COLOURS FROM
ANILINE.
177
100 K
90 K
85 K
80 K
75 K
62* K
60 K
50 K
374 K
25 K
100 K
Deg. C.
0 B
xo B
15 B
20 B
25 B
374 B
40 B
50 B
62! B
75 B
100 B
180 0
24
7
2i
54
34
4
—
4
2
3
—
—
6
—
—
—
34
3
—
3
2
2j
—
185“
54
50
29 i
22
54
24
7
4 i
—
24
—
190°
34
34
5 6 4
554
554
41
37
74
54
4 h
14
195°
—
5
74
84
15
25
33
42
40
*7
8
200°
—
—
—
—
9
84
—
19
284
36
18
205°
—
_
—
—
44
5
16
10
II
16
39
210°
—
—
—
—
44
—
34
74
8
19
215°
—
44
7
Residue
34
4
4
84
34
64
7
64
34
5
54
All that is required is to distil over a sample in the manner described above,note the quantities coming over at different temperatures, and compare thefigures thus obtained with the table. In this manner the composition of asample may be ascertained accurately enough for all practical purposes.
The aniline of commerce is a mixture of pure aniline and toluidine invariable proportions, the former preponderating in the light, and the latter inthe heavy samples. Odorine and other substances are also present in smallamount. Its colour is darker than that of pure aniline, and its smell moreoffensive.
Toluidine, C 7 H 9 N, was discovered by Muspratt and Hofmann (“ Annalender Chemie und Pharmacie,” vol. liv., p. i). It is a solid, crystalline body,which liquefies at 40° C. and boils at ig8° C. It has an odour like that ofaniline, and a burning taste. It is soluble in wood-spirit, alcohol, ether,aceton, and in the volatile and fatty oils. It forms with the acids a series ofcrystalline salts, most of which are soluble in water. Its acid solutions stainfir wood and elder pith a deep yellow, just like aniline. With hypochloriteof soda it yields, not a violet, but a reddish tinge. With nitric acid it becomesa deep red, whilst aniline gives an indigo-colour, and with chromic acid itfurnishes a brown precipitate. The toluidine of commerce is obtained fromnitro-toluol, in the same manner as aniline is obtained from nitro-benzol.
The methodical classification of the coloured reactions of aniline is not freefrom difficulty, as some of the results have not been scientifically investigated.The faCt is that many manufacturers used in their experiments commercialanilines of unknown composition, and did not care to examine either the exaCtnature or origin of the tinctorial substances obtained. Under the commonname of “ aniline colours ” we find included bodies which result from thesimultaneous action of other bases. It should further be observed, that oneand the same chemical reagent is capable of giving rise to several colouredderivatives, according to the time of action, temperature, degree of concen-tration, &c. Still we generally find a primary result of the reaction, the othersbeing merely by-produCts, or, indeed, impurities which it is difficult to remove.We shall give such faCts only as are of practical value, or which serve toelucidate the history of the aniline manufacture. The following colours arederived from aniline :—
N