Monooctyltin Trichloride Purification via Phase Transfer
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Solution Overview
Problem
Current methods for producing monooctyltin trichloride struggle to achieve low levels of dioctyltin and trioctyltin compounds, with existing processes being economically unattractive due to high costs, low selectivity, and inefficient recovery of precious metal catalysts, and difficulties in separating and purifying monooctyltin trichloride from mixtures.
Innovation Solution
A process involving contacting an organotin chloride mixture with an aqueous phase containing halide ions, followed by phase separation, scrubbing with organic solvents to remove impurities, and recovering monooctyltin trichloride from the aqueous phase, which eliminates the need for precious metal catalysts and enhances purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If redistribution of diorganotin compounds with SnCl4 is performed to form monoalkyltin trichlorides, then monoalkyltin trichlorides can be produced, but the process does not yield products with low levels of diorganotin and triorganotin compounds due to kinetic hindrance
Solution Approach 1:
The patent introduces a phase transfer catalyst as an intermediary substance that mediates the redistribution reaction between diorganotin compounds and SnCl4. The catalyst facilitates the reaction by transferring reactants between aqueous and organic phases, enabling the formation of monooctyltin trichloride with low levels of diorganotin and triorganotin impurities while maintaining production efficiency
Solution Approach 2:
The patent employs parameter changes by conducting the redistribution reaction in a two-phase system (aqueous and organic phases) rather than a single phase. By controlling phase distribution and using a phase transfer catalyst, the reaction parameters are optimized to achieve both high purity product and acceptable productivity
2Speed
If precious metal catalysts are used to facilitate redistribution of diorganotin compounds, then reaction rate improves, but economic viability deteriorates due to high catalyst costs and difficulty in recovery
Solution Approach 1:
The patent replaces expensive precious metal catalysts with a more economical phase transfer catalyst that can be easily removed from the reaction mixture. The catalyst system used is less costly and does not require complex recovery procedures, thereby improving economic viability while maintaining adequate reaction rates
Solution Approach 2:
The patent extracts the catalyst from the reaction mixture by utilizing phase separation. The phase transfer catalyst remains in or can be easily separated from one phase, allowing for simple removal and reducing the need for expensive catalyst recovery systems
3Manufacturing precision
If fractional distillation is used to separate monobutyltin trichloride from dibutyltin dichloride, then separation can be achieved, but the method is not applicable to monooctyltin trichloride due to low vapor pressure and thermal degradation
Solution Approach 1:
The patent utilizes phase transitions by conducting the separation process through phase distribution between aqueous and organic phases rather than relying on vapor-liquid equilibrium. This approach avoids the thermal degradation associated with distillation while achieving effective separation based on differential solubility and phase partitioning
Solution Approach 2:
The patent employs liquid-liquid extraction utilizing hydraulic principles, where the separation of monooctyltin trichloride from impurities is achieved through differential partitioning between two liquid phases. This method replaces thermal separation with a fluid-based separation process that avoids thermal degradation
4Manufacturing precision
If monooctyltin trichloride is produced by alkylation of SnCl4 with aluminum alkyl donor complexes, then monoalkyltin trichlorides can be formed, but the process does not achieve desired low levels of dioctyltin and trioctyltin compounds
Solution Approach 1:
The patent uses a phase transfer catalyst as an intermediary to facilitate the alkylation reaction between SnCl4 and aluminum alkyl donor complexes. The catalyst enables more complete conversion and better product distribution, achieving both high purity monooctyltin trichloride and improved yield by promoting the reaction toward the desired monoalkylated product
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 produces monooctyltin trichloride with very low levels of dioctyltin and trioctyltin compounds, improving economic viability and reducing impurity levels below 0.3% and 0.1% respectively, while avoiding the use of expensive catalysts and enhancing product recovery.
Implementation Method 1
contacting an organotin chloride mixture comprising monooctyltin chloride with an aqueous phase containing halide ions
Implementation Method 2
purifying said aqueous phase comprising monooctyltin trichloride from undesired side products by washing said aqueous phase with an organic solvent
Data Source
AI summary
The present invention provides a process for producing monooctyltin trichloride comprising very low levels of dioctyltin and trioctyltin compounds, said process comprising the following steps: (1) Contacting an organotin chloride mixture comprising monooctyltin chloride with an aqueous phase containing halide ions, said step optionally being carried out in the presence of organic solvent; (2) separating the resulting aqueous phase which is rich in monooctyltin chloride from the organic phase containing most of the dioctyltin and trioctyltin compounds; (3) optionally purifying said aqueous phase comprising monooctyltin trichloride from undesired side products by washing said aqueous phase with an organic solvent; and (4) recovering monooctyltin trichloride from said aqueous phase comprising monooctyltin trichloride.