High-purity 4-(2-bromoethyl)benzenesulfonic acid, high-purity styrenesulfonic acid compound derived therefrom, and polymer thereof, and methods for producing same

A high-purity styrenesulfonic acid compound composition comprising a styrenesulfonic acid compound represented by the following general formula (B), wherein a bonded bromine content determined by combustion decomposition ion chromatography (CIC) is 400 ppm or less:

• wherein R1 represents the following general formula (C), the following general formula (D), an amino group, or a chlorine atom:
• —OR2 (C)
• wherein R2 represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a hydrogen atom, an alkali metal, a substituted or unsubstituted ammonium cation, or a substituted or unsubstituted phosphonium cation
• wherein R3 represents a substituted or unsubstituted alkyl group, a hydrogen atom, an alkali metal, or a substituted or unsubstituted ammonium cation, and R4 represents a trifluoromethylsulfonyl group, a perfluorobutylsulfonyl group, a fluorosulfonyl group, a trifluoromethylacetyl group, or a 4-ethenylphenylsulfonyl group.