883-90-9Relevant articles and documents
In SituAnodically Oxidized BMIm-BF4: A Safe and Recyclable BF3Source
Bortolami, Martina,Mattiello, Leonardo,Scarano, Vincenzo,Vetica, Fabrizio,Feroci, Marta
, p. 16151 - 16157 (2021/07/26)
The anodic oxidation of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF4) efficiently generates BF3from BF4-. This Lewis acid, strongly bound to the ionic liquids, can be efficiently used in classical BF3-catalyzed reactions. We demonstrated the BF3/BMIm-BF4reactivity in four reactions, namely, a domino Friedel-Crafts/lactonization of phenols, the Povarov reaction, the Friedel-Crafts benzylation of anisole, and the multicomponent synthesis of tetrahydro-11H-benzo[a]xanthen-11-ones. In comparison with literature data using BF3-Et2O in organic solvents, in all the presented cases, analogous or improved results were obtained. Moreover, the noteworthy advantages of the developed method are thein situgeneration of BF3(no storing necessity) in the required amount, using only the electron as redox reagent, and the recycling of BMIm-BF4for multiple subsequent runs.
Multifunctional oxygen vacancies in WO3–x for catalytic alkylation of C–H by alcohols under red-light
Gu, Xianmo,Sun, Xichen,Wang, Yunwei,Zhang, Jin,Zheng, Zhanfeng,Zhu, Pengqi
, p. 208 - 217 (2021/09/06)
Surface reaction kinetics and light absorption properties of a photocatalyst are essential demands for efficiently solar to chemical energy converting. In this study, plasmonic WO3–x was firstly applied to photocatalytic alkylation of arenes under red light irradiation. The oxygen vacancies, both on the surface and in the bulk of WO3–x, allow abundant free electrons to increase carrier densities and support its LSPR using low energy photons. The surface oxygen vacancies have more functions: they not only release surface tungsten sites which ensure the chemisorption of alcohols due to the coordianation ability but also promote the activation of alcohols via an efficient transport of the holes on the neighbouring O sites to chemisorption alcohol species. In brief, the bulk oxygen vacancies provide abundant charges and the surface vacancies promote the bond adsorption and activation abilities, which ensure the high efficiency of photocatalytic alkylation of C–H.
Enhanced Friedel-Crafts benzylation activity of bimetallic WSn-KIT-6 catalysts
(Feng) Tao, Franklin,Araújo do Nascimento Araújo, Aline,Chapman, Clint,Maheswari, Rajamanickam,Ramanathan, Anand,Subramaniam, Bala,Tang, Yu,Zhu, Hongda
, p. 657 - 666 (2020/07/31)
A series of W and Sn-containing KIT-6 mesoporous silicates (designated as WxSn5) with similar Sn (~5 wtpercent) and varying W (x = 3–23 wtpercent) loadings were prepared by a one-pot hydrothermal synthesis method. No detectable bulk WO3 species were observed for W loading up to 14 wtpercent with preferential dispersion of WOx species near SnO2 sites. The WxSn5 materials exhibited superior performance for Friedel-Crafts anisole benzylation with intrinsic rate constants for all WxSn5 catalysts being greater than those without Sn. Based on results from DR-UV–Vis, XRD, XPS, EXAFS techniques, we postulate that the WxSn5 materials contain both isolated [WO4]2-/SnO2 and isolated [WO4]2-/SiO2 as active species, with the former being more active. The relative populations of these two highly dispersed species dictate the overall catalyst activity. The intrinsic activities of the WxSn5 catalysts are found to scale linearly with total acidity but are mainly dictated by the Lewis acid sites.
