urbaf2

OTHER NITRO DERIVATIVES OF PHENOLS 539

Aubertein and Emeury examined the solubility in a spent acid mixture of the compo-

sition :

HNO 3 10%

H 2 SO 4 72%

H 2 O 18%

At room temperature it is below 0.005%. At 35-40°C the solubility is below

0.01%, and at 80°C it is below 0.1%.

Styphnic acid is slightly hygroscopic. It absorbs 2-3% of water after being

exposed for 30-100 hr at an atmosphere of 60% humidity at 25°C [29].

Styphnic acid is readily soluble in glycol diacetate : 100 g of the solvent at 20-25°C

can dissolve about 13 g of the substance.

Chemical properties

Trinitroresorcinol, like other compounds of this type, forms addition

compounds with aromatic hydrocarbons. Some of them investigated by Je-

fremov [24], containing the two components in the molar ratio of 1:1, are

listed below:

melting point, °C

with naphthalene 165.5

,, acenaphthene 156.0

,, anthracene 176.3

,, phenanthrene 132.7

,, retene 135.7

With chloro- and bromo-naphthalenes it yields compounds melting within a wide

temperature range.

With regard to explosive power and sensitiveness trinitroresorcinol is similar

to picric acid. Since its price is considerably higher than that of picric acid it is not

used in explosive technology. Only lead trinitroresorcinate is of great practical

importance as an initiator (Vol. III). On the whole the properties of trinitroresor-

cinol salts are similar to those of picrates.

Purity

The purity of the product depends on the method of carrying out the reaction.

The melting point of the product prepared by Aubertein and Emeury [29] was

176.2-176.5%.

However, high purity of styphnic acid is not required when the substance is

used to produce the lead salt by the continuous method according to Meissner
(Vol. III). Some manufactures claim to achieve better results with an impure brown

product of low melting point - max. 170°C.

Styphnic acid of low purity can be obtained by sulphonating resorcinol with spent

sulphuric acid or by sulphonation with sulphuric acid added with sodium nitrite
according to the method of Wilkinson [31].