Alkyl Chloride Synthesis Using Solid Quaternary Ammonium Catalysts
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Solution Overview
Problem
Existing processes for preparing alkyl chlorides are inefficient due to long reaction times, high wastewater production, and the need for aqueous catalyst solutions, which complicate purification and storage, and may produce unwanted byproducts like alkyl bromides.
Innovation Solution
The process utilizes gaseous hydrogen chloride and catalysts of specific structures, such as N-n-butylalkylpyridinium chloride, which have lower melting points and can be used independently of the alcohol type, reducing reaction times and wastewater generation while minimizing the production of alkyl bromides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous catalyst solutions are used, then catalytic activity is achieved, but purification and storage become complicated
Solution Approach 1:
The patent changes the physical state parameter of the catalyst from aqueous solution to solid form. The solid catalysts (quaternary ammonium salts, phosphonium salts, or sulfonium salts) can be handled as solids, eliminating the complications of aqueous solution handling, filtration, and storage while maintaining catalytic activity through their solid-state ionic structures.
2Reliability
If conventional catalysts are used, then the reaction can proceed, but reaction times are long
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by using quaternary ammonium salts, phosphonium salts, or sulfonium salts with specific structures (where R1-R6 are alkyl, aryl, or heteroaryl groups). These structurally optimized catalysts significantly enhance the reaction rate between alcohols and gaseous hydrogen chloride, reducing reaction time while ensuring complete conversion.
3Reliability
If aqueous hydrogen chloride is used, then the reaction can proceed, but wastewater production increases
Solution Approach 1:
The patent changes the physical state parameter of hydrogen chloride from aqueous solution to gaseous form. By using gaseous hydrogen chloride with solid catalysts, the reaction produces minimal wastewater, eliminating the need for large volumes of aqueous acid and the subsequent wastewater treatment requirements.
4Quantity of substance
If conventional processes are used, then alkyl chlorides can be produced, but purification steps are complicated
Solution Approach 1:
The patent changes multiple parameters simultaneously: using gaseous hydrogen chloride instead of aqueous solution, and solid catalysts instead of aqueous catalyst solutions. These changes result in a cleaner reaction system where the product can be obtained in high purity (99% or higher) with minimal purification steps, eliminating complicated extraction and filtration procedures.
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 approach results in high space-time yields, simplified workup and storage of catalysts, and high conversion rates, producing alkyl chlorides with purities over 99% without the need for aqueous solutions or heated components, and allows for the use of a single catalyst for various alkyl chloride preparations.
Implementation Method 1
reacting the corresponding alcohols with gaseous hydrogen chloride in the presence of a catalyst
Data Source
AI summary
The invention relates to a process for preparing alkyl chlorides by reacting alcohols with gaseous hydrogen chloride in the presence of a catalyst, wherein the catalyst comprises at least one compound of the structure:whereinR1 is a linear alkyl group having from 1 to 20 carbon atoms,R2, R3, and R4 is selected from a hydrogen, an alkyl, an alkenyl, an aralkyl or an alkylaryl group from 1 to 20 carbon atoms, wherein the substituents of R2, R3, and R4 are all identical, are all different or two of the substituents of R2, R3, and R4 type are identical.