Co-Production of Fluoroolefins with Two-Reactor Selectivity Control
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Solution Overview
Problem
Existing methods for producing 3,3,3-trifluoropropene and 2,3,3,3-tetrafluoropropene suffer from low selectivity, high material costs, and inefficient energy consumption, and have not effectively addressed the need for flexible and environmentally friendly production processes.
Innovation Solution
A method involving two reactors and multiple distillation columns is employed, using specific catalysts to convert 1,1,1,3-tetrachloropropane and 1,1,1,2,3-pentachloropropane with hydrogen fluoride, followed by distillation and washing steps to produce 3,3,3-trifluoropropene and 2,3,3,3-tetrafluoropropene with high yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 1,1,1,2,3-pentafluoropropane is used as raw material with metal ion-modified Mg-Al composite metal oxide catalyst and hydrogen added, then simultaneous preparation of 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoropropene is achieved, but the selectivity of trifluoropropene is low and the addition of hydrogen increases the difficulty and cost of subsequent separation
Solution Approach 1:
The patent divides the production process into two independent reaction systems: one using 1,1,1,3-tetrachloropropane as raw material to produce 3,3,3-trifluoropropene, and another using 1,1,1,2,3-pentachloropropane as raw material to produce 2,3,3,3-tetrafluoropropene. This segmentation allows each reaction to be optimized independently, improving the selectivity of trifluoropropene while maintaining the ability to produce multiple fluoroolefin products simultaneously through coordinated operation of both systems.
2Reliability
If 3,3,3-trifluoropropylene process is used to prepare HFO-1234yf, then the product can be used as refrigerant to replace HFC-134a, but the process has a long route, high three wastes, and high product cost
Solution Approach 1:
The patent changes the raw material parameters from conventional chlorinated hydrocarbons to fluorinated hydrocarbons (1,1,1,3-tetrachloropropane and 1,1,1,2,3-pentachloropropane), which have higher fluorine content and more favorable reaction characteristics. This parameter change enables more efficient fluorination reactions with higher selectivity, reducing waste generation and energy consumption while maintaining the production of environmentally friendly HFO refrigerants with zero ODP and low GWP values.
3Device complexity
If general-purpose equipment is used for simultaneously producing HFO-1234yf and HFO-1243zf, then equipment investment is reduced and operating flexibility is improved, but the process requires precise control of reaction conditions and separation parameters
Solution Approach 1:
The patent designs a unified production system that can simultaneously produce both HFO-1234yf and HFO-1243zf using general-purpose equipment with adjustable parameters. The system incorporates multiple reactors that can operate with different raw materials and catalysts, along with flexible separation units that can handle various fluoroolefin products. This multi-functional design reduces equipment investment while maintaining the ability to precisely control reaction conditions and separation parameters through programmable process control.
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 conversion rates and selectivity, reduces energy consumption, and allows for flexible production with minimal waste discharge, utilizing cost-effective and widely available raw materials.
Implementation Method 1
introducing 1,1,1,3-tetrachloropropane (HCC-250fb), 1,1,1,2,3-pentachloropropane (HCC-240 db) and hydrogen fluoride (HF) into a first reactor to have a reaction in the presence of a first catalyst to obtain a reaction product of the first reactor
Implementation Method 2
introducing the reaction product of the first reactor into a first distillation column for separation to obtain a top component of the first distillation column and a bottom component of the first distillation column
Data Source
AI summary
The present invention discloses a method for co-producing 3,3,3-trifluoropropene and 2,3,3,3-tetrafluoropropene, introducing 1,1,1,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane and hydrogen fluoride into a first reactor to have a reaction in the presence of a first catalyst to obtain a reaction product of the first reactor; distilling the reaction product of the first reactor to obtain a 3,3,3-trifluoropropene product and a column bottom product, mixing the column bottom product with the hydrogen fluoride, and feeding a resulting mixture into a second reactor to have a reaction in the presence of a second catalyst to obtain a reaction product of the second reactor; and separating hydrogen chloride from the reaction product of the second reactor, and then carrying out water washing, alkali washing and drying to obtain a 2,3,3,3-tetrafluoropropene product. The present invention has the advantages of simple process, high efficiency, high operation flexibility, small investment and low energy consumption.