Di:hydroxy-di:benzo-phenazine(s) - prepd. by heating corresp. di:sulphonic acids or their salts in alkaline alcoholic medium, e.g. in mixt. of glycol and alkali hydroxide

摘要

Hydroxy-dibenzophenazine derivs (I) of formula (II) (with R = 0H) are produced by heating the corresp disulphonic acids (III) (II; R = S03H) or salts thereof in alkaline alcoholic medium, opt contg water. Suitable alcohols are glycols, ie methyl, ethyl, propyl, isopropyl, butyl, diethylene, triethylene or tetraethylene glycol, PEG 300-600, propylene, dipropylene, tripropylene, tetramethylene glycol, pentaglycol, hexamethylene glycol, 2-methyl-2-propyl-propane-1,3-diol, 2,2-diethylpropane-1,3-diol, 2-ethylhexane-1,3-diol, 2,5-dimethylhexane-2,5-diol, octadecane-1,12-diol or 1-8C alkanols, or mixts thereof with water; amt of alcohol is 1.5-20 (pref 2-8) pts wt/1pt wt (III); amt of alkali (pref K0H and/or Na0H) is 0.4-10 (pref 1-3) pts wt/1 pt wt (III); esp (I) is 8,8'-dihydroxynaphthazine. USE/ADVANTAGE - Cpds (I) (esp 8,8'-dihydroxynaphthazine) are useful as dyes and pigments and as intermediates for such dyes (eg tetra-halogenated derivs) (I) opt by this process can be used without further purification (contrast prior-art processes, which require several recrystallisations or sublimation to remove by-prods.