Integrated HFO-1234ze Production via Catalytic Isomerization
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Solution Overview
Problem
Existing processes for producing trans-1,3,3,3-tetrafluoropropene (HFO trans-1234ze) are not economical and result in significant generation of cis-1234ze, necessitating a method to isolate trans-1234ze and convert cis-1234ze into trans-1234ze for higher yield and purity.
Innovation Solution
A process involving dehydrofluorination of 1,1,1,3,3-pentafluoropropane to produce a mixture of cis- and trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride, followed by catalytic isomerization of cis-1234ze to trans-1234ze, with optional hydrogen fluoride recovery and recycling of unconverted cis-1234ze and HFC-245fa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluorination of HCC-240fa is used to produce HFO-1234ze, then trans-1234ze can be formed, but significant amount of cis-1234ze is generated together with trans-isomer reducing product yield and purity
Solution Approach 1:
The patent divides the production process into two distinct stages: (1) fluorination of HCC-240fa to produce both cis- and trans-1234ze, and (2) selective isomerization of cis-1234ze to trans-1234ze using a specific catalyst. This segmentation allows the first stage to focus on production while the second stage purifies the product, resolving the contradiction between yield and purity.
Solution Approach 2:
The patent introduces an isomerization catalyst as an intermediary substance that selectively converts cis-1234ze to trans-1234ze without affecting the trans-isomer. This intermediary enables the transformation of the unwanted byproduct (cis-1234ze) into the desired product (trans-1234ze), simultaneously improving both yield and purity.
2Productivity
If known fluorination processes are used, then trans-1234ze production is achieved, but the process is not economical due to low yield and need for cis-1234ze isolation
Solution Approach 1:
The patent converts the harmful byproduct (cis-1234ze) into a beneficial component by using catalytic isomerization to transform it into trans-1234ze. This eliminates the need for expensive isolation and disposal processes, making the manufacture economically viable while maximizing yield.
Solution Approach 2:
The patent changes the reaction parameters by introducing specific catalysts and controlling reaction conditions (temperature, pressure, catalyst composition) to favor the isomerization of cis-1234ze to trans-1234ze. This parameter optimization enables high yield and economical production by minimizing waste and additional processing steps.
3Productivity
If cis-1234ze is isolated and recycled via fluorination to HFC-245fa, then some trans-1234ze can be recovered, but this multi-step process reduces overall efficiency and yield
Solution Approach 1:
The patent merges the isomerization function into the existing fluorination process by adding an isomerization catalyst to the reaction system. This combines two previously separate processes (fluorination and isomerization) into a single integrated process, simplifying the overall process complexity while maintaining high yield.
Solution Approach 2:
The patent implements continuous isomerization of cis-1234ze to trans-1234ze within the reaction system, eliminating the need for interruption, isolation, and separate recycling steps. This continuous action maintains high productivity while reducing process complexity by keeping the system in steady-state operation.
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 integrated process achieves a higher yield of highly pure trans-1234ze and effectively converts cis-1234ze into trans-1234ze, improving the economic viability and efficiency of the production process.
Implementation Method 1
catalytically dehydrofluorinating 1,1,1,3,3-pentafluoropropane to thereby produce a mixture of cis-1,3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride
Implementation Method 2
catalytically isomerizing cis-1234ze into trans-1234ze
Data Source
AI summary
A process for the manufacture of HFO trans-1,3,3,3-tetrafluoropropene (HFO trans-1234ze) by first catalytically dehydrofluorinating 1,1,1,3,3-pentafluoropropane to thereby produce a mixture of cis-1,3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride, optionally recovering hydrogen fluoride, catalytically isomerizing cis-1234ze into trans-1234ze, and recovering trans-1,3,3,3-tetrafluoropropene.