An Efficient Benzaldehyde Oxidation by Hydrogen Peroxide over Metal Substituted Lacunary Potassium Heteropolyacid Salts

How the Cobalt Position in the Keggin Anion Impacts the Activity of Tungstate Catalysts in the Furfural Acetalization with Alkyl Alcohols

“…In previous works, the characterization data of the lacunar Potassium undecatungstosilicate salt (i. e., K 8 SiW 11 O 39 ), Cobalt‐doped Potassium undecatungstosilicate salt (i. e., K 6 SiW 11 CoO 39 ), and Co 2+ ‐exchanged silicotungstic acid salt (i. e., Co 2 SiW 12 O 40 ) were described by the literature [34,39,41] . These results were compared to those obtained in the characterization data of Cobalt‐POMs, Potassium dodecatungstocobaltate (i. e., K 6 CoW 12 O 40 ) and Cobalt‐doped Potassium undecatungstocobaltate salts (i. e., K 8 CoW 11 CoO 39 ).…”

“…Due to their structural versatility, various modifications on the Keggin anion have improved their catalytic activity. These are the main changes performed: (i) to convert HPAs to salts after exchange their protons by metal or organic cations, resulting in catalysts highly active in esterification, etherification, acetalization, and hydrolysis reactions; [21–29] (ii) to transform the Keggin HPAs to lacunar salts, removing one MO unit (M=W or Mo), leading to the highly active catalysts in oxidation reactions with hydrogen peroxide of olefins, alcohols, and aldehydes; [30–35] and (iii) to doping lacunar Keggin anion with a transition metal cation, resulting in efficient catalysts in oxidative transformations [36–41] …”

One-pot synthesis at room temperature of epoxides and linalool derivative pyrans in monolacunary Na7PW11O39-catalyzed oxidation reactions by hydrogen peroxide

“…20,21 Moreover, the removal of one MO unit of heteropolyanions (i.e., WO or MoO) results in a lacunar salt catalyst that may be more active than its precursor with saturated anion. [22][23][24] The synthesis of linalool oxides and diepoxides, using lacunar polyoxometalates as catalysts, has not yet been reported in the literature. In this work, we present an innovative method of one-pot synthesis of linalool oxides with high conversion and selectivity, using a lacunar polyoxometalate as catalyst and hydrogen peroxide as an oxidant.…”

Aerobic oxidation of aldehydes to acids in water with cyclic (alkyl)(amino)carbene copper under mild conditions

“…9,10 Silva et al reported Keggin solid heteropolyacids with high reusability for the efficient oxidation of benzaldehyde by H 2 O 2 in CH 3 CN. 11 Hu et al reported a procedure for oxidation of aldehydes with H 2 O 2 catalyzed by Co 4 HP 2 Mo 15 V 3 O 62 in an acidic ionic liquid at 50 1C. 12 Kappe and co-workers demonstrated the oxidation of aldehydes with acidified H 2 O 2 as the oxidant in a continuous flow process at elevated temperatures.…”

“…29 It should be noted that the use of H 2 O 2 as an oxidant is limited by its relatively high cost. [9][10][11][12][13][14] The literature demonstrates that, when using O 2 as a sole oxidant, relatively high reaction temperatures are required. Besides, organic solvents (CH 3 CN, THF, DMSO, et al) or alkaline substances (NaOH, Na 2 CO 3 , DBU, et al) are always accompanied.…”