Hydro naphthylamines

Rubber antioxidants are commonly of an aromatic amine type, such as dibeta-naphthyl-para-phenylenediamine and phenyl-beta-naphthylamine. Usually, only a small fraction of a percent affords adequate protection. Some antioxidants arc substitute phenolic compounds (butylatcd hydro -vamsole, di-tert-butyl-para-cresol, and propyl gallate). 

The yield of pure distilled base, b.p. ii8.5°/8 mm., 127.5-128°/12 mm., i4o-i4o.50/2° mm., amounts to 53-59 g. (51-57 per cent of the theoretical amount). The pure base can be preserved only by sealing it in ampules (containing as litde air as possible) immediately after distillation. The ac.-tetra-hydro-0-naphthylamine is a colorless, water-clear liquid which shows no fluorescence (Note 12), and possesses a strong odor similar to piperidine. In the air the base soon turns brown, rapidly absorbs carbon dioxide and changes to the carbonate. 

Hydrated Naphthylamines.— We have referred to the hydrated naphthylamines in our discussion of the constitution of naphthalene (p. 772). The tetra-hydro products are of two kinds (i) Those termed aromatic in which the hydrogen is added to the benzene nucleus which does not contain the amino group and which possess the characters of aromatic amines. (2) Those termed alicyclic in which the hydrogen is added to the benzene nucleus which does contain the amino group and which possess the characters of aliphatic amines. Now while the alpha- and g/a-naphthylamines each yield both kinds of tetra-hydro products if subjected to proper treatment yet by the same treatment, viz., with sodium amalgam in amyl alcohol, the atpha-naphthylamine yields an aromatic tetra-hydro compound while the i>e/o-naphthylamine yields mostly an alicyclic compound. 

From a solution of 6 4 grams of sodium naphthionate and 6 4 grams of mercuric acetate in 150 c.c, of water, treated with a large excess of sodium hydroxide, a colourless product is obtained. This does not react with ammonium sulphide, and towards halogen salts it reacts similarly to hydroxymercuri - j8 - naphthylamine - 6 - sifiphonic acid (sodium salt). Wlien dried over phosphorus pentoxide the body becomes canary yellow, and on addition of water becomes white again. It has been formulated as the sodium salt of 2-hydro xymermri-naphthionic acid. 

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