Method of preparing benzenesulfonyl compound

A method of preparing a benzenesulfonyl compound, the method comprising:

• preparing a benzenesulfonyl compound represented by the following Chemical Formula 1 by reacting a compound represented by the following Chemical Formula 2 and an n-hydric alcohol in the presence of a phase transfer catalyst and an alkali metal hydroxide aqueous solution:
• wherein
• R1 to R5 are independently of one another hydrogen, a halogen, C1-C7 alkoxy, or C1-C7 alkyl;
• X is a residue derived from the n-hydric alcohol;
• n is an integer of 1 to 4;
• and
• Y is a halogen,
• wherein the alkali metal hydroxide is used at 1 mol to 5 mol with respect to 1 mol of the compound of Chemical Formula 2, wherein the alkali metal hydroxide and the phase transfer catalyst are used at a mole ratio of 1:0.005 to 0.05, and
• wherein the reaction is performed under a temperature condition of 20 to 40° C. for 1 to 10 hours.