Halogenated Acrylic Acid Ester Synthesis via Vapor Phase Catalysis
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Solution Overview
Problem
Existing methods for producing halogenated acrylic acid derivatives are inefficient due to the use of toxic and corrosive reagents, high costs, and low productivity, leading to safety concerns and economic inefficiencies.
Innovation Solution
A novel method involving a vapor phase reaction using a solid catalyst to convert an orthocarboxylic acid ester into an ethene derivative, followed by reaction with a halogenated methane in the presence of a basic compound and phase transfer catalyst to produce a cyclopropane derivative, which is then decomposed to obtain a halogenated acrylic acid ester with high yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thionyl chloride is used to convert 3-hydroxy-2-fluoropropionic acid ester to 3-chloro-2-fluoropropionic acid ester, then the conversion can be achieved, but toxic thionyl chloride is used and corrosive hydrogen chloride is generated, creating safety problems
Solution Approach 1:
The patent uses 1,1-dichloro-2-fluoroethane as an intermediary reagent to replace thionyl chloride in the conversion process. This intermediary achieves the same chemical transformation (converting hydroxy group to chloro group) without generating corrosive hydrogen chloride gas, thereby eliminating the safety hazards while maintaining manufacturing capability
Solution Approach 2:
The patent employs easily available and inexpensive reagents such as 1,1-dichloro-2-fluoroethane and common bases (potassium hydroxide, sodium hydroxide, or potassium carbonate) to replace expensive and hazardous thionyl chloride. The process uses readily disposable, non-hazardous materials that can be handled safely while achieving the desired chemical transformation
2Quantity of substance
If F2 is used to prepare 3-hydroxy-2-fluoropropionic acid ester, then the material can be obtained, but F2 is expensive and difficult to handle, reducing economical efficiency and productivity
Solution Approach 1:
The patent replaces expensive and hazardous fluorine gas (F2) with inexpensive and easily available starting materials. The fluorine atom is introduced through commercially available fluorinated compounds rather than through direct fluorination with F2, dramatically reducing cost and improving safety while maintaining material availability
Solution Approach 2:
The patent performs preliminary fluorination in the starting material (3-hydroxy-2-fluoropropionic acid ester or its ester) before the main conversion step. By pre-installing the fluorine atom in an easily handled precursor compound, the process avoids the need to handle expensive and dangerous fluorine gas during the actual synthesis step
3Ease of manufacture
If potassium t-butoxide and chlorofluorocarbon in large excess are used to prepare α-fluoroacrylic acid ethyl ester, then the reaction can proceed, but the cost is high due to expensive reagents
Solution Approach 1:
The patent replaces expensive potassium t-butoxide with inexpensive common bases such as potassium hydroxide, sodium hydroxide, or potassium carbonate. These readily available bases achieve the same deprotonation and cyclization function at a fraction of the cost, dramatically improving economic efficiency while maintaining reaction capability
Solution Approach 2:
The patent uses exactly 1 equivalent of base (potassium hydroxide, sodium hydroxide, or potassium carbonate) instead of large excess amounts. This stoichiometric approach is sufficient for the reaction and eliminates the need for large excess reagents, reducing cost and simplifying workup procedures
4Productivity
If conventional methods are used to produce halogenated acrylic acid derivatives, then production can occur, but highly corrosive hydrogen bromide is generated and expensive potassium t-butoxide is used, reducing productivity
Solution Approach 1:
The patent uses 1,1-dichloro-2-fluoroethane as an intermediary reagent to replace sources of hydrogen bromide. This intermediary provides the necessary halogen atoms without generating corrosive hydrogen bromide gas, enabling production while eliminating harmful emissions and associated safety concerns
Solution Approach 2:
The patent replaces expensive potassium t-butoxide with inexpensive common bases (potassium hydroxide, sodium hydroxide, or potassium carbonate) that are readily available and handleable. This substitution maintains production capability while dramatically reducing material costs and improving economic efficiency
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 achieves a high conversion ratio, selectivity, and yield while avoiding the use of hazardous materials and reducing production costs, enabling safe and industrially advantageous production of halogenated acrylic acid derivatives.
Implementation Method 1
a vapor phase reaction using a solid catalyst to convert an orthocarboxylic acid ester into an ethene derivative
Implementation Method 2
reaction with a halogenated methane in the presence of a basic compound and phase transfer catalyst to produce a cyclopropane derivative
Data Source
AI summary
To provide a novel method for producing a halogenated acrylic acid derivative. A compound represented by the formula (1): (wherein each of R1 and R2 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom, or R1 and R2 together form a ring, R3 is a monovalent group capable of being desorbed by R3OH removal reaction, and each of R4 and R5 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom) and having a boiling point of at most 500°C, is subjected to R3OH removal reaction in a vapor phase in the presence of a solid catalyst to obtain an ethene derivative represented by the formula (2): the ethene derivative represented by the formula (2) and a halogenated methane represented by the formula (3): C HXYZ (3) (wherein each of X, Y and Z which are independent of one another, is a halogen atom) are reacted in the presence of a basic compound and a phase transfer catalyst, to obtain a cyclopropane derivative represented by the formula (4): and the cyclopropane derivative represented by the formula (4) is reacted by heating in a liquid phase or in a vapor phase to obtain a halogenated acrylic acid ester derivative represented by the formula (5):