Patent ID: 7390917

Claim:
A method of producing a mixture of fluorine-containing (meth)acrylate esters, each of which is represented by the formula (III): R f (CF 2 CF 2 ) n CH 2 CH 2 OCOCR 1 ═CH 2 (III) wherein R f represents a fluoroalkyl group whose number of carbon atoms is in the range of 1 to 10, R 1 represents a hydrogen atom or a methyl group, and n is an integer representing polymerization degree, with the polymerization degree n greater than or equal to k that is an integer of 3 or more, which comprises: (A) a telomerization step of obtaining the mixture of the fluoroalkyl iodide telomers represented by the formula (I) with the polymerization degree n greater than or equal to k that is an integer of 3 or more, comprising the steps of: (1) obtaining a first reaction mixture containing a mixture of fluoroalkyl iodide telomers represented by the formula (I): R f (CF 2 CF 2 ) n I (I) wherein R f represents a fluoroalkyl group whose number of carbon atoms is in the range of 1 to 10 and with the polymerization degree n of 1 or more by reacting with tetrafluoroethylene a fluoroalkyl iodide represented by the formula: R f I wherein R f represents a fluoroalkyl group whose number of carbon atoms is in the range of 1 to 10 in a first reactor; (2) separating the first reaction mixture into: a first fraction including a fluoroalkyl iodide telomer of the formula (I) with the polymerization degree n less than or equal to (k−2) or a mixture thereof, and the fluoroalkyl iodide represented by the formula: R f I; a second fraction including a fluoroalkyl iodide telomer represented by the formula (I) with the polymerization degree n of (k−1); and a third fraction including a mixture of fluoroalkyl iodide telomers each of which is represented by the formula (I) with the polymerization degree n greater than or equal to k; and (3) obtaining a second reaction mixture including a mixture of fluoroalkyl iodide telomers each of which is represented by the formula (I) with the polymerization degree n greater than or equal to k, by reacting the second fraction with tetrafluoroethylene in a second reactor; (B) an ethylene addition step of adding ethylene to the mixture of the fluoroalkyl iodide telomers obtained in the step (A) to give a mixture of ethylene adducts, each of which is represented by the formula (II): R f (CF 2 CF 2 ) n CH 2 CH 2 I (II) in which polymerization degree n is greater than or equal to k that is an integer of 3 or more; and (C) an esterification step of reacting the mixture of the ethylene adducts obtained in the step (B) with a (meth)acrylate compound to obtain fluorine-containing (meth)acrylate esters.