79-74-3Relevant articles and documents
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.
PRODUCTION OF A DISUBSTITUTED HYDROQUINONES
-
Page/Page column 6-8; 11, (2008/06/13)
A process for the production of a disubstituted hydroquinone which comprises alkylating hydroquinone in the presence of a sulphonic acid condensation catalyst with an olefin or a substance which under the reaction conditions acts as a source thereof. The preferred olefin is 2-methyl-2-butene either alone or in admixture- with isomers thereof, and the preferred catalyst is methane sulphonic acid and the reaction product is 2,5-di-tert-amylhydroquinone. Only catalytic amounts of catalyst are required. The reaction product is worked-up by complete dissolution of the desired product and washing with an aqueous medium containing a pH buffering agent and a reducing agent.
Thioether substituted hydroxybenzophenones and stabilized compositions
-
, (2008/06/13)
2-Hydroxybenzophenone derivatives substituted in the 4′-position by a thioether moiety exhibit enhanced absorption in the UV at longer wavelength. Compositions comprising organic material subject to actinic degradation are beneficially stabilized with such derivatives.