Abstract: A process for separating 1,6-naphthalenedisulfonic acid, 2,6-naphthalenedisulfonic acid or 2,7-naphthalenedisulfonic acid selectively from reaction mixtures obtained by disulfonation of naphthalene under different reaction conditions is disclosed. For example, a particular disulfonation reaction of naphthalene is carried out which favors the formation of a particular isomer. This reaction mixture is diluted with water to adjust the sulfuric acid concentration to 35 to 90% by weight and the temperature is maintained at 0.degree. to 80.degree. C.; 1,6-naphthalene-disulfonic acid is selectively separated at high purity.

Abstract: A process for preparing o-phenylphenol by dehydrogenating at least one of cyclohexanone dimer and o-cyclohexylphenol in the presence of a catalyst, characterized in that the catalyst is one prepared by causing a metal oxide carrier to support at least one compound substantially producing platinum or palladium on the resulting catalyst, at least one compound substantially producing an alkali metal oxide on the resulting catalyst and at least one of hydrogen sulfide, organic sulfur compound and alkali metal sulfide, and heating the carrier at 300.degree. to 400.degree. C.

Abstract: A process for preparing o-phenylphenol by dehydrogenating at least one of cyclohexanone dimer and o-cyclohexylphenol in the presence of a catalyst, characterized in that the catalyst comprises a metal oxide carrier, and at least one of alkali metal salts of sulfur-oxygen acids and at least one of platinum and palladium supported by the carrier.