Nitrolic acids, heating

Z-Acetonitrolic acid rapidly loses N02 to form unstable acetonitrile oxide, which could be detected by monitoring its subsequent reactions (86). Arylnitrolic acids 12 (X = />-Cl. m-N02, o-N02) exist in the -configuration and undergo slow loss of N02 to give nitrile oxides. Subsequently it was shown (87) that nitrolic acids are converted to nitrile oxides in practically quantitative yields under neutral conditions (heating in THF). 

Nitrile oxides are generated from nitrolic acids [RC(N02)=N0H] by elimination of the elements of nitrous acid. This can occur spontaneously, on heating, or by the action of sodium bicarbonate, and it thereby provides access to symmetrically substituted dialkyl-, diaryl-, and diacyl-furoxans. 

Aryl, alkyl, and acyl nitrolic acids (27) can form furoxans by loss of nitrous acid, either spontaneously,169,170 on heating,171 173 or by the action of sodium bicarbonate.174 In addition, they are probably intermediates in a wide variety of other preparations involving nitric or nitrous acid, or oxides of nitrogen, and nitro compounds or their precursors. 

B) Preparation of Nitrol nzene (M.). The same procedure is used as described in section (A). Use a 500-ml roxmd-bottom or Florence flask. Place in it 35 g (25 ml) of concentrated nitric acid, immerse the flask in a pail of cold water, and add in small portions 50 g (28 ml) of concentrated sulfuric acid, shaking between additions. Cool and add in small portions 25 g (30 ml) of benzene at such rate that the temperature does not rise above 50°. Heat for about 45 minutes at 50-60° and follow the procedure in section (A). Use 10 g of calcium chloride to dehydrate the product, and warm in a water bath for a few minutes to aid the dehydration. The yield is about 35 g. 

NITROL (55-63-0) Heat-, UV-, acid-, friction-, shock-sensitive high explosive. A flammable liquid (at flash point explodes). Hydrolyzed in water, forming an explosive solution of nitric acid and glycerol. Explodes on contact with ozone or in temperatures above approximately 350°F/176°C. The pure material is rarely used the commercial material is desensitized. 

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