HFO-1234yf Production via Impurity-Free Dehydrochlorination
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Solution Overview
Problem
Current methods for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) face challenges such as high costs, hazardous handling of hydrogen gas, low yield, and catalyst deactivation due to impurities like metal halides and carbonaceous materials, which reduce the production rate and selectivity of HFO-1234yf and increase the formation of undesired byproducts.
Innovation Solution
A process involving the dehydrochlorination of 2-chloro-1,1,1,2-tetrafluoropropane in a reactor, where impurities are reduced by introducing a reducing or oxidizing agent, or through mechanical means to improve selectivity and production rate of HFO-1234yf, and prevent the formation of HCFO-1233xf, by maintaining the reactor in a substantially impurity-free state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen gas is used for dehydrochlorination, then high yield of HFO-1234yf is achieved, but handling becomes hazardous and cost increases
Solution Approach 1:
The invention changes the chemical parameter of the dehydrochlorination reaction by replacing hydrogen gas with alternative reducing agents such as carbon monoxide, carbon, or hydrocarbons. This parameter change maintains the high yield of HFO-1234yf while eliminating the hazardous handling requirements associated with hydrogen gas
Solution Approach 2:
The invention employs carbon-based materials (carbon monoxide, carbon, hydrocarbons) as disposable reducing agents that can be easily handled and do not require the specialized safety infrastructure needed for hydrogen gas, thereby reducing both hazard and cost
2Productivity
If pyrolysis of methyl chloride and tetrafluoroethylene is used, then HFO-1234yf is produced, but yield is low and catalyst deactivates due to carbon black formation
Solution Approach 1:
The invention extracts and removes the harmful byproduct (carbon black) from the reaction system by using alternative reducing agents that do not produce carbonaceous deposits, thereby preventing catalyst deactivation and maintaining reliable operation
Solution Approach 2:
The invention changes the reaction parameters by replacing the pyrolysis process with dehydrochlorination using carbon-based reducing agents, which alters the reaction pathway to eliminate carbon black formation while maintaining HFO-1234yf production
3Duration of action of moving object
If reaction proceeds in presence of impurities, then continuous production is maintained, but selectivity decreases and HCFO-1233xf forms
Solution Approach 1:
The invention performs preliminary action by pre-treating the reactor with reducing agents to remove impurities before initiating the dehydrochlorination reaction, and by continuously maintaining reducing conditions during production to prevent impurity formation, thereby preserving high selectivity throughout continuous operation
Solution Approach 2:
The invention ensures continuity of useful action by implementing a continuous supply of reducing agents (carbon monoxide, carbon, or hydrocarbons) during the dehydrochlorination process, which continuously prevents impurity formation and maintains high selectivity to HFO-1234yf throughout the production period
Data Source
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AI summary
The present invention relates, in part, to the discovery that the presence of impurities in a reactor for dehydrochlorinating HCFC-244bb to HFO-1234yf results in a reduced conversion rate and/or a selectivity changeover from HFO-1234yf to HCFO-1233xf. By substantially removing such impurities, it is shown that the conversion rate may be improved and selectivity to HFO-1234yf via dehydrochlorination of HCFC-244bb is also improved.