Chlorinated Hydrocarbon Production via Cascade Catalysis
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Solution Overview
Problem
The preparation of chlorinated hydrocarbons, such as 1,1,1,2,3-pentachloropropane and 1,1,2,3-tetrachloropropene, often requires multiple steps and extended reaction times, leading to increased economic costs due to the need for refrigeration and extended processing periods.
Innovation Solution
A method involving the reaction of 1,1,1,3-tetrachloropropane with chlorine in the presence of a polyvalent antimony compound, followed by heating with ferric chloride, to produce 1,1,1,2,3-pentachloropropane and subsequently 1,1,2,3-tetrachloropropene, reducing the number of steps and reaction time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to prepare chlorinated hydrocarbons, then the reactions can be completed with existing processes, but the process requires multiple steps and extended reaction times leading to increased economic costs
Solution Approach 1:
The patent combines multiple reaction steps into a single integrated process by using a cascade reaction system where the first reaction (formation of chloroalkane intermediate) and the second reaction (formation of chlorinated hydrocarbon product) occur sequentially in the same reaction vessel without isolation of intermediates. This merging of steps reduces processing time and eliminates the need for separate reaction equipment for each step.
Solution Approach 2:
The patent performs preliminary formation of the chloroalkane intermediate in situ during the first reaction step, so that when the second reaction step begins, the intermediate is already available for immediate conversion to the final product. This eliminates the need for separate preparation and isolation steps, reducing overall process time and complexity.
2Temperature
If conventional methods are used to prepare chlorinated hydrocarbons, then the reactions can proceed with standard equipment, but refrigeration equipment is required which increases economic costs
Solution Approach 1:
The patent changes the temperature parameters of the reaction process by conducting both reaction steps at elevated temperatures (typically 50-150°C) rather than requiring refrigeration. This parameter change allows the use of simpler heating equipment instead of expensive refrigeration systems, while still achieving high conversion rates and selectivity through the specific catalyst system and reaction conditions.
3Manufacturing precision
If multiple reaction steps are used to prepare chlorinated hydrocarbons, then the process can achieve desired conversion, but the extended processing periods increase economic costs
Solution Approach 1:
The patent maintains continuous useful action by immediately converting the chloroalkane intermediate formed in the first reaction step into the final chlorinated hydrocarbon product in the second reaction step, without any interruption or idle time. The reaction conditions and catalyst system are optimized so that as soon as the intermediate forms, it is consumed to form the final product, eliminating any period where the intermediate accumulates or the reaction vessel is idle.
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 method significantly reduces the steps and time required for production, improving product selectivity and minimizing byproduct formation, thereby lowering costs and enhancing efficiency.
Implementation Method 1
reacting 1,1,1,3-tetrachloropropane with a source of chlorine in the presence of a polyvalent antimony compound comprising a pentavalent antimony compound, thereby forming a product comprising 1,1,1,2,3-pentachloropropane
Implementation Method 2
heating a chlorinated alkane substrate in the presence of ferric chloride and a polyvalent antimony compound comprising a pentavalent antimony compound, thereby forming a product comprising the alkene product
Data Source
AI summary
The preparation of chlorinated hydrocarbons, such as pentachloropropanes, such as 1,1,1,2,3-pentachloropropane, from tetrachloropropanes, such as 1,1,1,3-tetrachloropropane, in the presence of a polyvalent antimony compound that includes a pentavalent antimony compound, such as antimony pentachloride, is described. Also described are methods for preparing optionally chlorinated alkenes, such as, tetrachloropropenes, from chlorinated alkanes, such as pentachloropropanes, in the presence of ferric chloride and a polyvalent antimony compound that includes a pentavalent antimony compound.