- Deoxyalkylation of guaiacol using haggite structured V4O6(OH)4
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When V2O5 is used for the deoxygenation of guaiacol in methanol, it is reduced in situ to haggite structured V4O6(OH)4. Guaiacol prevents further reduction of the haggite phase in methanol and haggite catalyzes the partial deoxygenation of guaiacol. Haggite is a metastable redox catalyst for the deoxygenation of guaiacol, which follows the reverse Mars-van Krevelen mechanism. In addition, haggite is also a Lewis acid catalyst and catalyzes the alkylation of guaiacol with methanol as the alkylation reagent. The main products of the guaiacol deoxyalkylation are 2,6-dimethylphenol, 2-methoxy-6-methylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, 2,3,5,6-tetramethylphenol and 6-methyl-2-tert-butylphenol. Oligomerization takes place during the reaction but it is reversible. When the reaction is performed at 300 °C for 6 h, the 83.5% total selectivity for alkylphenols is achieved with a 99.0% conversion.
- Yan, Fei,Wen, Zhe,Wu, Kai,Cui, Kai,Mai, Fuhang,Ma, Zewei,Sang, Yushuai,Bai, Yunfei,Chen, Hong,Li, Yongdan
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- Alkylation of Phenols with tert-Butanol Catalyzed by H-Form of Y Zeolites with a Hierarchical Porous Structure
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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.
- Bayguzina,Makhiyanova,Khazipova,Khusnutdinov
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p. 1554 - 1559
(2019/10/14)
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- Phenol o-position alkylation method
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The invention provides a phenol o-position alkylation method which comprises the following step: in the presence of a catalyst, a phenol substance and an alkylating agent react, wherein the catalyst is an aryl zinc salt generated from a reaction of zinc and a phenol compound; the alkylating agent is olefin; the phenol substance comprises polyphenol such as catechol and hydroquinone, and further comprises one to two alkyl groups, or halide based phenols; the alkyl group is straight-chain or branched paraffin with 1-10 carbons. By adopting the phenol o-position alkylation method, the preparation efficiency is greatly improved, and the conversion rate can be further increased. The invention further provides a method for preparing 2,6-di-tert-butyl-4-methylphenol, and a reaction kettle for preparation.
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Paragraph 0061; 0062; 0063; 0064
(2017/08/27)
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- About selective methods of synthesis of 6-tert-butyl-2-methylphenol and 6-tert-butyl-2,4-dimethylphenol
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Vapor phase catalytic methylation with methanol of 2-tert-butylphenol at the temperature 280-300°C proceeds selectively with formation of 6-tert-butyl-2-methylphenol. Elevating reaction temperature above 300°C leads to formation of 2,6-dimethylphenol. Reaction of 2-tert-butylphenol with methanol in alkaline medium in the presence of zinc oxide is shown to lead initially to formation of a mixture of calixarenes and methylenebisphenols that at elevated temperature exert splitting leading in future to 6-tert-butyl-2,4-dimethylphenol. Obtaining it in this reaction from 2,2′-methylenebis-(6-tert-butyl-4-methylphenol) proceeds selectively. Pathways of the reductive methylation of methylenebisphenols with methanol in alkaline medium is considered.
- Krysin,Khlebnikova,Khlebnikov,Pokrovskii,Vasil'ev
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experimental part
p. 1156 - 1162
(2011/05/04)
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- Ruthenium-catalyzed rearrangement of cis-1-ethynyl-2-vinyloxiranes to substituted phenols
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Catalytic cyclization of cis-1-ethynyl-2-vinyloxiranes was implemented with TpRuPPh3(CH3CN)2PF6 catalyst (10 mol%), to give 2,6-disubstituted phenols in reasonable yields. Under similar conditions, 1,1,2,2-tetrasubstituted oxirane gave the 2,3,6-trisubstituted phenol with skeleton reorganization. On the basis of 2H- and l3C-labeling results, we propose that the reaction mechanism involves electrocyclization of ruthenium-vinylidene intermediate with cleavage of the carbon-oxygen bond of the epoxide. Georg Thieme Verlag Stuttgart.
- Maddirala, Shambabu Joseph,Odedra, Arjan,Taduri, Bhanu Pratap,Liu, Rai-Shung
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p. 1173 - 1176
(2007/10/03)
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- Preparation of biphenols by oxidative coupling of alkylphenols using a recyclable copper catalyst
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A method for producing biphenols by oxidative coupling of dialkylphenols which proceeds in two stages using a copper amine complex which is catalytically effective in each stage is disclosed. A novel copper amine complex is also disclosed wherein the complex exhibits high catalytic activity for the oxidative coupling of substituted phenols under mild conditions, has dual (two stage) activity and can be readily recycled and reused.
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- Preparation of biphenols by oxidative coupling of alkylphenols using a recyclable copper catalyst
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A method for producing biphenols by oxidative coupling of dialkylphenols which proceeds in two stages using a copper amine complex which is catalytically effective in each stage is disclosed. A novel copper amine complex is also disclosed wherein the complex exhibits high catalytic activity for the oxidative coupling of substituted phenols under mild conditions, has dual (two stage) activity and can be readily recycled and reused.
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- Preparation of biphenols by oxidative coupling of alkylphenols using copper catalyst
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This invention relates to a method for producing biphenols by oxidative coupling of dialkylphenols which proceeds in two stages using a copper amine complex which is catalytically effective in each stage.
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- 4-Hydroxytetrahydropyran-2-one derivatives
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4-hydroxytetrahydropyran-2-one derivatives with general formula (I) are useful as cholesterol reducing agents as well as lipid reducing agents, serving as inhibitors of HMG-CoA reductase, and capable of inhibiting the biosynthesis of peroxidized lipids, and therefore effective for curing arteriosclerosis: STR1 wherein R1 represent hydrogen or a 2-tetrahydropyranyl group; R2 and R3 each represent hydrogen or an alkyl group having 1 to 6 carbon atoms; R4 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, an aralkyl group, an acyl group, an aroyl group or a substituted sulfonyl group; A represents --CH2 CH2 --, or --CH=CH--; and n is an integer of 1 or 2, and intermediates for synthesizing the 4-hydroxytetrahydropyran-2-one derivatives are disclosed.
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- Antioxidant synthesis
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A process for making a 2,6-di-hydrocarbyl-4-alkoxyalkylphenol, e.g. 2,6-di-tert-butyl-4-methoxymethylphenol, by reacting a 2,6-dihydrocarbylphenol with formaldehyde in a stoichiometric excess of alcohol and in the presence of a Mannich base catalyst preferably formed in situ by adding a catalyst-forming amount of a secondary amine, e.g. dimethylamine, to the mixture of 2,6-di-hydrocarbylphenol, formaldehyde and alcohol. Unreacted alcohol and amine are distilled out and the 2,6-di-hydrocarbyl-4-alkoxyalkylphenol is reacted with a benzene-type compound, e.g. mesitylene, to make a hindered phenolic antioxidant, e.g. 1,3,5-trimethyl-2,4,6-tri-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.
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- EQULIBRATION OF TERT-ALKYLPHENOLS (THERMODYNAMIC ANALYSIS OF THE ALKYLATION OF PHENOLS USING BRANCHED-CHAIN OLEFINS).
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The authors describe the results of a study to evaluate the thermodynamic properties of t-Alk PHI ; these results; combined with earlier results, have enabled the authors to complete a thermodynamic analysis of the process for preparing tertiary alkylphenols.
- Nesterova,Verevkin,Malova,Pil'shchikov
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p. 748 - 754
(2007/10/02)
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- REACTIVITY OF 2,4- AND 2,6-DIALKYLPHENOLS DURING SUBSTITUTION BY WEAK ELECTROPHILIC AGENTS
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The 2,4- and 2,6-dialkylphenols have different reactivities during substitution by weak electrophiles. 2,4-Dialkylphenols enter readily into acid-catalyzed alkylation and condensation with aldehydes, and their reactivity is practically independent of the structure of the alkyl substituents. 2,6-Dialkylphenols have significantly lower reactivity in these reactions, while sterically hindered 2,6-dialkylphenols hardly react at all with alkenes and aldehydes under the conditions of acid catalysis.This is evidently due to weakening of the interaction between the hydroxyl group and the aromatic ring in the conjugation mechanism.
- Gurvich, Ya. A.,Kumok, S. T.,Starikova, O. F.,Styskin, E. L.
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p. 371 - 375
(2007/10/02)
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- Trans-substitution and equilibration of phenols. Part IV. The influence of various catalysts on the trans-tert-butylation reaction of phenols; mechanistic aspects
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The trans-tert-butylation reaction by 2,6-di-tert-butyl-4-methylphenol has been studied for a number of phenols in the presence of different catalysts.Equilibria, as well as reaction kinetics, have been investigated.The mechanism involves the intermediacy of a tert-butyl ether.This mechanism is supported both by the kinetics and the initially high ortho/para ratio as well as by the reversed substituent effect.
- Willemse, F. R. J.,Kooyman, E. C.,Lamoen, H. B. van,Vos, D. de,Wolters, J.
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p. 206 - 209
(2007/10/02)
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