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82 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

nitrating agent, while the role of nitric acid is to regenerate the NO 2 radical.

The course of the reaction between acetylene and nitric acid is much more

complicated. By passing acetylene through fuming nitric acid at ordinary tem-

perature in 1901 Baschieri [7] and in 1902 Mascarelli and Testoni [8] obtained,

besides nitroform, CH(NO 2 ) 3 , two other crystalline compounds: an acid C 4 H 3 O 3 N

and an explosive, C 4 H 2 O 7 H 6 [9]. A thorough investigation of these subs-

tances was carried out by Quilico and Freri in numerous papers published

between 1929 and 1932 [10,11]. They recognized that these compounds were all

isoxazole derivatives (II) and they established their structure and mechanism of

formation. The following is the scheme drawn up by Quilico [10] and Quilico and

Simonetta [12] in 1946. It is closely related to the classic interpretation by Wie-

land [13,14] of the formation of fulminic acid from ethanol, nitric acid and mer-

curic nitrate (Vol. III):

(1)

Here, isoxazole-3-carboxylic acid (IV)-the main product of the reaction-is formed

from nitrile oxide (III) on adding acetylene to it.

The formation of nitroform is presented by Quilico as follows:

(2)

(3)

From compound III the loss of CO 2 could lead directly to the formation of

fulminic acid (V) which in Wieland’s scheme would take its origin from (II) through
loss of CO 2 and HNO 2.

In the presence of mercuric nitrate, a high yield of tetranitromethane is obtained

through the intermediate formation of nitroform. This reaction is dealt with on

p. 594 (manufacture of tetranitromethane).
Experimental support for this mode of formation of the isoxazole derivative

(IV) was found in 1946 by Quilico and Simonetta [12]. They obtained V from