Silane Methylation via Ammonium Salt Catalysis
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Solution Overview
Problem
The Müller-Rochow process does not enable the conversion of methyl-H-silanes or H-silanes into methylated and higher methylated methylchlorosilanes (MCSs), limiting the production of methylchlorosilanes on an industrial scale.
Innovation Solution
A process involving the reaction of methyl chloride (MeCl) with silanes such as H2SiMe2, H2SiMeCl, H3SiMe, H3SiCl, HSiMe2Cl, and HSiMeCl2 in the presence of ammonium and/or phosphonium salts as catalysts, at temperatures ranging from 70-350°C, to dehydrogenate and methylate silanes, thereby producing methylchlorosilanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Müller-Rochow process is used, then methylchlorosilanes can be produced from elemental silicon and simple organochlorine compounds, but methyl-H-silanes or H-silanes cannot be converted into methylated and higher methylated methylchlorosilanes
Solution Approach 1:
The invention changes the reaction parameters by introducing ammonium and phosphonium salts as catalysts and operating at elevated temperatures (70-350°C), which enables the conversion of methyl-H-silanes and H-silanes into methylated methylchlorosilanes, thereby expanding the substrate scope and conversion capability beyond the traditional Müller-Rochow process
Solution Approach 2:
The invention employs ammonium and phosphonium salts as intermediary catalysts that facilitate the dehydrogenation and methylation reactions. These catalysts enable the transformation of silanes with hydrogen atoms into methylated products by mediating the reaction between silanes and methyl chloride, thus overcoming the limitation of the Müller-Rochow process
2Adaptability or versatility
If dehydrogenation and methylation reactions are performed to convert H-containing silanes into methylated methylchlorosilanes, then product diversity increases, but process complexity increases
Solution Approach 1:
The invention merges the dehydrogenation and methylation steps into a single integrated reaction process. By using ammonium and phosphonium salts as catalysts, both transformations occur simultaneously in one reactor system, producing a range of methylated methylchlorosilanes without requiring separate process steps, thus increasing product diversity while maintaining process simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process efficiently produces methylchlorosilanes by forming additional methyl and chlorine functions on the silane molecules, while also regenerating chloride ions as catalysts, thus enabling economic production on an industrial scale.
Implementation Method 1
methyl chloride is reacted with a silane selected from the group consisting of H2SiMe2, H2SiMeCl, H3SiMe, H3SiCl, HSiMe2Cl, and HSiMeCl2 in the presence of at least one ammonium and/or phosphonium salt
Data Source
AI summary
A process for dehydrogenating and methylating silanes. The process includes providing methyl chloride that is reacted with a silane selected from the group consisting of SiH4, H2SiMe2, H2SiMeCl, H3SiMe, H3SiCl and HSiMe2Cl, in the presence of at least one ammonium and/or phosphonium salt at a temperature in the range of 70-350° C.