HFC-1234yf Production via Palladium Catalysis and Segmentation
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Solution Overview
Problem
There is a need for new manufacturing processes for the production of 2,3,3,3-tetrafluoropropene (HFC-1234yf), a potential refrigerant with zero ozone depletion and low global warming potential, as existing methods are not efficient or scalable.
Innovation Solution
A process involving the reaction of HCFC-235cb with hydrogen in the presence of a palladium catalyst supported on chromium oxide or aluminum oxide, or dehydrofluorination followed by hydrogenation, to produce HFC-1234yf, along with the synthesis of HCFC-235cb from chlorofluorocarbons and tetrafluoroethylene using aluminum halide compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing manufacturing processes are used for HFC-1234yf production, then production can be maintained through traditional methods, but the processes are not efficient or scalable and lack high selectivity
Solution Approach 1:
The patent employs parameter changes by optimizing the hydrogen to HCFC-235cb mole ratio (1:1 to 4:1), controlling reaction temperature (100-400°C), and adjusting catalyst composition (palladium on chromium oxide, fluorinated chromium oxide, chromium fluoride, aluminum oxide, aluminum fluoride, or fluorinated alumina) to achieve high selectivity for HFC-1234yf while maintaining scalable production efficiency
Solution Approach 2:
The patent uses an intermediary approach by first converting HCFC-235cb to HFC-245cb through hydrogenation, then dehydrofluorinating HFC-245cb to form HFC-1234yf. This two-step process with intermediate product isolation and purification enables better control over selectivity and scalability compared to direct conversion methods
2Object-affected harmful factors
If new refrigerant production methods are developed to meet environmental requirements, then environmental impact is minimized, but new manufacturing processes need to be established from scratch
Solution Approach 1:
The patent applies preliminary action by first synthesizing HCFC-235cb from readily available starting materials (CH2ClF and CF2═CF2) using aluminum halide catalysts, then using this intermediate in subsequent hydrogenation and dehydrofluorination steps. This staged approach allows for optimized conditions at each step and facilitates easier implementation compared to developing a completely new one-step process
Solution Approach 2:
The patent segments the overall HFC-1234yf production process into distinct stages: (1) synthesis of HCFC-235cb, (2) hydrogenation to HFC-245cb, and (3) dehydrofluorination to HFC-1234yf. Each stage uses specific catalysts and conditions optimized for that transformation, making the overall process more manageable and easier to implement while achieving high environmental compliance
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
The proposed processes enable the production of HFC-1234yf with high selectivity and efficiency, addressing the need for new refrigerant production methods while minimizing environmental impact.
Implementation Method 1
contacting CH2ClCF2CF3 (HCFC-235cb) with hydrogen (H2) in a reaction zone in the presence of a catalyst comprising a catalytically effective amount of palladium supported on a support selected from the group consisting of chromium oxide, fluorinated chromium oxide, chromium fluoride, aluminum oxide, aluminum fluoride, fluorinated alumina, and mixtures thereof, to produce HFC-1234yf
Implementation Method 2
reacting HCFC-235cb with H2 in the presence of a catalytically effective amount of hydrogenation catalyst to form CH3CF2CF3 (HFC-245cb)
Implementation Method 3
dehydrofluorinating HCFC-235cb in the presence of a catalytically effective amount of dehydrofluorination catalyst to form CHCl═CFCF3 (HCFC-1224yd)
Implementation Method 4
reacting CH2ClF (HCFC-31) with CF2═CF2 (TFE) in a reaction zone in the presence of a catalytically effective amount of an aluminum halide composition having a bulk formula of AlClxBryF3-x-y
Data Source
AI summary
A process is disclosed for making CH2═CFCF3. The process involves contacting CH2ClCF2CF3 with H2 in a reaction zone in the presence of a catalyst including a catalytically effective amount of palladium supported on a support selected from chromium oxide, fluorinated chromium oxide, chromium fluoride, aluminum oxide, aluminum fluoride and/or fluorinated alumina, to produce CH2═CFCF3. The mole ratio of H2 to the CH2ClCF2CF3 fed to the reaction zone is between about 1:1 and about 4:1. Also disclosed is another process for making CH2═CFCF3 that involves (a) reacting CH2ClCF2CF3 with H2 in the presence of a catalytically effective amount of hydrogenation catalyst to form CH3CF2CF3; and (b) dehydrofluorinating CH3CF2CF3 from (a) to form CH2═CFCF3; and another process for making CH2═CFCF3 that involves (1) dehydrofluorinating CH2ClCF2CF3 in the presence of a catalytically effective amount of dehydrofluorination catalyst to form CHCl═CFCF3; and (2) hydrogenating CHCl═CFCF3 from (1) in the presence of a hydrogenation catalyst including a catalytically effective amount of palladium supported on a support selected from chromium oxide, fluorinated chromium oxide, chromium fluoride, aluminum oxide, aluminum fluoride and/or fluorinated alumina to form CH2═CFCF3. Also disclosed is a process for making CH2ClCF2CF5. This process involves reacting CH2ClF with CF2═CF2 in a reaction zone in the presence of a catalytically effective amount of an aluminum halide composition having a bulk formula of AlClxBryF3-x-y wherein the average value of x is 0 to 3, the average value of y is 0 to 3-x, provided that the average values of x and y are not both 0. Also disclosed is an azeotropic composition including CF3CF═CHCl and HF.