Preparation of Chloropolysilane from the Copper-catalyzed Reaction of Silicon Metal and Hydrogen Chloride

Abstract

The copper catalyzed reaction of silicon metal powder with hydrogen chloride by flow method was studied in order to find a convenient preparative method of chloropolysilane, and also to elucidate the mechanism of this reaction. This reaction was found to start at about 170∼230°C, and once the reaction occurred, the contact mass is activated and the reaction takes place even at 170°C. When the most adequate conditions were adopted, chloropolysilanes were obtained in the condensate as efficiently as 30 wt.% yield based on hydrogen chloride. As to the mechanism of the reaction, it seems to be plausible that the first step of the reaction is an attack of hydrogen chloride on aluminum which is usually present in the commercial silicon metal. The second step is the reaction between silicon hydride, which is derived from the first step reaction upon the silicon contact mass and metallic copper forming the silicon-copper bonding. The third step is the cleavage reaction of copper-activated silicon by hydrogen chloride to produce chlorosilanes under the presence of aluminum chloride. The aluminum chloride is also derived from the first step reaction, and copper is regenerated in metal form which can circulate among the latter two reaction steps as long as the effective silicon component is present.

SEM-EDX and SAM-AES Investigations on Rochow Contact Masses

“…This surfacealloying of silicon with copper seems to be the precondition of the synthesis reaction, acting either via the formation of Cu-Si pairs, necessary for a dissociative adsorption, 1 and/or via a weakening of the Si-Si bond. 7,23,24 The above key observation was only possible by investigating a sample with such clear surface topography as the 20 min sample of CuCl 2 /Si tech / Zn. After 3 h (Fig.…”

Direct Synthesis of Organotrichlorogermanes by the Reaction of Elemental Germanium, Hydrogen Chloride, and Alkene

“…Furthermore, the intermediacy of surface silylene in the reaction of silicon with hydrogen chloride has also been revealed . The reaction of silicon with hydrogen chloride gave di-, tri-, and tetrachlorosilanes, while the reaction in the presence of alkene resulted in the formation of alkyldichlorosilane together with chlorosilanes . The alkyldichlorosilane formation also indicates that surface silylene is the reaction intermediate.…”

Direct synthesis of organodichlorosilanes by the reaction of metallic silicon, hydrogen chloride and alkene/alkyne and by the reaction of metallic silicon and alkyl chloride

“…Just after adding isopropyl chloride, only the rate of formation of dichloroisopropylsilane increased. This strongly indicates that isopropyl (3) chloride participates in the formation of dichloroisopropylsilane. As shown in eqn.…”

“…A plausible mechanism for propyldichlorosilanes formation is shown in eqn. (3). The reaction of surface silylene 1 with propylene gives a methylsilacyclopropane species 6, which is attacked by hydrogen chloride.…”

“…Hydrogen chloride also reacts with metallic silicon to afford trichlorosilane as a main product together with dichlorosilane and tetrachlorosilane. 3 We have found that the reaction of metallic silicon and hydrogen chloride in the presence of ethylene affords ethylchlorosilanes, mainly dichloroethylsilane, together with chlorosilanes. 4 Furthermore, when acetylene was used instead of ethylene dichlorovinylsilane was obtained.…”