1070-4272/01/7408-1403 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 8, 2001, pp. 1403!1404. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 8, 2001,
Original Russian Text Copyright C 2001 by Shiryaev.
Utilization of N,N-Dichloro-p-chlorobenzenesulfonamide
V. K. Shiryaev
Karpov Institute of Physical Chemistry, State Scientific Center of the Russian Federation, Obninsk Branch,
Obninsk, Kaluga oblast, Russia
Received November 23, 2000; in final form, March 2001
Abstract-The kinetic parameters of the reaction of N,N-dichloro-p-chlorobenzenesulfonamide with hy-
drochloric acid were determined, and the main parameters of the commercial process were estimated.
In the context of elimination of chemical weapons,
a problem arises of utilization of agents used for ren-
dering war gases harmless. One of such agents is N,N-
dichloro-p-chlorobenzenesulfonamide (I, Russian com-
mercial name DTKh-2). Owing to the high reactivity
of the N3Cl bond, a promising way of its utilization
is replacement of active chlorine atoms by hydrogen
atoms with the formation of p-chlorobenzenesulfon-
amide (II), which can be used for synthesis of sulfamide
drugs, dyes, and effective means for plant protection
. For this process, a reagent should be chosen
that would be cheap and readily available and would
give the minimum amount of minor or difficult-to-trap
products. One of such agents is hydrochloric acid.
The goals of this study were to determine the ki-
netic characteristics of the reaction of I with HCl
and estimate the main parameters of the commercial
The reaction was performed in a glass vessel
equipped with a jacket and a thermometer. The vessel
was charged with 10 g of I, after which 50 ml of 2 N
HCl (equivalent excess 0.34 mmol) was added, and
the solution was heated to a required temperature
(77 or 92oC) under stirring with a magnetic stirrer.
The experimental conditions should be chosen so
as to ensure the most active reaction (i.e., to eliminate
possible diffusion hindrance); the optimal temperature
and concentration should be determined. Preliminary
experiments showed that at a stirrer rotation rate of no
less than 700 rpm the conversion is independent of the
stirring rate. The suitable reaction temperature is re-
stricted by the thermal stability of the melt of I under
water (up to 95oC ); 2 N HCl is convenient as it
is sufficiently concentrated, but does not fume yet.
Also, it is known that in more concentrated HCl the
solubility of chlorine increases, which complicates
At appropriate intervals, we sampled the reaction
mixture to determine the HCl concentration by alkali
titration. Samples of the solid phase were analyzed for
available chlorine by iodometric titration  after dry-
ing to constant weight and dissolution in a 1 : 1 mix-
ture of 1,2-dichloroethane and glacial acetic acid.
When calculating the conversion, we took into account
the variation of the molecular weight of the solid
phase in the course of the reaction.
Amide II was identified by the melting point (143+
1oC; according to , 1433144oC) and IR spectrum.
The IR spectra of I and II in mineral oil were meas-
ured on a Specord-80 spectrophotometer. The spec-
trum of II shows two bands (3332 and 3240 cm
belonging to antisymmetric and symmetric stretching
vibrations of the NH
group. Such bands are absent
in the spectrum of I.
Figure 1 shows as a function of time t the con-
version h with respect to available chlorine (1, 3) and
HCl (2, 4), at 92 and 77oC; the conversion with re-
spect to HCl was calculated by the formula
C ), (1)
C, and C
are the current, excess, and initial
concentrations of HCl, respectively.
It is seen from the figure that the conversion is
complete only with respect to dichloramide I (with
respect to HCl, h < 1). This means that reversible
reaction  is shifted to the right (owing to removal