Halogenated Aniline Production via Copper Catalysis
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Solution Overview
Problem
Current methods for producing 2,3-difluoroaniline require high temperature and high pressure conditions, making them industrially impractical due to equipment costs and safety concerns, and often involve difficult-to-obtain raw materials or low yields.
Innovation Solution
A method involving the halogenation of 1,2-difluorobenzene or 1-halogeno-3,4-difluorobenzene, followed by nitration and reduction to produce a halogenated nitrobenzene, which is then dehalogenated to yield 2,3-difluoroaniline, using Lewis acid catalysts and fuming sulfuric acid, allowing for production at lower temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature and high pressure conditions are used in fluorination and amination reactions, then the reaction can proceed to produce 2,3-difluoroaniline, but the equipment costs increase and safety concerns arise
Solution Approach 1:
The patent changes the reaction parameters from high temperature and high pressure to milder conditions by using a copper catalyst and optimizing the amination reaction conditions. This allows the reaction to proceed at lower temperatures and pressures, reducing equipment complexity and safety concerns while maintaining productivity
Solution Approach 2:
The patent introduces a copper catalyst as an intermediary to facilitate the amination reaction. The copper catalyst enables the reaction to proceed under milder conditions by providing an alternative reaction pathway with lower activation energy, thus reducing the need for high temperature and pressure equipment
2Productivity
If Raney nickel is used in the fluorination reaction, then the reaction can proceed, but the chemical reagents become difficult to handle
Solution Approach 1:
The patent replaces Raney nickel with a copper catalyst that is easier to handle and more stable. The copper catalyst can be used in a more convenient form (such as copper salts or copper metal) that does not require the same special handling precautions as Raney nickel, improving ease of operation while maintaining reaction effectiveness
3Productivity
If 1,2,3-trichlorobenzene is fluorinated to obtain 2,3-difluorochlorobenzene, then the amination reaction can proceed, but a regioisomer (2,6-difluorochlorobenzene) is produced as a by-product reducing the yield
Solution Approach 1:
The patent performs preliminary fluorination of 1,2,3-trichlorobenzene to selectively produce 2,3-difluorochlorobenzene before the amination reaction. By optimizing the fluorination conditions and using appropriate catalysts, the patent minimizes the formation of the 2,6-difluorochlorobenzene regioisomer, thereby improving the yield and reducing the need for separation operations
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 enables the production of 2,3-difluoroaniline cheaply, simply, and in large quantities, avoiding the limitations of previous methods by reducing the need for high temperature and pressure, and utilizing more accessible starting materials.
Implementation Method 1
Patent Document 9 discloses that 2,3-difluoroaniline can be obtained by fluorinating 1,2,3-trichlorobenzene to obtain 2,3-difluorochlorobenzene, and then aminating the 2,3-difluorochlorobenzene using a copper catalyst
Implementation Method 2
A method involving the halogenation of 1,2-difluorobenzene or 1-halogeno-3,4-difluorobenzene, followed by nitration and reduction to produce a halogenated nitrobenzene, which is then dehalogenated to yield 2,3-difluoroaniline, using Lewis acid catalysts
Data Source
AI summary
The present invention provides a halogenated aniline represented by formula (I) (wherein each of X1 and X2 independently represents a chlorine atom, a bromine atom or an iodine atom), a method for producing the halogenated aniline, and other aspects.