Aniline is a limpid liquid, with strong refracting power, colourless when pure, but generally of a pale-sherry colour, which rapidly turns brown on exposure to air and light; it possesses an agree able, aromatic, vinous odour ; it burns slowly and with a smoky flame, at ordinary temperatures, but with great violence when strongly heated ; its sp. gr. is 1 -02 at 16° (61° F.); it boils at 182° (360° F.); it forms well-defined salts with acids, which furnishes a means of separating it from any unaltered benzol ; it is very poisonous ; its sulphate has been used medicinally.
Commercial anilines are of variable character, and consist principally of aniline, para-toluidine, meta-toluidine, xylidines, and cumidiues. Light aniline oils distil generally at about 162° (360° F.), the heavy oils, above this point ; the term " aniline-tailings " is applied to the heaviest oils, of high boiling-points. Tables have been drawn up, showing the proportion of heavy and light aniline oils for different shades of colour ; but they are eearcely reliable. Reimann says that the best oil for " fuchsine" is that yielding 01 per cent. of distillato between 185° and 190° (365° and 374° F.), and 28.5 per cent. between 190° and 205° (374° and 401° F.); Girard and De Laire state that the most suitable oils are those oontaining about equal quantities of true aniline and toluidiae, and yielding 10 per cent. between 182° and 185° (360° and 365° F.), 40 per cent. between 185° and 195° (365° and 383° F.), and 10 per cent. between 195° and 200° (383° and 392° F.); Kopp says the best " fucheine " oils aro those which almost wholly pass over between 185° and 210° (365° and 410° F.); while Hofmann found that various specimens of the oils actually in use on tbe large scale boiled between 182° and 220° (360' and 428° F.).
These anilines, or " aniline oils," as they are called, eerve for the industrial production of the " aniline coloure," or " toluidino colours," of which the principal are-1. Red : rosaniline or magenta, toluidine, xylidine, &c. ; 2. Blue : pbenyl-rosanilines, diplieuylamine, tulnidine, aldehyde, &c.; 3. Violet : rosaniline, mauve, phenyl, ethyl, methyl, &c. ; 4. Green : iodine, aniline, leucaniline, chrysotoluidine, aldehyde, toluidine, methyl-aniline, &c. ; 5. Yellow, and orange : leucauiline, phenylamine, &c. ; 6. Brown : chrysotoluidine, &c. ; 7. Blacks : aniline, toluidine, &c.; 8. Greye.
Aniline readily combines with the iodidee and bromides of akohol radicals ; it comports iteelf in this reaction like an " amine," and, for this reason, was formerly called " phenyl-amine." The narnes of these aniline products are made up of a prefix from the name of the stleohol employed and the terminal " aniline." Methyl-aniline. C6115N 33.—When aniline is mixed with methyl-iodide, a violent reaction sets in, accompanied by copious efferveeeence, so that on mixing it is best to agitate the vessel, to faci litate the escape of the vapours ; on cooling, the mass solidifies into crystals of methyl-aniline hydriodide. It is also produced, together with dimethylamine, by treating aniline hydrochlcuide with methyl-alcohol under great pressure in a " cohobator," The base (methylanile) ie obtained free, by adding cauetie potash, and distilling. It is a colourlees liquid, resembling aniline, and boiling at 193° (378°F.); it gives a blue coloration with bleaching powder ; and forms salts having a striking resemblance to aniline. The amido derivative of dimethyl-aniline, or diwethyl-phenylene-diamine, is converted iuto a blue colouring matter, by Cato (1877, No. 3751), by adding a solution of ferric ehloride to the aeid fied mad diluted solution, and passing a current of sulphuretted hydrogen, until the colour is producod.
Ethyl-aniline. CAN {elk —When anhydrous aniline and bromide of ethyl are mixed to gether, and slightly heated in a flask, so as to allow the bromide of ethyl which evaporates to fall back again into the aniline, the mixture eoon boils, and, un cooling, becomes a crystalline mass. If this product is mixed with a eolution of caustic potash, and distilled, there will be obtained a clear colourless liquid, readily turning brown on exposure to the air, and boiling at 204° (400° F.). It does not yield a violet colour with alkaline hypochlorites. Its salts are readily soluble, and with difficulty crystallizable.
Di-ethyl-aniline. CAN(C,H5)2.—This is obtained by acting on mono-ethyl-aniline with bro mide or iodide of ethyl in excess. At ordinary temperatures, the bromhydrate of di-ethyl-aniline requiree four or five days to separate out ; it boils at 157° (315° F.).