Picryl sulphide

This compound, first prepared by Wedekind [33], is even more reactive than dinitrophenylpyridinium chloride (p. 454). Bielig and Reidies [23] described a reaction after Zincke and Weisspfennig s work [22] which resulted in the formation of hexanitrodiphenyl sulphide (picryl sulphide) (p. 553). 

Only one representative of this group is known in industrial practice, namely hexanitrodiphenyl sulphide (picryl sulphide, hexasulphide, Hexide) of melting point 234°C. 

The product does not colour the skin and, according to the German literature, is not toxic. However, Roche and V. Thomas [19] reported its vapour to be strongly irritant. During World War I the Germans used picryl sulphide in mixtures with TNT, with or without ammonium nitrate, for filling bombs. 

Since the explosive decomposition of picryl sulphide and of its mixtures yields S02 among other decomposition products, the compound has been proposed for filling shells to be used against confined objectives, such as ships interiors, bunkers, etc. As a result of explosion a noxious atmosphere containing S02 would result. 

Picryl sulphide is a stable explosive. Van Duin and van Lennep [8] found its initiation temperature to be 302-319°C depending on the rate of heating. When kept at 95°C for 30 days the substance remained unchanged. 

The lead block expansion given by picryl sulphide is equal or, according to some authors, slightly larger than that given by picric acid (325-350 cm3). 

In 1912 Sprengstoff A. G. Carbonit [17] was granted a patent for a method of preparation of this explosive, consisting in reacting hexanitrodiphenyl sulphide with nitric acid. Since picryl chloride, as the starting material for picryl sulphide was rather expensive, another method of preparation of hexanitrodiphenyl sulphone, via tetranitrodiphenyl sulphide, was also used. The latter was obtained by treating chlorodinitrobenzene with sodium thiosulphate. Then it was nitrated and oxidized simultaneously with nitric acid to hexanitrodiphenyl sulphone ... 

It is a more powerful explosive than hexyl or picryl sulphide, mainly due to a more favourable oxygen balance, and also surpasses picric acid. Its sensitivity to impact is of the order of tetryl. 

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