Halocarbon Separation via Selective Freezing
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Solution Overview
Problem
Conventional separation techniques are inadequate for isolating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) due to their formation of a binary azeotrope or azeotrope-like composition, which prevents effective separation.
Innovation Solution
The method involves cooling the mixture to a temperature below the freezing point of HCFC-244bb but above the freezing point of HCFO-1233xf, allowing for the separation of HCFC-244bb in solid form while HCFO-1233xf remains in liquid or gaseous form, enabling subsequent recovery through decantation, filtration, or centrifugation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation techniques are used, then the separation process is simple and equipment is standard, but the halocarbons cannot be separated due to azeotrope formation
Solution Approach 1:
The patent changes the temperature parameter to below the freezing point of HCFC-244bb but above the freezing point of HCFO-1233xf, transforming the separation mechanism from vapor-liquid equilibrium to solid-liquid equilibrium, which eliminates the azeotrope problem and enables effective separation
Solution Approach 2:
The patent utilizes the phase transition of HCFC-244bb from liquid to solid at temperatures below its freezing point, while HCFO-1233xf remains liquid, creating a solid-liquid mixture that can be separated by filtration or decantation, thus resolving the azeotrope separation issue
2Manufacturing precision
If freezing temperature is used for separation, then effective separation of azeotropic mixtures is achieved, but energy consumption increases due to cooling requirements
Solution Approach 1:
The patent optimizes the temperature parameter to the specific range below HCFC-244bb freezing point but above HCFO-1233xf freezing point, achieving maximum separation purity while minimizing energy consumption by avoiding excessive cooling
Solution Approach 2:
The patent applies localized cooling only to the extent necessary to freeze HCFC-244bb while keeping HCFO-1233xf liquid, rather than cooling the entire system to extremely low temperatures, thus reducing overall energy consumption while maintaining separation effectiveness
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 approach effectively isolates essentially pure HCFC-244bb and HCFO-1233xf, facilitating their use as intermediates in the production of 2,3,3-tetrafluoropropene (HFO-1234yf), a refrigerant with zero ozone depletion and low global warming potential.
Implementation Method 1
cooling the composition to a temperature below the freezing point of HCFC-244bb but above the freezing point of HCFO-1233xf
Data Source
AI summary
The invention provides a method for separating halocarbons. In particular, a method for separating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) based on differences in melting points of these compounds. More particularly the invention pertains to a method for separating HCFC-244bb from HCFO-1233xf which are useful as intermediates in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf).