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.
Formation and properties of a catalyst based on sodium and potassium hydroxides in the reaction of 2,6-di-tert-butylphenol with methyl acrylate
Volod'kin,Zaikov
, p. 2189 - 2195 (2002)
The nature of the cation (K+ or Na+) in hydroxides affects the temperature plot of the equilibrium constant of the reaction of KOH and NaOH with 2,6-di-tert-butylphenol (ArOH) and the conversion of KOH and (or) NaOH to potassium or sodium 2,6-di-tert-butyl phenoxides, which are catalysts for the alkylation of ArOH by methyl acrylate. The kinetic method for determination of the composition of the catalyst formed from NaOH and ArOH was proposed. The nature of the cation in phenoxides ArOK or ArONa is a factor determining the kinetics of the reaction of ArOH with methyl acrylate. Two different kinetic schemes were proposed to describe the transformation of ArOH in the presence of ArONa or ArOK.
Ethylene/hindered phenol substituted norbornene copolymers: Synthesis and NMR structural determination
Viglianisi, Caterina,Menichetti, Stefano,Assanelli, Giulio,Sacchi, Maria Carmela,Tritto, Incoronata,Losio, Simona
, p. 4647 - 4655 (2012)
A new family of ethylene-based copolymers with controlled amounts of a norbornene comonomer (NArOH) bearing a stabilizing antioxidant functionality (2,6-di-tert-butyl phenol) was prepared. Due to unavoidable exo/endo equilibrium operative in NArOH comonomer, a complete and detailed NMR assignment of the structure of the prepared ethylene/N ArOH copolymers was carried out for the determination of the exo/endo ratio inside the polymer. These novel functionalized comonomers can be considered suitable starting material for preparing ethylene-based copolymers, with tunable comonomer content, as non-releasing macromolecular antioxidant additives for specific application in safe food and/or drug packaging 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 Copolymers of ethylene with an antioxidant phenolic functionalized norbornene comonomer have been prepared and their structure fully determined by NMR. These novel materials can be used as non-releasing macromolecular antioxidant additives for specific application in safe food and/or drug packaging. Copyright
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.
Highly efficient alkylation of phenol with tert-butyl alcohol using environmentally benign Bronsted acidic ionic liquids
Patra, Tanmoy,Ahamad, Salahuddin,Upadhyayula, Sreedevi
, p. 228 - 236 (2015)
A series of SO3-H functionalized environmentally benign Bronsted acidic ionic liquids were prepared using triethylamine, 1-methyl imidazole, pyridine, diethanolamine, 1,4-butane sultone and methane sulfonic acid as the starting materials. These synthesized ionic liquid catalysts were characterized using spectroscopic tools like 1H NMR, 13C NMR. The catalytic activity of the synthesized ionic liquids was investigated in tert-butylation of phenol with tert-butyl alcohol. The effect of kinetic parameters like reaction time, reaction temperature, reactant mole ratio, reactant to catalyst mole ratio, on the conversion of phenol and selectivity to 2-tert-butyl-phenol and 2,4-di-tert-butyl-phenol were investigated. Phenol conversion upto 94.2% was achieved at temperature as low as 80 °C and low alcohol to phenol molar ratio of 2:1, ionic liquid to phenol ratio of 1:1 and reaction time of 2 h. The catalyst was found to retain its activity even after 8 recycles and was completely recoverable. The plausible reaction mechanism was formulated based on product distribution. The kinetic data was found to agree well with classical phenomenological models and the kinetic parameters were estimated. The experimental results were further validated by Density Functional Theory (DFT) optimizations of the ionic liquid structures performed at the B3LYP/6-311G??level using Gaussian 09 package.
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.
Guaiacol demethoxylation catalyzed by Re2O7 in ethanol
Yan, Fei,Sang, Yushuai,Bai, Yunfei,Wu, Kai,Cui, Kai,Wen, Zhe,Mai, Fuhang,Ma, Zewei,Yu, Linhao,Chen, Hong,Li, Yongdan
, p. 231 - 237 (2019/08/12)
Re2O7 is used to convert guaiacol in alcohols at 280–320 °C. In ethanol, guaiacol is deoxygenated and alkylated, and the major products are phenol and alkylphenols (including ethylphenol, diethylphenol, diisopropylphenol, di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol), accounting for 97 mol% of all products after 6 hour reaction at 320 °C. Both catechol and phenol are the intermediates of guaiacol demethoxylation. Among the substituents, ethyl is directly provided by ethanol while isopropyl and tert-butyl are formed by the addition of methyl to ethyl step by step. In addition, Re2O7 has negligible activity for the saturation of benzene ring so it does not cause considerable over-consumption of reductant. The actual catalyst for guaiacol demethoxylation is likely a ReIV?VI species.
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.
Ambident Reactivity of Phenolate Anions Revisited: A Quantitative Approach to Phenolate Reactivities
Mayer, Robert J.,Breugst, Martin,Hampel, Nathalie,Ofial, Armin R.,Mayr, Herbert
, p. 8837 - 8858 (2019/07/08)
Prompted by the observation that the regioselectivities of phenolate reactions (C versus O attack) are opposite to the predictions by the principle of hard and soft acids and bases, we performed a comprehensive experimental and computational investigation of phenolate reactivities. Rate and equilibrium constants for the reactions of various phenolate ions with benzhydrylium ions (Aryl2CH+) and structurally related quinone methides have been determined photometrically in polar aprotic solvents. Quantum chemical calculations at the SMD(MeCN)/M06-2X/6-31+G(d,p) level confirmed that O attack is generally favored under kinetically controlled conditions, whereas C attack is favored under thermodynamically controlled conditions. Exceptions are diffusion-limited reactions with strong electrophiles, which give mixtures of products arising from O and C attack, as well as reactions with metal alkoxides in nonpolar solvents, where oxygen attack is blocked by strong ion pairing. The Lewis basicity (LB) and nucleophilicity (N, sN) parameters of phenolates determined in this work can be used to predict whether their reactions with electrophiles are kinetically or thermodynamically controlled and whether the rates are activation- or diffusion-limited. Comparison of the measured rate constants for the reactions of phenolates with carbocations with the Gibbs energies for single-electron transfer manifests that these reactions proceed via polar mechanisms.
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.
