The present invention relates to a photocatalytic coating film composition and method for producing thereof. More specifically, it relates to an acidic anti-mould and anti-fungal photocatalytic coating film formed by the decomposition and evaporation of the volatile organic base from the photocatalytic coating composition after the application and the drying on substrate. The photocatalytic coating liquid composition consisting of a strong acidic nature of Nafion with pH<2 as an indispensable binder resin; a volatile organic base to neutralize the acidic binder resin temporarily and photocatalysts to generate strong oxidizing compounds which decompose harmful organic compounds and also to provide protection for the acidic environment by decomposing neutralizing chemicals from outside.

A method of producing a fluorine-containing compound is a method of producing a compound (30) having partial structure (3) by an insertion reaction of compound (20) into compound (10) that has partial structure (1), in the presence of an ionic catalyst formed from a specific monovalent anion and a counter cation. In the formulas, * represents a bonding site, and X.sup.1 and R.sup.1 to R.sup.4 each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, or an organic group having a carbon number of 1 to 20 which may have a substituent. ##STR00001##