98-54-4Relevant articles and documents
Efficiency of sulfonic cation-exchange resins used in para-tert-butylphenol production: A comparison based on the kinetics of transalkylation in the phenol-tert-butylphenols system
Voronin,Nesterova,Strelchik,Zhuravskii
, p. 705 - 711 (2014)
The kinetics of transalkylation in the phenol-tert-butylphenols system in the presence of Amberlyst 36 Dry sulfonic cation-exchange resin has been investigated at 353-403 K in the tert-Bu/Ar = 0.10-0.55 mol/mol range. Kinetic characteristics of the o-tert-butylphenol + phenol ai p-tert-butylphenol + phenol (I) and 2,4-di-tert-butylphenol + phenol ai 2p-tert-butylphenol (II) reactions have been determined. The chemical equilibrium in the presence of Amberlyst 36 Dry is reached much sooner than in the presence of KU-23 10/60, a cation-exchange resin used at present. On passing from Amberlyst 36 Dry to KU-23 10/60, the preexponential factor for reaction (I) increases by a factor of 10 and that for reaction (II) increases by a factor of 2000. Thermodynamic characteristics of reaction (I) between 353 and 523 K have been calculated from experimental data and data available from the literature. The thermodynamic characteristics of reaction (II) have been determined experimentally. The enthalpy and entropy of reaction (I) are equal to those of reaction (II). The difference between the equilibrium constants of these reactions is explained. It is recommended that Amberlyst 36 Dry, which proved more efficient than KU-23 10/60, be used in the industrial production of p-tert-butylphenol.
Aromatic C?H Hydroxylation Reactions with Hydrogen Peroxide Catalyzed by Bulky Manganese Complexes
Masferrer-Rius, Eduard,Borrell, Margarida,Lutz, Martin,Costas, Miquel,Klein Gebbink, Robertus J. M.
, p. 3783 - 3795 (2021/03/09)
The oxidation of aromatic substrates to phenols with H2O2 as a benign oxidant remains an ongoing challenge in synthetic chemistry. Herein, we successfully achieved to catalyze aromatic C?H bond oxidations using a series of biologically inspired manganese catalysts in fluorinated alcohol solvents. While introduction of bulky substituents into the ligand structure of the catalyst favors aromatic C?H oxidations in alkylbenzenes, oxidation occurs at the benzylic position with ligands bearing electron-rich substituents. Therefore, the nature of the ligand is key in controlling the chemoselectivity of these Mn-catalyzed C?H oxidations. We show that introduction of bulky groups into the ligand prevents catalyst inhibition through phenolate-binding, consequently providing higher catalytic turnover numbers for phenol formation. Furthermore, employing halogenated carboxylic acids in the presence of bulky catalysts provides enhanced catalytic activities, which can be attributed to their low pKa values that reduces catalyst inhibition by phenolate protonation as well as to their electron-withdrawing character that makes the manganese oxo species a more electrophilic oxidant. Moreover, to the best of our knowledge, the new system can accomplish the oxidation of alkylbenzenes with the highest yields so far reported for homogeneous arene hydroxylation catalysts. Overall our data provide a proof-of-concept of how Mn(II)/H2O2/RCO2H oxidation systems are easily tunable by means of the solvent, carboxylic acid additive, and steric demand of the ligand. The chemo- and site-selectivity patterns of the current system, a negligible KIE, the observation of an NIH-shift, and the effectiveness of using tBuOOH as oxidant overall suggest that hydroxylation of aromatic C?H bonds proceeds through a metal-based mechanism, with no significant involvement of hydroxyl radicals, and via an arene oxide intermediate. (Figure presented.).
Hydroperoxide method for the synthesis of p-tert-butylphenol
Frolov, A. S.,Korshunova, A. I.,Koshel’, G. N.,Kurganova, E. A.,Yarkina, E. M.
, p. 1951 - 1956 (2021/11/05)
The results of studies related to the development of a highly selective three-stage method for the synthesis of p-tert-butylphenol along with acetone are presented. The alkylation of isopropylbenzene with tert-butyl alcohol in the presence of concentrated sulfuric acid makes it possible to obtain only the para-isomer of tert-butylcumene. For the liquid-phase aerobic oxidation of p-tert-butylcumene in the presence of the phthalimide catalysts, the hydrocarbon conversion reaches 45% with a selectivity of hydroperoxide formation of 90–95%. The process of acid decomposition of p-tert-butylcumene hydroperoxide to p-tert-butylphenol and acetone was studied. Conditions providing the production of p-tert-butylphenol in a yield of 90% were found.
The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
, p. 18040 - 18049 (2021/05/29)
An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.