Utilization of N,N-dichloro-p-chlorobenzenesulfonamide

Article abstract of DOI:10.1023/A:1013747522160

The kinetic parameters of the reaction of N,N-dichloro-p-chlorobenzenesulfonamide with hydrochloric acid were determined, and the main parameters of the commercial process were estimated.

Full text of DOI:10.1023/A:1013747522160

Russian Journal of Applied Chemistry, Vol. 74, No. 8, 2001, pp. 1403 1404. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 8, 2001,
pp. 1365 1366.
Original Russian Text Copyright
2001 by Shiryaev.
BRIEF
COMMUNICATIONS
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 N Cl 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
water (up to 95 C [4]); 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
its separation.
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 [5] 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.
[1 3]. 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
process.
Amide II was identified by the melting point (143
C; according to [4], 143 144 C) and IR spectrum.
The IR spectra of I and II in mineral oil were meas-
1
ured on a Specord-80 spectrophotometer. The spec-
1
trum of II shows two bands (3332 and 3240 cm )
EXPERIMENTAL
belonging to antisymmetric and symmetric stretching
vibrations of the NH group. Such bands are absent
in the spectrum of I.
2
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
Figure 1 shows as a function of time the con-
version with respect to available chlorine (1, 3) and
HCl (2, 4), at 92 and 77 C; the conversion with re-
spect to HCl was calculated by the formula
(77 or 92 C) under stirring with a magnetic stirrer.
The experimental conditions should be chosen so
= 1
(C
C )/(C0
C ),
(1)
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
where C, C, and C are the current, excess, and initial
concentrations of HCl, respectively.
0
It is seen from the figure that the conversion is
complete only with respect to dichloramide I (with
respect to HCl,
< 1). This means that reversible
reaction [4] is shifted to the right (owing to removal
1
070-4272/01/7408-1403 $25.00 2001 MAIK Nauka/Interperiodica

1404
SHIRYAEV
The experimentally estimated activation energy
confirms the assumed kinetic control of the process.
Formulas (3) and (4) allow approximate estimation
of the most important parameter of the commercial
process, specific output V of a reactor of unit volume.
If the reaction is performed at 92 C to 98% conver-
sion, then, according to formulas (3) and (4), the res-
3
1
idence time will be 5 h; hence, V = 40 kg m h ,
i.e., the specific output is moderate.
A significant factor in this process is stirring.
Calculation of the power of the electric stirrer accord-
3
ing to [6] gave a value of 0.65 kW m . The heat
3
consumption for heating of the reaction volume (1 m )
is 0.1 Gcal. It is seen that the power consumption is
low. Note also that the released gaseous chlorine can
be readily absorbed in a standard alkaline absorber [7]
to form a valuable product, hypochlorite.
Fig. 1. (a) Conversion
chlorine and (2, 4) HCl vs. time ; (b) linearization of
curves 1 and 3 in the coordinates ln(1
ture, C: (1, 2) 92 and (3, 4) 77.
with respect to (1, 3) available
) . Tempera-
Thus, the proposed procedure for utilization of I
is attractive owing to the low power consumption and
low environmental impact.
of chlorine) and that HCl is not only consumed, but
also formed (most probably, by reaction of chlorine
with water):
ACKNOWLEDGMENTS
p-ClC H SO NCl + 2HCl p-ClC H SO NH + 2Cl . (2)
6
4
2
2
6
4
2
2
2
The author is grateful to V.V. Shapovalov and
A.Yu. Ivanov for assistance in the experiments.
Therefore, the kinetic parameters were calculated
only from dependences 1 and 3 linearized in the coor-
1
dinates ln(1
)
(Fig. 1b). From the slope of
REFERENCES
the straight lines we determined the rate constants of
removal of available chlorine k, and from their temper-
ature dependence we estimated the activation energy
1
. Grigorovskii, A.M. and Dykhanov, N.N., Zh. Prikl.
Khim., 1957, vol. 30, no. 8, pp. 1215 1230.
1
of the process to be 89.1 kJ mol .
2. Stepanov, B.I., Vvedenie v khimiyu i tekhnologiyu or-
ganicheskikh krasitelei (Introduction to Chemistry and
Technology of Organic Dyes), Moscow: Khimiya,
Then, in the formula for calculating the conversion
of available chlorine
1
984.
. Arbuzov, B.A., Izv. Akad. Nauk SSSR, Ser. Khim.,
990, no. 9, p 2151.
3
=
1
exp( k )
(3)
1
1
4. Promyshlennye khlororganicheskie produkty (Com-
mercial Organochlorine Products), Oshin, L.A., Ed.,
Moscow: Khimiya, 1978.
the rate constant k (h ) is
1
2
k = 3.6 10 exp( 89100/RT).
(4)
5
. Charlot, G., Les methods de la chimie analytique.
Analyse quantitative minerale, Paris: Masson, 1961,
1
1
where R = 8.314 J mol K .
4
th ed.
1
6. Strenk F., Mieszanie
i
mieszalniki, Warszawa:
,
Linearization of dependences 1 and 3 in the coordinates of
a first-order reaction equation is probably due to the mutual
compensation of two opposite processes: acceleration owing
to additional formation of HCl and deceleration owing to
the reaction reversibility. Therefore, the constants determined
in this work should be regarded as apparent.
Wydawnictwa Naukowo-Techniczne, 1971.
7. Planovskii, A.N. and Gurevich, D.A., Apparatura pro-
myshlennosti organicheskikh poluproduktov i krasitelei
(Apparatus for Production of Organic Intermediates
and Dyes), Moscow: Goskhimizdat, 1961.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 8 2001