Patent ID: 8524941

Claim:
A process for producing a monomer of the formula [3] for a fluorinated resist by reaction of a fluorinated alkene of the formula [1] with an α-substituted acrylic acid of the formula [2] in the presence of an acid catalyst, wherein the acid catalyst is a sulfonyl-containing acid of the formula [4]: where R 1 represents a hydrogen atom, a fluorine atom or a C 1 -C 6 straight or branched alkyl group whose part or all of hydrogen atoms may be substituted with a fluorine atom where R 1 has the same meaning as in the formula [2] HA SO 2 R f ) n [4] where A represents an oxygen atom or a carbon atom; each R f independently represents a fluorine atom, a hydroxyl group or a C 1 -C 6 fluorinated alkyl group; and n represents an integer of 1 or 3.