Selective Olefin Purification via Terminal CF2 Group Reaction
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Solution Overview
Problem
The challenge lies in effectively reducing the relative content of compounds with a terminal CF2 group, such as 1,1,3,3-pentafluoropropene, in mixtures with similar boiling points, as distillation becomes difficult due to their close boiling points, posing a purification issue in manufacturing fluorinated compounds used as refrigerants and other applications.
Innovation Solution
A process involving selective addition reactions between compounds with a terminal CF2 group and selective removal agents like SO3 or RSO3H, forming addition compounds with higher boiling points, thereby facilitating the reduction of the mole ratio of these compounds in a mixture through selective reaction and subsequent separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate compounds with close boiling points, then separation is achieved, but the process becomes difficult or impossible when boiling points are too close
Solution Approach 1:
The patent changes the chemical parameter of the impurity compound by reacting it with a selective removal agent (SO3 or RSO3H) to form an addition compound. This chemical transformation alters the boiling point and other physical properties of the impurity, enabling effective separation from the desired compound that cannot be achieved by distillation alone when boiling points are too close.
Solution Approach 2:
The patent extracts the impurity compound (containing terminal CF2 group) from the mixture by selectively reacting it with a removal agent. The impurity is converted into a different chemical form (addition compound) that can be easily separated from the desired product through simple distillation or other separation techniques.
2Manufacturing precision
If selective removal agents are used to react with compounds containing terminal CF2 group, then the mole ratio of these compounds is reduced, but additional reaction and separation steps are required
Solution Approach 1:
The patent introduces a selective removal agent (SO3 or RSO3H) as an intermediary substance that specifically reacts with impurity compounds containing terminal CF2 groups. This intermediary enables selective transformation of the impurity into a separable form without affecting the desired product, achieving high purification effectiveness.
Solution Approach 2:
The patent changes the chemical structure and physical parameters of the impurity compound by forming addition compounds with the selective removal agent. This parameter change (chemical structure modification) enables the impurity to be separated from the desired compound through simple physical methods like distillation, improving overall process efficiency despite adding a reaction step.
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 allows for the efficient reduction of the mole ratio of compounds like 1,1,3,3-pentafluoropropene in mixtures, enabling effective separation and purification by exploiting the higher boiling points of the addition compounds formed, thus overcoming the limitations of distillation in separating closely boiling impurities.
Implementation Method 1
selective addition reactions which form addition compounds between a compound of the formula Y1Y2C═CF2 and a selective removal agent selected from the group consisting of SO3 and RSO3H
Data Source
AI summary
A process is disclosed for reducing the mole ratio of (1) compounds of the formula Y1Y2C═CF2 wherein Y1 and Y2 are each independently H, F, Cl, Br, C1-C6 alkyl or C1-C6 haloalkyl containing no more than 3 chlorine substituents, 2 bromine substituents and 1 iodo substituent to (2) saturated compounds of the formula CdHeFfClgBrhIk wherein d is an integer from 1 to 10, and e+f+g+h+k is equal to 2d+2, provided that g is 0, 1, 2 or 3, h is 0, 1 or 2 and k is 0 or 1 and/or unsaturated compounds of the formula Y3Y4C═CY5Y6, wherein Y3, Y5 and Y6 are each independently H, F, Cl, Br, C1-C6 alkyl or C1-C6 haloalkyl containing no more than 3 chlorine substituents, 2 bromine substituents and 1 iodo substituent, provided that Y5 and Y6 are not both F, and Y4 is C1-C6 alkyl or C1-C6 haloalkyl containing no more than 3 chlorine substituents, 2 bromine substituents and 1 iodo substituent, in a mixture. The process involves contacting the mixture with at least one selective removal agent selected from the group consisting of SO3 and RSO3H, wherein R is selected from the group consisting of F, Cl, OH, C1-C8 alkyl, C1-C8 fluoroalkyl, and C1-C8 fluoroalkoxyalkyl containing no more than two ether oxygens to selectively react the formula Y1Y2C═CF2 compounds.