2D Carbon-Supported Platinum Catalysts for Hydrosilylation Reactions

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arbon-Supported Platinum Catalysts for Hydrosilylation Reactions A. P. Voznyakovskiia,b,*, A. Yu. Neverovskayaa, A. V. Kalinina, A. A. Voznyakovskiic, and G. A. Nikolaeva a Lebedev

Research Institute of Synthetic Rubber, St. Petersburg, 198035 Russia Petersburg State Institute of Technology (Technical University), St. Petersburg, 190013 Russia c Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia *e-mail: [email protected]

b St.

Received June 9, 2020; revised June 9, 2020; accepted June 19, 2020

Abstract—2D carbon structures were prepared by carbonization of biopolymers (starch) via self-propagating hightemperature synthesis process. Electron microscopic, Raman spectroscopic, and X-ray diffraction examinations showed that the structure of the resultant particles corresponded to graphene nanoplatelets. Based on the Raman spectroscopy data, the average number of graphene layers in a graphene nanoplatelets particle was estimated at 2–5. The graphene nanoplatelets synthesized were applied as a support of a platinum-based catalyst (Speier’s catalyst). The resultant supported catalyst was successfully used in the hydrosilylation of 1-hexene with methyldichlorosilane and then separated from the reaction products and reused. The catalytic activity of the supported catalyst was maintained for 4 months. Keywords: biopolymers, decomposition, self-organization, nanoparticles, catalysts, hydrosilylation reaction

DOI: 10.1134/S1070363220100163 Hydrosilylation reaction is important in crosslinking of materials (rubbers) based on organosilicon polymers, e.g., in production of items processed by injection molding, as well as of sealants and coatings [1, 2]. This process, involving the reaction between the crosslinking agent and the terminal vinyl groups of the polysiloxane in the presence of a catalyst, is typically catalyzed by platinum [3]. Crosslinking of macrochains by the hydrosilylation reaction can be generally employed for producing organosilicon polymer materials based on any polysiloxane and copolymers thereof. Expensive as they are, platinum catalysts remain the sole viable option available today. This motivates numerous research groups to explore the possibility of obtaining more efficient and less expensive reusable platinum catalysts. For example, supported catalysts proved to be useful in increasing active surface area of the catalyst, saving expensive substances (Pt, Pd), preventing recrystallization and sintering of the active component at high temperatures, lengthening service life of the catalyst, and in some cases also in stabilizing the latter in a particular chemical form [4, 5].

Supported catalysts are considered today not only as inert support–active substance additive systems; possible influence of the support structure on the course of the hydrosilylation reaction is taken into account as well. In particular, by the example of the reaction of trichlorosilane with acetylene it was demonstrated that platinum supported on cubic γ-Al2O3 exhibits much higher activity th

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