VCM Vapor Diffusion for HCC-240fa PVC Prevention
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Solution Overview
Problem
The formation of polyvinyl chloride (PVC) during the production of 1,1,1,3,3-pentachloropropane (HCC-240fa) leads to yield loss, heat management difficulties, and reduced catalyst activity due to the addition of liquid vinyl chloride to a reactor containing carbon tetrachloride and catalysts.
Innovation Solution
Feeding vinyl chloride as a vapor through a diffusing device, such as a dip tube or sponge type gas diffuser, into a reactor precharged with carbon tetrachloride and iron powder, increases the contact surface and reactivity, thereby avoiding PVC formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid vinyl chloride is added to the reactor, then the reaction proceeds, but polyvinyl chloride forms causing yield loss and heat management difficulties
Solution Approach 1:
The patent changes the physical state parameter of vinyl chloride from liquid to vapor phase. By feeding VCM as vapor instead of liquid, the reaction conditions are modified to prevent PVC polymerization while maintaining the desired addition reaction with carbon tetrachloride to produce HCC-240fa
Solution Approach 2:
The patent introduces a diffusing device (dip tube or sponge type gas diffuser) as an intermediary component. This device facilitates the controlled introduction of VCM vapor into the liquid reaction mixture, increasing contact surface area and improving mass transfer while preventing direct liquid addition that would cause PVC formation
2Productivity
If liquid vinyl chloride is added to the reactor, then the reaction proceeds, but heat management becomes difficult due to excessive exotherm
Solution Approach 1:
The patent changes the physical state parameter of vinyl chloride from liquid to vapor phase. By feeding VCM as vapor instead of liquid, the reaction conditions are modified to prevent PVC polymerization while maintaining the desired addition reaction with carbon tetrachloride to produce HCC-240fa
Solution Approach 2:
The patent introduces a diffusing device (dip tube or sponge type gas diffuser) as an intermediary component. This device facilitates the controlled introduction of VCM vapor into the liquid reaction mixture, increasing contact surface area and improving mass transfer while preventing direct liquid addition that would cause PVC formation
3Productivity
If liquid vinyl chloride is added to the reactor, then the reaction proceeds, but catalyst activity is reduced due to iron particle encapsulation
Solution Approach 1:
The patent changes the physical state parameter of vinyl chloride from liquid to vapor phase. By feeding VCM as vapor instead of liquid, the reaction conditions are modified to prevent PVC polymerization while maintaining the desired addition reaction with carbon tetrachloride to produce HCC-240fa
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 enhances the yield of HCC-240fa by preventing PVC formation, improving heat management, and maintaining catalyst activity, resulting in higher efficiency and purity of the product.
Implementation Method 1
VCM vapor is fed into a reactor precharged with CCl4, TBP and iron powder through a dip tube... through a sponge type gas diffuser to further increase the contact surface between VCM vapor and CCl4
Data Source
AI summary
Disclosed is a process for the manufacture of haloalkane compounds, and more particularly, to an improved process for the manufacture of the compound 1,1,1,3,3-pentachloropropane (HCC-240fa), which mitigates the formation of by-products. The present invention is also useful in the manufacture of other haloalkane compounds such as HCC-250 and HCC-360. One embodiment of the process comprises a method and system for avoiding the formation of polyvinyl chloride during the production of HCC-240fa from CCl4, in which vinyl chloride (VCM) is fed into a reactor as a vapor instead of as a liquid, using a diffusing device to further increase the contact surface between VCM vapor and CCl4.