1948-33-0Relevant articles and documents
Preparation and catalytic performance of perfluorosulfonic acid-functionalized carbon nanotubes
Zhang, Mengxiao,Li, Cuican,Hua, Weiming,Yue, Yinghong,Gao, Zi
, p. 1874 - 1882 (2014)
Perfluorosulfonic acid-functionalized carbon nanotubes were prepared by liquid deposition of the perfluorosulfonic acid-polytetrafluoroethylene copolymer and characterized by N2 adsorption, scanning electron microscopy, transmission electron mi
Candida antarctica lipase B-catalyzed regioselective deacylation of dihydroxybenzenes acylated at both phenolic hydroxy groups
Miyazawa, Toshifumi,Hamada, Manabu,Morimoto, Ryohei
, p. 44 - 49 (2015)
Candida antarctica lipase B proved to be highly active in the deacylation of substituted hydroquinones and resorcinols acylated at both phenolic hydroxy groups. The deacylation reactions were much faster than the corresponding direct acylations of these dihydroxybenzenes catalyzed by the same lipase. More importantly, they took place generally in a markedly regioselective manner: the acyloxy group remote from the substituent was preferentially cleaved. The main or exclusive products obtained were the regioisomers of those produced through the direct acylation of the dihydroxybenzenes. In the case of alkyl-substituted hydroquinone derivatives, the regioselectivity increased with an increase in the bulk of the substituent. In the case of 4-substituted diacylated resorcinols, the 3-O-monoacyl derivatives were obtained generally as the sole products. Quite interestingly, some secondary alcohols proved to act as better acyl acceptors than the corresponding primary alcohols in these enzymatic deacylations.
Can Donor Ligands Make Pd(OAc)2a Stronger Oxidant? Access to Elusive Palladium(II) Reduction Potentials and Effects of Ancillary Ligands via Palladium(II)/Hydroquinone Redox Equilibria
Bruns, David L.,Musaev, Djamaladdin G.,Stahl, Shannon S.
supporting information, p. 19678 - 19688 (2020/12/18)
Palladium(II)-catalyzed oxidation reactions represent an important class of methods for selective modification and functionalization of organic molecules. This field has benefitted greatly from the discovery of ancillary ligands that expand the scope, reactivity, and selectivity in these reactions; however, ancillary ligands also commonly poison these reactions. The different influences of ligands in these reactions remain poorly understood. For example, over the 60-year history of this field, the PdII/0 redox potentials for catalytically relevant Pd complexes have never been determined. Here, we report the unexpected discovery of (L)PdII(OAc)2-mediated oxidation of hydroquinones, the microscopic reverse of quinone-mediated oxidation of Pd0 commonly employed in PdII-catalyzed oxidation reactions. Analysis of redox equilibria arising from the reaction of (L)Pd(OAc)2 and hydroquinones (L = bathocuproine, 4,5-diazafluoren-9-one), generating reduced (L)Pd species and benzoquinones, provides the basis for determination of (L)PdII(OAc)2 reduction potentials. Experimental results are complemented by density functional theory calculations to show how a series of nitrogen-based ligands modulate the (L)PdII(OAc)2 reduction potential, thereby tuning the ability of PdII to serve as an effective oxidant of organic molecules in catalytic reactions.
Tert-butylhydroquinone preparation method
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Paragraph 0025-0031, (2020/04/02)
The invention relates to the technical field of organic synthesis, and relates to a tert-butylhydroquinone preparation method, which comprises: 1) sequentially adding 2-tert-butylphenol, a transitionmetal copper (I) cooperation compound and a solvent to a high pressure reaction kettle, introducing oxygen to achieve a specified pressure, heating and stirring to a specified temperature, and carrying out a reaction for 0.5-3 h; 2) after the reaction is finished, evaporating out the solvent, washing the residual solid with a solvent, and carrying out steam stripping to obtain 2-tert-butyl p-benzoquinone; 3) sequentially adding the 2-tert-butyl p-benzoquinone obtained in the step 1), a catalyst and a solvent into a high-pressure reaction kettle, introducing hydrogen to a specified pressure after gas exchange is completed, heating and stirring to a specified temperature, and carrying out a reaction for 0.5-3 hours; and 4) after the reaction is finished, evaporating out the solvent, and rectifying to obtain the tert-butylhydroquinone product. According to the invention, the method has the advantages of high product yield, convenient operation, cheap raw materials, economy and reliability, and is suitable for large-scale production.
