935-92-2Relevant articles and documents
SHIFF'S BASES IN THE POLYMER MATRIX. COMMUNICATION 2. STRUCTURE AND CATALYTIC PROPERTIES OF Cu(II) COMPLEXES WITH AROMATIC AND HETEROCYCLIC AZOMETHINES IN THE STYRENE-DIVINYLBENZENE COPOLYMER IN OXIDATION OF 2,3,6-TRIMETHYLPHENOL
Skobeleva, V. D.,Men'shikov, S. Yu.,Molochnikov, L. S.,Kolenko, I. P.,Novoselova, A. A.,et al.
, p. 1598 - 1601 (1987)
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Titanium dioxide xerogel modified with powder cellulose in oxidation of trimethylhydroquinone
Shishmakov,Mikushina,Valova,Koryakova,Petrov
, p. 2107 - 2110 (2007)
A procedure was developed for modification of titanium dioxide xerogel by addition of powder cellulose in the stage preceding hydrolysis of tetramethoxytitanium. The resulting catalytic systems based on the new material were studied in a model liquid-phase catalytic process of oxidative dehydrogenation of trimethylhydroquinone with atmospheric oxygen.
An efficient synthesis of 2,3,5-trimethylbenzoquinone by metal-free oxidation of 1,2,4-trimethylbenzene
Yerramreddy, Thirupathi Reddy,Pelton, Egan,Dawson, Karl A,Yiannikouris, Alexandros
, p. 565 - 568 (2019)
The oxidation of 1,2,4-trimethylbenzene with phthaloyl peroxide has been investigated under solvent-free and optimized conditions. 2,3,5-Trimethylbenzoquinone was obtained with great purity in 92% yield at 95% conversion of 1,2,4-trimethylbenzene at 120°C for 2.5 h under solvent-free conditions. The important factors such as the efficiency of the different cyclic acid anhydrides or carboxylic acid peroxides, the concentration of phthalic anhydride and 30% H2O2, the reaction time, the effect of solvent system, and the reaction temperature have been studied. An important advantage of this oxidizing system, aside from the organic solvent-free conditions, is that it is non-toxic, eco-friendly, and inexpensive. In addition, this methodology will be of great use in the preparation of commercially valuable benzoquinones from the corresponding aromatic compounds.
Hierarchical mesoporous TS-1 zeolite: A highly active and extraordinarily stable catalyst for the selective oxidation of 2,3,6-trimethylphenol
Zhou, Jian,Hua, Zile,Cui, Xiangzhi,Ye, Zhengqing,Cui, Fangming,Shi, Jianlin
, p. 4994 - 4996 (2010)
We report the synthesis of a new hierarchical mesoporous TS-1 type zeolite by a simple steam-assisted crystallization method. This novel product exhibits high catalytic activity and a strongly prolonged lifetime in the selective oxidation of 2,3,6-trimethylphenol to trimethyl-p-benzoquinone.
Efficient oxidation of 2,3,6-trimethyl phenol using non- exchanged and H+ exchanged manganese oxide octahedral molecular sieves (K-OMS-2 and H-K-OMS-2) as catalysts
Opembe, Naftali N.,King'Ondu, Cecil K.,Suib, Steven L.
, p. 427 - 432 (2012)
A new and efficient oxidation process of 2,3,6- trimethyl phenol to 2,3,6-trimethyl benzoquinone (TMQ) is reported forthwith using non-exchanged and H+-exchanged manganese oxide octahedral molecular sieves (K-OMS-2 and H-K-OMS-2) as benign catalysts. The oxidation reaction is efficiently carried out using TBHP as oxidant and with catalytic amounts of OMS-2 achieving >95% conversion with excellent selectivity (～99%) to TMQ in 30 min. Springer Science+Business Media, LLC 2012.
CATALYTICAL PROPERTIES OF POLYVANADOMOLYBDIC ACIDS IN OXIDATION OF 1,2,4-TRIMETHYLBENZENE BY PERACETIC ACID
Petrov, L. A.,Lobanova, N. P.,Volkov, V. L:,Zakharova, G. S.,Kolenko, I. P.,Buldakova, L. Yu.
, p. 1806 - 1808 (1989)
Polyvanadomolybdic acids catalyze the process of peracid oxidation of 1,2,4-trimethylbenzene.The selectivity with respect to 2,3,5-trimethyl-1,4-benzoquinone increases with increasing degree of replacement of vanadium atoms in the PVMA by molybdenum; this is related to increased stability of the intermediate peroxides of the heteropolyvanadates.
Oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel
Kharchuk,Buldakova,Shishmakov,Kuznetsova,Kovaleva,Koryakova,Molochnikov,Yanchenko,Petrov
, p. 101 - 104 (2004)
Liquid-phase oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel was studied by a kinetic method. Associative interactions between the substrate, oxidant, and gel were detected by voltammetry and ESR and IR spectroscopy.
Kornfeld,Weissberger
, p. 360 (1939)
Polyoxometalate-based supramolecular porous frameworks with dual-active centers towards highly efficient synthesis of functionalized: P -benzoquinones
An, Haiyan,Chang, Shenzhen,Chen, Yanhong,Huang, Yaohui,Luo, Huiyun,Zhu, Qingshan
, p. 8591 - 8603 (2021/11/17)
Selective oxidation of substituted phenols is an ideal method for preparing functionalized p-benzoquinones (p-BQs), which serve as versatile raw materials for the synthesis of a variety of biologically active compounds. Herein, two new polyoxometalate-based supramolecular porous frameworks, K3(H2O)4[Cu(tza)2(H2O)]2[Cu(Htza)2(H2O)2][BW12O40]·6H2O (1) and H3K3(H2O)3[Cu(Htza)2(H2O)]3[SiW12O44]·14H2O (2) (Htza = tetrazol-1-ylacetic acid), were synthesized and structurally characterized by elemental analysis, infrared spectroscopy, thermal analysis, UV-vis diffuse reflectance spectroscopy, and single-crystal X-ray and powder diffraction. The single-crystal X-ray diffraction analysis indicates that both compounds possess unique petal-like twelve-nucleated Cu-organic units composed of triangular and hexagonal metal-organic loops. In 1, the Cu-organic units are isolated and [BW12O40]5- polyoxoanions are sandwiched between staggered adjacent triangular channels in the structure. However in 2, the Cu-organic units extend into a two-dimensional layered structure, and the [SiW12O44]12- polyoxoanions occupy the larger hexagonal channels in the stacked structure. Both compounds as heterogeneous catalysts can catalyze the selective oxidation of substituted phenols to high value-added p-BQs under mild conditions (60 °C) with TBHP as the oxidant, particularly in the oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-p-benzoquinone (TMBQ, key intermediate in vitamin E production). Within 8-10 min, the yield of TMBQ is close to 100%, and oxidant utilization efficiency is up to 94.2% for 1 and 90.9% for 2. The turnover frequencies of 1 and 2 are as high as 5000 and 4000 h-1, respectively. No obvious decrease in the yield of TMBQ was observed after five cycles, which indicates the excellent sustainability of both compounds. Our study of the catalytic mechanism suggests that there is a two-site synergetic effect: (i) the copper ion acts as the catalytic site of the homolytic radical pathway; and (ii) the polyoxoanion acts as the active center of the heterolytic oxygen atom transfer pathway. This journal is
Organophotocatalytic Aerobic Oxygenation of Phenols in a Visible-Light Continuous-Flow Photoreactor
Wellauer, Jo?l,Miladinov, Dragan,Buchholz, Thomas,Schütz, Jan,Stemmler, René T.,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
supporting information, p. 9748 - 9752 (2021/05/27)
A mild photocatalytic phenol oxygenation enabled by a continuous-flow photoreactor using visible light and pressurized air is described herein. Products for wide-ranging applications, including the synthesis of vitamins, were obtained in high yields by precisely controlling principal process parameters. The reactor design permits low organophotocatalyst loadings to generate singlet oxygen. It is anticipated that the efficient aerobic phenol oxygenation to benzoquinones and p-quinols contributes to sustainable synthesis.
