Efficient Oxidative Cleavage of Olefins to Carboxylic Acids with Hydrogen Peroxide Catalyzed by Methyltrioctylammonium Tetrakis(oxodiperoxotungsto)phosphate(3−) under Two-Phase Conditions. Synthetic Aspects and Investigation of the Reaction Course

Abstract

The oxidative cleavage of alkenes to carboxylic acids with 40% w/v aqueous hydrogen peroxide catalyzed by methyltrioctylammonium tetrakis(oxodiperoxotungsto)phosphate(3-) (Ia) is reported to occur in high yields and selectivities under two-phase conditions in the absence of organic solvents. On the basis of a study of the reaction, two main reaction pathways leading to acids have been recognized, the first one involving the perhydrolysis and the second one the hydrolysis of the epoxide initially formed. The "perhydrolytic" reaction pathway appears to play a primary role in the oxidation of medium- and long-chain alkenes to acids, while it intervenes to a rather limited extent in the oxidation of arylalkenes and C(5)-C(7) cycloalkenes. The occurrence of this pathway has been proved by the isolation of the intermediate beta-hydroperoxy alcohols and their transformation into acids with H(2)O(2) and Ia. The course of this transformation, involving an initial oxidation (to alpha-oxo hydroperoxide) or decomposition (to carbonyl compounds) of the beta-hydroperoxy alcohol intermediate, is described. The primary oxidation products, alpha-hydroperoxy ketones, have been isolated in the case of internal beta-hydroperoxy alcohols, whereas their presence has been evidenced with terminal beta-hydroperoxy alcohols bearing a secondary hydroxy group. Hydrogen peroxide concentration appears to exert a remarkable influence on medium acidity, and its effects on the reaction efficiency are shown.

Influence of peroxometallic intermediaries present on polyoxometalates nanoparticles surface on the adipic acid synthesis

“…As can be seen, the evolution of the conversion over time follows the trend of a sigmoid curve, which is typical of processes that require a catalyst induction period. This might be related to the formation of peroxometallic intermediates on the surface of CsPMo nanoparticles (and, in general of other similar salts) [3,20,26,27]. Because, after catalyst pre-treatment with hydrogen peroxide, the induction period disappears, this experimental observation supports the above hypothesis.…”

A peroxotungstate-ionic liquid brush assembly: an efficient and reusable catalyst for selectively oxidizing sulfides with aqueous H2O2 solution in neat water

“…This is important, since tungsten-based catalysts are well known to promote epoxidation reactions or carbon-carbon double bond cleavage hydrogen peroxide based processes. [29][30][31][32][33] Hydroxyl groups also remained intact under these conditions (entry 16) and the corresponding sulfoxide was obtained in 93.9% of yield. The reaction times required for sulfoxide formation ranged from 1.5 to 4 h for all substrates except for diphenyl sulfide, which took 7 h and led to the lowest yield (entry 14).…”

Synthesis of azelaic acid from vegetable oil‐based feedstocks

“…Depending on these influencing factors the yields of AA varied between 67 and 92%. Venturello and co-workers [67] identified two main reaction pathways for this type of reaction leading from alkenes to acids. The first one involves the perhydrolysis and the second one the hydrolysis of the epoxide formed primarily, whereas the former plays a significant role in the oxidation of medium-and long-chain alkenes to acids.…”