GB509303A - Improvements in the manufacture and production of water-soluble condensation products - Google Patents

Abstract

509,303. Tanning-agents. I. G. FARBENINDUSTRIE AKT.-GES., and JOHNSON, G. W. Jan. 10, 1938, No. 732. Addition to 471,968. [Class 2 (iii)] [Also in Group VIII] The products obtained according to the parent Specification by treating in alkaline media (a) cyclic sulphonic acids containing at least one hydroxyl group, but excluding lignin sulphonic acids, and (b) hydroxy compounds of the benzene series with (c) addition compounds of salts of sulphurous acid and aldehydes or ketones, which may also contain hydroxyl or carboxylic groups, are further condensed in an acid medium with (2a) lignin sulphonic acids or (2b) water-soluble condensation products of lignin sulphonic acids and urea or mono- or poly-hydric phenols or naphthols, and (3) aldehydes or ketones containing up to 4 carbon atoms per molecule. The urea condensation products (2b) may be formed in acid media, and the phenolic condensation products (2b) may be prepared according to Specifications 189,190, [Class 2 (iii)], 471,968 and German Specification 479,162. The main condensation may be carried out at elevated temperature and pressure,' and the particular lignin sulphonic acid used is that found in sulphite cellulose waste liquor. The products are water-soluble tanning agents, and may be used directly or after pH adjustment with buffer substances, e.g. ammonia with formic, glycollic or saccharic acid or sodium formate-formic acid. According to the Provisional Specification, the condensing agent for the main condensation may be alkalin, and reagent (3) may be omitted.