Synthesis, Organo-Functionalization, and Catalytic Properties of Tungsten Oxide Nanoparticles As Heterogeneous Catalyst for Oxidative Cleavage of Oleic Acid As a Model Fatty Acid into Diacids

Abstract

A series of tungsten oxide nanoparticles (NPs) has been synthesized via a green and straightforward approach exploiting bare tungsten powder as a precursor. The synthesized NPs were further organo-functionalized by cetyltrimethylammonium bromide (CTAB) in order to adjust their surface state and enhance their compatibility with biphasic oxidation of vegetable oils with H2O2. Simply, different structures of tungsten oxide were observed, which were characterized by XRD, FTIR, TGA, TEM, N2 adsorption/desorption isotherms, and zeta potential analysis. All the synthesized nanocatalysts could fully convert oleic acid, and the highest yield of production of the desired diacid (azelaic acid), ∼80%, was achieved by optimization of the CTA+ amount on the nanocatalyst’s surface, which show excellent activity compared to the reported heterogeneous works. Thanks to the organo-functionalization, this water-tolerant catalyst exhibited no significant leaching, as well as convenient recovery and steady reuse without a noticeble decrease in activity, at least up to four cycles.

Crystalline WO3 nanoparticles for No2 sensing

“…72-0199), having an average particle size of 25 nm, as calculated using the Scherrer's formula. The dissolution mechanism of metallic tungsten in hydrogen peroxide for the synthesis of WO 3 -based materials has been extensively discussed earlier [66][67][68]. Surprisingly, only very few attempts have been made to analyse the solid-state products formed upon ageing of peroxotungstic acid solutions.…”

Synthesis of magnetic core@dual shell Fe3O4@SiO2@WO3 nanocatalysts for olefin double bond oxidative cleavage

“…Heterogeneous catalytic tests were carried out, for comparison purposes, strictly following a method previously developed in our laboratory. [ 22,23 ] A specified amount of catalyst was dispersed in tert‐butanol (6 mL), typically 0.2 g. Subsequently, 1 g of substrate (here oleic acid) were dissolved in 2 mL of tert‐butanol and 4 mL of an aqueous solution of hydrogen peroxide (30%). This catalyst/substrate ratio will be further expressed as a mass ratio, 20% for the above‐given quantities (0.2 g:1 g catalyst/substrate).…”

“…However, sole nanoparticles present similar recovery issues to those of a homogeneous catalyst. [ 22–25 ]…”

Aerobic Oxidative Cleavage of Vicinal Diol Fatty Esters by a Supported Ruthenium Hydroxide Catalyst

“…When polyoxotungstates is associated with hydrogen peroxide, yields of 2a and 3a close to 80% were obtained. [9][10][11] Results obtained with tungsten oxide nanoparticles 12 or supported tungsten oxide has been reported. 13 In 2013, Behr et al 14…”