Chromium Catalyst Isomerization for 1233zd Refrigerant Production
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Solution Overview
Problem
Current methods for producing hydrochlorofluoroolefins, such as trans 1-chloro-3,3,3-trifluoropropene, face challenges in achieving low ozone depletion potential (ODP) and global warming potential (GWP) while meeting environmental regulations, as existing processes may not efficiently separate and isomerize cis and trans isomers, leading to suboptimal environmental performance.
Innovation Solution
A process involving the fluorination of 1,1,3,3-tetrachloropropene or 1,1,1,3,3-tetrachloropropane to produce a mixture of cis and trans 1-chloro-3,3,3-trifluoropropene, followed by separation and isomerization using homogeneous or heterogeneous catalysts, specifically employing salts of aluminum, titanium, or chromium, to achieve the desired trans isomer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fluorination methods are used to produce hydrochlorofluoroolefins, then the basic chemical transformation is achieved, but the process fails to efficiently separate and isomerize cis and trans isomers resulting in suboptimal environmental performance
Solution Approach 1:
The patent applies preliminary action by performing isomerization of cis-1233zd to trans-1233zd before final separation. The process first fluorinates 1,1,3,3-tetrachloropropene to produce a mixture of cis and trans isomers, then isomerizes the cis isomer using a chromium catalyst, and finally separates the enriched trans isomer. This sequence of operations before final product isolation improves separation efficiency while managing process complexity.
Solution Approach 2:
The patent employs parameter changes by utilizing the different boiling points of cis-1233zd (27.5°C) and trans-1233zd (13.5°C) to achieve separation through distillation. The fractional distillation column operates at controlled temperatures and pressures to exploit this physical property difference, enabling efficient separation of the isomers after isomerization.
2Object-affected harmful factors
If environmental regulations are met with negligible ODP and low GWP, then environmental acceptability is achieved, but the manufacturing process becomes more complex requiring specific catalysts and separation steps
Solution Approach 1:
The patent applies the taking out principle by selectively removing the cis isomer through isomerization to trans isomer, which then separates more easily. The chromium-based catalyst selectively converts cis-1233zd to trans-1233zd, and the fractional distillation column extracts and separates the trans isomer from remaining cis isomer and other byproducts, achieving the environmentally desirable trans isomer with high purity.
Solution Approach 2:
The patent uses an intermediary approach by introducing a chromium-based catalyst as a mediator in the isomerization step. The catalyst facilitates the conversion of cis-1233zd to trans-1233zd without being consumed, enabling selective transformation that simplifies subsequent separation while maintaining environmental benefits of the trans isomer product.
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 effectively produces trans 1-chloro-3,3,3-trifluoropropene with negligible ODP and low GWP, suitable for use as a blowing agent, solvent, and refrigerant, while adhering to environmental regulations by optimizing the separation and isomerization steps.
Implementation Method 1
isomerization of cis 1233zd (Z-1233zd) to form trans 1233zd (E-1233zd) in the gas phase in the presence of a high surface area heterogeneous Cr catalyst
Implementation Method 2
The effluent from the isomerization reactor is fed to a fractional distillation column, with the overhead enriched in trans 1233zd (E-1233zd) and the bottoms enriched in cis 1233zd (Z-1233zd)
Data Source
Figure 1~2
AI summary
The present invention provides a process for the manufacture of trans 1-chloro-3,3,3-trifluoropropene (E-1233zd). The first step of the process comprises the fluorination of 1,1,3,3- tetrachlororopropene (1230za, CCh=CH-CHCh) and/or 1,1,1,3,3- pentaachloropropane (240fa) to a mixture of cis 1233zd (Z-1233zd) and trans 1233zd (E-1233zd). The second step of the process comprises a separation of the mixture formed in the first step to isolate cis 1233zd (Z-1233zd) from the mixture. The third step of the process comprises isomerization of cis 1233zd (Z-1233zd) to trans 1233zd (E- 1233zd).