HFO-1234ze Preparation via Segmented Reactor Temperature Control
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Solution Overview
Problem
Current methods for producing 1,3,3,3-tetrafluoropropene (HFO-1234ze) face challenges such as high costs of starting materials, difficulty in obtaining intermediates, generation of liquid wastes, short catalyst service life, and complex, energy-intensive processes, making them unsuitable for large-scale industrial use.
Innovation Solution
A two-stage gas-phase fluorination process using HCC-240fa as a starting material, with separate temperature control for catalyst sections in a reactor to facilitate the production of HCFC-1233zd and then HFO-1234ze, and subsequent distillation to optimize selectivity and catalyst longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas-phase catalytic fluorination is used to convert HCC-240fa to HFO-1234ze, then the reaction efficiency is improved, but if the reaction temperature is too high, HCC-240fa polymerizes and carbonizes, and if the temperature is too low, HFO-1234ze selectivity decreases
Solution Approach 1:
The reactor is divided into two distinct sections: a first section for converting HCC-240fa to HCFC-1233zd at lower temperature (200-300°C), and a second section for converting HCFC-1233zd to HFO-1234ze at higher temperature (350-450°C). This segmentation allows each section to operate at optimal temperatures for its specific reaction, avoiding polymerization in the first section while ensuring high selectivity in the second section.
Solution Approach 2:
Different temperature conditions are applied to different locations within the reactor. The first section maintains lower temperature to prevent polymerization of HCC-240fa, while the second section uses higher temperature to maximize HFO-1234ze selectivity. This local quality approach optimizes reaction conditions spatially within the same reactor system.
2Manufacturing precision
If two separate reactors are used for the two-step fluorination process, then each reaction can be optimized, but the process becomes complicated and energy-intensive requiring distillation of intermediates
Solution Approach 1:
Two separate reaction steps are merged into a single reactor system with two distinct sections. The first section performs fluorination of HCC-240fa to HCFC-1233zd, and the second section performs fluorination of HCFC-1233zd to HFO-1234ze. This merging eliminates the need for intermediate distillation and separate reactor operations, simplifying the overall process while maintaining reaction optimization.
Solution Approach 2:
The process achieves continuous conversion through the reactor system, where the product of the first section (HCFC-1233zd) is immediately available as reactant for the second section. This continuous action eliminates interruptions for intermediate purification and maintains steady-state operation, improving process efficiency and reducing complexity.
3Productivity
If supported catalysts are used for gas-phase dehydrohalogenation, then the reaction can proceed, but the catalysts do not have long service lives
Solution Approach 1:
The catalyst preparation parameters are optimized by controlling the water content during catalyst formation. The patent specifies using HF with controlled water content (0.1-5% by mass) to prepare the catalyst, which creates a more stable catalyst structure with extended service life while maintaining high reaction activity for fluorination.
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 method allows for mild reaction conditions, simple process, and stable catalyst activity, making it suitable for large-scale industrial production with improved selectivity and extended catalyst life.
Implementation Method 1
A method for the preparation of HFO-1234ze using gas-phase fluorination with a fluorination catalyst
Implementation Method 2
passing the product stream through a distillation tower
Data Source
AI summary
Disclosed is an HFO-1234ze preparation process. The present invention is realized by loading two fluorination catalysts into the same reactor, and controlling the temperature in each section. The preparation process of the present invention is of moderate reaction condition, stable catalyst activity, and simple process.