618 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table X Phenolic Compounds Mixed with p-Aminophenol Compound Patent Solubility at pH 9.7 (g/100 ml) Fades After Color on Hair • (in hours) Hydroquinone G.P. 51,073 5.915øC Resorcinol G.P. 162,625 58.42øøC Pyrocatechol G.P. 276,761 31.22øøC Chlororesorcinol G.P. 276,761 29.9 Pyrogallol G.P. 104,622 62.525øC a-Naphthol G.P. 162,625 0.26 1,5-Dihydroxynaphthalcnc G.P. 51,073 0.27 2,7-Dihydroxynaphthalcne G.P. 367,680 0.84 p-Aminophenol (alone) ...... Blond 6 Grey blond 14 Red brown 12 Green blond 8 Light golden 12 brown Red 6 Red 6 Yellow blond 2 Light golden 4 brown Solutions were 0.01 M with regard to both the phenolic and P.A.P. might consist of spectrophotometric or photographic records of freshly dyed samples compared with the same samples after definite periods of aging. In Table VIII the results obtained with m-aminophenol derivatives dyed alone and mixed with equimolar quantities of P.A.D.A. are given. With the exception of p-amino-o-cresol the colors given with m-amino- phenol derivatives, when dyed alone, were so light that no fadeometer tests were run. Hair dyed with p-amino-o-cresol faded after an expo- sure of seven hours. The results of dyeing hair with equimolar quantities of m-amino- phenol derivatives mixed with P.P.D. and P.A.P. are given in Table IX. In Table X the results obtained with phenolic compounds mixed with equimolar quantities of P.A.P. are given. None of these phenolic com- pounds gave any color when used alone. The results of dyeing hair with equimolar quantities of phenolic compounds mixed with P.P.D. are given in Table XI. Included in this table are the results of phase diagrams taken from the International Critical Tables (11). These are relevant since fusions of P.P.D. and phenolic compounds are often used in dyeing hair. This shows, for ex- ample, that, when mixtures of P. P.D. and resorcinol are melted together, a compound is formed and that the composition of this new compound is I mole of P.P.D. for each mole of resorcinol. Judged by light fastness alone it would appear that, for mixing with P.P. D, resorcinol is the most

HAIR COLORING WITH OXIDATION DYE INTERMEDIATES 619 Table X I Phenolic Compounds Mixed with p-Phenylenediamine Depth Mole Ratio of of Phenolic Shade Fades % Phenolic to P.P.D. (Darkest After (in Fusion in Fusion Color on to (in Compound Compound) Compound Hair • Lightest) hours) Hydroquinone 75.5 and 50.4 Resorcinol 49. ,5 Pyrocatechol 60.4 Chlororesorcinol . . . Pyrogallol 69.9 and 53.8 a-Naphthol 72.7 1,5-Dihydroxynaph- . . . thalene 2,7-Dihydroxynaph- 74.8 thalene p-Phenylenediamine . . . (alone) 3 to 1 and Light grey 4 4 1 to 1 brown 1 to 1 Golden brown 6 14 3 to 2 Grey brown ,5 12 ... Yellow brown 7 10 2 to 1 and Grey brown 8 4 ltol 2 to 1 Purple black 1 10 ... Grey purple 2 10 2 to 1 Grey brown 3 2 Dark brown ... 4 Solutions were 0.01 M with regard to both the phenoli½ and P.P.D. effective compound to use, followed by pyrocatechol and chloro- resorcinol. However, examination of dyeings that had been in files for over thirteen years showed that the tendency to turn red on ageing in- creased in this order: chlororesorcinol (the least), resorcinol, pyrogallol, hydroquinone, pyrocatechol, and P.P.D. alone (the most). It appears that more attention to chlororesorcinol might be fruitful. All of the dyeings discussed thus far were made by immersion, while the application to heads must be made by brushing. However, it was felt that conditions could be much better controlled and the conclusions drawn more valid with dyeings made by immersion rather than by brushing. In order to make direct comparisons of the depth of shade obtained by brush and dip dyeing a base solution was prepared, as de- scribed by Cook (12). Natural white hair was dyed using the mixture shown in Table XII, in which the concentration of P.P.D. was varied from 0.1 lC•o to 0.66c•0 for the brush application. It was conduded that in order to obtain the same depth of shade with a brush application (in the presence of surface active agents) as with dipping, it would be neces- sary to use approximately four times the concentration of dye used in the dip application.