GB332560A - Process for the manufacture of new dyestuffs of the triphenyl methane series - Google Patents

Abstract

332,560. Carpmael, A., (I. G. Farbemindustrie Akt.-Ges.). April 22, 1929. Triarylmethane dyes; amines.-Triarylmethana dyes or their leuco compounds are prepared by reacting upon an a- or #-haJogenethylbenzene with a primary or secondary aromatic amine, condensing the secondary or tertiary amine produced or a sulphonic acid derivative thereof with an aromatic aldehyde, ketone or hydrol, or with formaldehyde and an aromatic tertiary amine, and, if necessary, oxidizing any resulting leuco compound to the dyestuff in the customary manner. Thus the amines produced by condensing 2 mols. of ethylaniline with 1 mol. of #-chlorethylbenzene or 2 mols. of o-toludine with 1 mol. of alpha-chlorethylbenzene or the sulphonic acid derivatives (prepared by sulphonation with fuming sulphuric acid) may be used to prepare the dyes. In examples, (1) Michler's ketone (1 mol.) and ethyl-(a-methylbenzyl)-aniline (1 mol.) are melted together with phosphorus oxychloride; (2) o-chlorbenzaldehyde (1 mol.) and (a-methylbenzyl)-o-toluidine sulphonic acid (2 mols.) are heated together in water and the leuco compound oxidized with lead dioxide or sodium dichromate and sulphuric acid; o-sulphobenzaldehyde may be used in place of o-chlorbenzaldehyde; (3) formaldehyde solution is condensed with ethyl-(#-phenethyl)-aniline sulphonic acid, the resulting diphenylmethane derivative heated with diethylaniline, and the leuco compound oxidized with sodium dichromate. These products, particularly those containing a. sulphonic acid group, dye very clear shades frequently different from that of the corresponding dyestuffs derived from the benzylated aromatic amines.