128-39-2Relevant articles and documents
Oxidation of 2,6-Di-tert-butylphenol by Molecular Oxygen. 2. Catalysis by Cobaltous Polyamine Chelates through Their (μ-Peroxo)- and (μ-Peroxo)(μ-hydroxo)dicobalt(III) Complexes
Bedell, Stephen A.,Martell, Arthur E.
, p. 7909 - 7913 (1985)
The oxidation of 2,6-di-tert-butylphenol by molecular oxygen is catalyzed by the cobaltous chelates of tetraethylenepentamine (TETREN), dipicolyldiethylenetriamine (PYDIEN), and 1,4,10,13-tetraaza-7-thiatridecane (TATTD), through their (μ-peroxo)dicobalt(III) complexes and by those of dipicolylethylenediamine (PYEN), tris(aminoethyl)amine (TREN), and triethylenetetramine (TRIEN) through their (μ-hydroxo)(μ-peroxo)dicobalt(III) complexes.Reaction products are identified as the oxidative coupling product 3,3'5,5'-tetra-tert-butyldiphenoquinone and the partial oxygen insertion product, 2,6-di-tert-butylbenzoquinone.The rates of reaction of the substrate as well as the formation of products are shown to be first order with respect to the concentrations of both the cobalt-dioxygen complex and the substrate.The reaction with (4+) does not occur in the absence of free molecular oxygen in solution and occurs at a reduced rate under air relative to oxygen.
Bolton et al.
, p. 3415 (1968)
Tertiary butylation of phenol on Cu1-xCoxFe 2O4: Catalysis and structure-activity correlation
Mathew, Thomas,Rao, Bollapragada S.,Gopinath, Chinnakonda S.
, p. 107 - 116 (2004)
A systematic study of catalytic tertiary butylation of phenol was carried out with isobutene as a function of temperature, feed composition, time on stream, space velocity, and catalyst composition on Cu1-xCo xFe2O4 (x=0 to 1) system. Tertiary butylation of phenol gives three products, namely, 2-tert-butyl phenol, 4-tert-butyl phenol, and 2,4-di-tert-butyl phenol. The phenol conversion and selectivity of these products depend on the reaction parameters. A good correlation was found between the activity, in terms of phenol conversion and various product selectivities for this reaction, and the acid-base properties of the catalysts. High activity is achieved with x=0.5 composition, illustrating the importance of a 1:1 combination of Cu and Co and the necessity for optimum concentrations of acid-base centers for this reaction. A reaction mechanism involving the interaction of phenoxide from phenol and the tert-butyl cation from isobutene on Cu1-xCoxFe2O4 is proposed. X-ray photoelectron spectroscopy and X-ray induced Auger electron spectroscopic analysis of fresh and spent catalysts revealed a partial reduction of metal ions due to reaction. Valence band studies clearly revealed an increase in the overlap of metal ion 3d bands from fresh to spent catalysts as reflected from a large decrease in the energy gap between them. The better catalytic results observed with x=0.5 are attributed to an optimum distribution of Cu species with heteroatom neighbors, maximum overlap between the Cu and Co 3d bands, and intermediate acid-base character.
Synthesis and structural characterization of a 4-coordinate molybdenum(VI) dioxo diaryloxide, MoO2(O-2,6-t-Bu2C6H3)2·Ho-2,6-t-Bu2C6H3
Hanna, Tracy A.,Incarvito, Christopher D.,Rheingold, Arnold L.
, p. 630 - 631 (2000)
The facile solution synthesis and spectroscopic and structural characterization of 4-coordinate MoO2(OAr)2. ArOH (1) where Ar = 2,6-di-tert-butylphenyl are described. MoO2(O-2,6-t-Bu2C6H3)2·HO-2,6-t-Bu2C6H3 (1) was synthesized by addition of LiOAr to MoO2Cl2 in CH3CN. Yields are reduced by concurrent oxidation of the phenolic anion to form 3,3',5,5'-tetra-tert-butyl-4,4'-diphenoquinone (4). Relatively strong Mo=O double bonds and p-electron donation from the aryloxide oxygens appear to compensate for the unsaturation of the pseudotetrahedral metal center.
Alkylation of Phenols with tert-Butanol Catalyzed by H-Form of Y Zeolites with a Hierarchical Porous Structure
Bayguzina,Makhiyanova,Khazipova,Khusnutdinov
, p. 1554 - 1559 (2019/10/14)
tert-Butyl-substituted phenols have been synthesized via the reaction of phenol, o-, m-, and p-cresols with tert-butanol under the action of CBr4-promoted Y-zeolites in the H-form with a hierarchical porous structure.
Highly selective conversion of guaiacol to: Tert -butylphenols in supercritical ethanol over a H2WO4 catalyst
Mai, Fuhang,Cui, Kai,Wen, Zhe,Wu, Kai,Yan, Fei,Chen, Mengmeng,Chen, Hong,Li, Yongdan
, p. 2764 - 2771 (2019/02/01)
The conversion of guaiacol is examined at 300 °C in supercritical ethanol over a H2WO4 catalyst. Guaiacol is consumed completely, meanwhile, 16.7% aromatic ethers and 80.0% alkylphenols are obtained. Interestingly, tert-butylphenols are produced mainly with a high selectivity of 71.8%, and the overall selectivity of 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol is as high as 63.7%. The experimental results indicate that catechol and 2-ethoxyphenol are the intermediates. Meanwhile, the WO3 sites play an important role in the conversion of guaiacol and the Br?nsted acid sites on H2WO4 enhance the conversion and favour a high selectivity of the tert-butylphenols. The recycling tests show that the carbon deposition on the catalyst surface, the dehydration and partial reduction of the catalyst itself are responsible for the decay of the H2WO4 catalyst. Finally, the possible reaction pathways proposed involve the transetherification process and the alkylation process during guaiacol conversion.