HFO-1234yf Purification via Liquid Phase Fluorination
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Solution Overview
Problem
Current methods for purifying 2,3,3-tetrafluoro-1-propene are inefficient in removing impurities like halogenated propynes, which can lead to catalyst deactivation and coke formation, due to their physical properties and close boiling points with the desired compound.
Innovation Solution
A process involving the use of HF under specific conditions to produce a composition that includes 2,3,3-tetrafluoropropene, followed by multiple distillation steps to separate and recover the desired product, effectively removing impurities such as halogenated propynes and other secondary products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to purify 2,3,3,3-tetrafluoropropene, then separation of impurities is achieved, but the process is inefficient due to close boiling points and azeotropic compositions
Solution Approach 1:
The patent applies preliminary action by conducting the fluorination reaction in the liquid phase rather than gas phase, which prevents the formation of certain impurities (HCFO-1233zd and HFC-245fa) before they can accumulate. This preliminary prevention step reduces the burden on subsequent purification steps and improves overall process efficiency.
Solution Approach 2:
The patent changes the physical state parameter from gas phase to liquid phase for the fluorination reaction. This parameter change fundamentally alters the reaction pathway and impurity profile, enabling more effective purification and resolving the contradiction between achieving high purity and maintaining process efficiency.
2Productivity
If gas phase fluorination is used to produce 2,3,3,3-tetrafluoropropene, then production is achieved, but impurities such as HCFO-1233zd and HFC-245fa accumulate and prevent product formation
Solution Approach 1:
The patent changes the reaction phase from gas to liquid, which fundamentally alters the reaction mechanism and selectivity. This parameter change eliminates the formation of problematic impurities HCFO-1233zd and HFC-245fa, simultaneously improving both productivity and product purity.
Solution Approach 2:
The patent converts the potential harm of liquid phase reaction (which might be expected to create more byproducts) into a benefit by demonstrating that liquid phase fluorination actually produces fewer and more easily separable impurities, thereby improving both production efficiency and product quality.
3Manufacturing precision
If extractive distillation is used to separate impurities, then separation capability is improved, but process complexity increases
Solution Approach 1:
By performing preliminary prevention of impurity formation through liquid phase reaction, the patent reduces the complexity of subsequent purification steps. Fewer impurities need to be separated, simplifying the overall process while maintaining high product purity.
Solution Approach 2:
The liquid phase reaction parameter change creates a more favorable impurity profile that is easier to separate through conventional distillation, reducing the need for complex extractive distillation processes and their associated equipment.
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 process achieves high purity of 2,3,3-tetrafluoro-1-propene by effectively separating and removing impurities, thereby preventing catalyst deactivation and improving product quality.
Implementation Method 1
contacting, in the presence of a catalyst, the starting composition with HF under conditions effective in producing a composition A including HCl, some unreacted HF, 2,3,3,3-tetrafluoropropene
Implementation Method 2
purification, preferably by distillation, of this gas to form and recover a gas stream G1
Implementation Method 3
when the compounds to be purified have boiling points that are too close, or when they form azeotropic or quasi-azeotropic compositions, distillation is not an efficient process
Data Source
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AI summary
The invention relates to a method for the production of 2,3,3,3-tetrafluoropropene using a starting composition, comprising the steps of: bringing the starting composition into contact with HF, in the presence of a catalyst, in order to produce a composition A comprising 2,3,3,3-tetrafluoropropene (HFO-1234yf), intermediate products B consisting of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), 1,1,1,2,2-pentafluoropropane (HFC-245cb), and secondary products C consisting of E-1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zd E), trans-1,3,3,3-tetrafluoro-1-propene (HFO-1234zeE) and 1,1,1,3,3-pentafluoropropane (HFC-245fa); recovering composition A and purifying same in order to form and recover a first gas stream G1 comprising HCl, 2,3,3,3-tetrafluoropropene (HFO-1234yf), some of the unreacted HF, some of the intermediate products B and some of the secondary products C, and a preferably liquid stream L1 comprising some of the unreacted HF, some of the intermediate products B and some of the secondary products C.