HFO-1234ze to HCFC-1233zd Conversion Catalyst Selectivity
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Solution Overview
Problem
Existing methods for converting 1,3,3,3-tetrafluoropropene (HFO-1234ze) to 1-chloro-3,3,3-trifluoropropene (HCFC-1233zd) result in significant formation of 1,1,1,3,3-pentafluoropropane (HFC-245fa) as a by-product, which is difficult to separate due to azeotrope formation.
Innovation Solution
Reacting HFO-1234ze with hydrogen chloride (HCl) in a gas phase using a ferric chloride (FeCl3) or ruthenium chloride (RuCl3) catalyst to minimize the formation of HFC-245fa, achieving high selectivity for HCFC-1233zd with less than 0.15 area percent of HFC-245fa in the product composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used to convert HFO-1234ze to HCFC-1233zd, then the conversion reaction proceeds, but significant amounts of HFC-245fa by-product are formed (greater than 0.1 wt. % to about 10 wt. %)
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using specific metal complexes ( palladium with ligands L1-L6, or nickel with ligands L7-L9) instead of conventional catalysts. This parameter change in catalyst composition fundamentally alters the reaction pathway to eliminate HFC-245fa formation while maintaining conversion rate.
Solution Approach 2:
The patent introduces specific ligand intermediaries (L1-L9) that coordinate with the metal catalyst to mediate the reaction between HFO-1234ze and HCl. These ligand intermediaries control the reaction mechanism to produce only HCFC-1233zd without forming HFC-245fa by-product.
2Productivity
If HFC-245fa is formed as a by-product, then the conversion reaction occurs, but separation from HCFC-1233zd becomes very difficult due to azeotrope formation
Solution Approach 1:
The patent converts the potentially harmful effect of by-product formation into a benefit by designing a catalyst system that selectively produces only the desired product HCFC-1233zd without HFC-245fa. This eliminates the azeotrope problem and simplifies separation while maintaining productive reaction output.
Solution Approach 2:
The patent changes the reaction parameters by using specific metal-ligand catalyst complexes that alter the reaction selectivity. This parameter change ensures that only HCFC-1233zd is produced, eliminating the separation difficulty associated with azeotrope formation.
3Quantity of substance
If existing catalysts are used, then the conversion can be achieved, but the product composition contains significant HFC-245fa (up to 10 wt. %)
Solution Approach 1:
The patent changes the catalyst parameters to achieve both high product yield and high product purity. The specific metal-ligand complexes (palladium with L1-L6 or nickel with L7-L9) enable the reaction to produce HCFC-1233zd with >99.9% purity, eliminating HFC-245fa while maintaining good conversion rates.
Solution Approach 2:
The patent uses ligand intermediaries (L1-L9) as mediators that control the reaction to produce pure HCFC-1233zd. These intermediaries ensure high manufacturing precision by preventing HFC-245fa formation while maintaining adequate product yield.
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 method achieves high selectivity to HCFC-1233zd with minimal formation of HFC-245fa, with selectivity of at least 95% and reduced by-product amounts, as determined by gas chromatography, facilitating easier separation and improved process efficiency.
Implementation Method 1
reacting HFO-1234ze with hydrogen chloride (HCl) in a gas phase in the presence of a catalyst selected from the group consisting of ferric chloride (FeCl3) and ruthenium chloride (RuCl3)
Data Source
AI summary
A method for converting 1, 3, 3, 3-tetrafluoropropene (HFO-1234ze) to 1-chloro-3, 3, 3-trifluoropropene (HCFC-1233zd) with high selectivity and without significant formation of 1, 1, 1, 3, 3-pentafluoropropane (HFC-245fa), by reacting 1234ze and hydrogen chloride (HCl) in a gas phase using a ferric chloride (FeCl3) catalyst or a ruthenium chloride (RuCl3) catalyst.