GB1033662A - - Google Patents

Abstract

1,033,662. Sulphonated phenol condensation products. GEIGY CO. Ltd. Dec. 18, 1962 [April 5, 1962], No. 13075/62. Heading C2C. [Also in Division C7] An additive for a tin plating bath is made by sulphonating phenol and/or cresol with oleum containing from 60% to 66% by weight of sulphur trioxide, and thereafter heating the resulting sulphonated product for at least one hour, without adding further phenol, at a subatmospheric pressure, preferably in the range up to 25 mm., and at a temperature in the range of from 120‹ to 190‹ C. The sulphonation may be performed with the amount of oleum necessary for formation of the sulphonic acid or by using an excess of phenol and/or cresol. The course of the reaction during the condensation step during the heating is not known with certainty. The crude mixture may be worked up by cooling and grinding the mass, or pouring the hot reaction mixture into an excess of cold water and separating the solid material, or by dissolving it in aqueous alkali metal hydroxide solution and either evaporating to dryness or precipitating with mineral acid. An after-treatment may comprise fractional precipitation, fractional crystallization or chromatographic separation.