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428 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

PHYSICAL PROPERTIES

They are fine grey-yellowish (sand-coloured) crystals. The colour of the commer-

cial product frequently depends on its purity. The reddish colour met sometimes

is evidence that nitrogen dioxide is present, absorbed by the product.

All the isomers mentioned are sparingly soluble in alcohol and ether. They

dissolve more easily in benzene, toluene, acetic acid, acetone and turpentine.

The solubilities of both isomers of dinitronaphthalene, collected from the data

of various authors are given in Table 95 (after Orlova [20b].

TABLE 95

SOLUBILITY OF DINITRONAPHTHALENES

Solvent

Ethanol

(anhydrous)

Ethanol 95%

Acetone

Acetic acid

Chloroform

Dichloroethane

Benzene

Water

Temperature

°C

22 0.37

19 0.06

19 6.59

boiling point 15.98

boiling point 2.01

19 1.37

19 2.08

50 0.06

boiling point 0.07

Solubility, %

l,8-dinitro-

napthalene

1,5-dinitro-

naphthalene

0.16

0.06

0.59

2.3

0.43

2.01

0.45

0.02

insoluble

The commercial product obtained by the nitration of α− nitronaphthalene is

a mixture of the 1,5- and 1,8- isomers, with only a small content of the 1,3-isomer.

The melting point of the product ranges from 140-160°C. It is used for the prepara-

tion of explosives or for further nitration, without separating the isomers. The

FIG. 107. System of 1,5- and l,8-dinitronaphthalenes (Pascal [20]).