Disilane Cleavage with Selected Alkali and Alkaline Earth Metal Salts |
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Authors: | Tobias Santowski Alexander G. Sturm Dr. Kenrick M. Lewis Dr. Thorsten Felder Prof. Dr. Max C. Holthausen Prof. Dr. Norbert Auner |
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Affiliation: | 1. Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Straße 7, 60438 Frankfurt/Main, Germany;2. Momentive Performance Materials Inc., 769 Old Saw Mill River Rd, Tarrytown, NY, 10591 USA;3. Momentive Performance Materials GmbH, Chempark, 51368 Leverkusen, Germany |
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Abstract: | The industry-scale production of methylchloromonosilanes in the Müller–Rochow Direct Process is accompanied by the formation of a residue, the direct process residue (DPR), comprised of disilanes MenSi2Cl6-n (n=1–6). Great research efforts have been devoted to the recycling of these disilanes into monosilanes to allow reintroduction into the siloxane production chain. In this work, disilane cleavage by using alkali and alkaline earth metal salts is reported. The reaction with metal hydrides, in particular lithium hydride (LiH), leads to efficient reduction of chlorine containing disilanes but also induces disproportionation into mono- and oligosilanes. Alkali and alkaline earth chlorides, formed in the course of the reduction, specifically induce disproportionation of highly chlorinated disilanes, whereas highly methylated disilanes (n>3) remain unreacted. Nearly quantitative DPR conversion into monosilanes was achieved by using concentrated HCl/ether solutions in the presence of lithium chloride. |
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Keywords: | alkali and alkaline earth metal salts disilane cleavage lithium chloride lithium hydride monosilanes |
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