Patent ID: 7687546

Claim:
A quaternary ammonium compound represented by general formula (I) or (I′): (wherein, A represents a linear alkyl group having 1 to 4 carbon atoms, a branched alkyl group having 2 to 4 carbon atoms, a linear alkyl group having 1 to 4 carbon atoms and a hydroxyl group, or a branched alkyl group having 2 to 4 carbon atoms and a hydroxyl group, R 1 to R 3 may be the same or different and represent a linear or branched alkyl group having 1 to 12 carbon atoms, one of R 4 to R 8 represents CO 2 − or SO 3 − , while no more than three of the remaining R 4 to R 8 represent a group selected from the group consisting of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms, and other R 4 to R 8 represent a hydrogen atom, one of R′ 4 to R′ 8 represents CO 2 H or SO 3 H, while no more than three of the remaining R′ 4 to R′ 8 represent a group selected from a protected hydroxyl group and an alkoxy group having 1 to 4 carbon atoms, while other R′ 4 to R′ 8 represent a hydrogen atom, and X − represents chlorine ion, bromine ion, iodine ion, hydroxide ion, formate anion, acetate anion, propionate anion, methanesulfonate anion, p-toluenesulfonate anion, oxalate anion, succinate anion, maleate anion, phthalate anion, carbonate ion, sulfate ion, nitrate ion or phosphate ion).