Organylhydrogensilane Comproportionation Using Silica-Supported Catalysts
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Solution Overview
Problem
Existing processes for preparing organylhydrogensilanes, such as comproportionation reactions, suffer from low selectivity, high energy consumption, and the formation of waste products due to the use of volatile catalysts and high reaction temperatures, resulting in inefficient production of methyldichlorosilane and dimethylchlorosilane.
Innovation Solution
A comproportionation reaction employing an organyl chlorosilane, a chlorosilane, and a fully organically substituted ammonium or phosphonium compound as catalyst, which selectively catalyzes H/Cl exchange, reducing energy costs and minimizing waste by maintaining low reaction temperatures and achieving high yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AlCl3 catalyst is used in comproportionation reaction, then catalytic activity is achieved, but catalyst volatility and sublimation occur requiring inhibitors and distillation
Solution Approach 1:
The patent employs a disposable silica gel support that carries the aluminum chloride catalyst. The silica gel provides a stable, non-volatile matrix that prevents catalyst sublimation while allowing the catalyst to function. After use, the entire catalyst system can be discarded or regenerated by simple heating, eliminating the need for complex inhibitor systems and extensive distillation purification.
Solution Approach 2:
The patent creates a composite catalyst system where aluminum chloride is supported on silica gel. This composite material combines the high catalytic activity of AlCl3 with the thermal stability and non-volatility of silica gel, resolving the contradiction between catalytic effectiveness and catalyst stability under reaction conditions.
2Productivity
If high reaction temperatures are used in comproportionation reaction, then reaction rate increases, but energy consumption increases and selectivity decreases
Solution Approach 1:
The patent modifies the catalyst support parameters by using silica gel with specific surface area and pore structure characteristics. This changes the physical environment of the catalyst, allowing it to function effectively at lower temperatures. The silica gel support provides a high surface area that enhances catalyst dispersion and activity, enabling efficient reactions at reduced temperatures and thus lowering energy consumption while maintaining productivity.
3Productivity
If high reaction temperatures are used, then reaction proceeds faster, but waste products increase due to lower selectivity
Solution Approach 1:
The patent changes the physical parameters of the catalyst system by supporting AlCl3 on silica gel. This modification allows the reaction to proceed at lower temperatures with higher selectivity. The silica gel support creates a controlled microenvironment that favors the desired comproportionation reaction over side reactions, thereby reducing waste product formation while maintaining acceptable reaction rates.
4Object-generated harmful factors
If inhibitors are added during distillation, then catalyst volatility is controlled, but process complexity increases
Solution Approach 1:
The patent uses a disposable silica gel-supported catalyst system that inherently prevents volatility issues. The silica gel matrix physically anchors the aluminum chloride, eliminating sublimation problems without requiring additional inhibitors or complex distillation setups. The entire catalyst system can be easily removed by filtration or simple distillation, significantly simplifying the process.
5Use of energy by moving object
If quaternary ammonium and phosphonium salts are used as catalysts, then low reaction temperatures can be used, but catalytic activity and stability must be maintained
Solution Approach 1:
The patent employs quaternary ammonium or phosphonium salts supported on silica gel, creating a composite catalyst system. The silica gel support provides thermal stability and prevents catalyst decomposition at the reaction temperatures, while the quaternary ammonium or phosphonium salt provides the necessary catalytic activity for H/Cl exchange. This composite structure maintains both activity and stability under reduced temperature conditions.
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
The process achieves high yields of organylhydrogensilanes with low energy consumption and minimal waste production, utilizing catalysts like quaternary ammonium and phosphonium salts that maintain catalytic activity and stability, even at lower temperatures.
Implementation Method 1
a comproportionation reaction employing an organyl chlorosilane, a chlorosilane, and a fully organically substituted ammonium or phosphonium compound as catalyst, which selectively catalyzes H/Cl exchange
Data Source
AI summary
Organylhydrogensilanes are prepared by means of a comproportionation reaction according to the equationZ RaSiCl4−a+SiHbCl4−b→Z RaSiHCl3−a+SiHb−yCl4−b+y,in the presence of a catalyst which contains at least one completely organically substituted ammonium or phosphonium unit, whereR is an optionally halogen-substituted alkyl, aryl, or alkaryl radical,a is 1, 2 or 3,y and Z are 1, 2, 3 or 4 andb is 2, 3 or 4.