Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Straße 7, 60438, Frankfurt/Main, Germany.
Momentive Performance Materials Inc., 769 Old Saw Mill River Rd, Tarrytown, NY, 10591, USA.
Chemistry. 2019 Oct 11;25(57):13202-13207. doi: 10.1002/chem.201902722. Epub 2019 Sep 13.
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 Me Si Cl (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.
在 Müller-Rochow 直接法中，大规模生产甲基氯硅烷时会生成副产物，即直接法残渣（DPR），其由一系列通式为 MeSiCl（n=1-6）的二硅烷组成。为了将这些二硅烷循环再利用为一硅烷，重新引入硅氧烷生产链，人们付出了巨大的研究努力。本工作报道了利用碱金属和碱土金属盐对二硅烷进行裂解的方法。二硅烷与金属氢化物，特别是氢化锂（LiH）反应，可以有效地还原含氯二硅烷，但也会导致歧化反应生成单硅烷和多硅烷。在还原过程中形成的碱金属和碱土金属氯化物会特别促使高氯代二硅烷发生歧化反应，而高度甲基化的二硅烷（n＞3）则保持未反应状态。在氯化锂存在下，使用浓盐酸/乙醚溶液可以将 DPR 几乎定量转化为一硅烷。
