Kinetic study of the reaction of chlorine atoms with chloromethane in the gas phase

Article abstract of DOI:10.1016/j.cplett.2009.04.086

The kinetics of the gas phase reactions of chlorine atoms with chloromethane and D-chloromethane CD₃Cl was studied experimentally. The relative rate method was applied using Cl + CH₃Br as the reference reaction. The rate constants fo

Full text of DOI:10.1016/j.cplett.2009.04.086

Chemical Physics Letters 476 (2009) 138–142
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Chemical Physics Letters
journal homepage: www.elsevier.com/locate/cplett
Kinetic study of the reaction of chlorine atoms with chloromethane in the gas phase
*
´
´
Dariusz Sarzynski, Agnieszka A. Gola, Andrzej Drys, Jerzy T. Jodkowski
Department of Physical Chemistry, Wroclaw Medical University, pl. Nankiera 1, 50-140 Wroclaw, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
The kinetics of the gas phase reactions of chlorine atoms with chloromethane and D-chloromethane
CD3Cl was studied experimentally. The relative rate method was applied using Cl + CH3Br as the reference
reaction. The rate constants for H-abstraction from CH3Cl (kH) and D-abstraction from CD3Cl (kD) were
measured in the temperature range of 298–527 K and at a total pressure of 100 Torr. The derived temper-
ature dependencies of the rate constants are given by kH = (1.7 0.1) ꢀ 10ꢁ11 ꢀ exp(ꢁ1040 10/T) and
kD = (1.3 0.2) ꢀ 10ꢁ11 ꢀ exp(ꢁ1470 10/T) cm3 moleculeꢁ1 sꢁ1. The kinetic isotope effect, described
by the ratio kH/kD, was (1.35 0.05) ꢀ exp(420 10/T).
Received 13 January 2009
In final form 28 April 2009
Available online 14 June 2009
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
kH [17,18] than that found experimentally [6–10,13,14]. Therefore,
a credible estimation of the temperature dependence of kH was
Chloromethane (CH3Cl) is the most abundant naturally pro-
duced chlorine-containing organic compound in the atmosphere
[1]. The annual global flux of CH3Cl into the atmosphere is esti-
mated to be at least 4 million t [1,2], with an atmospheric lifetime
of 17 months [1,3]. Chloromethane has a significant impact on
chlorine chemistry in the atmosphere and is involved in various
catalytic cycles responsible for the depletion of the stratospheric
ozone layer. Despite its importance, the understanding of the
atmospheric budget of CH3Cl is still unsatisfactory [4,5]. The recog-
nized sources of CH3Cl can only account for approximately 50% of
the emission required to balance the known sinks. The reaction of
CH3Cl with OH is the dominant loss pathway for atmospheric
CH3Cl, but in the marine boundary layer and polar regions, reaction
with Cl atoms can also become of some importance [4]. The reac-
tion of chloromethane with chlorine atoms
among the main aims of our kinetic investigations.
In this study we present measurements of the rate constant for
the hydrogen abstraction reaction from CH3Cl by Cl atoms using
the relative rate technique. The experiments were performed in
the temperature range of 298–527 K to examine the temperature
dependence of the rate constant kH and the values of the activation
energy reported in literature. The reaction of the entirely deuter-
ated chloromethane
CD3Cl þ Cl ! CD2Cl þ DCl
ð2Þ
was also studied in the same temperature range. The independent
measurements of the rate constant kD for reaction (2) enabled us
to estimate the kinetic isotope effect (KIE). Values of KIE can provide
useful information for interpreting the stable isotope composition
of the organic compounds in the atmosphere. Experimental infor-
mation on the kinetics of isotopomers of CH3Cl is limited to only
a single estimate of KIE at room temperature obtained by Gola
et al. [16]. The hydrogen abstraction from bromomethane by chlo-
rine atoms
CH3Cl þ Cl ! CH2Cl þ HCl
ð1Þ
has been the subject of several experimental [6–16] and theoretical
studies [17–20]. It is worth noting that the reported room temper-
ature values of the rate constant, kH, for reaction (1) estimated by
different experimental techniques are in satisfactory agreement.
The most recent IUPAC and NASA evaluations of the kinetic data
therefore recommend very similar values for kH of
(4.8 0.5) ꢀ 10ꢁ13 [21] and (4.9 0.5) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1
[22], respectively, at 298 K. The temperature dependencies of kH ex-
pressed in the Arrhenius form show some differences in the re-
ported values of both the A-factor and activation energy.
However, only the results of Clyne and Walker [8] differ markedly
from the other measurements at high-temperatures. Results of the-
oretical calculations predict a steeper temperature dependence of
CH3Br þ Cl ! CH2Br þ HCl
ð3Þ
was utilized as a reference reaction in our investigations. Reaction
(3) has been studied by the flash photolysis-resonance fluorescence
technique by Piety et al. [23] over a wide range of temperatures
using nitrogen as a buffer gas. The rate constant k3 for reaction
(3) and its temperature dependence are well known and have been
determined with sufficiently high accuracy.
2. Experimental
The experiments were conducted in a greaseless static system
in a cylindrical Pyrex reactor of ca. 250 cm3 (dead volume ꢂ2%)
placed in an aluminium heating block. Reactions of chlorine atoms
* Corresponding author. Fax: +48 71 7840230.
E-mail address: jurek@kchfiz.am.wroc.pl (J.T. Jodkowski).
0009-2614/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.cplett.2009.04.086

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D. Sarzynski et al. / Chemical Physics Letters 476 (2009) 138–142
where kA and kB are the rate constants for the competing reaction
channels, [AH]0 and [BH]0 the starting concentrations of AH and
BH, and [AH]t and [BH]t the concentrations of the reactants at a gi-
ven time t. Eq. (4) is valid only when both reactants, AH and BH, are
consumed only in the reaction with chlorine atoms. The plot of
ln([AH]0/[AH]t) vs. ln([BH]0/[BH]t) should therefore be linear, which
enables a determination of the rate constant ratio kA/kB as the slope
and, finally, kA if the absolute value of kB is known with sufficient
accuracy at the given temperature.
The results of these measurements were analyzed on the basis
of Eq. (4) with the reactant AH (CH3Cl or CD3Cl), the reference reac-
tant BH (CH3Br), and the rate constants kA (kH or kD) and kB = k3. All
experiments were conducted at a high concentration of molecular
with chloromethane and D-chloromethane were investigated with
bromomethane used as the reference at five temperatures over the
temperature range of 298–527 K. Temperature was maintained by
a power regulator connected to a temperature regulator equipped
with a Pt-100 resistance sensor placed inside the chamber of the
electrically heated block. A chrome–nickel thermocouple, used
for temperature measurements, was fixed at half length of the side
wall of the reactor. The temperature of the reactor was constant to
within 0.5° during the experiments. The reactants were introduced
into the reaction cell by expansion, starting from CH3Cl or CD3Cl
followed by CH3Br and the mixture Cl2/N2. At the end, N2 was
introduced to reach a total pressure of 100 Torr.
All experiments were conducted at a total pressure of about
100 Torr, while the partial pressure was varied from 9 to 10 Torr
for Cl2 and from 3 to 5 Torr for CH3Cl/CD3Cl and CH3Br. The Cl2
mixtures in N2 were prepared (at least 24 h prior to their first
use) from pure Cl2 (>99.5%) and N2 (>99.995%) and stored in 4L
blackened Pyrex bulbs. The reactants CH3Cl, CD3Cl, and CH3Br were
expanded under vacuum from the producers’ containers into light-
tight Pyrex bulbs for storage. Pressure measurements were carried
out with a 127A MKS Baratron capacity manometer equipped with
two gauges (0–100 and 0–1000 Torr).
A Xe arc lamp (Osram XBO 150 W/1 OFR) served as the light
source. The optical train consisted of a manually operated shutter,
a condensing lens, a variable-width slit, and a monochromator
with the Czerny-Turner optical system (dispersing element: a
1200 line/mm grating and aperture F/4, range: 200–900 nm, band
variability: 2–20 nm) of a Hitachi MPF-4 fluorescence spectropho-
tometer. The light from the monochromator was introduced into
the cylindrical reactor through its bottom window and, after pass-
ing through the reactor, reflected back by a mirror placed above the
upper window of the reactor. The reaction cell, feed lines, and the
optical assembly were housed in a light-tight enclosure to prevent
photolysis initiated by room or stray light. The absence of such
reactions was confirmed by repeated blank analysis. Chlorine
atoms were generated in their ground state (Cl(2P3/2) > 99%,
Cl(2P1/2) < 1% at 298 K) [24] by the photolysis of Cl2 at 420 nm or
by thermolysis at 527 K. The irradiation time (0.25–45 min) was
varied depending on the reaction temperature in order to obtain
appropriate conversion of the reactants.
Quantitative analysis of the products was performed by a gas
chromatograph (HP, Model 5890 Series II) equipped with a thermal
conductivity detector. All separations were done with a 25 m
long ꢀ 0.53 mm PoraPlot Q Chrompack capillary column using
temperature programming. Helium was used as the carrier gas
and a 2 ml thermostated stainless steel gas loop as the sampling
unit. Before and after every experiment, calibration of the reac-
tant’s peak area vs. its partial pressure in the reactor was con-
ducted by GC analysis. The reactants used in this study had the
following stated minimum purities CH3Br (>99.5%), CH3Cl
(>99.5%), and Cl2 (>99.5%) from Aldrich, CD3Cl (>99.5%) from Isotec
Inc., and N2 (99.999%) from BOC. All reactants were used directly
from the producers’ containers.
chlorine Cl2.
A large excess of Cl2 causes the reactions of
Cl2 + CH2Cl/CD2Cl/CH2Br producing chlorine atoms to be the fastest
secondary processes in the reaction system. Other radical pro-
cesses, such as radical–radical recombinations and reactions of
radicals with the reactants CH3Cl, CD3Cl, and CH3Br proceed con-
siderably more slowly. The reverse reactions CH2Cl/CD2Cl + HCl/
DCl (ꢁ1,ꢁ2) and CH2Br + HCl (ꢁ3), which reproduce the parent
compounds CH3Cl/CD3Cl and CH3Br, are very slow [21,22] and
hence are considered unimportant processes even at a higher de-
gree of conversion of the reactants. The influence of secondary rad-
ical reactions on the kinetics of the primary H-abstraction
reactions (1–3) is therefore negligible under the reaction condi-
tions applied in our investigation.
Preliminary tests showed that a ca. 10 min mixing time was suf-
ficient for the reactants in the cell to reach ambient temperature. In
order to test possible photolysis or thermal decomposition of the
organic reactants, mixtures of the organics were irradiated in the
absence of Cl2 at the highest temperature used for more than
60 min. No photolysis or thermal reaction of CH3Cl, CD3Cl, and
CH3Br was observed. Prior to each set of experiments at tempera-
tures above 298 K, tests for a dark reaction were performed. A mix-
ture of the organic species and molecular chlorine was allowed to
stand in the dark for at least 60 min. At temperatures of 448 K and
lower, the reaction of the organic species with molecular chlorine
was negligible in the absence of photolytic light. No products of the
thermal reaction were detected. At the highest temperature of this
study (527 K), thermolysis of Cl2 occurred. This allowed us to uti-
lize the thermolysis of Cl2 as an additional source of Cl atoms at
this temperature. Photolysis of only Cl2 in the reactor ensured that
CH3Cl or CD3Cl were not produced by the reaction of impurities on
the wall of the reactor.
The values of the rate constants for the studied reactions were
determined at five temperatures in the temperature range of 298
to 527 K at a nearly constant total pressure of 100 Torr. Fig. 1
shows sample kinetic data obtained from the experiments at
381 K plotted according to Eq. (4) for the reaction of Cl with CH3Cl
and CD3Cl measured with respect to CH3Br. The linearity of the
plots shown in Fig. 1 supports the assumption that the organic
reactants are consumed only in reaction with chlorine atoms. The
kinetic expression derived by Piety et al. [23] describing the tem-
perature dependence of the rate constant k3 for the reaction
CH3Br þ Cl ! CH2Br þ HCl as k3 = 3.32 ꢀ 10ꢁ12 ꢀ (T/298)1.42
ꢀ
exp(ꢁ605/T) cm3 moleculeꢁ1 sꢁ1 was utilized in our experiments.
The results of the measurements were analyzed using a weighted
least squares procedure which included uncertainties in the reac-
tant concentrations and allowed a zero-point offset. Values of the
ratios kH/k3 and kD/k3 as well as the absolute values of kH and kD
at five temperatures (298, 325, 381, 448, and 527 K) are gathered
in Table 1.
3. Results and discussion
The relative rate method was employed in these kinetic investi-
gations. This experimental approach is based on the competition
between two reactants reacting with the same reactive species.
The concentrations at any given time of two reactants, AH and
BH, reacting simultaneously with chlorine atoms are described
by the relation:
Fig. 2 shows the Arrhenius plots for the reactions studied. The
experimental points are only slightly scattered around the regres-
sion lines, which indicates the validity of the experimental meth-
½AHꢃ0 kA
¼
½BHꢃ0
½BHꢃt
ln
ꢄ ln
ð4Þ
½AHꢃt kB

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D. Sarzynski et al. / Chemical Physics Letters 476 (2009) 138–142
1.0
0.8
0.6
0.4
0.2
0.0
CH3Cl+Cl
CD3Cl+Cl
X=CH3Cl
X=CD3Cl
-11.5
-12.0
-12.5
-13.0
1.5
2.0
2.5
1000K/T
3.0
3.5
0.0
1.0
ln([CH3Br]0/[CH3Br]t)
2.0
Fig. 2. Arrhenius plot for the reactions of Cl atoms with CH3Cl (d) and CD3Cl (j) in
the temperature range of 298 to 527 K (error limits represent 2 ).
r
Fig. 1. Relative rate data obtained at 527 K and a pressure of 100 Torr for the
reactions of Cl with CH3Cl (d) and CD3Cl (j) using CH3Br as the reference
compound.
the reference reaction CH4 + Cl. Using the value for k(CH4 + Cl) of
1.0 ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 presently recommended by IUPAC
and NASA kinetic data evaluations [21,22] results in an increase
in the estimate of Beichert et al. [12] to 4.7 ꢀ 10ꢁ13 cm3 mole-
culeꢁ1 sꢁ1 at 298 K. Values for the rate constant kH were determined
by Orlando [13] relative to two reference reactions: CH4 + Cl and
CH3Br + Cl. The room temperature value for k(CH3Br + Cl) of
4.3 ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 of Gierczak et al. [25] used by Or-
lando [13] is very close to that of 4.4 ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1
of Piety et al. [23] utilized in our study. The ratios of kH/
k(CH4 + Cl) = 4.7 0.6 and kH/k(CH3Br + Cl) = 1.1 0.1 at 298 K de-
rived by Orlando [13] combined with the values of the rate constant
for reference reactions [21,22,25] yield a mean value for kH of
(4.7 0.6) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1. This value, similarly to that
of (4.8 0.4) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 obtained by Wallington
et al. [11], are a little lower than the (5.2 0.4) ꢀ 10ꢁ13 cm3 mole-
culeꢁ1 sꢁ1 found in this study. The values of (4.8 0.5) ꢀ 10ꢁ13
[21] and (4.9 0.5) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 [22] recommended
by the kinetic data evaluations at 298 K are also less than our esti-
mate. This is certainly caused by the favoring of the results of the
relative rate studies of Tschuikow-Roux et al. [10], Wallington
et al. [11], and Beichert et al. [12] in the IUPAC and NASA kinetic
analysis [21,22]. The results of our investigations predict a slightly
higher value of kH at room temperature. The insert of Fig. 3 shows
a comparison of the experimental results obtained near room tem-
perature. A large portion of the results is located above the bottom
odology used. The temperature dependence of the rate constant kH
can be expressed in the temperature range 298–527 K as:
kH ¼ ð1:7 ꢅ 0:1Þ ꢀ 10ꢁ11 ꢀ expðꢁ1040 ꢅ 10=TÞ
cm3 moleculeꢁ1 sꢁ1
ð5Þ
where the error limits include either the 2
r
error of the derived ra-
tio kH/k3 and the 2
reaction CH3Br + Cl reported by Piety et al. [23] (details in Table
1). The room temperature value of kH of
r error of the rate constant k3 for the reference
(5.2 0.4) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 derived from Eq. (5) is in line
with the absolute rate determinations of (5.4 0.2) ꢀ
10ꢁ13 cm3 moleculeꢁ1 sꢁ1 of Manning and Kurylo [9] and
(5.1 1.3) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 obtained by Pritchard et al.
[6] using the standard relative rate technique. A similar value of
(5.1 0.7) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 at 298 K can be derived from
the expression describing the temperature dependence of the rate
constant found by Tschuikow-Roux et al. [10]. Our kH value is also
in excellent agreement with the recent estimate of
(5.2 0.3) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 of Bryukov et al. [14]. Only
the result of (4.4 0.6) ꢀ 10ꢁ13 cm3 moleculeꢁ1 sꢁ1 at 298 K ob-
tained in the relative rate study of Beichert et al. [12] differs more
distinctly from our kH value. However, their finding was based on
a value of 9.4 ꢀ 10ꢁ14 cm3 moleculeꢁ1 sꢁ1 for the rate constant of
Table 1
The measured rate constant ratios kH/k3 and kD/k3, the absolute values of kH and kD, and the derived values of the kinetic isotope effect kH/kD.
1013 ꢀ kH
kD/k3
1014 ꢀ kD
kH/kD
a
b
a
b
a
T
(K)
kH/k3
(cm3 moleculeꢁ1 sꢁ1
)
(cm3 moleculeꢁ1 sꢁ1
)
298
325
381
448
527
1.189 0.026
1.183 0.038
1.141 0.024
1.053 0.016
0.999 0.022
5.2 0.4
6.9 0.6
11.0 0.9
16.2 1.0
23.7 1.8
0.220 0.012
0.226 0.024
0.271 0.006
0.310 0.008
0.343 0.012
9.7 1.1
5.4 0.3
5.2 0.5
4.2 0.2
3.4 0.2
2.9 0.2
13.2 2.1
26.1 2.1
47.7 3.4
81.3 7.3
a
With 2
r
error limits.
b
With errors derived as the sum of the 2
r
errors of kH(D)/k3 and of the reference rate constant k3.

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D. Sarzynski et al. / Chemical Physics Letters 476 (2009) 138–142
6
-12.2
-12.3
-12.4
-11.0
-11.5
-12.0
-12.5
-13.0
5
3.3 3.4
4
Pritchard et al. (1955)
Knox (1962)
Clyne & Walker (1973)
Manning & Kurylo (1977)
Wallington et al. (1990)
Beichert et al. (1995)
Orlando (1999)
Bryukov et al. (2002)
3
Wallington & Hurley (1992)
Gola et al. (2005)
this study
this study
1
2
3
4
5
2
1000K/T
300
400
T (K)
500
600
Fig. 3. Arrhenius plot for the CH3Cl + Cl reaction comparing the available results of
kinetic measurements. The solid line corresponds to the plot of Eq. (5). The insert
shows experimental results obtained in the temperature range of 295–308 K.
Fig. 4. Comparison of the derived values of the kinetic isotope effect kH/kD (d) with
those obtained by Wallington and Hurley [15] at 295 K (e) and Gola et al. [16] at
298 K (h). The error limits correspond to 2r.
limit of our estimate at 298 K. However, our kH is within the error
limits of the recommended IUPAC and NASA values [21,22].
The temperature dependence of the rate constant kH is deter-
mined by the value of the activation energy which, as calculated
from Eq. (5), is small (8.6 kJ molꢁ1). This implies a weak depen-
dence of kH on temperature. A comparison of the former measure-
ments of the temperature dependence of kH is shown in Fig. 3. The
results reported by Clyne and Walker [8] are characterized by a sig-
nificantly higher value of the activation energy and a strong tem-
perature dependence of kH. However, their high-temperature
results are rather overestimated because they distinctly exceed
the results of measurements of the other researchers. The temper-
ature dependence of kH derived in this study is in good agreement
with the results of previous experimental investigations [7–
10,13,14] and can be considered the best compromise for all exper-
imental points below 500 K. At the high-temperature range, i.e.
above 500 K, only the results of Bryukov et al. [14] are greater than
those obtained from Eq. (5). The temperature dependence of the
rate constant kH derived by Bryukov et al. [14] is steeper in this
temperature range and shows a non-Arrhenius behavior. Unfortu-
nately, there are no other credible measurements which can verify
the results of the high-temperature experiments of Bryukov et al.
[14].
by a factor of 5. However, the significance of the kinetic isotope ef-
fect declines with rising temperature. At 527 K the value of KIE is
slightly lower than 3. The temperature dependence of KIE, de-
scribed by the ratio kH/kD, can be expressed (error limits represent
2r) in the form
kH=kD ¼ ð1:35 ꢅ 0:05Þ ꢀ expð420 ꢅ 10=TÞ
ð7Þ
The temperature dependence of KIE was determined for the first
time in this study. A single measurement of KIE was performed
by Gola et al. [16] at room temperature. Their value of kH/
kD = 4.91 0.07 is only 10% lower than our estimate of 5.4 0.3.
Wallington
and
Hurley
[15]
obtained
a
value
of
(8.9 0.3) ꢀ 10ꢁ14 cm3 moleculeꢁ1 sꢁ1 at 295 K for the rate con-
stant of the reaction CD3Cl + Cl. Using the kH value of Wallington
et al. [11] leads to a KIE of 5.4 0.4 at 295 K, which is in excellent
agreement with our value of 5.4 0.3 at 298 K (see Fig. 4). This
agreement supports the reliability of the values for KIE derived in
this study. A detailed interpretation of the KIE is difficult without
the results of theoretical investigations. Replacing the hydrogen
atom by deuterium leads to a change in the molecular properties
of the reactants and products. An increase in molecular mass
changes the rotational constants only slightly. More distinct
changes occur in vibrational frequencies, especially those related
to C–H and C–D stretch modes. This decreases the zero-point of
the vibrational energy of the D-substituted compound compared
with that of the unsubstituted one. D-abstraction is thus related
to the higher energy barrier than the H-abstraction process. The
changes in the vibrational frequencies of the reactants, the energy
barrier, and the tunneling contribution related to deuterium substi-
tution have a dominant share in the KIE at low temperatures. At
higher temperatures the value of KIE strongly decreases to unity.
The available kinetic data on KIE related to reactions of chlorine
with chloromethanes are very limited. The value derived in this
study of a primary KIE of 5.4 0.3 at 298 K is slightly higher than
that of 4.7 0.6 we obtained for the reaction system CHCl3/
The Arrhenius plot for the reaction CD3Cl + Cl is also shown on
Fig. 2. The experimental measurements of kH and kD were done at
the same temperatures, which also enables us to calculate the val-
ues of KIE directly from the results of the measurements. Kinetic
analysis of the experimental results obtained in the temperature
range 298–527 K leads to the following temperature dependence
of kD
kD ¼ ð1:3 ꢅ 0:2Þ ꢀ 10ꢁ11 ꢀ expðꢁ1470 ꢅ 10=TÞ
cm3 moleculeꢁ1 sꢁ1
ð6Þ
with a 2r error limit. The abstraction of deuterium from CD3Cl pro-
ceeds distinctly more slowly and shows a slightly higher depen-
dence on temperature than hydrogen abstraction from CH3Cl. The
room temperature value of the rate constant kD is lower than kH

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D. Sarzynski et al. / Chemical Physics Letters 476 (2009) 138–142
142
CDCl3 + Cl [26], but considerably lower than the 17.5 2.5 esti-
mated for CH4/CD4 + Cl [15,21,22,27]. The value of the KIE of the
reactions of chloromethanes with chlorine at room temperature
decrease when the number of chlorine atoms in the reactant mol-
ecule rises. Explanation of the derived values of KIE needs theoret-
ical calculations, which enable insight into the molecular structure
and the properties of the reactants during reaction. Our experi-
mental study provides information on the temperature depen-
dence of KIE for the CH3Cl/CD3Cl + Cl reaction system useful for
the verification of theoretical results.
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Acknowledgment
´
´
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This research was supported by Wroclaw Medical University
under Grant No. ST-263.
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