urbaf2

NITRO DERIVATIVES OF HIGHER BENZENE HOMOLOGUES 411

Nitration of MNX to DNX. For 100 parts of MNX 140 parts of a nitrating

mixture of the composition:

HNO 3 11%

H 2 SO 4 74%

H 2 O 15%

are used.
The mixture is prepared from the spent acid from trinitration by fortifying
it with concentrated acids. During the mixing of mononitroxylene with the acid
a temperature of 35-50°C is maintained. Then it is raised to 85°C and the reaction
mixture is allowed to remain at this temperature for one hour. From 100 parts
of mononitroxylene 137 parts of dinitroxylene are obtained, thus the yield is 95%

of the theoretical.

Nitration of dinitroxylene to trinitroxylene. For 100 parts of dinitroxylene

230-300 parts of a nitrating mixture of the following composition are applied:

after Kravchiiskii [3] after Pascal [20]

HNO 3 10-15% HNO 3 15-21%

H 2 SO 4 76-81% H 2 SO 4 70-75%

H 2 O 9-10% H 2 O 9-10%

The nitrating mixture is gradually run into dinitroxylene in the nitrator, at

first at 60-70°C, and by the end of the procedure at 80-85°C. Then all is carefully

heated to 95-100°C or 110-120°C.

When the reaction has been completed the nitrator contents are cooled and

the product obtained is separated from the spent acid.

As Pascal [20] reported, from 100 parts of dinitroxylene 105 parts of trinitro-

xylene were obtained, the yield being 85% of the theoretical. In Table 92 the condi-

tions and yields (calculated on toluene or xylene) obtained in the nitration of toluene

and xylene are tabulated for comparison.

TABLE 92

COMPARISON OF NITRATION CONDITIONS FOR TOLUENE AND XYLENE (PASCAL [20])

Product obtained

MNT MNX DNT DNX TNT TNX

Compositionof HNO 3

the nitrating H 2 SO 4

mixture H 2 O

Maximum temperature, °C

28 28 32 11 19 15-21

56 56 61 74 80 70-75

16 16 7 15 0 9-10

60 35 90 85 120 95-120

143 130-135 188 178-185 190 170

Yield 149 144 198 187 246 229

obtained

calculated

Yield ratioXylene

Toluene 0.930 0.962 0.894

Mononitration of xylene (I. G. Leverkasen method). To the nitrator containing

I400 1. of spent acid from the previous nitration, 50 1. of xylene are added (thus the