Sulphonated, aromatic reaction products, processes for their manufacture and their use as substances having a tanning action

Claim 1

A sulphonated, aromatic reaction product of (1) 100 parts by weight of a sulphonation product of (A) 10 to 90 percent by weight of an unsubstituted diphenyl ether or of a diphenyl ether which is substituted by methyl, (B) 90 to 10 percent by weight of an unsubstituted phenol, or of a phenol which is substituted by methyl, the sum of components (A) and (B) being 1 mol, and (C) 1 to 2 mols, calculated as sulphonic acid, of a sulphonating agent and (2) 1 to 6 parts by weight of formaldehyde or of a formaldehydeforming agent, said aromatic reaction product being produced by a process, which comprises reacting components (A), (B) and (C) simultaneously at 110° to 180° C. or initially reacting component (A) with component (C) at 110° to 120° C. and then with component (B) at 110° to 180° C. or initially reacting component (B) with component (C) at 110° to 120° C. and then with component (A) at 110° to 180° C. to give the sulphonation product (1), further reacting said sulphonation product (1) at a temperature from 60° to 95° C. with component (2) to give a reaction product, then adding an organic or inorganic base to said reaction product and finally optionally adding an organic acid to said reaction product.