Naphthyls

Naphthyl Acetate. CHgCOOCi H,. Dissolve 1 g. of pure 2-naphtnol in 5 ml. (r8 mols.) of 10% sodium hydroxide solution as before, add 10 g. of crushed ice, and i-i ml. (1-14 g., 1 5 mols.) of acetic anhydride. Shake the mixture vigorously for about 10-15 minutes the 2-naphthyl acetate separates as colourless crystals. Filter at the pump, wash with water, drain, and dry thoroughly. Yield of crude material, 1-4 g. (theoretical). Recrystallise from petroleum (b.p. 60-80 ), from which, on cooling and scratching, the 2-naphthyl acetate separates as colourless crystals, m.p, 71 yield, 10 g. 

Methyl 2-Naphthyl Ether. (Nerolin.) C10H7OCH3. (Method 3, p. 218.)... 

Recrystallise from methylated spirit, from which the methyl 2-naphthyl ether separates readily as colourless crystals, m.p. 72° yield, 9 g. 

Physical properties. Majority are liquids except p toluidine and 1- and 2-naphthylamine. All are colourless when pure, but rapidly darken on exposure to air and light. All are very sparingly soluble in water, but dissolve readily in dilute mineral acids (except the naphthyl-amines, which are only moderately soluble in adds). They form colourless crystalline salts e.g., CjHjNH2,HCl) which are soluble in water these aqueous solutions usually have an add reaction owing to hydrolysis, and give the reactions of both the amine and the acid from which they are derived. Addition of alkali to the acid solution liberates the amine. 

R NHa + C.HjNCO = RNH CO NHC,Hj Traces of water will contaminate the product with diphenylurea (p. 336) if the solution is boiled hence the need for anhydrous conditions. i-Naphthylisocyanate reacts more slowly with water, and the i-naphthyl-urea derivative can often be obtained using a cold aqueous solution of an aliphatic amine it is particularly necessary in such cases to purify the product by recrystallisation from, or extraction with, boiling petroleum, leaving behind any insoluble di i-naphthylurea. Note that the amine must also be free from alcohols (p. 335) and phenols (p. 337). 

Alkyl and aryl-alkyl halides form 2-naphthyl ethers with 2-naphthol. 

Formation of 2 naphthyl ethers. Alkyl halides and aryl-alkyl halides (e.g. benzyl chloride) are converted into 2-naphthyl ethers thus ... 

Nitroamlines. Acetyl derivatives (p. 388), Benzoyl derivatives (p. 388). Diamines. Diacet> l derivatives (p. 388), Dibenzoyl derivatives (p. 388). Halogeno-hydrocarbons, a-Naphthyl ethers (from reactive halogen compounds, p. 391, and their Picratcs, p. 394), Nitro-derivatives (p.39i). Carboxylic acid (if oxidisable side chain) (p. 393). 

Various basic substances, such as aromatic amines (naphthyl-amines dissolve with difficulty in dil. HCl, diphenylamine only in cone. HCl, triphenylamine insoluble) nitro-anilines some amino-carboxylic acids. 

TEST Aniline 0- toluidine m-> toluidine P-. toluidine I- naphthyl- amine 2- naphthyl- amine mono- methyl- aniline diphenyl- amine dimethyl- aniline triphenyl- amine... 

Phenyl- and a-naphthyl-urethanes (Phenyl- and a-naphthyl-carbamates). Both phenyl isocyanate and a-naphthyl isocyanate react with alcohols to yield phenyl-urethanes and a-naphthyl-urethanes respectively ... 

If the alcohol is not anhydrous, reaction also occurs between the water and the reagent to produce diphenylurea (m.p. 242°) and di-a-naphthyl-urea (m.p. 284°) respectively, for example ... 

If dry apparatus and dry reagents have not been used, diphenyl urea (m.p. 241°) or di-a-naphthyl urea (m.p. 297°) are obtained. 

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