Continuous Thiocarboxylate Silane Synthesis via Solid Catalyst
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Solution Overview
Problem
Batch processes for producing thiocarboxylate-functional silanes are inefficient due to long reaction times, formation of meta-stable rag layers, and the presence of phase transfer catalysts as impurities, leading to high costs and limited capacity.
Innovation Solution
A continuous process using a solid-supported phase transfer catalyst in a combination of continuous stirred tank and plug flow reactors to react an aqueous phase of thiocarboxylate acid salts with a non-aqueous haloalkylalkoxysilane, eliminating the need for phase transfer catalysts and improving reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-phase batch process with phase transfer catalyst is used, then the reaction can proceed with soluble alkali halide salts, but the phase transfer catalyst remains as an undesirable impurity in the product
Solution Approach 1:
The patent extracts and removes the phase transfer catalyst from the reaction system by using a solid-supported catalyst that can be easily separated from the reaction mixture. The solid support allows the catalyst to be taken out of the liquid phase, eliminating the impurity problem while maintaining the benefits of phase transfer catalysis.
Solution Approach 2:
The patent introduces a solid support as an intermediary carrier for the phase transfer catalyst. This solid-supported catalyst acts as a mediator that enables phase transfer functionality while providing easy separation, thus resolving the contradiction between maintaining catalytic activity and ensuring product purity.
2Ease of operation
If a two-phase batch process is used, then alkali metal salts can be handled without filtration, but the process requires long reaction times due to diffusion control
Solution Approach 1:
The patent transitions from batch processing to continuous flow processing, enabling continuous reaction and elimination of downtime between batches. This continuous operation maintains the ease of handling alkali metal salts while dramatically reducing the total reaction time required for production.
Solution Approach 2:
The patent introduces dynamic flow conditions and continuous mixing in the reactor system, replacing the static batch conditions. This dynamic approach enhances mass transfer and reaction kinetics, reducing diffusion control limitations while maintaining operational simplicity.
3Ease of manufacture
If a two-phase batch process is used, then the reaction can be conducted with phase transfer catalyst, but meta-stable rag layers form making phase separation difficult
Solution Approach 1:
The patent extracts the catalyst into a solid support phase, which can be easily removed from the liquid reaction mixture. This prevents the formation of emulsified rag layers by eliminating the soluble phase transfer catalyst that causes stabilization of the emulsion, thereby simplifying phase separation.
Solution Approach 2:
The patent changes the physical state parameter of the catalyst from soluble (liquid phase) to insoluble (solid phase). This parameter change fundamentally alters the phase behavior of the reaction system, preventing rag layer formation and enabling easy phase separation while maintaining reaction conductibility.
4Adaptability or versatility
If batch processes are used for production, then the process can be operated with existing equipment, but the production capacity is limited and costs are high
Solution Approach 1:
The patent implements continuous flow processing that allows uninterrupted reaction and production, replacing the stop-start nature of batch processing. This continuity dramatically increases production capacity while the modular reactor design allows adaptation to existing facility infrastructure.
Solution Approach 2:
The patent introduces dynamic continuous flow conditions that enhance mixing, heat transfer, and mass transfer efficiency compared to static batch conditions. This dynamic approach increases reaction rate and throughput, boosting productivity while maintaining compatibility with standard chemical processing equipment.
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 continuous production of thiocarboxylate-functional silanes with improved purity and reduced impurities, enhancing reaction efficiency and capacity while avoiding the limitations of batch processes.
Implementation Method 1
the use of a continuous stirred tank reactor and a continuous plug flow reactor and their use in continuously producing thiocarboxylate-functional silanes, such as octanethioic acid S-[3-(triethoxy-silanyl)-propyl] ester, in the presence of a solid-supported phase transfer catalyst
Implementation Method 2
The long reaction times results from the diffusion control transport of the alkali metal salts into the non-aqueous phase
Implementation Method 3
A continuous process using a solid-supported phase transfer catalyst in a combination of continuous stirred tank and plug flow reactors
Data Source
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AI summary
The invention is directed to a process for the preparation of thiocarboxylate silane comprising reacting an aqueous solution of a salt of a thiocarboxylic acid with a haloalkylalkoxysilane in the presence of a solid supported catalyst. The invention is also directed to a process for the preparation of an aqueous solution of a salt of a thiocarboxylic acid which comprises reacting an aqueous solution of a sulfide and/or hydrosulfide with a carboxylic acid halide and/or acid anhydride.