PURPOSE: To obtain the titled compound useful as a catalyst for wet desulfurization of TAKAHAKUS process, by reacting naphthoquinone with a hydrogensulfite in an aqueous medium to give a reaction product, treating it with active carbon.

CONSTITUTION: Naphthoquinone is reacted with a hydrogensulfite in an aqueous medium to give an aqueous solution of naphthohydroquinonesulfonate. Ammonium hydrogensulfite, sodium hydrogensulfite, etc. may be used as the hydrogensulfite, and an amount of the hydrogensulfite used is ≥1.2mol, preferably ≥1.3mol based on 1mol naphthoquinone. Industrial naphthoquinone having about 90W 98wt% purity obtained by catalytic gaseous phase oxidation of naphthalene is ordinarily used as naphthoquinone. When the reaction is carried out using ammonium hydrogensulfite, effectively an aqueous solution of ammonium hydrogensulfite is adjusted to about 4.5W6pH, preferably about 4.7W5.5pH.