Fusion with soda lime

Upon warming with 10-20 per cent, sodium or potassium hydroxide solution, no ammonia is evolved (distinction from primary amides). The base, however, is usually liberated upon fusion with soda lime (see experimental details in Section IV,175) and at the same time the acyl group yields a hydrocarbon. Thus benz-p-toluidide affords p-tolu-idine and benzene. 

On boiling the methiodide with 70% sulfuric acid an N-methyl-oxo derivative was obtained, and this in turn gave 3-amino-2-phenyl-quinoline, methylamine, and ammonia on fusion with soda lime. The bulk of the evidence therefore favors quaternization at N-2 (cf, 154), in which case the acid-hydrolysis product is 155. Quaternization at N-2 would be expected because of the steric influence of the 10-phenyl group and the influence of the 4-amino group (cf. 4-hydroxy-pyridazine ) in the pyridazine-type ring, although the partial double-bond character of that ring is probably different from that in pyridazine itself. 

There are three straightforward tests which will provide useful information as to the general properties of the compound, and the presence of the more important of the elements noted above other than carbon, hydrogen and oxygen these tests are the ignition test heating with soda-lime and the sodium fusion test (Lassaigne s test). 

The mineral scheelite (calcium tungstate) is beneficiated by fusion with soda ash and separation of the soluble sodium tungstate from insoluble impurities (31.12). Purified calcium tungstate is precipitated by the addition of slaked lime (31.13). It is used in the production of ferrotimgsten and phosphors for items such as lasers, fluorescent lamps and oscilloscopes [31.12]. 

Carry out a preliminary soda lime fusion test to determine whether the base is liberated under these conditions if it is, repeat the experiment with 1 g. of the substance. Identify the base (amine) by its m.p. (if a solid) and the preparation of a solid derivative (Section IV,100). 

Technical Observations. The process described above is the best and least expensive. There is, however, another method which is analftgous to the preparation of -naphthol. Sodium naphthalene-a-sulfonate is fused with caustic soda at 290° (not to exceed 300°). The sulfonation is carried out at 80-90°, and the product is salted out in as concentrated a solution as possible. The sulfonate can also be isolated by removing the excess acid with lime or chalk, treating with soda, and evaporating to obtain the product. The sulfonate, thus obtained, can be used in the fusion without further purification, but the resulting a-naphthol is impure. 

A number of nitrogen compounds, for example, proteins, do not yield cyanide ions easily with sodium fusion. It is advisable to perform the soda lime test for nitrogen if the sodium fusion shows absence of cyanide ion. 

E) Detection of Nitrogen. (1) Calcium Oxide Fusion. Mix 0.1 g of urea or casein with five times its bulk of pulverized soda lime. Place in a small evaporating dish, and cover with a watch glass, on the inner surface of which is laid a strip of moist red litmus paper. Now heat gently to avoid spattering, and observe the litmus paper. Allow the ignition mixture to cool, place a portion In a test tube, and test for sulfide ion. 

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