Where the nitrous fumes prevail and there is less water present, sulphur dioxide combines with nitrous acid and oxygen to form nitroso-sulphuric acid, a crystalline substance of the formula SO 2 (OH)(ONO).
It is obtained by condensing benzal chloride with mercury diphenyl (Kekule and Franchimont, Ber., 1872, 5, p. 907); from benzal chloride or benzotrichloride and zinc dust or aluminium chloride; from chloroform or carbon tetrachloride and benzene in the presence of aluminium chloride; and deamidating diand tri-aminotriphenylmethane with nitrous acid and alcohol (0.
The orthoand parasemidines can be readily distinguished by their behaviour with different reagents; thus with nitrous acid the ortho-semidines give azimido compounds, whilst the para-semidines give complex diazo derivatives; with formic or acetic acids the ortho-semidines give anhydro compounds of a basic character, the para-semidines give acyl products possessing no basic character.
C (: NOH)NO 2, may be prepared by the action of nitrous acid on the primary nitroparaffins; by the action of hydroxylamine on the dibromnitroparaffins; and by the action of nitrogen peroxide on the a-isonitroso fatty acids (G.
Amidotetrazotic acid yields addition compounds with amines, and by the further action of nitrous acid yields a very explosive derivative, diazotetrazol, CN 3.
The acid may also be synthesized by the decomposition of alanine (a-aminopropionic acid) by nitrous acid (K.
Fischer (Ber., 1880, 13, p. 2204) as follows: Nitrous acid converts pararosaniline into aurin, which when superheated with water yields para-dioxybenzophenone.
Busch, Ber., 1892, 25, p. 445), or in small quantity by the action of nitrous acid on ortho-aminobenzoylphenylhydrazines (A.
Wurtz); by the action of nitrous acid on aniline; by passing oxygen into boiling benzene containing aluminium chloride (C. Friedel and J.
NHR, may be prepared by the action of the primary and secondary amines on the diazonium salts, or by the action of nitrous acid on the free primary amine.