Perfluorobutanesulfonyl Fluoride is a perfluorinated compound that exists as a liquid at room temperature. It is primarily used in the synthesis of fluorocarbon surfactants, fluorine-containing pesticides, dyes, and as a dispersant in polycarbonate processing.
 

Synthesis Methods
1. Two-Step Electrofluorination:
Starting with butanesulfonyl chloride, perfluorobutanesulfonyl fluoride is readily prepared via a fluorine displacement reaction using potassium fluoride (KF) to yield butanesulfonyl fluoride. Butanesulfonyl fluoride is then charged into an electrolytic cell along with anhydrous hydrogen fluoride (AHF). Electrolysis is carried out under atmospheric pressure in a nitrogen atmosphere, where the hydrogen atoms in the alkyl group of butanesulfonyl fluoride are replaced by fluorine, generating perfluorobutanesulfonyl fluoride. The reaction equation is as follows:
(Note: Reaction equation not provided in text)
 

2. Electrofluorination of Sulfone Precursor:
Using tetrahydrothiophene-1,1-dioxide (sulfolane) as the raw material, perfluorobutanesulfonyl fluoride is generated directly via an electrofluorination reaction. The reaction equation is as follows:
(Note: Reaction equation not provided in text)
 

Application Fields
1. Catalyst for Fluorination Reactions
Perfluorobutanesulfonyl fluoride serves as a catalyst for fluorination reactions. For instance, in the fluorination of 2-trichloromethyldichlorotoluene, perfluorosulfonyl fluoride catalysts (including perfluoropropyl-, perfluorobutyl-, perfluoropentyl-, and perfluorooctyl-sulfonyl fluoride) offer advantages such as low toxicity, high safety, excellent catalytic selectivity, low dosage requirements, and high fluorination yields.
 

Specific Procedure:
In a 5L stainless steel high-pressure reactor equipped with a stirrer and thermometer, cool the system to below 5°C. Sequentially add hydrogen fluoride (HF) and 2-trichloromethyldichlorotoluene in a 1:1 mass ratio. Add the catalyst, perfluorobutanesulfonyl fluoride, such that the mass ratio of 2-trichloromethyldichlorotoluene to catalyst is 1:0.01. Heat the mixture to 50~60°C and maintain a reaction pressure of 0.8-1.2 MPa for 4 hours.
 

Post-Processing:
Take a sample for GC analysis; the content of the intermediate 2-difluoromonochloromethyldichlorotoluene should be 0.2%. Upon completion, purge with nitrogen to remove excess HF. Neutralize the mixture with an aqueous potassium carbonate solution to a pH of 6~7. Allow to settle and separate the product, 2-trifluoromethyldichlorotoluene. The product typically achieves a purity of 97.5% and a yield of 93.5%. The reaction equation is as follows:
(Note: Reaction equation not provided in text)
 

2. Formulation of Anti-Corrosive Cutting Fluid for Auto Parts
Perfluorobutanesulfonyl fluoride can be mixed with other components to formulate anti-corrosive cutting fluids for automotive parts.
Specific Formulation (by weight):
Mixed vegetable oil: 25 parts
Tribasic lead sulfate: 15 parts
Triacetamine phosphate (Triethyl phosphate amine): 16 parts
Succinic acid monoethoxylate ester sulfonate: 16 parts
Sodium laureth sulfate (SLES): 10 parts
Cocamidopropyl betaine: 20 parts
Sodium sulfate: 20 parts
Perfluorobutanesulfonyl fluoride: 15 parts
Triethanolamine: 18 parts
Citric acid: 5 parts
Sodium petroleum sulfonate: 15 parts
Fatty alcohol polyoxyethylene ether: 4 parts
p-Nitrobenzoic acid: 4 parts
Sodium tetraborate: 2 parts
Dimethylmaleic anhydride: 3 parts
Deionized water: q.s. (quantity sufficient)
 

3. Synthesis of Fluorine-Containing Surfactants
Fluorinated surfactants are indispensable in the emulsion polymerization of fluoromonomers, providing good emulsification and stable product performance. The preparation of perfluorobutanesulfonyl fluoride quaternary ammonium salts involves the following steps:
Step 1: Charge a reaction flask with ethylenediamine and isopropyl ether. Slowly add an equivalent amount of perfluorobutanesulfonyl fluoride dropwise at low temperature. After the addition, heat to 50°C and react for 1 hour.
Step 2: After cooling, wash twice with water. Distill off the isopropyl ether solvent under low pressure and heat to obtain a pale yellow solid. Recrystallize from ethanol and dry under vacuum to yield a white solid.
Step 3: Charge the white solid into a three-neck flask, add DMF (dimethylformamide), and stir at room temperature until fully dissolved. Add an equimolar amount of maleic anhydride, stir at room temperature for 0.5 hours, then heat to 50°C and stir for 1 hour.
Step 4: After cooling, pour into distilled water to precipitate. Filter to obtain a white solid product. Dissolve this solid in NaOH solution, add glycidyltrimethylammonium chloride, and heat to react. This yields a fluorine-containing quaternary ammonium salt cationic surfactant.
 

4. Synthesis of Oxetane Monomers with Short Fluorocarbon Side Chains

Fluorinated polyethers possess low surface energy; longer perfluorocarbon chains generally provide better water and oil repellency. However, their degradation produces persistent environmental contaminants like perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Functional polymers with short fluorocarbon chains mitigate these environmental risks.