Heterocyclic Amine Catalyst Conversion of Direct Process Residue
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Solution Overview
Problem
Current processes for converting highly methylated chlorodisilanes and carbosilanes into organohalosilane monomers are inefficient, often requiring expensive noble metals and resulting in monomer mixtures enriched with less valuable CH3SiCl3, with existing catalysts failing to effectively convert uncleavable components from Direct Process Residue.
Innovation Solution
A catalytic process using heterocyclic amines and quaternary Group 15 onium compounds at moderate temperatures and short reaction times to convert high-boiling residues into organohalosilane monomers, specifically producing (CH3)2SiHCl, CH3SiHCl2, and (CH3)2SiCl2, without the use of expensive noble metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrochlorination with tertiary amine catalyst is used, then some components of DPR are converted to organohalosilane monomers, but conventionally unreactive components are discharged to waste treatment
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by replacing conventional tertiary amine catalysts with heterocyclic amine catalysts (such as imidazole, pyridine, triazole derivatives) and quaternary phosphonium or ammonium salts. This parameter change enables the catalyst system to effectively convert conventionally unreactive DPR components including highly methylated chlorodisilanes and carbosilanes, thereby improving overall conversion efficiency and reducing material loss
Solution Approach 2:
The patent employs inexpensive heterocyclic amine catalysts and quaternary phosphonium/ammonium salts that can be used in small amounts (0.1-10 wt% based on DPR) to achieve complete conversion of unreactive components. These catalysts are much cheaper than noble metal catalysts and can be easily removed or recycled, providing a cost-effective solution for converting all DPR components without significant material loss
2Productivity
If existing catalysts are used for DPR conversion, then some monomers are produced, but the monomer mixture is enriched with less valuable CH3SiCl3
Solution Approach 1:
The patent optimizes reaction parameters including temperature (75-300°C), pressure (atmospheric or superatmospheric), and catalyst composition to control the product distribution. By adjusting these parameters, the process achieves selective conversion that produces a more balanced monomer mixture with reduced CH3SiCl3 content and increased proportions of valuable monomers such as (CH3)2SiHCl, CH3SiHCl2, and (CH3)2SiCl2
Solution Approach 2:
The patent employs periodic addition of HCl gas or organohalide during the reaction process to maintain optimal reaction conditions and control monomer composition. This periodic action allows for better control over the redistribution and cleavage reactions, preventing excessive formation of less valuable CH3SiCl3 while maintaining high productivity
3Productivity
If expensive noble metal catalysts are used for DPR conversion, then conversion efficiency improves, but process cost increases significantly
Solution Approach 1:
The patent replaces expensive noble metal catalysts with inexpensive heterocyclic amine catalysts (such as imidazole, pyridine, triazole derivatives) and quaternary phosphonium or ammonium salts. These cheap catalysts achieve comparable or superior conversion efficiency for uncleavable DPR components and can be used in small amounts (0.1-10 wt%), dramatically reducing catalyst cost while maintaining high productivity
Solution Approach 2:
The patent uses heterocyclic amine catalysts and quaternary phosphonium/ammonium salts as intermediary substances that facilitate the conversion of unreactive DPR components. These intermediaries form transient complexes with the substrate molecules, enabling cleavage and redistribution reactions without requiring expensive noble metals, thus achieving both high efficiency and cost-effectiveness
4Reliability
If long reaction times are used for complete DPR conversion, then conversion completeness improves, but energy consumption and production time increase
Solution Approach 1:
The patent optimizes reaction parameters including temperature (75-300°C), pressure (atmospheric or superatmospheric), and catalyst concentration to achieve rapid and complete conversion of DPR components. By adjusting these parameters, the process achieves 95%+ conversion within 0.5-4 hours, balancing conversion completeness with reasonable reaction time and energy consumption
Solution Approach 2:
The patent employs continuous heating and stirring during the reaction process to maintain optimal reaction conditions throughout. This continuous action ensures that all DPR components are consistently exposed to the catalyst and react completely, achieving high conversion completeness in relatively short times without requiring extended reaction periods
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 effectively converts conventionally uncleavable compounds into valuable organohalosilane monomers, reducing the proportion of less valuable CH3SiCl3 and increasing the yield of desired monomers like (CH3)2SiHCl and (CH3)2SiCl2, while being economically viable and environmentally friendly.
Implementation Method 1
heating the high-boiling residue in the presence of a catalyst comprising (1) one or more heterocyclic amines and/or one or more heterocyclic ammonium halides, and (2) one or more quaternary Group 15 onium compounds
Implementation Method 2
to convert the high-boiling residue to an organohalosilane monomer composition
Data Source
AI summary
Disclosed herein is a catalytic process for the synthesis of organohalosilane monomers from tetraorganodihalodisilanes and other compounds that are not cleaved during the conventional hydrochlorination of Direct Process Residue. The process is characterized by the use of a catalyst containing (1) one or more heterocyclic amines and/or one or more heterocyclic ammonium halides, and (2) one or more quaternary Group 15 onium compounds.