Abstract: Disclosed are an adsorption process whereby a fluorocarboxylic acid having an ether bond can be adsorbed to a high extent by using active carbon without changing the form thereof, and a desorption process whereby the adsorbed material can be desorbed from the active carbon to thereby enable the reuse of the active carbon and the adsorbed material. In the aforesaid processes, a solution containing a fluorocarboxylic acid having an ether bond is contacted with active carbon and thus the active carbon is allowed to adsorb the fluorocarboxylic acid, to thereby give a solution having a small fluorocarboxylic acid content. Then, the active carbon having adsorbed the fluorocarboxylic acid is heated to thereby desorbs the fluorocarboxylic acid from the active carbon.

Abstract: A process for preparing a fluorocarboxylic acid, which includes a dehydration step of removing from a mixture containing a fluorocarboxylic acid and water at least a part of the water to obtain a dehydrated fluorocarboxylic acid solution, and a purification step of purifying the dehydrated fluorocarboxylic acid solution.

Abstract: There is provided a method for separating and collecting at least alcohol with a high purity from an azeotropic mixture of olefin and alcohol.

Abstract: A process for preparing a fluorocarboxylic acid, which includes a dehydration step of removing from a mixture containing a fluorocarboxylic acid and water at least a part of the water to obtain a dehydrated fluorocarboxylic acid solution, and a purification step of purifying the dehydrated fluorocarboxylic acid solution.

Abstract: There is provided a method for separating and collecting at least alcohol with a high purity from an azeotropic mixture of olefin and alcohol.

Abstract: In a first sulfation step, 2-perfluoroalkylethyl iodide is brought into contact with fuming sulfuric acid to obtain a reaction mixture comprising 2-perfluoroalkylethyl sulfate and bis(2-perfluoroalkylethyl)sulfate. Then, in a first hydrolysis step, 2-perfluoroalkylethyl sulfate produced in the first sulfation step is hydrolyzed to obtain a reaction mixture comprising 2-perfluoroalkylethyl alcohol. In a second sulfation step, bis(2-perfluoroalkylethyl)sulfate produced in the first sulfation step is brought into contact with fuming sulfuric acid to obtain a reaction mixture comprising 2-perfluoroalkylethyl sulfate. Then, in a second hydrolysis step, 2-perfluoroalkylethyl sulfate produced in the second sulfation step is hydrolyzed to obtain a reaction mixture comprising 2-perfluoroalkylethyl alcohol. According to such procedures, 2-perfluoroalkylethyl alcohol can be obtained in a high yield.

Abstract: In a first sulfation step, 2-perfluoroalkylethyl iodide is brought into contact with fuming sulfuric acid to obtain a reaction mixture comprising 2-perfluoroalkylethyl sulfate and bis(2-perfluoroalkylethyl)sulfate. Then, in a first hydrolysis step, 2-perfluoroalkylethyl sulfate produced in the first sulfation step is hydrolyzed to obtain a reaction mixture comprising 2-perfluoroalkylethyl alcohol. In a second sulfation step, bis(2-perfluoroalkylethyl)sulfate produced in the first sulfation step is brought into contact with fuming sulfuric acid to obtain a reaction mixture comprising 2-perfluoroalkylethyl sulfate. Then, in a second hydrolysis step, 2-perfluoroalkylethyl sulfate produced in the second sulfation step is hydrolyzed to obtain a reaction mixture comprising 2-perfluoroalkylethyl alcohol. According to such procedures, 2-perfluoroalkylethyl alcohol can be obtained in a high yield.

Abstract: Processes for producing a fluoromonomer from a fluoropolymer, among which one that can be carried out more simply is a process wherein thermal decomposition of a fluoropolymer is preformed by means of a rotary kiln (5) so as to produce a fluoromonomer, the process comprising feeding a fluoropolymer and steam (3) into a rotary kiln and heating the fluoropolymer.

Abstract: A fluorocarboxylic acid preparation process which includes hydrolyzing fluorocarboxylic acid fluoride in the presence of an aqueous sulfuric acid solution to form a reaction product containing a fluorocarboxylic acid and hydrogen fluoride (present as hydrofluoric acid); and removing at least some of the hydrogen fluoride from the reaction product by washing the reaction production with aqueous sulfuric acid solution. The hydrolyzing and washing are carried out at a temperature at which the fluorocarboxylic acid is a liquid.

Abstract: A fluorocarboxylic acid preparation process continuously carries out acidification reaction treatment and washing treatment, and includes subjecting a fluorocarboxylate-containing aqueous solution to acidification reaction treatment in the presence of sulfuric acid so as to form a sulfate-containing fluorocarboxylic acid phase; and subjecting the fluorocarboxylic acid phase to washing treatment using an aqueous sulfuric acid solution.

Abstract: Processes for producing a fluoromonomer from a fluoropolymer, among which one that can be carried out more simply is a process wherein thermal decomposition of a fluoropolymer is preformed by means of a rotary kiln (5) so as to produce a fluoromonomer, the process comprising feeding a fluoropolymer and steam (3) into a rotary kiln and heating the fluoropolymer.

Abstract: Upon recovering a fluorochemical surfactant from a fluorochemical-containing aqueous solution, there is provided a method for recovering the fluorochemical surfactant from the aqueous solution containing the surfactant. In the method, the fluorochemical surfactant is recovered by subjecting the aqueous solution containing the fluorochemical surfactant to a filtration treatment step with a reverse osmosis membrane so as to obtain from the aqueous solution, a concentrated aqueous solution in which the concentration of the fluorochemical surfactant is increased.

Abstract: A fluorocarboxylic acid preparation process continuously carries out acidification reaction treatment and washing treatment, and includes subjecting a fluorocarboxylate-containing aqueous solution to acidification reaction treatment in the presence of sulfuric acid so as to form a sulfate-containing fluorocarboxylic acid phase; and subjecting the fluorocarboxylic acid phase to washing treatment using an aqueous sulfuric acid solution.

Abstract: A fluorocarboxylic acid preparation process which includes hydrolyzing fluorocarboxylic acid fluoride in the presence of an aqueous sulfuric acid solution to form a reaction product containing a fluorocarboxylic acid and hydrogen fluoride (present as hydrofluoric acid); and removing at least some of the hydrogen fluoride from the reaction product by washing the reaction production with aqueous sulfuric acid solution. The hydrolyzing and washing are carried out at a temperature at which the fluorocarboxylic acid is a liquid.

Abstract: Separation of an anionic fluorochemical surfactant from an aqueous solution containing the anionic fluorochemical surfactant is carried out by i) contacting the aqueous solution with a basic anion-exchange resin so that the anionic fluorochemical surfactant is adsorbed on the resin, and ii) eluting the anionic fluorochemical surfactant adsorbed on the resin with an eluent which is an alkaline solution containing water and an organic solvent.

Abstract: Upon recovering a fluorochemical surfactant from a fluorochemical-containing aqueous solution, there is provided a method for recovering the fluorochemical surfactant from the aqueous solution containing the surfactant. In the method, the fluorochemical surfactant is recovered by subjecting the aqueous solution containing the fluorochemical surfactant to a filtration treatment step with a reverse osmosis membrane so as to obtain from the aqueous solution, a concentrated aqueous solution in which the concentration of the fluorochemical surfactant is increased.