Bimodal cesium hydrogen salts of 12-tungstosilicic acid, Cs H4−SiW12O40, as highly active solid acid catalysts for transesterification of glycerol tributyrate with methanol

Cesium‐Exchanged Lacunar Keggin Heteropolyacid Salts: Efficient Solid Catalysts for the Green Oxidation of Terpenic Alcohols with Hydrogen Peroxide

“…In accordance with the literature, phosphotungstic acid is the most acidic and widely used Keggin HPA in acid‐catalyzed reactions . Several works have described the partial exchange of their protons by cesium, resulting in solid catalysts with a higher activity than their soluble parent acids …”

“…The literature has described different values for the surface area of saturated cesium phosphotungstate or phosphomolybdate salts (i. e., Cs 3 PW 12 O 40 , Cs 3 PMo 12 O 40 ), which may vary of 40–190 m 2 g −1 . Ever since a long time, the characterization of the cesium partially exchanged salts (i. e., Cs 3‐x H x PW 12 O 40 ) have been widely exploited .…”

Frontiers and progress in cation-uptake and exchange chemistry of polyoxometalate-based compounds

“…Acidic salts of α-Keggin-type POM (H 3 [α-PW 12 O 40 ]· n H 2 O, H 4 [α-SiW 12 O 40 ]· n H 2 O) have been well known as excellent acid catalysts, and partial substitution of protons with Cs + in aqueous solutions, stabilizes the solid-state structure and increases the surface area 50–52. The cesium hydrogen salt of silicododecatungstate Cs x H 4– x [α-SiW 12 O 40 ] adopts a body-centered cubic cell in analogy to the cesium salt of phosphododecatungstate Cs 3 [α-PW 12 O 40 ] 53.…”

Heteropolycompounds as catalysts for biomass product transformations

“…In the case of PW/SiO 2 the TOF values were explained in terms of leaching of the active phase, while reduced acid sites accessibility could explain the lower TOF exhibited by Cs 2 PW. Magnetic Cs SiW materials with mesopores interconnected with micropores were synthesized by Iwase and coworkers191 . They tested their catalytic activity (after being treated with sulfuric acid) in the transesterification of glycerol tributyrate with methanol.…”