Polymer-Supported Selenium Affording Opportunities in Catalyst Design

Polymer-supported selenium has been reported as a heterogeneous catalyst that is easily separated from the reaction system, thereby making the recovery and reuse of the catalyst more convenient. However, the utilization of polymer-supported selenium in the preparation of catalysts is not restricted to the aforementioned technical advantages. Recent studies have shown that polymer-supported selenium and small-molecule organoselenium catalysts have significant performance differences, leading to distinct reaction mechanisms, which offer more opportunities for the development of new organic reactions.

Designing bimetallic zeolitic imidazolate frameworks (ZIFs) for aqueous catalysis: Co/Zn-ZIF-8 as a cyclic-durable catalyst for hydrogen peroxide oxidative decomposition of organic dyes in water

ZIF-8 is well known hybrid material that is self-assembled from inorganic and organic moieties. It has several potential applications due to its unique structure. One of these potential applications is in advanced oxidation processes (AOP) via a heterogeneous catalysis system. The use of modified ZIF-8/H2O2 for the destruction of the azo dye methyl orange (MO) is presented in this work to explore its efficacy. This work presents the bimetallic Co/Zn-ZIF-8 as an efficient catalyst to promote H2O2 oxidation of the MO dye. Co/Zn-ZIF-8 was synthesized through a hydrothermal process, and the pristine structure was confirmed using XRD, FTIR, and XPS. The Co/Zn-ZIF-8/H2O2 system successfully decolorized MO at the selected pH 6.5. It was found that more than 90% of MO (10 ppm) was degraded within only about 50 minutes. Proposed radical and redox mechanisms are presented for H2O2 decomposition where the redox mechanism is suggested to predominate via a Co(ii)/Co(iii) redox consecutive cyclic process.

Synthesis of nanoscale CuO via precursor method and its application in the catalytic epoxidation of styrene

Nanoscale CuO with diameters in the range of 7-8 nm has been synthesized via a two-step precipitation-calcination method using copper(ii) isonicotinate tetrahydrate as the precursor. The first step involves the room temperature stirring of an alkaline ethanolic solution of the precursor which gives a non-crystalline CuO species, while the second step involves the calcination of the product of the first step at 180 °C to form nanocrystalline CuO which has been characterized by PXRD, TEM, SEM, H2-TPR and Raman spectroscopy, etc. The CuO material has shown excellent catalytic activity in the oxidation of styrene using TBHP as the oxidizing agent leading to complete styrene conversion with more than 95% styrene oxide selectivity at the end of 6 h. The oxide catalyst can be reused for at least 6 successive runs without significant loss in activity.

PhSe(O)OH/Al(NO3)3-Catalyzed selectivity controllable oxidation of sulphide owing to the synergistic effect of Se, Al3+ and nitrate

Catalyzed by PhSe(O)OH/Al(NO3)3, selective oxidation of sulphides to produce sulfoxides or sulphones could be achieved under mild conditions. The synergistic effect of Se, Al3+ and nitrate is the key factor for the reaction.

Progresses in synthetic technology development for the production of L-lactide

L-Lactide is an intermediate for the industrial production of polylactic acid (PLA). The chemical and optical purities of lactide determine the quality of the prepared PLA. It is of great challenge to synthesize L-lactide efficiently with high chemical and optical purities under the conditions applicable for industrial production. With the national plastic reduction order issued, developing biodegradable materials such as PLA has gradually become a hot topic, and the production of upstream lactide is the key technique for the whole industrial chain. This mini-review aims to summarize typical works on the related synthetic technology development in recent years.

Catalytic epoxidation of β-ionone with molecular oxygen using selenium-doped silica materials

Se-doped silica could catalyze the β-ionone epoxidation reaction. Interestingly, by doping with fluorine in the catalyst, the reaction selectivity was significantly enhanced. The metal-free process is suitable for pharmaceutical synthesis.