Electrolyte solution and method for producing sulfate salt

A method for producing a compound represented by the following formula (1), comprising:

• reacting a compound represented by the following formula (3) and a lithium alkoxide,
• the formula (1) being R11X11—SO3M11
• wherein R11 is a C1-C6 linear or branched alkyl group, a C2-C6 linear or branched alkenyl group, a C2-C6 linear or branched alkynyl group, a C3-C6 cycloalkyl group, a C3-C6 cycloalkenyl group, or a C3-C6 alkylsilyl group, the alkyl group, the cycloalkyl group, and the alkylsilyl group may have a halogen atom which substitutes for a hydrogen atom bonding to a carbon atom, may have a cyclic structure, and may have an ether bond or a thioether bond;
• X11 is O;
• and M11 is Li, and
• the formula (3) being R31O—SO2—OR32
• wherein R31 and R32 may be the same as or different from each other, and are individually a C1-C6 linear or branched alkyl group, a C2-C6 linear or branched alkenyl group, a C2-C6 linear or branched alkynyl group, a C3-C6 cycloalkyl group, a C3-C6 cycloalkenyl group, or a C3-C6 alkylsilyl group, the alkyl group, the cycloalkyl group, and the alkylsilyl group may have a halogen atom which substitutes for a hydrogen atom bonding to a carbon atom, may have a cyclic structure, and may have an ether bond or a thioether bond.