108 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVESA very interesting result was obtained with benzene. At room temperature
nitryl chloride dissolved in benzene without reacting. When warmed the nitryl
chloride evaporated off unchanged. When benzene and nitryl chloride were
heated under pressure, 1-chloro-2-nitrocyclohexadiene was formed and decomposed,
producing nitrobenzene.
On the other hand Price and Sears [107] studied the reactions of nitryl chloride
with various aromatic compounds in the presence of aluminium chloride, and
found that phenol, anisole and naphthalene tended to undergo oxidative degrada-
tion. In the case of naphthalene they obtained a 31% yield of α− nitronaphthalene,
whereas with anisole and phenol they were able to isolate only traces of nitro com-
pounds without any evidence of chlorination.
Goddard and co-workers [108-111] found that nitryl chloride in various sol-
vents at room temperature and below (-10°C) chlorinates, rather than nitrates,
toluene, m- and p- xylene, and mesitylene, though not benzene.
Thus, p- xylene yielded 2,5-dichloro-p-xylene. The principal reaction with anisole
was also chlorination and with phenol nitration when nitration temperature was
low (-80°C) both o- and p- nitrophenols were formed. At room temperature chlori-
nation also occurred yielding 2,4-dichloro-6-nitrophenol and 3,6-dichloro-2-nitro-
phenol.
Steinkopf and Kühnel [106] also examined the action of nitryl chloride on
ethylene and reported that only 1,2-dichloroethane was formed. Petri [112] however
reported the formation of 1-chloro-2-nitroethane (with 45% yield) and 2-chloro-
ethyl nitrate (35% yield). Ville and DuPont [113] confirmed the formation of
1-chloro-2-nitroethane (50% yield) and Goddard [111] confirmed the results of
Petri. Price and Sears [107] obtained 2-chloro-1-nitropropane from propane.
Thus it should be accepted that the main reaction of ethylene (and probably
olefins in general) with NO 2 Cl is:(42)According to Goddard, styrene reacted with nitryl chloride to yield 1,2-di-
chloro-1-phenylethane in 70-80% yield. Another product 1-chloro-2-nitro-l-phenyl-
ethane was thought to be present, but could not be isolated. On distillation it de-
composed, evolving HCl, and o- nitrostyrene was obtained.
Finally T. Urbanski and Siemaszko [114] used nitryl chloride in the gas phase
to O-nitrate cellulose. They obtained a stable product containing 12.2% N.
On the basis of the formation of chloroalkyl nitrites (e.g. 2-chloroethyl nitrite
from ethylene) Goddard drew the conclusion that nitryl chloride could be sub-jected to heterolysis :
ClNO 2 -> Cl+ + NO 2 - (43)
This dissociation would also be confirmed by the chlorinating action of the sub-
stance.