The solvent effects in the reactions of carboxylic acids with oxiranes. 1. Kinetics of the reaction of acetic acid with epichlorohydrin in butan-1-ol

Article abstract of DOI:10.1002/(SICI)1097-4601(2000)32:6<378::AID-KIN4>3.0.CO;2-3

Kinetics of the reaction of acetic acid with epichlorohydrin in the presence of chromium(III) acetate in butan-1-ol solution have been studied. The partial reaction orders with respect to reagents were found. The reactions were of first-order with respect to both epichlorohydrin and catalyst and zeroth order with respect to acetic acid. A kinetic model for the overall process has been proposed. The reaction constants have been calculated along with the activation parameters. The effect of dilution on the rate of addition is discussed. In the equimolar mixture of acetic acid and epichlorohydrin the apparent rate constant of the addition k₁ initially decreases to increase again at the concentration of butan-1-ol exceeding 3 M.

Full text of DOI:10.1002/(SICI)1097-4601(2000)32:6<378::AID-KIN4>3.0.CO;2-3

The Solvent Effects in the
Reactions of Carboxylic
Acids with Oxiranes.
1. Kinetics of the
Reaction of Acetic Acid
with Epichlorohydrin
in Butan-1-ol
WIKTOR BUKOWSKI
Faculty of Chemistry, Rzeszo´w University of Technology, 35-959 Rzeszo´w, Poland
Received 16 February 1999; accepted 9 February 2000
ABSTRACT: Kinetics of the reaction of acetic acid with epichlorohydrin in the presence of
chromium(III) acetate in butan-1-ol solution have been studied. The partial reaction orders
with respect to reagents were found. The reactions were of first-order with respect to both
epichlorohydrin and catalyst and zeroth order with respect to acetic acid. A kinetic model for
the overall process has been proposed. The reaction constants have been calculated along
with the activation parameters. The effect of dilution on the rate of addition is discussed. In
the equimolar mixture of acetic acid and epichlorohydrin the apparent rate constant of the
addition k1 initially decreases to increase again at the concentration of butan-1-ol exceeding
3 M. ᭧ 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 378–387, 2000
INTRODUCTION
tionship between solvent polarity and the rate of ad-
dition of carboxylic acids to oxiranes. While studying
the reaction of chloroacetic acid with ethylene oxide
in several organic solvents, they observed an increase
of the rate constant with increasing solvent polarity for
the reaction carried out both without catalyst or with
a catalytic amount of potassium hydroxide added. The
rate of the catalysed reaction increased somewhat
more than that of the uncatalysed one. The same au-
thors pointed at the negative effect of water on the rate
of reaction between acetic acid and ethylene oxide in
the presence sodium acetate.
The course of reaction of carboxylic acids with oxi-
ranes significantly depends on the properties of solvent
used [1–9]. The solvent may affect both the rate and
mechanism of reaction. The solvent effect is also dif-
ferent for different reagents and products and depends
on its polarity and donor-acceptor properties. Le-
biedev et al. [1] were the first to report on the rela-
Correspondence to: W. Bukowski (wbuk@prz.rzeszow.pl)
᭧ 2000 John Wiley & Sons, Inc.

THE SOLVENT EFFECTS IN THE REACTION OF CARBOXYLIC ACIDS WITH OXIRANES
379
An attempt to express this effect quantitatively was
EXPERIMENTAL
Materials
presented by Tanaka and Takeuchi [2], who used di-
electric constant as the measure of solvent polarity. In
the double-logarithmic plot, they obtained linear re-
lationships between the rate constant k and the solvent
dielectric constant for the reaction of phenylglycidyl
ether with benzoic acid in the presence of pyridine, all
dissolved in an aromatic solvent (toluene, chloroben-
zene, o-dichlorobenzene, nitrobenzene, o-nitrotolu-
ene, xylenes, and mixtures of the above).
The effect of electron-donor properties of solvents
in the reaction in question was studied by Klebanov
[3]. He obtained a linear relationship between log k
and donor and acceptor numbers of solvents in the
reaction of benzoic acid with selected oxiranes in ni-
trobenzene, dimethylacetamide, and hexamethylphos-
phoamide. The correlations of this type as well as
those obtained by Tanaka and Takeuchi [2] are valid
only for a limited number of solvents. A more exten-
sive study on this problem is under way [4].
Much more complicated relationships between the
rate constants and solvent concentrations were de-
scribed by Dumitriu and Oprea [5]. They have found
that for the reaction between acrylic acid and epichlo-
rohydrin in N,N-dimethylformamide (DMF), the rate
constants k1 and k2 characteristic for the two autocat-
alytic reactions (catalyzed by the substrate and prod-
uct, respectively) initially increased with DMF con-
centration and then rapidly decreased to rise again at
the high solvent concentration.
Acetic acid (CH3COOH, AA) (glacial, 99.99%) and
epichlorohydrin (C3H5ClO, ECH) were purchased
from Aldrich and were purified by using standard
methods [13]. Butan-1-ol (C4H10O, BuOH) (99.5%)
was purchased from Chempur. Chromium(III) acetate
((CH3COO)3Cr, cat) (grade p.a.) was purchased from
Sverdlovskij Khimicheskij Zavod. Solvent and cata-
lyst were used without further purification. Acetone
(CH3COCH3) (99% and 99.9% GC grade), chloroform
(CH3Cl) (98.5%), acetic anhydride (C4H6O3) (99%),
sodium hydroxide (NaOH) (0.1 M standard solution),
and bromthymol blue (C27H28Br2O5S) (indicator) were
purchased from POCH. Glycidyl acetate was pre-
pared following the procedure of a previous paper
[14]. Perchloric acid (HClO4) (60 wt%), crystal vio-
let (indicator), and 1,3-dichloro-2-hydroxypropane
(C4H6Cl2O) (98%) were purchased from Merck. Tet-
raethylammonium bromide ((C2H5)4NBr) was a prod-
uct from Fluka.
Instrumentation
A 5890 Hewlett Packard series II gas chromatograph
with Flame Ionization Detector, FID, and a HP 3394
integrator were used to analyze reaction mixtures. The
separation column used was a polar capillary column
(FFAP, 10 m ϫ 0.53 mm i.d., Hewlett Packard). The
optimum column separation was obtained by using an
initial temperature of 50ЊC and heating rate 30ЊC
minϪ1 up to 130ЊC. In this temperature the column was
kept for 6 min, and then the temperature was raised to
220ЊC. This final temperature level was maintained for
6 min in order to elute all components out of the col-
umn. Helium was used as the carried gas and the spit-
ting ratio was set to 1:10. The operation temperature
of the detector and injector were set to 220ЊC.
The temperature of the reaction was controlled
using a thermal equilibrium water bath HAAKE C10
(Ϯ 0.1ЊC).
Other reported observations [3,10] suggest a sol-
vent may influence the mechanism of reactions
between carboxylic acids and oxiranes. N,N-Dime-
thylacetamide,
N,N,NЈ,NЈ,NЉ,NЉ-hexamethylphos-
phoamide, N,N-dimethylformamide, and dimethylsul-
phoxide may serve as examples. The s-shaped kinetic
curves observed for these solvents are not just the re-
sult of the autocatalytic effect of addition products as
claimed previously [5,11,12], but reflect more com-
plicated reaction mechanisms. It has been shown
[3,10] that the reason might be a catalytic effect of the
side products formed in the reaction of epoxy groups
with the solvent. The ion pairs of the onium type thus
formed and containing acetic anions are effective ad-
dition catalysts.
The complexity of these reactions and the lack of
general theories describing these processes leave open
questions to explore. This article is the first of the se-
ries dealing with the effect of the environment on the
kinetics and selectivity of the addition of carboxylic
acids to oxiranes carried in the presence of chro-
mium(III) compounds. The results obtained for the re-
action of acetic acid with epichlorohydrin in the so-
lution in a selected protic solvent—butan-1-ol.
General Procedure for the Kinetics
Measurements
The kinetics of addition was studied in the purpose
designed glass reactors (50 cm3) equipped with a tem-
perature control system. The equimolar ratio of acetic
acid to epichlorohydrin was used or the concentration
of one of the reagents was changed while that of the
other was kept constant. The total mass for each re-
action mixture was 30 g. The concentration of chro-

380
BUKOWSKI
mium(III) acetate was in the range 2.5–17.5.10Ϫ3 M.
The temperature was 60, 70, 80, or 90ЊC. Butan-1-ol
concentration was adjusted to obtain round molar ra-
tios of reagents (1 : 1, 2 : 2, etc). The experimental data
concerning temperature and catalyst concentration are
summarized in Table I. Other experimental data are
moved to Tables IV and V.
reaction of excess BuOH with epichlorohydrin in the
presence of chromium(III) acetate).
The external standard method was used to calculate
concentrations of components. A 0.015 g sample of
reaction mixture was dissolved in 5 ml of acetone.
Then, 0.1 ␮l of the solution was injected into the gas
chromatograph for analysis.
The concentration of unreacted acid and epichlo-
rohydrin were determined by dissolving 0.1–1g sam-
ples withdrawn from reaction mixtures in 10 cm3 ac-
etone. They were titrated with 0.1 M NaOH aqueous
solution in the presence of bromthymol blue us indi-
cator. The concentration of epichlorohydrin was de-
termined by dissolving similar samples in 10 ml of
chloroform. 10 cm3 of 25 wt% tetraethylammonium
bromide solution in glacial acetic acid was then added
and the solution titrated with 0.1 M HClO4 solution in
glacial acetic acid in the presence of crystal violet as
indicator [15].
RESULTS AND DISCUSSION
In our previous papers, the reactions of some carbox-
ylic acids with epichlorohydrin [16–18] or 1,2-epoxy-
3-phenoxypropane ether [19] carried out in the pres-
ence of chromium(III) acetate homogeneous catalyst
were described. The reactions were carried out without
any solvent. The addition was found to be a relatively
highly selective and regioselective reaction. Both se-
lectivity and regioselectivity were much better than for
the same reactions carried out in the presence basic
catalysts, such as alkali metal acetates [20].
GLC Analysis
The rate of addition was well described by an equa-
tion of the first-order with respect to both chro-
mium(III) acetate and epoxy compound and of the zer-
oth order with respect to acetic acid concentration. The
zeroth reaction order with respect to acetic acid fol-
lows from the coordination mechanism of the addition
carried out in the presence of chromium(III) acetate.
The rate-limiting step is the reaction of the chro-
mium(III)–acetic acid complex with epichlorohydrin.
Sorokin et al. [21] observed the same reaction order
with respect to acetic acid for the reaction of the acid
The final reaction mixtures were analyzed by GLC.
Byproducts were identified by comparing their reten-
tion times with those of known species: commercial
glycidyl acetate, commercial 1,2-dichloro-2-hydroxy-
propane, isomeric products of addition of acetic acid
to epichlorohydrin compounds prepared and isolated
in separate experiments [16], glycerin diacetate (pre-
pared in the reaction of acetic acid with glycidyl ace-
tate in the presence of chromium(III) acetate), and
butyl-3-chloro-2-hydroxypropyl ether (prepared in the
Table I The Experimental Conditions Used in the Kinetic Investigations of the System Acetic Acid-Epichlorohydrin-
Chromium(III) Acetate-Butan-1-ol
Temperature, K
[AA]0 (M)
[ECH]0 (M)
[BuOH]0 (M)
[cat] (M)
333.2
333.2
333.2
333.2
343.2
343.2
343.2
343.2
353.2
353.2
353.2
353.2
363.2
363.2
363.2
363.2
1.002
0.998
1.001
1.003
0.999
0.994
1.004
1.046
0.997
0.997
0.997
1.000
0.999
1.001
1.000
1.000
0.998
0.999
1.002
1.002
1.011
0.996
1.002
0.993
1.000
1.000
0.999
1.000
1.000
1.001
0.999
1.002
8.968
8.962
8.948
8.939
8.801
8.807
8.800
8.761
8.624
8.616
8.609
8.637
8.569
8.575
8.563
8.551
0.010
0.013
0.015
0.018
0.010
0.015
0.013
0.018
0.010
0.013
0.015
0.005
0.008
0.005
0.010
0.013

THE SOLVENT EFFECTS IN THE REACTION OF CARBOXYLIC ACIDS WITH OXIRANES
381
with oxiranes in the presence of ternary amines. How-
ever, they explained this observation in terms of for-
mation of a cyclic intermediate state.
The subsequent-parallel reaction between a-ABH and
ECH is less likely since the concentration of the ab-
normal product is substantially smaller than that of n-
ABH. No traces, however, of AA-butan-1-ol ester
have been detected in the reaction products.
Furthermore, the following side reactions are also
possible:
Usually one or two molecules of acetic acid take
part in the addition to oxiranes. They act as a nucle-
ophilic reagent and/or as a component activating oxi-
rane molecule by forming hydrogen bond. Hence, the
reaction order with respect to acid in the addition to
oxiranes, carried out with acidic or basic catalysts, is
1 or 2 [22]. In some cases, variable orders were en-
countered in dependence of stoichiometry [23].
While trying to unravel the role of the homoge-
neous chromium catalyst, we extended our study to
the systems containing solvents, both protic and
aprotic. The system: acetic acid–epichlorohydrin–
chromium(III) acetate–butan-1-ol was evaluated with
respect to reagent concentrations, reaction order, the
effect of temperature, and degree of dilution.
CH3COO
ϩ
Cl
OH
Cl
O
OH
CH3COO
(4)
Cl
Cl
O
ϩ
O
CH3COOH ϩ CH3COO
Interpretation of the Primary Kinetic
Curves
CH3COO
OOCCH3
OH
OH
ϩ
In the reaction system consisting of acetic acid
(AA), epichlorohydrin (ECH), butan-1-ol, and chro-
mium(III) acetate, the main reaction leads to two iso-
meric esters:
(5)
CH3COO
OOCCH3
RCOOH ϩ
Cl
Some traces of 1,3-dichloro-2-hydroxypropane and
glycerin diacetate were indeed detected among reac-
tion products.
O
RCOO
Cl ϩ RCOO
In a series of complementary experiments, the
possibilities of other reactions in the system were
excluded by GLC analysis of individual systems:
(mixture of 3-chloro-2-hydroxypropyl acetate and
1-(chloromethyl)-2-hydroksyethyl acetate) ϩ epichlo-
rohydrin, glycidyl acetate ϩ acetic acid, butan-1-ol ϩ
epichlorohydrin and butan-1-ol ϩ acetic acid all in the
presence of catalytic amount of chromium(III) acetate.
The systems were kept in the typical reaction condi-
tions.
Cl
OH
(1)
OH
n-ABH
a-ABH
One cannot exclude the reactions of epichlorohydrin
with hydroxy groups of the solvent and with those of
the products, mainly of n-ABH:
C4H9OH ϩ
Cl
By GLC analysis we have found that epichloro-
hydrin, beside the main reaction (1), was consumed by
reactions (2–4). Acetic acid, on the other hand, took
part in the side reaction (5) only to a negligible extent.
Nevertheless, the excess in the rate of epichlorohydrin
consumption over that of acetic acid could not be jus-
tified by the amount of side products identified. Some
amount of epichlorohydrin was probably consumed in
homopolymerization of the epoxy ring. An indirect ev-
idence for this conclusion is that even in the system
where ABH or butan-1-ol is present in a large excess,
the chromatographically determined amount of prod-
ucts obtained in the presence of chromium(III) acetate
O
C4H9O
Cl (2)
OH
Cl
CH3COO
ϩ
Cl
O
OH
OH
O
Cl
(3)
CH3COO
Cl

382
BUKOWSKI
Figure 3 The effect of catalyst concentration on the
change of epichlorohydrin concentration during its reaction
with acetic acid carried out in the presence of chromium(III)
acetate in butan-1-ol; [AA]0 Х [ECH]0 Х 1 M; temperature
343.2 K; [cat]: 1–0.01, 2–0.0125, 3–0.015, 4–0.0175 M.
Figure 1 The change of acetic acid (AA) and epicloro-
hydrin (ECH) concentration during the reaction carried
out in the presence of chromium(III) acetate in butan-1-ol,
[AA]0 ϭ [ECH]0 Х 1 M; [cat] ϭ 0.0125 M; temperature
353.2 K.
ments at the equimolar substrate ratio with [AA]0 Х
[ECH]0 Х 1 M are shown in Figure 1. The shapes of
these curves indicate a somewhat faster consumption
of ECH compared to that of AA. This is related to the
subsequent reactions in which the former takes part.
In the logarithmic scale, the primary kinetic curves
obtained for the series of experiments with [AA]0 Х
[ECH]0 Х 1 M become straight lines (Figs. 2 and 3).
This indicates that the reaction is of the first-order with
respect to the substrates. The slopes of the lines line-
arly correlate with the catalyst concentration (Figs. 4
and 5), which means that the reaction is monomolec-
ular with respect to chromium(III) ions both for the
main reaction exemplified by the change of AA con-
centration and for the global conversion of epichlo-
rohydrin. The lines start at the origin of the coordinate
system; hence the effect of noncatalytic reactions is
negligible at the range of temperature studied.
was always smaller than that calculated from epichlo-
rohydrin consumption.
The results confirm the high selectivity of chro-
mium catalyst in addition of acetic acid to epichloro-
hydrin. It limits the extent of competing addition of
alcohol hydroxyl groups to epoxy rings much more
effectively than do acidic or basic catalysts, for which
the reactivity of a hydroxyl group in alcohol is not
much different than that in carboxylic group.
The difference becomes particularly small in the
presence of acidic catalysts, as follows from the study
by Soucek et al. [24–29] of the system cyclohexene
oxide–acetic acid–methanol.
The typical curves illustrating the change of AA
and ECH concentrations in the series of experi-
Figure 2 The effect of catalyst concentration on the
change of acetic acid concentration during its reaction with
epichlorohydrin carried out in the presence of chromium(III)
acetate in butan-1-ol; [AA]0 Х [ECH]0 Ϸ 1 M; temperature
343.2 K; [cat]: 1–0.01, 2–0.0125, 3–0.015, 4–0.0175 M.
Figure 4 The effective rate constant determined from ace-
tic acid concentration as a function of catalyst concentration.

THE SOLVENT EFFECTS IN THE REACTION OF CARBOXYLIC ACIDS WITH OXIRANES
383
Figure 5 The effective rate constant determined from ep-
ichlorohydrin concentration variations as a function of cat-
alyst concentration.
Figure 7 The variation of epichlorohydrin concentration
during its reaction with acetic acid carried out in the presence
of chromium(III) acetate in butan-1-ol; [AA]0 ϭ 1.0 M; tem-
perature 353.2 K; [cat] ϭ 0.01 M.
Additional information on the reaction order with
respect to substrates provides the series of experiments
with varying concentrations of one of the substrates
(Figs. 6 and 7). Under conditions required by the iso-
lation method of reaction order evaluation, a linear
dependence of AA concentration on time was obtained
at the large excess of epichlorohydrin (Fig. 6). This
indicates the zeroth order or the reaction relative to
acetic acid.
The linearization of the primary kinetic curves by
plotting them in the semilogarithmic system (Fig. 7)
proves the first-order of the reaction with respect to
epichlorohydrin. The lines in Figure 7 are practically
parallel, which additionally confirms the independence
of reaction rate on AA concentration.
Mechanism and Kinetics of Reaction
The graphical relationships obtained for the reaction
of acetic acid with epichlorohydrin in the presence of
chromium(III) acetate carried out in butan-1-ol are
similar to those observed for the analogous reaction
carried out without any solvents. Introduction of a
protic solvent, butan-1-ol, to the system acetic acid–
epichlorohydrin–chromium(III) acetate does not alter
the reaction orders. In both cases, the rate of addition
is determined by an interaction of the solvated form
of catalyst with ECH. The following attack of carbox-
ylate ion does not affect the overall rate. The reaction
taking place in the coordination sphere of chro-
mium(III) ions directs the addition towards the normal
isomer. The amount of a-ABH formed in the series of
experiments with [AA]0 Х [ECH]0 Х 1 M is 5.5–10.7
mol-% and increased with increasing temperature. Ac-
cording to the same mechanism—i.e., in the coordi-
nation sphere of chromium ions—but much slower,
the subsequent reaction of epichlorohydrin with hy-
droxy groups of the solvent and with those of chlo-
rohydroxypropyl esters takes place.
It was found that in the system acetic acid–epi-
chlorohydrin–chromium(III) acetate the following
rate equations hold [17]:
d[AA]
Ϫ
ϭ k1[cat][ECH]
(6)
dt
d[ECH]
Ϫ
ϭ k1[cat][ECH] ϩ k2[cat][ECH] (7)
dt
Figure 6 The variation of acetic acid concentration during
its reaction with epichlorohydrin carried out in the presence
of chromium(III) acetate in butan-1-ol; [ECH]0 ϭ 1 M; tem-
perature 353.2 K; [cat] ϭ 0.01 M.
where k1 is the rate constant of addition of acetic acid
to epichlorohydrin and k2 is the overall rate constant
of all side reactions involving epichlorohydrin. The

384
BUKOWSKI
Table II The Rate Constants of the Reaction of Acetic Acid with Epichlorohydrin Carried Out in the Presence of
Chromium(III) Acetate in Butan-1-ol at [AA]0 Х [ECH]0 Х 1 M
102[cat],
(M)
T
(K)
102k1
103k2
102k1 without Solvent [15]
Ϫ
1
Ϫ
1
Ϫ
1
Ϫ
1
Ϫ1 Ϫ1
(dm3mol s )
(dm3mol s )
(dm3mol s )
1.00–1.75
1.00–1.75
0.50–1.50
0.25–1.25
333.2
343.2
353.2
363.2
0.37 Ϯ 0.04
0.78 Ϯ 0.11
1.72 Ϯ 0.18
3.40 Ϯ 0.04
0.43 Ϯ 0.03
0.98 Ϯ 0.07
1.55 Ϯ 0.22
3.85 Ϯ 0.78
0.36
0.72
1.50
2.74
same rate equations seem to hold also in the presence
of butan-1-ol. The rate constants calculated for the se-
ries with [AA]0 Х [ECH]0 Х 1 M are presented in
Table II.
above in activation parameters of the reactions carried
out with or without solvent may serve as evidence. The
values of rate constant k1 depend on the molar ratio of
reagents, as shown in Table IV. Analogous depen-
dence was observed before for the reaction of acetic
acid with epichlorohydrin without a solvent and cat-
alyzed with chromium(III) [17] or sodium [20] acetate.
The series of experiments at different concentra-
tions of butan-1-ol revealed that k1 constant changed
with the dilution of reaction system (Table V).
The dependence of the apparent rate constant k1 on
the concentration of butan-1-ol is shown in Figure 8.
The plot splits into two straight lines of roughly op-
posite slopes. At low solvent concentration, below ca.
3 M, the rate constant decreases with dilution of the
system. At the concentration ca. 3 M, the rate constant
k1 starts to rise with concentration. These difficult-to-
interpret changes in the values of the apparent rate
constant k1 are definitely higher than the error of their
determination.
At low temperature (60o) the values of k1 obtained
in the presence of butan-1-ol are very similar to those
in the system without a solvent (cf. Table II). The dif-
ference becomes more significant at elevated temper-
ature. This different temperature characteristic for the
two systems leads to different values of activation en-
ergy, enthalpy, and entropy of the reaction (Table III).
The addition of acetic acid to epichlorohydrin in
the presence of chromium(III) acetate has a slightly
higher activation energy (enthalpy) in butan-1-ol so-
lution than in the system without solvent. Furthermore,
the solvent affects the reaction kinetics by increasing
the activation entropy of the addition. The reason
seems to be interactions between the solvent with sub-
strates.
One should notice that the small extent of the sub-
sequent reactions makes the accuracy of k2 determi-
nation pretty poor. The ratio of k2 to k1 at different
temperatures remains roughly constant, suggesting
that the share of side reactions is independent of tem-
perature.
Two straight lines can approximate the butan-1-ol
concentration dependence of k1:
line a ([BuOH]0 Ͻ 3 M)
2
k ϭ (1.50 Ϯ0.10) · 10Ϫ
Ϫ (1.94 Ϯ 0.04) · 10Ϫ [BuOH]0 (8)
3
The Effect of Environment
As mentioned in the introduction, the kinetics of ad-
dition of carboxylic acids to oxiranes depends on the
reaction environment. The differences presented
line b (([BuOH]0 Ͼ 3 M
3
k1 ϭ (6.40 Ϯ 0.68) · 10Ϫ
ϩ (9.81) Ϯ 1.04) · 10Ϫ [BuOH]0 (9)
4
Table III The Activation Parameters for the Reaction of Acetic Acid with Epichlorohydrin in
the Presence of Chromium(III) Acetate
In Butan-1-ol at
Activation Parameters
[AA]0 Х [ECH]0 Х 1 M
Without Solvent [17]
Ϫ
1
и
Ea, kJ mol
74.78 Ϯ 1.58
72.25 Ϯ 0.96
Ϫ75.68 Ϯ 2.77
68.64 Ϯ 1.50
65.81 Ϯ 1.53
Ϫ93.33 Ϯ 4.28
ꢀ
⌬H , kJиmol
Ϫ1
ꢀ
⌬S , Jиmol K
Ϫ
1
Ϫ1

THE SOLVENT EFFECTS IN THE REACTION OF CARBOXYLIC ACIDS WITH OXIRANES
385
Table IV The Values of Rate Constants for the
Reaction of Acetic Acid with Epichlorohydrin in the
Presence of Chromium(III) Acetate in Butan-1-ol at
353.2 K for the Series of Experiments with Varying
Substrate Concentration, [cat] ϭ 0.01 M
[AA]0
(M)
[ECH]0
(M)
[BuOH]0
(M)
102k1
Ϫ
1 Ϫ1
(dm3mol s )
0.997
0.404
0.605
0.801
0.998
1.003
0.998
1.000
1.004
0.999
0.999
0.402
0.602
0.800
8.624
8.998
8.868
8.731
9.182
8.985
8.802
1.51 Ϯ 0.03
2.42 Ϯ 0.06
2.38 Ϯ 0.09
2.03 Ϯ 0.08
1.72 Ϯ 0.08
1.78 Ϯ 0.07
1.72 Ϯ 0.06
Figure 8 The dependence of rate constant on butan-1-ol
concentration; [AA]0 ϭ [ECH]0, [cat] ϭ 0.01 M; tempera-
ture 353.2 K.
The complexity of interactions in the reaction sys-
tem does not allow equations (8) and (9) to be related
to any particular physicochemical parameter usually
considered in kinetic studies, such as dielectric con-
stant or the acceptor or donor number. It is possible
that butan-1-ol directly affects the donor-acceptor in-
teractions in the system. It is known that chro-
mium(III) ions, the hard acids, form complexes with
compounds containing oxygen. Both reagents and the
solvent contain oxygen. The acid and alcohol, how-
and IV seem to confirm these remarks. At a practically
constant butan-1-ol, constant ECH, and variable AA
concentrations, one observes a marked increase of k1
constant as AA concentration decreases from the stoi-
chiometric value. The effect of ECH concentration is
much less pronounced. A decrease in butan-1-ol and
simultaneous increase of reagent concentrations result
in an initial drop in the k1 value, which reaches mini-
mum at [BuOH]0 ϭ 2.98 M (cross section of lines a
and b) and then starts to linearly increase.
The chromatographic analysis of the postreaction
mixtures revealed the effect of butan-1-ol concentra-
tion on the yield of (1-chloromethyl)-2-hydroxyethyl
acetate (a-ABH), the product of abnormal addition of
AA to ECH (Table VI, Fig. 9). With a decrease of
solvent content (increase of substrate concentration),
the content of a-ABH drops down to reach a minimum
at [BuOH]0 ca. 3.6 M and then rises again. Unfortu-
nately, this does not correlate with the system without
a solvent. In the undiluted system, the amount of a-
ϩ
ever, solvate Cr3 ions better than epichlorohydrin.
The coordination of the latter with chromium(III) ions
is a slow process, and hence it is the rate-limiting step
determining the reaction order. Most of the catalysts
in the reacting system are either in the form solvated
by acid or alcohol or in the form of mixed complexes.
The ability of these two forms to activate the epoxy
group is not necessarily the same, hence the different
values of the effective rate constant k1 and the depen-
dence on acid and/or solvent concentration. A change
of ECH concentration should affect the value of k1 less
significantly. The values of k1 presented in Tables III
Table V The Values of Rate Constants for the Reaction of Acetic Acid with Epichlorohydrin in the Presence of
Chromium(III) Acetate in Butan-1-ol at 353.2 K for the Series of Experiments with Varying Butan-1-ol Concentration,
[cat] ϭ 0.01 M
k1 · 102
k2102
[AA]0 (M)
[ECH]0 (M)
[BuOH]0 (M)
(dm3mol s )
(dm3mol s )
Ϫ
1
Ϫ
1
Ϫ
1 Ϫ1
0.997
2.037
3.002
4.000
5.011
5.997
1.000
1.994
2.998
4.002
4.997
8.62
7.03
5.54
3.67
2.69
1.38
1.51 Ϯ 0.03
1.28 Ϯ 0.04
1.20 Ϯ 0.02
1.01 Ϯ 0.01
0.99 Ϯ 0.03
1.23 Ϯ 0.03
1.52 Ϯ 0.02
0.11 Ϯ 0.02
0.21 Ϯ 0.02
0.13 Ϯ 0.02
0.13 Ϯ 0.02
0.10 Ϯ 0.03
0.01 Ϯ 0.03
0.07 Ϯ 0.02
5.999
Without solvent [17]

386
BUKOWSKI
Table VI The Molar Fraction of 1-(Chloromethyl)-
2-Hydroxyethyl Acetate at Different Reaction
Temperature
zeroth order with respect to acid, similar to the anal-
ogous system without solvent. Furthermore, the rate
constant, activation parameters, as well as the regio-
selectivity of the reaction depend on both the molar
ratio of reagents and the degree of dilution of the sys-
tem.
Temperature, 102[cat],
a-ABH,
[AA]0 :[ECH]0
(K)
(M)
(%-mol)
1:1
1:1
1:1
1:1
2:2
3:3
4:4
5:5
6:6
333.2
343.2
353.2
363.2
353.2
353.2
353.2
353.2
353.2
1.00–1.75
1.00–1.75
0.50–1.50
5.55 Ϯ 0.32
8.87 Ϯ 0.91
9.61 Ϯ 0.80
BIBLIOGRAPHY
0.25–1.25 10.73 Ϯ 0.58
1.00
1.00
1.00
1.00
1.00
8.55
7.67
7.52
8.11
8.68
1. Lebedev, N. N.; Guskov, K. A. Kinet Katal 1963, 4(1),
116–127.
2. Tanaka, Y.; Takeuchi, H. Tetrahedron 1968, 24, 6433–
6448.
3. Klebanov, M. S. Zh Obshch Khim 1986, 56(7), 1596–
1601.
Without
solvent [16]
353.2
0.81–1.50
8.2 Ϯ 0.1
4. Bukowski, W., to be published.
5. Dumitriu, E.; Oprea, S. Rev Roum Chim 1983, 28(5),
535–542.
ABH is still smaller than that at butan-1-ol concentra-
tion of 1.48 M.
6. Sarancha, V. N.; Guzechak, O. Ya.; Romanyuk, I. M.;
Ilnickaya, L. A.; Prisarznyuk, S. M. Zh Prikl Khim
1987, 3, 566–569.
7. Oprea, S.; Dumitriu, E.; Hulea, T.; Hulea, V. Bull Soc
Chim Belg 1985, 94(1), 7–13.
8. Malek, J.; Silhavy, P. Collect Czech Chem Commun
1976, 41, 84–100.
9. Stepanov, E. G.; Podgornova, V. A.; Ivanova, I. I.; Us-
tavshchikov, V. F. Osnovn Org Sint Neftekhim 1974,
1, 62–67.
The molar fraction of the abnormal addition prod-
uct depends on temperature as well. It increases when
temperature rises (Table VI). The higher energy sup-
plied with the substrates favors crossing the barrier of
formation of the abnormal isomer. Its yield becomes
higher at higher temperature.
10. Bukowska, A.; Guskov, A. K.; Makarov, M. G.; Ro-
kaszewski, E.; Svets, V. F. J Chem Technol Biotechnol
1995, 63, 379–383.
CONCLUSIONS
11. Rokaszewski, E.; Rut, J. Pol J Chem 1981, 55, 1595–
1605.
12. Rokaszewski, E. Pol J Chem 1978, 52, 1487–1493.
13. Perrin, D. D.; Armarego, W. L. F. Purifictation of Lab-
oratory Chemicals, 3rd ed.; Pergamon Press Ltd.: Ox-
ford, 1988.
The present study confirmed that the addition of acetic
acid to epichlorohydrin carried out in the presence of
chromium(III) acetate in butan-1-ol as a selected protic
solvent is a bimolecular reaction. It is a first-order re-
action with respect to both catalyst and oxirane and of
14. Bukowska, A.; Bukowski, W.; Mossety-Leszczak, B. J
Chem Technol Biotechnol 1999, 74, 1145–1148.
15. Jay, R. Anal Chem 1964, 36, 667.
16. Bukowska, A.; Bukowski, W. J Chem Technol Bio-
technol 1998, 73, 341–344.
17. Bukowska, A.; Bukowski, W. J Chem Technol Bio-
technol 1996, 67, 176–182.
18. Bukowska, A.; Bukowski, W. J Chem Technol Bio-
technol 1999, 74, 675–678.
19. Bukowska, A.; Bukowski, W. Organic Process Re-
search & Development 1999, 3(6), 432–436.
20. Bukowska, A.; Guskov, A. K.; Makarov, M. G.; Ro-
kaszewski, E.; Svets, V. F. J Chem Technol Biotechnol
1995, 63, 374–378.
21. Sorokin, M. F.; Gershanova, E. L. Kinet Katal 1967,
7(3), 512–519.
22. Bukowska, A.; Bukowski, W.; Galina, H. Wiad Chem
(Poland) 1997, 3–4, 217–233.
23. Szakacs, S.; Gobolos, S.; Nagy, F. J Chem Soc, Perkin
Trans 2 1983, 4, 417–420.
Figure 9 The content of a-ABH in the product versus
butan-1-ol concentration; [AA]0 Х [ECH]0, [cat] ϭ 0.01
mol.dm ; temperature 353.2 K.
Ϫ
3

THE SOLVENT EFFECTS IN THE REACTION OF CARBOXYLIC ACIDS WITH OXIRANES
387
24. Wu, Shaobing; Soucek, M. D. Polym Prepr, Am Chem
Soc 1996, 37(2), 303–304.
27. Wu, Shaobing; Soucek, M. D. J Coat Technol 1997, 69,
43–49.
25. Wu, Shaobing; Soucek, M. D. Polym Prepr, Am Chem
Soc 1996, 37(2), 305–306.
28. Wu, Shaobing; Soucek, M. D. Polymer 1998, 39(23),
5747–5759.
26. Wu, Shaobing; Soucek, M. D. Polym Prepr, Am Chem
Soc 1997, 38(1), 93–94.
29. Soucek, M. D.; Abu-Shanab, O. L.; Anderson, C. D.;
Wu, S. Macromol Chem Phys 1998, 199, 1035–1042.