conditions has been demonstrated. Two types of catalyst, Pd alone and CuPd composite catalysts both being supported on silica, were found to behave in remarkably different ways which are dependent also on the mode of reactant gas feeding. The Pd single component catalyst is powerful when hydrogen and oxygen are simultaneously present in the reacting system and produces phenol almost exclusively. On the other hand, the composite catalyst can be used irrespective of the mode of gas feeding. If quinones are desired, the use of the composite catalyst is recommended but if phenol is desired the Pd single component catalyst seems to be advantageous.

ChemInform Abstract: The Role of Oxygen in the Hydroxylation Reaction of Benzene with Fenton′s Reagent. 18O Tracer Study.

AbstractIn order to study the role of O2 and H2O2 in the oxidation of benzene, labeled O2 and nonlabeled H2O2 are applied.

The role of oxygen in the hydroxylation reaction of benzene with Fenton's reagent. Oxygen 18 tracer study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe role of oxygen in the hydroxylation reaction of benzene with Fenton's reagent. Oxygen 18 tracer studyAtsutaka. Kunai, Shintaro. Hata, Sotaro. Ito, and Kazuo. SasakiCite this: J. Am. Chem. Soc. 1986, 108, 19, 6012–6016Publication Date (Print):September 1, 1986Publication History Published online1 May 2002Published inissue 1 September 1986https://doi.org/10.1021/ja00279a057RIGHTS & PERMISSIONSArticle Views649Altmetric-Citations122LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (638 KB) Get e-Alerts Get e-Alerts