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Russian scientists have synthesized a stable platinum catalyst that can be used repeatedly — at least 45 times — to accelerate chemical reactions. It will reduce the cost of silicone production, as well as reduce environmental pollution with toxic platinum-based catalysts. The results of the study, supported by grants from the Russian Science Foundation (RNF), are published in the Journal of Catalysis.

Silicones — organosilicon compounds — are widely used in various fields of human activity. They are used in the aerospace and construction industries, shipbuilding, medicine and agriculture, and are also part of household chemicals, cosmetics, paint and varnish materials and household goods. These substances are synthesized on an industrial scale using platinum-based catalysts. The catalyst accelerates the hydrosilylation reaction, which makes it possible to introduce silicon—containing fragments into the composition of alkenes - organic compounds that are products of oil refining.

Platinum catalysts have several disadvantages — high cost and environmental pollution with this metal. In addition, their use increases the cost of the materials obtained: about 30% of the price of silicones is the cost of a platinum catalyst. Considering that the annual consumption of platinum in 2007 alone amounted to more than 5.6 tons and is increasing, this can be considered a serious environmental and economic problem. Attempts to find a replacement among compounds based on cheaper, affordable and safer metals, for example, iron, copper, cobalt and chromium, have not been successful due to their low efficiency. In this regard, chemists are trying to create new platinum-based catalysts that can be reused and recycled.

Scientists from the A.V. Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences (Moscow), in collaboration with Russian colleagues, have synthesized an economical and environmentally friendly platinum catalyst resistant to moisture and air, which can be used repeatedly. As a basis, the authors took a commercially available metal salt dissolved in ethylene glycol. This widely available and cheap organic solvent stabilized platinum particles and allowed the catalyst to be regenerated again and again after application without losses and emissions into the environment.

The authors tested the ability of the obtained platinum catalyst to accelerate the chemical reactions of hydrosilylation. The yield of the target products reached 95-99%, which indicates the high efficiency of the resulting catalyst. At the same time, no side compounds were formed, and the desired substance could easily be cleaned from the catalyst.

The researchers also showed that the proposed platinum catalyst in ethylene glycol can be used at least 45 times in a row, while its activity did not decrease during the first 36 cycles, and the desired reaction took place in just a couple of minutes. However, starting from cycle 37, the rate of transformation gradually decreased, and in the final stages of the experiment, the transformation took several hours.

"The platinum catalyst proposed by us is not only as effective as industrial analogues, but also surpasses them in some cases. Moreover, it can be used repeatedly, unlike industrial hydrosilylation catalysts, which allows to reduce costs and irrevocable “spraying” of platinum and, consequently, reduce the cost of silicone production and reduce environmental pollution. Another undoubted advantage of the developed catalyst is the ease of preparation and use. In the future, we will continue to search for new high—performance catalysts," says Ashot Arzumanyan, one of the authors of the study, head of the project supported by the RNF grant, head of the groups "Catalysis in Organosilicon Chemistry" of INHS RAS and "Functional Compounds of Group IV elements" of INEOS RAS.

Researchers also participated in the work: post-graduate student Irina Goncharova (A.V. Topchiev Institute of the Russian Academy of Sciences and the A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow)), Candidate of Chemical Sciences Roman Novikov (N.D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences (Moscow)) and the head of the project supported by a grant from the Russian Academy of Sciences, Academician of the Russian Academy of Sciences, Doctor of Chemical Sciences Irina Beletskaya (Lomonosov Moscow State University (Moscow)).

Photo source: ria.ru

The information is taken from the portal "Scientific Russia" (https://scientificrussia.ru/, information provided by the press service of the Russian Science Foundation, posted by Irina Usyk)