Patent GB-1034926-A (GB)
Title: Hydrogen modified fluorocarbon ethers
IPC: G03F5/20
Filed: 1963-03-22
Abstract: The invention comprises compounds of formula XR1f-O(-CFRf-CF2-O)n-CFRf or <FORM:1034926/C2/1> in which Rf is F or -CF3, R1f is a perfluoroalkylene radical, X is H or fluorine, R11f is a perfluoroalkylene radical of at least 2 C atoms, and n and m are 0 or integers from 1 to 50, and the preparation thereof by the pyrolysis of a hydrogen containing derivative of the corresponding ether, e.g. the fluorocarbon ether acid, or its ammonium salt, at 115-450 DEG  C., or by the reaction of a monovalent metal salt of a fluorocarbon ether acid with water or an active hydrogen containing organic solvent, at a temperature of 0-300 DEG  C.  Preferred solvents are aliphatic mono- and polyhydric alcohols including methanol, ethylene glycol and cyclohexanol. The starting materials are prepared from the corresponding ethers having the end group -COF. These are converted to the acid on contact with water, the monovalent metal salt of the acid is prepared either by contacting the free acid, or the carbonyl fluoride, with an aqueous solution of the metal hyroxide.  A fluorocarbon polyether starting material of formula <FORM:1034926/C2/2> where n = 4-6 may be prepared by polymerizing hexafluoropropylene epoxide in the presence of caesium fluoride and diethylene glycol diethyl ether.  The compound of formula <FORM:1034926/C2/3> is obtained by performing this reaction in the presence of carbonyl fluoride and a compound of formula <FORM:1034926/C2/4> is prepared when the reaction is carried out in the presence of oxalyl fluoride.  Compounds of formula <FORM:1034926/C2/5> where n is 0 to 6 are made by reacting trifluoroacetyl fluoride and tetrafluoroethylene epoxide in a solvent of formula CHF2(CF2)3CH2Cl in the presence of tetraethyl ammonium cyanide.  In the absence of trifluoroacetyl fluoride similar products of higher molecular weight are obtained. In the presence of a diacid fluoride a compound having two carbonyl fluoride end groups is produced.  Reference has been directed by the Comptroller to Specifications 928,315 and 998,978.ALSO:The invention comprises compounds of formula XR1f-O(-CFRf-CF2-O)n -CFRfH or HCFRf-(OCF2-CFRf-)mO-R11f -O(-CFRf-CF2-O-)nCFRfH in which Rf is F or -CF3; R1f is a perfluoroalkylene radical; X is H or fluorine; R11f is a perfluoroalkylene radical of at least 2 C atoms; and n and m are O or integers from 1 to 50, and the preparation thereof by the pyrolysis of a hydrogen containing derivative of the corresponding ether, e.g. the fluorocarbon ether acid, or its ammonium salt at 115-450 DEG  C., or by the reaction of a monovalent metal salt of a fluorocarbon ether acid with water or an active hydrogen containing organic solvent, at a temperature of 0-300 DEG  C.  Preferred solvents are aliphatic mono- and polyhydric alcohols including methanol, ethylene glycol, and cyclohexanol. The starting materials are prepared from the corresponding ethers having the end-group-COF. These are converted to the acid on contact with water, the monovalent metal salt of the acid is prepared either by contacting the free acid, or the carbonyl fluoride, with an aqueous solution of the metal hydroxide.  Reference has been directed by the Comptroller to Specifications 928,315 and 998,978.