Spongy titanosilicate promotes the catalytic performance and reusability of WO3 in oxidative cleavage of methyl oleate

A tungsten containing catalyst catalyzed oxidative cleavage of methyl oleate (MO) by employing H2O2 as an oxidant and is known as an efficient approach for preparing high value-added chemicals, however, the tungsten leaching problem remains unresolved. In this work, a binary catalyst consisting of tungsten oxide (WO3) and spongy titanosilicate (STS) zeolite is proposed for MO oxidative cleavage. The function of STS in this catalyst is investigated. On the one hand, STS converts MO to 9,10-epoxystearate (MES), which further forms nonyl aldehyde (NA) and methyl azelaaldehydate (MAA) with the catalysis of WO3. In this way, MO oxidation and hydrolysis that generates unwanted diol product 9,10-dihydroxystearate (MDS) decreases obviously. On the other hand, STS decomposes peroxide and promotes the conversion of soluble peroxotungstate to insoluble polytungstate. Meanwhile, these tungsten species are allowed to precipitate on its surface instead of remaining in the liquid phase owing to its relative large specific area. Therefore, tungsten leaching can be reduced from 37.0% to 1.2%. Due to the cooperation of WO3 and STS, 94.4% MO conversion and oxidative cleavage product selectivity of 63.1% are achieved, and the WO3-STS binary catalyst maintains excellent catalytic performance for 8 recycling reactions.

The Oxidative Cleavage of 9,10-Dihydroxystearic Triglyceride with Oxygen and Cu Oxide-based Heterogeneous Catalysts

This paper deals with a new heterogeneous catalyst for the second step in the two-step oxidative cleavage of unsaturated fatty acids triglycerides derived from vegetable oil, a reaction aimed at the synthesis of azelaic and pelargonic acids. The former compound is a bio-monomer for the synthesis of polyesters; the latter, after esterification, is used in cosmetics and agrochemicals. The reaction studied offers an alternative to the currently used ozonization process, which has severe drawbacks in terms of safety and energy consumption. The cleavage was carried out with oxygen, starting from the glycol (dihydroxystearic acid triglyceride), the latter obtained by the dihydroxylation of oleic acid triglyceride. The catalysts used were based on Cu²⁺ , in the form of either an alumina-supported oxide or a mixed, spinel-type oxide. The CuO/Al₂ O₃ catalyst could be recovered, regenerated, and recycled, yielding promising results for further industrial exploitation.

Hetero-structured Iron Molybdate Nanoparticles: Synthesis, Characterization and Photocatalytic Application

This study focuses on the synthesis of iron molybdate [Fe2(MoO4)3] nanoparticles (NPs) using simple co-precipitation process. The catalyst synthesized was characterized by advanced instrumental techniques such as XRD, SEM, EDX, TGA and FTIR, which confirmed the successful synthesis of NPs. Organic compound Rhodamine B (Rh. B) dye was selected for photo-degradation due to its complex structure and carcinogenic nature. Results exhibited that at neutral pH, the synthesized catalyst is highly effective for the degradation of Rh. B. For 20 mg/L initial concentration with an initial pH of 6.7, the degradation efficiency of Rh. B reaches 98  % within 180 min. Furthermore, the solution pH (1 to 11) affects the catalytic activity. This indicates that at neutral and/or alkaline pH, the usage of iron molybdate overwhelms the efficiency of Fenton-like reaction. It has been observed that Fe2(MoO4)3 showed excellent stability as after recycling it for 9 times its performance remained effective. Based on these data, the synthesized catalyst could be conveniently employed for degradation of toxic pollutants.