Manufacture of new condensation products, being more especially improved tanning agents and their application

Abstract

Abstract Condensation products with good tanning properties are obtained by condensing in an acid medium formaldehyde, urea or thiourea and a polysulphone formed by heating under vacuum at 150-190 DEG C. a monosulphonic acid of phenol, cresol or anisole; (see Group IV (b)). Dimethylol urea or similar condensation products may be used instead of free urea, thiourea and formaldehyde. For each mol. urea or thiourea about 2 mols. formaldehyde are used and between 3 and 13, preferably between 4 and 6 mols. of phenol, cresol or anisole. The condensation is performed at from room to boiling temperature, preferably 40-80 DEG C. The products are prepared for tanning by neutralizing with alkali and acidifying with an organic acid, e.g. formic or acetic acid. Examples are given using polysulphones derived from phenol, anisole, raw cresol and o-cresol. Specifications 493,997, 504,994 and 595,211 are referred to.ALSO:Polysulphones for condensation with formaldehyde and urea or thiourea to produce tanning agents (see Group IV (a)), are made by heating monosulphonic acids of phenol, cresol or anisole under vacuum to a temperature of between 150 DEG and 190 DEG C., preferably 170 DEG C. The vacuum should be less than 20 mm., preferably 10-12 mm. pressure. Condensation occurs with elimination of water derived from the sulphonic acid groups and nuclear hydrogen atoms. Examples are given of the sulphonation of phenol, anisole, raw cresol and o-cresol, with subsequent condensation of the resulting sulphonic acids under the stated conditions. Specifications 493,997, 504,994 and 595,211 are referred to.

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