Halosilane Preparation via Copper Spinel Catalyst
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Solution Overview
Problem
The production of halosilanes, such as diorganodihalosilanes, is energy-intensive and costly due to the need for high-temperature reduction of SiO2 to produce zero-valent silicon and results in the generation of costly byproducts like aluminum chloride or zinc chloride, which require expensive disposal.
Innovation Solution
A method involving a spinel catalyst comprising copper, activated at elevated temperatures, is used to contact silanes with organohalides, allowing for the production of halosilanes without the need for zero-valent silicon and minimizing the formation of costly metal halides, through a process involving multiple steps of catalyst activation and reactant recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Mueller-Rochow Direct Process is used to produce halosilanes, then halosilanes can be produced commercially, but high energy consumption is required for high-temperature reduction of SiO2
Solution Approach 1:
The invention changes the chemical parameters of the starting materials from SiO2 (in Direct Process) to silicon tetrachloride and methyl chloride. This parameter change eliminates the need for high-temperature reduction while maintaining halosilane production capability, directly resolving the energy consumption contradiction.
2Productivity
If alkylation of silicon tetrachloride with aluminum or zinc is used, then diorganodihalosilanes can be produced, but large amounts of aluminum chloride or zinc chloride byproducts are generated requiring costly disposal
Solution Approach 1:
The invention replaces expensive metal catalysts (aluminum or zinc) with a cheaper copper-based catalyst system. The copper catalyst enables the same alkylation reaction but produces no costly metal halide byproducts, as copper chloride can be easily removed or recycled, thus resolving the substance loss contradiction.
Solution Approach 2:
The copper catalyst acts as an intermediary that facilitates the alkylation reaction between silicon tetrachloride and methyl chloride without being consumed or forming problematic byproducts. It mediates the reaction to produce the desired diorganodihalosilane while avoiding the formation of aluminum chloride or zinc chloride, resolving the byproduct issue.
3Productivity
If zero-valent silicon is used in Direct Process, then halosilanes can be produced, but the process is costly due to SiO2 reduction requirements
Solution Approach 1:
The invention changes the starting material parameter from zero-valent silicon (requiring costly SiO2 reduction) to silicon tetrachloride, which is a more readily available and economically viable starting material. This parameter substitution directly reduces manufacturing costs while maintaining production capability.
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 method reduces energy consumption and avoids the costly disposal of metal halides, achieving efficient and selective production of halosilanes like dimethyldichlorosilane with repeated cycles of catalyst reactivation and reactant reuse.
Implementation Method 1
A method involving a spinel catalyst comprising copper, activated at elevated temperatures, is used to contact silanes with organohalides, allowing for the production of halosilanes
Data Source
AI summary
A method for preparing a reaction product includes: steps (1) and (2). Step (1) is contacting, at a temperature from 200°C to 1400 °C, a first ingredient including a silane of formula HaRbSiX(4-a-b), where subscript a is an integer from 0 to 4, subscript b is 0 or 1, a quantity (a + b) < 4, each R is independently a monovalent organic group, and each X is independently a halogen atom, with the proviso that when the quantity (a + b) < 4, then the ingredient further includes H2; with a spinel catalyst including copper; thereby forming a reactant. Step (2) is contacting the reactant with a second ingredient including an organohalide at a temperature from 100°C to 600 °C; thereby forming the reaction product and a spent reactant. The reaction product is distinct from the silane used in step (1). The method may be used to prepare diorganodihalosilanes from silicon tetrahalides.