H5CoW12O40 supported on nano silica from rice husk ash: A green bifunctional catalyst for the reaction of alcohols with cyclic and acyclic 1,3-dicarbonyl compounds
abundant agricultural by-product. The present research work deals with the production of nanosilica powders, with high surface area and in amorphous form, from RHA using optimized technique. 12-Tungestocobaltic acid, H5CoW12O40 (CoW), was supported on silica from RHA to produce silica supported CoW (CoW/NSiO2) as a nano catalyst. The characterization data derived from FT-IR reveal that the Keggin structure
benzylation of 1,3-dicarbonylcompounds. β-Keto enol ethers were obtained when cyclic1,3-dicarbonylcompounds used in this conditions instead of linear ones. The present methodology offers a practical, simple, mild, environmentally friendly, and time-saving method for etherification. Very low loading of catalyst, ease of workup, ease of handling, and reusability of catalyst are other advantages of
Reversible chemoselective transetherification of vinylogous esters using Fe-catalyst under additive free conditions
作者:Nenavath Parvathalu、Sandip G. Agalave、Nirmala Mohanta、Boopathy Gnanaprakasam
DOI:10.1039/c9ob00307j
日期:——
An additive/Brønsted acid/base free, highly efficient and chemoselective transetherification of electron deficient vinylogousesters and water mediated de-alkylation using an earth-abundant Fe-catalyst under very mild reaction conditions is described. This reaction is highly selective to primary alcohols over secondary alcohols, has good functional group tolerance, is scalable to gram scale and a purification
Iron(III) Tosylate in the Preparation of Dimethyl and Diethyl Acetals from Ketones and <font> <b>β</b> </font>-Keto Enol Ethers from Cyclic <font> <b>β</b> </font>-Diketones
作者:Horacio Mansilla、María M. Afonso
DOI:10.1080/00397910802219361
日期:2008.7.24
Abstract An efficient method for conversion of ketones to their corresponding dimethyl and diethyl acetals and of cyclic β-diketones into β-keto enol ethers using Fe(OTs)3 as a catalyst is described.
Polyoxometalate-based acid salts with tunable separation properties as recyclable Brönsted acid catalysts for the synthesis of β-keto enol ethers
作者:Ezzat Rafiee、Sara Eavani
DOI:10.1016/j.catcom.2012.04.009
日期:2012.8
combining Keggin anions with sulfonated ammonium, imidazolium and pyridiniumcations and used as catalyst for the synthesis of β-keto enol ethers. The sulfonated pyridiniumcation with SiW12O404 − anion ([PyPS]4SiW), showed the best activity and recyclability. Depending on the polarity of reaction mixture, “self-separation” or heterogeneous catalysis was observed. The catalyst was conveniently separated from
通过将Keggin阴离子与磺化铵离子,咪唑鎓离子和吡啶鎓阳离子混合,合成了各种基于多金属氧酸盐的酸盐,并将其用作合成β-酮-烯醇醚的催化剂。带有SiW 12 O 40 4-阴离子([PyPS] 4 SiW)的磺化吡啶鎓阳离子显示出最佳的活性和可回收性。根据反应混合物的极性,观察到“自分离”或多相催化。催化剂可方便地从产物中分离出来,易于回收利用,可重复使用多次,而不会显着降低其活性。