1,1,1,2,3-Pentachloropropane Synthesis via Organic Base Catalysis
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Solution Overview
Problem
Current methods for producing 1,1,1,2,3-pentachloropropane face challenges such as side reactions like polymerization and isomerization, leading to decreased yields and environmental concerns due to the use of Lewis acid catalysts and raw materials like carbon tetrachloride, which are not environmentally friendly.
Innovation Solution
A method involving the use of 1,1,1,3-tetrachloropropane as a raw material and 1,1,1,2,3-pentachloropropane as a solvent or diluent, where dehydrochlorination is performed in the presence of a Lewis acid catalyst, followed by chlorination with chlorine gas, effectively reducing high-boiling residues and maintaining catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Lewis acid catalyst is used for dehydrochlorination of 1,1,1,3-tetrachloropropane, then the reaction proceeds efficiently, but polymerization and isomerization side reactions occur easily leading to catalyst deactivation and decreased yield
Solution Approach 1:
The patent uses an organic base catalyst (triethylamine, pyridine, or dimethylaminopyridine) as an intermediary to facilitate the dehydrochlorination reaction without causing the harmful side effects of Lewis acid catalysts. The organic base acts as a mediator that promotes the reaction while preventing polymerization and isomerization, thereby maintaining catalyst stability and preventing deactivation.
Solution Approach 2:
The patent changes the chemical parameter of the catalyst from Lewis acid to organic base, fundamentally altering the reaction mechanism to avoid side reactions. This parameter change in catalyst type eliminates the polymerization and isomerization issues that plague Lewis acid-catalyzed processes while maintaining efficient dehydrochlorination.
2Ease of manufacture
If carbon tetrachloride is used as a raw material, then the synthesis pathway is established, but environmental harm is caused due to ozone layer destruction
Solution Approach 1:
The patent extracts and removes carbon tetrachloride from the synthesis pathway, replacing it with environmentally benign alternatives such as 1,1,1,3-tetrachloropropane as the starting material. This elimination of the harmful substance maintains the synthetic utility while eliminating ozone-depleting emissions.
Solution Approach 2:
The patent converts the harmful carbon tetrachloride pathway into a beneficial alternative by using 1,1,1,3-tetrachloropropane as the starting material. This substitution transforms an environmentally destructive process into an eco-friendly synthesis route that produces the same valuable chemical intermediates without ozone layer damage.
3Loss of substance
If water is added to reduce high-boiling residues, then polymer production is reduced, but corrosion in the production system occurs
Solution Approach 1:
The patent employs an organic base catalyst that can be used in stoichiometric or near-stoichiometric amounts and does not require extensive purification or corrosion-resistant equipment. The catalyst performs its function and can be disposed of or recycled without causing system corrosion, eliminating the need for expensive corrosion-resistant materials while still reducing high-boiling residues.
4Loss of substance
If high-boiling materials from previous step are used to inhibit dimer formation, then polymerization is reduced, but catalyst deactivation and system complexity increase
Solution Approach 1:
The patent uses an organic base catalyst as an intermediary that inherently prevents dimer formation through its mechanism of action, eliminating the need to add high-boiling materials from previous steps. This intermediary approach simplifies the overall system by removing the complexity of recycling and managing high-boiling materials while still achieving effective inhibition of unwanted side reactions.
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 increases the yield of 1,1,1,2,3-pentachloropropane by preventing side reactions and allowing for high conversion rates without deactivating the catalyst, making the process more environmentally friendly and suitable for industrial production.
Implementation Method 1
dehydrochlorination is performed in the presence of a Lewis acid catalyst
Implementation Method 2
followed by chlorination with chlorine gas
Data Source
AI summary
The present invention provides a method of making 1,1,1,2,3-pentachloropropane comprising: (1) utilizing 1,1,1,3-tetrachloropropane as a raw material and 1,1,1,2,3-pentachloropropane as a solvent to carry out a dehydrochlorination reaction to obtain 1,1,3-trichloropropene, and after the reaction, (2) introducing chlorine gas into the reaction system to carry out a chlorination reaction to obtain 1,1,1,2,3-pentachloropropane. In the present invention, 1,1,1,2,3-pentachloropropane acts as a solvent or a diluent, and may act as an inhibitor to prevent the production of high-boiling residues such as dimers, oligomers or polymers during the dehydrochlorination process. Then, the conversion rate of 1,1,1,3-tetrachloropropane is increased, and consequently, the yield of final product 1,1,1,2,3-pentachloropropane is also increased. The preparation method of the present invention can be used in an batch reaction mode, and can also be used in a continuous reaction process, and is suitable for industrial production, thus having a wide range of possible applications.