Xpr., 1921
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
309
The Anilides of P-Oxynaphthoic Acid' By E. R. Brunskill CINCINNATI CHEMICAL WORKS, NORWOOD, OHIO
The colors obtained b y substituting P-oxynaphthoic acid for P-naphthol in t h e ice process are brighter a n d are of a somewhat greater range in shade. They do n o t have the brownish appearance which P-naphthol colors sometimes have, a n d t h e solutions can be kept longer and with more ease t h a n is t h e case with Pnaphthol. T h e /3-oxynaphthoic acid colors, however, have t h e very serious fault of washing out easily, and are not fast t o rubbing. I n order t o overcome these serious defects t h e carboxy-group has been covered b y substituted amines, t h e principal one of which is t h e aniiide, known also as Naphthol AS. A great number of t h e anilides of P-oxynaphthoic acid are described in t h e patent literature, b u t for the comparison t o be made here only t h e anilide, t h e ptolurdide, a n d t h e p-chloroanilide are considered. METHOD O F PREPARATION
They were made b y a process similar t o those described in t h e various patents. One mole (in grams) of P-oxynaphthoic acid, one mole of amine, and 1400 cc. of toluene were heated t o gentle boiling under a reflux condenser. They, with stirring, t h e theoretical quantity of phosphorus trichloride was slowly dropped in. The hydrochloric acid gas evolved was absorbed over water, and t h e reaction was ended when no more gas was e,volved. The time required was from 2 t o 4 hrs. T h e mixture was poured into water and t h e toluene drawn off. T h e water suspension of t h e anilide was made slightly alkaline with soda ash, in which t h e anilide is insoluble. The solution, containing t h e uncombined P-oxynaphthoie acid, was filtered, a n d t h e precipitate washed with a little water. It was then dissolved in t h e necessary quantity of 1 per cent caustic soda solution a t about 50" C. Upon filtration a n d precipitation with acid, a very pure product was obtained. The anilides are very slightly soluble in alcohol and toluene, while t h e free acid is quite soluble. T h e anilides melt with decomposition above 200 O C. They are soluble with a yellow color and without decoinposition in warm, dilute, caustic soda solution. METHOD O F DYEING
%he ordinary methods of dyeing were tried, b u t owing t o t h e slow coupling properties of t h e anilides good
results were not obtained.
The method adopted was
as follows:
The cotton, which had been boiled out with soap a n d thoroughly rinsed, was soaked for a n hour in a 2 pes cent solution of t h e anilide i n t h e theoretical a m o u n t of caustic soda. I n t h e meantime t h e diazo solutions were prepared in t h e usual manner and made u p t o a concentration of 0.1 mole in 500 cc. An icecold saturated salt solution was treated with enough soda ash t o make a 3 per cent solution, a n d filPresented before the Division of Dye Chemistry a t the 60th Meeting of the American Chemical Society, Chicago, Ill., September 6 to 10, 1920.
tered t o remove t h e precipitated CaC03, B a C 0 3 , and LfgcOs. To dye a 10-g. skein, 300 cc. of t h e cold salt solution were measured into a liter beaker. The thoroughly wrung skein of treated cotton was immersed in t h e salt solution, and immediately 80 cc. of the diazo solution were added, with constant turning of t h e cotton. T h e cotton was turned for about an hour, then rinsed first in cold water, then in hot soap solution, and finally in warm water. I n t h e developing bath a test should show a slight excess of soda ash and diazo compound a t t h e finish. If not, more of t h e one which was lacking should be added for another dyeing, as t h e best dyeings were obtained only b y adding all t h e materials a t once. Dyeings were made using t h e following substances as naphthols: P-oxynaphthoic acid, t h e anilide, the toluidide, and t h e p-chloroanilide. Each naphthol was coupled with aniline, p-nitroaniline, p-chloroaniline-osulfonic acid, p-toluidine, m-nitro-p-toluidine, and o chloro-p-toluidine sulfonic acid. All t h e colors made from P-oxynaphthoic acid washed out and were not fast t o rubbing, especially those made from t h e sulfonated amines. Moreover, t h e colors were not as bright as those made from t h e anilides. T h e anilides gave colors which were fairly fast t o washing and rubbing, except in t h e case of t h e sulfonated amines. I n order t o make t h e colors from t h e latter faster t o washing they were treated as follows: The damp rinsed dyeings were dipped into a 3 per cent solution of calcium chloride and allowed t o remain with turning for a half hour a t 50" C. They were then rinsed and dried. This treatment made t h e colors fast t o washing and rubbing, with but very little change in shade. All t h e 0-oxynaphthoic acid colors were also treated with calcium chloride, which made them much faster t o washing, notably in t h e case of p-chloroaniline-osulfonic acid. One might expect t o obtain a difference in color between t h e three anilides, and as far as these dyeings show there are some differences, but, before one could definitely say just what effect a substituent in t h e amine of t h e amide has upon the color, a larger number of anilides must be studied. It appears, however, t h a t t h e p-chloroanilide, and t h e p-toluidide give brighter shades t h i n t h e anilide, and t h a t t h e p-chloroanilide gives a slightly brighter shade t h a n t h e p-toluidide, except in the case where there is a nitro group in t h e diazotized amine, in which case t h e p-toluidide gives t h e brightest colors. The effect of t h e nitro group can also be observed by comparing t h e colors from p-nitroaniline and mnitro-p-toluidine, those from t h e latter being in every case t h e brightest, so t h a t it seems t h a t a nitro group must be balanced with a methyl group in order t o obtain t h e best results.
