Patent ID: 6846956

Claim:
A process for preparing a triarylmethane dye of the formula I or II: where R 1 and R 2 are independently methyl, ethyl or hydroxyethyl, Q is a radical of the formula III or IV: R 3 and R 4 are independently hydrogen, methyl, ethyl or phenyl, A ⊖ is the equivalent of an anion of an inorganic or organic acid, and X is hydroxyl or amino, which comprises reacting an N-hydroxyethylaniline of the formula VI: with formaldehyde to form a 4,4′-bis(hydroxy-ethylamino)diphenylmethane of the formula VII: and treating the 4,4′-bis(hydroxyethylamino)diphenylmethane VII with an oxidizing agent in the presence of an aminoaromatic of the formula VIII or IX: and of an anion source to obtain a triarylmethane dye of the formula I which is optionally converted with an alkali metal hydroxide or ammonia into a triarylmethane dye of the formula II.