Integrated Fluorochemical Co-Production via Segmented Reactors
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Solution Overview
Problem
There is a need for an economical process to continuously produce trans-1-chloro-3,3,3-trifluoropropene (1233zd(E)) and trans-1,3,3,3-tetrafluoropropene (1234ze(E)), as well as 1,1,1,3,3-pentafluoropropane (245fa), which are candidates to replace chlorofluorocarbons and hydrochlorofluorocarbons in foam-blowing applications, due to environmental concerns.
Innovation Solution
An integrated three-step process involving the reaction of 1,1,1,3-tetrachloropropene with anhydrous HF in a liquid-phase catalyzed reactor to co-produce 1233zd(E) and 244fa, followed by dehydrochlorination or dehydrofluorination of the 244fa stream to produce 1234ze(E) and 245fa, respectively, while allowing for flexibility in product ratios and raw material recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation techniques such as distillation are used to separate 1233zd (E) and 245fa, then separation is impossible due to azeotropic composition formation, but the integrated process avoids intimate contact between these compounds to prevent azeotrope formation
Solution Approach 1:
The process extracts 1233zd (E) from the reaction mixture in the first reactor before it can mix with 245fa in the second reactor. By removing the intermediate 244fa and converting it to 1234ze (E) in a separate stream, the process prevents the formation of an azeotropic mixture between 1233zd (E) and 245fa, making separation feasible
Solution Approach 2:
The production process is segmented into two separate reactor systems: the first reactor produces 1233zd (E) from 1,1,1,3-tetrachloropropene, and the second reactor produces 245fa from the same feedstock through a different reaction pathway. This segmentation prevents intimate contact between 1233zd (E) and 245fa, avoiding azeotrope formation
2Loss of substance
If 245fa is used as a precursor to produce 1234ze (E), then one mole of HF must be removed per mole of 1234ze (E) produced, but using 244fa as precursor eliminates this HF waste
Solution Approach 1:
The process performs preliminary dehydrochlorination of 244fa to 1234ze (E) in the first reactor before fluorination to 245fa occurs. This preliminary action prevents the need to later remove HF from 245fa to produce 1234ze (E), eliminating HF waste
Solution Approach 2:
The process changes the reaction parameters in the first reactor to favor dehydrochlorination over fluorination by controlling temperature, catalyst selection, and residence time. This parameter optimization enables selective production of 1234ze (E) from 244fa without forming 245fa, preventing HF waste
3Quantity of substance
If a single feedstock (1,1,1,3-tetrachloropropene) is used to co-produce multiple products (1233zd (E), 1234ze (E), and 245fa), then raw material utilization is maximized, but the product mixture becomes complex
Solution Approach 1:
The first reactor is designed to perform multiple functions: it produces 1233zd (E) directly from 1,1,1,3-tetrachloropropene, converts 244fa to 1234ze (E) through dehydrochlorination, and prepares 244fa for subsequent fluorination to 245fa. This multi-functionality maximizes raw material utilization while managing product complexity through integrated reaction engineering
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 efficiently co-produces 1233zd(E), 1234ze(E), and 245fa, offering economic advantages and flexibility in production, avoiding azeotropic separation issues and maximizing raw material utilization, with the ability to isolate by-products for commercial value.
Implementation Method 1
the reaction of 1,1,1,3-tetrachloropropene and/or 1,1,3,3-tetrachloropropene with anhydrous HF in excess in a liquid-phase catalyzed reactor
Implementation Method 2
the 244fa stream can be dehydrochlorinated to produce the desired second product 1234ze (E)
Implementation Method 3
the 244fa stream can be dehydrofluorinated to produce 1233zd (E) if more of that product is desired
Implementation Method 4
the 244fa stream can be further fluorinated to form 245fa
Data Source
AI summary
Disclosed is an integrated process to co-produce trans-1-chloro-3,3,3-trifluoro-propene (1233zd (E)), trans-1,3,3,3-tetrafluoropropene (1234ze (E)), and 1,1,1,3,3-pentafluoropropane (245fa). Overall the co-production is a three-step process. The chemistry involves the steps of:(1) the reaction of 1,1,1,3-tetrachloropropene and/or 1,1,3,3-tetrachloropropene with anhydrous HF in excess in a liquid-phase catalyzed reactor in such a way as to co-produce primarily 1233zd (E) and 244fa (plus by-product HCl); an optionally(2) the 244fa stream can then be used to directly produce any (or all) of the following desired products;(a) the 244fa stream can be dehydrochlorinated to produce the desired second product 1234ze (E); and/or(b) the 244fa stream can be dehydrofluorinated to produce 1233zd (E) if more of that product is desired; and/or(c) the 244fa stream can be further fluorinated to form 245fa.