NAPHTHALENE DERTVAT1VES.—Clavel (No. 2296, 1868) obtains a red colour from napthylamine (q. v.), which is acted upon at ino (250° F.) with equal parts by weight glacial acetic acid and nitrite of soda, until the red colour is produced. The colour, after treatment with water, is dissolved in warm diluted acetic acid, from which it may be separated again, by common salt, for purification. Its solution in alcohol or wcak acid may be used for dyeing or printing ; it is less altered on exposure than rosaniline reds. A scarlet has been obtained by treating the sulphate of naphthyl amine with nitro-muriatic acid.
Magdala Pink,or Hofmann's Naphthalene Bed.—This colour is obtained by heating together amide azo and amide-naphthalenes (q. v.), and ie sold as a brown crystalline powder, which is the hydro chlerate, soluble in alcohol with a deep-red colour, almost insoluble in cold water, hut soluble in beiliug water. Its alcoholio solution is precipitated by ether in a crystalline, brownish powder. Its dilute solutions have a splendid bright-red fluorescence. A few drops of a concentrated solution dropped into a test-tube full of alcohol, will take, by reflected light, a bright-red cloudiness, as if turbid ; but by transmitted light, will appear perfectly clear, with a fine rose-red tint. This is the most important colour from naphthalene ; but its manufacture being more troublesome than that of the aniline colours, it has not been much taken up. It does not equal aniline colours in deeper shades, but gives brighter tints. It has been pointed out as a source of other colours.
Napthylamine Violet.—By using the same reaction as with aniline, arsenic acid, &c., violet colours have been obtained, but they are wanting in brilliancy and freshness. Ballo obtains a very fine violet, by heating acetate resaniline with naphthylamine ; its alcoholic solution dyes equal to the aniline colours.
Violacine.—A blue dye of this name ie obtained from an impure naphthalene by treating with strong caustic alkali, and submitting the product to oxidation (No. 3080, 1873). It is said to dye a fast blue colour with a reddish tinge, which, by complete purification, turns yellowish. By
oxidizing naphthalene with chromic acid, a beautiful red matter is produced, to which Laurent has given tho name of " Carminnaphte " ; it dyes silk and wool violets having orange or reddish shades.
Naphthalene Yellows.—Price (No. 89,1869) produces a sulpho-acid by heating at 100° (212° F.) about 1 lb. naphthalene with 1 lb. concentrated sulphuric acid, till most of tbe former is converted into sulphonaphthalic acid, which is neutralized by an alkaline solution. By evaporation and fusion with an alkali, naphthol is obtained on precipitation with a dilute acid. The naphthol or naplathylic alcohol is then dissolved in strong sulphuric acid, to which warm dilute nitric acid is added. The solution passes through different tints, and finally assumes a yellow ; on cooling, the colouring matter crystallizes out. It may be purified by solution in alkali, and repreeipitation with muriate of ammonia.
Manchester Yellow.—On the large scale, this is obtained by adding sodium nitrite to a solution of amido-naphthalene and hydrochloric acid, and boiling the diazo-naphthalene chloride thus formed with nitric acid. Ballo heats 1 part naphthylamine with 4-6 parts nitric acid (sp. gr. 1.35), as long as brown vapours are produced. The dinitio-naphthol thus formed dissolves in alcohol, ether, and benzol ; and crystallizes in fine citron-yellow needles. It is the finest and purest yellow known ; it dyes silk and wool all shades of yellow from bright citron to orange, and is largely used for dyeing wool and leather, and printing felt carpet ; 1 lb. will dye 2001b. wool an intense yellow.
Chlor-oxy-naphthalic Aoid.—Laurent and Casthelaz have adopted this substance for dyeing (1865, No: 1605). It dyes unmordanted wool an intense red ; by boiling with zinc in an alkaline solution for fifteen or twenty minutes, the liquid becomes yellow, from which hydrochloric acid deposits a brownish flocculent precipitate ; its alcoholic solution dyes wool and silk violet ; on cotton, the same may be fixed with albumen. The dilute solution dyes blue on wool, silk, mid mordanted cotton ; acids redden it.