2-Alkylcarbonyloxy-1,1-difluoroethanesulfonic Acid Salt Synthesis
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Solution Overview
Problem
Conventional methods for producing fluorine-containing sulfonic acid salts, such as alkoxycarbonyldifluoromethanesulfonic acid and 1,1,3,3-pentafluoro-2-benzoyloxypropane-1-sulfonic acid, face challenges including high reagent reactivity, safety hazards, and corrosion issues, making them difficult and costly to produce on an industrial scale. Additionally, there is a lack of methods for producing 2-alkylcaronyloxy-1,1-difluoroethanesulfonic acid salts, which are desirable for their acid strength and compatibility with solvents and resins.
Innovation Solution
A novel method involving the synthesis of 2-alkylcarbonyloxy-1,1-difluoroethanesulfonic acid ammonium salt using a carboxylic acid bromodifluoroethyl ester and a sulfinating agent in the presence of an amine, followed by oxidation and onium-salt exchange, allowing for the production of 2-alkylcarbonyloxy-1,1-difluoroethanesulfonic acid onium salt, which is suitable for use as a photoacid generator in chemically amplified resist materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods using tetrafluoroethylene and sulfur trioxide are used to produce fluorine-containing sulfonic acid salts, then the acid strength and fluorine content are sufficient, but the reagent reactivity is too high causing safety hazards and corrosion issues
Solution Approach 1:
The patent introduces 2-bromo-2,2-difluoroethyl ester as an intermediary compound that mediates the synthesis process. This intermediary allows the introduction of fluorine atoms and carboxyl groups in a controlled manner, avoiding the direct use of highly reactive tetrafluoroethylene and sulfur trioxide, thereby reducing safety hazards and corrosion while maintaining the desired acid strength and fluorine content in the final sulfonic acid salt product
Solution Approach 2:
The patent changes the chemical parameters of the synthesis process by using milder reagents (2-bromo-2,2-difluoroethyl ester instead of tetrafluoroethylene and sulfur trioxide) and controlling the reaction conditions (temperature, solvent system, addition rate) to achieve safe and efficient production of fluorine-containing sulfonic acid salts with appropriate acid strength
2Quantity of substance
If conventional methods are used to produce fluorine-containing sulfonic acid salts, then the product can be obtained, but the production cost is high due to difficulty in industrial-scale production
Solution Approach 1:
The patent employs 2-bromo-2,2-difluoroethyl ester as an intermediary that facilitates controlled synthesis, making the process more amenable to industrial-scale production. This intermediary approach allows for better process control, safer handling, and more efficient production while maintaining high product yield and purity
Solution Approach 2:
The patent optimizes synthesis parameters including using dichloromethane as solvent, controlling reaction temperature between -78°C to 0°C, and adjusting reagent addition rates to achieve efficient production. These parameter changes make the process more suitable for industrial-scale manufacturing while maintaining high yield and product quality
3Reliability
If perfluorooctane sulfonic acid and derivatives with 5 or more carbon atoms are used, then the acid strength is high, but stability and biological concentration problems occur due to C-F bonds and hydrophobicity
Solution Approach 1:
The patent applies local quality by selectively fluorinating only specific positions in the molecular structure (using 2-bromo-2,2-difluoroethyl ester) rather than full perfluorination. This localized fluorine introduction maintains the necessary acid strength for photoacid generator functionality while reducing the overall number of C-F bonds and hydrophobic character, thereby improving biological stability and reducing environmental persistence
Solution Approach 2:
The patent changes the molecular structure parameters by using a shorter carbon chain with selective fluorine substitution (2,2-difluoroethyl group) instead of longer perfluorinated chains (5+ carbons). This structural modification maintains sufficient acid strength for the intended application while improving biodegradability and reducing biological concentration and accumulation
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 economical and efficient production of fluorine-containing sulfonic acid salts on an industrial scale, overcoming safety and corrosion issues, and providing a high-purity intermediate for photoacid generators and solid polymeric electrolytes, suitable for micro-processing technologies like photolithography.
Implementation Method 1
reacting a carboxylic acid bromodifluoroethyl ester with a sulfinating agent in the presence of an amine thereby obtaining a 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfinic acid ammonium salt
Implementation Method 2
reacting the obtained 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfinic acid ammonium salt with an oxidizing agent thereby obtaining a 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfonic acid ammonium salt
Data Source
AI summary
By using an organic base when a carboxylic acid bromodifluoroethyl ester is sulfinated by using a sulfinating agent, there is obtained 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfinic acid ammonium salt. By oxidizing the 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfinic acid ammonium salt, there is obtained 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfonic acid ammonium salt. By using the 2-(alkylcarbonyloxy)-1,1-difluoroethanesulfonic acid ammonium salt as a raw material and exchanging it into an onium salt directly or through saponification/esterification, there can be obtained a 2-alkylcarbonyloxy-1,1-difluoroethanesulfonic acid onium salt.