NITRATION AGENTS AND METHODS MORE RARELY USED. 95nitroethane, l- and 2-nitropropane). Nitrohexanes (mainly 2- and 3-nitrohexanes
with a small proportion of 1-nitrohexane) formed 50-60% by weight. This result
would confirm the view expressed by Hass [33] and Asinger [65] on the statistical
distribution of NO 2 groups in the course of nitration of long chain paraffins. A large
proportion (ca. 10%) of aldehydes mainly formaldehyde and acetaldehyde and
fatty acids was also found among the volatile products.
A non-volatile oily fraction which did not distil under 10 mm Hg was also
formed with a yield of 10-22% by weight. This is a mixture difficult to identify,
composed of various compounds of a relatively high content of nitrogen suggestingthe presence of dinitroparaffins.
The authors found that dinitro compounds are readily decomposed at high
temperature. This would probably proceed through nitro-olefin formation accord-
ing to the scheme:Nitrolefin- would polymerize or be hydrolysed to yield an aldehyde and lower
nitroparaffin.
When lower reaction temperature (e.g. 220-230°) was used, the total yield
of nitro compounds was lower: ca. 20%, but the proportion of primary nitro-
hexane was higher. Also the yield of the non-volatile fraction with a higher nitro-
gen content was higher (ca. 30%).
In 1949, Titov [34] obtained a larger proportion of secondary nitro compounds
along with a smaller quantity of a primary nitro compound when nitrating n-pen-
tane at 260-270°C and at a molar ratio N 2 O 4 :n-C 5 H 12 = 1:3.
In the nitration of a hydrocarbon having a >CH group, first of all this group
was nitrated to form a tertiary nitro compound. Thus, for example, according
to T. Urbanski and Wolnicki [66], isobutane gave tertiary nitroisobutane.A quantity of the dinitro compound (primary-tertiary) was also obtained:
The same products of nitration of isobutane have been reported by Levy [66a].
According to Bachman, Hass and Addison [32] the addition of halogens (chlo-
rine, bromine) to the reacting system hydrocarbon-nitrogen dioxide increases the
yield of the nitro compounds.