Novelties of solid-liquid phase transfer catalysed synthesis of p-toluenesulfonyl fluoride from p-toluenesulfonyl chloride

Article abstract of DOI:10.1016/j.jfluchem.2004.10.005

Organic sulfonyl fluorides are of interest owing to their insecticidal, germicidal and enzyme inhibitory properties. In the current work, synthesis of p-toluenesufonyl fluoride was accomplished by reacting p-toluenesulfonyl chloride with solid potassium fluoride using PEG-400 as a catalyst under solid-liquid phase transfer catalysis (S-L PTC) at 30°C. p-Toluenesulfonyl fluoride is used as peroxygen bleach activator. It also finds use in the treatment of Alzheimer's disease. The mechanism is based on homogeneous solubilization of solid. PEG forms a complex with metal cation which associates with the nucleophile and it participates in SN₂ type reactions. The reaction is intrinsically kinetically controlled. A complete theoretical analysis is done to determine both the rate constant and equilibrium constant from the same set of data. The activation energy and Gibbs free energy are also calculated.

Full text of DOI:10.1016/j.jfluchem.2004.10.005

Journal of Fluorine Chemistry 126 (2005) 289–295
www.elsevier.com/locate/fluor
Novelties of solid–liquid phase transfer catalysed synthesis
of p-toluenesulfonyl fluoride from p-toluenesulfonyl chloride
*
Ganapati D. Yadav , Priyanvada M. Paranjape
Department of Chemical Engineering, University Institute of Chemical Technology,
University of Mumbai, Matunga, Mumbai 400019, India
Received 5 September 2004; received in revised form 12 October 2004; accepted 13 October 2004
Available online 2 February 2005
Abstract
Organic sulfonyl fluorides are of interest owing to their insecticidal, germicidal and enzyme inhibitory properties. In the current work,
synthesis of p-toluenesufonyl fluoride was accomplished by reacting p-toluenesulfonyl chloride with solid potassium fluoride using PEG-400
as a catalyst under solid–liquid phase transfer catalysis (S–L PTC) at 30 8C. p-Toluenesulfonyl fluoride is used as peroxygen bleach activator.
It also finds use in the treatment of Alzheimer’s disease. The mechanism is based on homogeneous solubilization of solid. PEG forms a
complex with metal cation which associates with the nucleophile and it participates in SN2 type reactions. The reaction is intrinsically
kinetically controlled. A complete theoretical analysis is done to determine both the rate constant and equilibrium constant from the same set
of data. The activation energy and Gibbs free energy are also calculated.
# 2004 Elsevier B.V. All rights reserved.
Keywords: Solid–liquid phase transfer catalysis; p-Toluenesulfonyl fluoride; KF; PEG-400; Rate constant; Equilibrium constant; Modeling
1. Introduction
dimethylformamide (62–72%) [1]. All of these methods give
low yield of the compound. On the other hand, if hydrogen
fluoride is used as fluorinating agent, it has been reported
that with sulfonyl chlorides, the reaction had to be carried
out under pressure and at elevated temperature for a longer
period. Due to high reaction temperatures required,
substantial amounts of energy must be employed when
the processes are carried out on an industrial scale.
Organic sulfonyl fluorides are of interest owing to their
insecticidal, germicidal and enzyme inhibitory properties.
p-Toluenesulfonyl fluoride is used as peroxygen bleach
activator. It also finds use in the treatment of Alzheimer’s
disease. There are several routes for manufacture of organic
sulfonyl fluorides, most of which involve halogen exchange
(i.e., conversion of the corresponding sulfonyl chloride to
the sulfonyl fluoride). Boiling of a sulfonyl chloride with an
aqueous solution of potassium fluoride will not work for
water sensitive compounds. Other synthesis include: (a)
refluxing the corresponding sulfonyl chloride and potassium
fluoride in a cosolvent system (e.g., dioxane/water) (70%
yield), (b) addition of sodium nitrite to a solution of the
corresponding sulfonamide in anhydrous hydrogen fluoride
(53–78%) and (c) heating the sulfonyl chloride with sodium
fluoride suspended in teramethylenesulfone, acetonitrile or
We would like to report a very facile and convenient
method (which generates a naked fluoride anion) to
synthesize p-toluenesulfonyl fluoride at room temperature.
Further, a general modeling method is devised by which it
would be possible to determine the rate constant and also the
overall equilibrium constant using the same set of data.
Phase transfer catalysis (PTC) has matured to over 600
industrial processes in a variety of industries such as
intermediates, dyestuffs, agrochemicals, perfumes, flavours,
pharmaceuticals and polymers [2–4]. A large number of
PTC processes use the liquid–liquid (L–L) mode of
operation. One of the ways to suppress by-product formation
and also intensify the rates of reactions of L–L PTC is
through the use of solid–liquid phase transfer catalysis (S–L
* Corresponding author. Tel.: +91 22 2410 2121; fax: +91 22 2414 5614.
E-mail addresses: gdyadav@yahoo.com, gdyadav@udct.org
(G.D. Yadav).
0022-1139/$ – see front matter # 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2004.10.005

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G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
PTC). The aqueous phase promoted reactions can thus be
totally suppressed and better selectivities obtained. While
L–L PTC involves heterogeneous reaction between two
reagents located in an aqueous, and an organic phase, S–L
PTC involves reaction of an anionic reagent in a solid phase
(usually a salt) with a reactant located in a continuous
organic phase. Yadav and Sharma [5] proposed the first
mechanistic and kinetic model of solid–liquid PTC followed
by Naik and Doraiswamy [6]. We have carried out the
detailed mechanistic and modelling studies for industrially
important reactions under S–L PTC conditions [7,8]. The
role of small amounts of water, the so-called omega phase, in
S–L PTC was analysed in our earlier work [9] including
others [2–4] and a rigorous model of S–L PTC with omega
phase has been established [9].
Scheme 1. Complex of PEG with metal cation K+.
step involves the reaction of the [PEG K+Fꢀ] with the
reactant [RX] located in the organic phase. There are
several possibilities by which this reaction can occur.
Finally, the third step involves the transport of the co-
product anion [Xꢀ], the leaving group to the solid and the
transport of another nucleophile [Fꢀ] into the organic
phase. In the current case, the S–L PTC mechanistic
description is the implication that the reaction takes place in
anhydrous condition, since both solid and liquid phases
were dry. So the formation of the omega phase was
discounted. There are two types of mechanisms for S–L
PTC, the homogeneous solubilization mechanism of
Yadav and Sharma [5] and heterogeneous solubilization
of Naik and Doraiswamy [6]. In the heterogeneous solubi-
lization, the particles are totally insoluble and the catalyst
get adsorbed on to the solid whereas in the case of homo-
geneous solubilization model, the particles are sparingly
soluble in the organic phase and the particle solubility is
augmented by the phase transfer agent [PEG]. The particle
size goes on decreasing with time due to the reaction in the
organic phase. Depending on the relative rate of transfer of
[PEG K+Fꢀ] in the organic film next to the solid and the
reaction of the species, four different regimes can be
identified just like the L–L PTC. [13] These are shown in
Fig. 1 and the importance of various steps is delineated in
the captions.
2. Results and discussion
The reaction scheme is given by
Preliminary experiments established that the reaction was
facile at 30 8C. To understand the enhanced rates of reaction
under these conditions, it was thought worthwhile to study
the mechanism and kinetics of this reaction. Since a typical
experiment produced 90% conversion of p-toluenesulfonyl
chloride, with 100% selectivity to the fluoride, a further
insight was obtained by studying the effect of various
parameters on the rates of reaction.
Preliminary experiments suggested that the homoge-
neous solubilization model illustrated by the SN2 type of
reaction of the substrate RX with the nucleophile Y of the
solid reactant MY.
2.1. Mechanism and kinetic model
The overall reaction is:
kobs
RXðorgÞ þ MYðsÞ þ PEGðorgÞꢀ! RYðorgÞ þ MXðsÞ
Polyethylene oxide chains form complexes with cations,
much like crown ethers, and these complexes cause the
anion to be transferred into the organic phase and to be
activated [10]. Complexation of solid alkali metal salts by
PEG is strongly dependent on both the anion and the cation
of the salt [11]. The phase transfer catalytic efficiencies of
polyethylene glycols were proven and analyzed [12]. It was
observed that best catalytic efficiencies were obtained by
using medium chain length PEG (n = 7–9).
þ PEGðorgÞ
(1)
The solid reactant is in equilibrium with its solution in the
organic phase. This is the solubility of KF in the solvent in
the presence of the catalyst. It was obtained by taking a large
and known amount of KF in the solvent and catalyst and
stirring for 1 h and then filtering the solution under vacuum
and weighing the dry solids again. It was obtained
2.62 Â 10ꢀ5 mol/cm3. In the absence of the catalyst the
solubility was less.
The first step of the reaction involves the complexa-
tion of PEG with metal cation [K+] (Scheme 1) and forms
[PEG K+Fꢀ], which is organophilic and is freely trans-
ported to the bulk organic phase. There could be a resis-
tance associated with the transfer of this complex across
the liquid film next to solid–liquid interface. The second
K2
½MYŠS Ð ½MþYꢀŠ
This represents saturation solubility of the solid in organic
liquid.
(2)
ðorgÞ

G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
291
Fig. 1. Typical S–L PTC under homogeneous solubilization. (a) Regime 1: very slow reaction. The reaction occurs in the bulk organic phase as a homogeneous
reaction. Mass transfer effects are unimportant. (b) Regime 2: slow reaction. The reaction occurs in the bulk organic phase. No free concentration of ion pairs
exists in the bulk organic phase. (c) Regime 3: fast reaction. Diffusion of [Q+Yꢀ]org and its reaction with RX are steps in parallel, and the reaction occurs in the
organic liquid film next to the S–L interface. (d) Regime 4: instantaneous reaction. The reaction between [Q+Yꢀ]org and RX is so fast that they cannot coexist in
the organic phase. [Q+Yꢀ]org diffuses from the L–L interface, and RX diffuses from the bulk organic phase into the organic liquid film and react at a plane from
the interface. No free [Q+Yꢀ]org exists beyond distance l and no free RX exists beyond distance (d0 ꢀ l) toward the interface. Note that for simplicity other ion
pairs are not shown.
PEG forms the complex with metal cation M+
The equilibrium constant, Ke, which is a sort of a
solubility parameter is defined by combining steps (2), (3),
(5) and (6) as follows:
K3
½PEGŠðorgÞ þ ½MþYꢀŠðorgÞ Ð ½PEG MþYꢀŠ
(3)
ðorgÞ
½MþYꢀŠ
½MYŠ
The substance RX reacts with the complex [PEG M+Yꢀ](org)
according to
ðorgÞ
K2 ¼
K3 ¼
(7)
s
kr
RXðorgÞ þ ½PEG MþYꢀŠðorgÞꢀ! RYðorgÞ
½PEG MþYꢀŠ
ðorgÞ
(8)
þ ½PEG MþXꢀŠ
where kr is rate constant.
(4)
½PEGŠ½MþYꢀŠ
ðorgÞ
ðorgÞ
½PEGŠ½MþXꢀŠ
½PEG MþXꢀŠ
1
¼
ðorgÞ
(9)
½PEG MþXꢀŠ
1Ð=K4½PEGŠðorgÞ þ ½MþXꢀŠ
(5)
(6)
K4
ðorgÞ
ðorgÞ
ðorgÞ
K5
½MþXꢀŠðorgÞ Ð ½MXŠ
½MXŠ
s
s
K5 ¼
(10)
½MþXꢀŠ
ðorgÞ
PEG is thus generated repeatedly to catalyze the reaction.

292
G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
½PEG MþYꢀŠ
½MXŠ
ðorgÞ
Eq. (12) can be further manipulated to the following to
extract both Ke and kr:
K2K3K5
K4
ðorgÞ
s
Ke ¼
¼
(11)
(11)
½MYŠ ½PEG MþXꢀŠ
s
ꢀ
ꢁ
2
3
M ꢀ XA
ꢂ
ꢃ
ln
½MYŠ
6
6
4
7
7
5
þ
ꢀ
½PEG MþYꢀŠ
¼ Ke
½PEG M X Š
s
1 ꢀ Ke þ KeM
M
ðorgÞ
ðorgÞ
ꢀ
½MXŠ
The rate of reaction of Eq. (4) is given by
s
ln ð1 ꢀ XAÞ
M
ꢂ
ꢃ
ðM ꢀ 1ÞkrQ0
t
ꢀd½RXŠ
¼
(24)
ðorgÞ
½PEG MþYꢀŠ
(12)
(13)
M
ln ð1 ꢀ XAÞ
¼ kr½RXŠ
ðorgÞ
ðorgÞ
dt
ꢄ
ꢅ
ꢃ
ꢂ
MꢀX
A
ln
ꢀd½RXŠ
dt
M
t
MYs
ðorgÞ
A plot of
versus
should give
½PEG MþXꢀŠ
ln ð1ꢀXAÞ
ln ð1ꢀXAÞ
¼ krKe
½RXŠ
ðorgÞ
ðorgÞ
MXs
ꢂ
ꢃ
But
ðM ꢀ 1ÞkrQ0
slope ¼
and intercept
M
Q0 ¼ ½PEG MþYꢀŠðorgÞ þ ½PEG MþXꢀŠ
ðorgÞ
ꢂ
ꢃ
ðM ꢀ 1ÞKe þ 1
¼
(25)
¼ Total concentration of catalyst in organic phase
(14)
M
Thus, both Ke and kr can be obtained from the slope and
intercept from the knowledge of M and Q0. Further for
equimolar quantities of substrate and nucleophile, the fol-
lowing form of the integrated equation results:
½PEG MþXꢀŠ
½PEG MþYꢀŠ
¼ ½Q0 ꢀ ½PEG MþYꢀŠ
Š
(15)
ðorgÞ
ðorgÞ
ðorgÞ
½MYŠ
s
¼ Ke
½Q0
ꢀ
ꢁ
½MXŠ
s
XA
þ ð1 ꢀ KeÞln ð1 ꢀ XAÞ ¼ krQ0t;
ꢀ ½PEG MþYꢀŠ
Š
(16)
(17)
1 ꢀ XA
ðorgÞ
(26)
for M ¼ 1
Eq. (15) can also be manipulated to the following:
½PEG MþYꢀŠ
¼ ½Q0 ꢀ ½PEG MþYꢀŠ
ŠR
ðorgÞ
ðorgÞ
Q0R
¼
½PEG MþYꢀŠ
(18)
(19)
ꢀ
ꢁ
ðorgÞ
XA
1 þ R
t
1 ꢀ XA
½MYŠ
¼ krQ0
þðKe ꢀ 1Þ
(27)
s
R ¼ Ke
ln ð1 ꢀ XAÞ
ð1 ꢀ XAÞ
½MXŠ
s
ꢆ
ꢇ
2
3
X
1ꢀX
A
A
The fractional conversion of RX at time t is defined by:
t
4
5
A plot of
versus ln ð1ꢀX Þ will give a straight line
ln ð1ꢀXAÞ
A
N
ꢀ NRX
RX0
RX0
XA ¼
(20)
N
with slope equal to krQ0 and intercept equal to (Ke ꢀ 1).The
validation of the above model was verified by conducting
several experiments.
where NRX are the initial moles of RX at time t = 0.
NMY
0
0
Let M ¼
= initial molar ratio of solid reactant (MY)
NRX
0
to organic substrate (RX) (21)
By substituting these terms in Eq. (13), the following is
obtained:
ꢀ
ꢁ
1 þ R
dXA
¼ krQ0t
(21)
R
1 ꢀ XA
Substituting for R, [MX]s and [MY]s in terms of XA and M,
and then separation of variable in Eq. (21) leads to:
ꢃ
ꢂ
Z
XA
XA þ KeM ꢀ KeXA
dXA ¼ krQ0t
(22)
KeðM ꢀ XAÞð1 ꢀ XAÞ
This integral is solved by the method of partial fractions to
0
get the following:
ꢀ
ꢀ
ꢁ
ꢁ
ꢀ
ꢁ
M
M ꢀ XA
1 ꢀ Ke þ KeM
M ꢀ 1
6
ln
ꢀ
Fig. 2. Effect of different catalysts. p-Toluenesulfonyl chloride, 0.02 mol;
KF, 0.04 mol; speed, 1500 rpm; acetonitrile, 46 ml; temperature, 30 8C,
time, 90 min.
M ꢀ 1
M
ln ð1 ꢀ XAÞ ¼ krQ0t; for M
(23)

G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
293
Fig. 5. Determination of kr and Ke values. p-Toluenesulfonyl chloride,
0.02 mol; KF, 0.04 mol; speed, 1500 rpm; acetonitrile, 46 ml; temperature,
30 8C; time, 90 min; kr, 77.1 cm3 molꢀ1 minꢀ1; Ke, 0.11.
Fig. 3. Effect of speed of agitation. p-Toluenesulfonyl chloride, 0.02 mol;
KF, 0.04 mol; PEG-400, 0.8 g; acetonitrile, 46 ml; temperature, 30 8C; time,
90 min.
2.2. Effect of various catalysts
Different catalysts such as tetrabutyl ammonium bromide
(TBAB), ethyl triphenyl phosphonium bromide (ETPB) and
PEG-400 were selected for the reaction under otherwise
similar concentration of catalyst at 30 8C and 1500 rpm
(Fig. 2). Out of these PEG-400 gave maximum rates of
reaction and conversion. It was conjectured that the
ineffectiveness of the quaternary salt in the overall reaction
process was due to the absence of chelating heteroatom
which can favour the process of removing ion pair from solid
matrix. Apart from high reactivity of PEG-400 as compared
to others it is very cheap (Rs. 160 kgꢀ1). Thus, further
experiments were conducted with PEG-400. The selectivity
to the product p-toluenesulfonyl fluoride was 100%.
Fig. 6. Effect of mole ratio of p-toluenesulfonyl chloride to KF. p-Tolue-
nesulfonyl chloride, 0.02 mol; PEG-, 0.8 g; speed, 1500 rpm; acetonitrile,
46 ml; temperature, 30 8C; time, 90 min.
2.3. Effect of speed of agitation
The reaction was carried out at four different speeds of
agitation (Fig. 3) with PEG-400 as catalyst. There was a
significant increase in the conversion from 1000 to 1500 rpm.
But it was almost constant at 1500 and 1800 rpm. All
Fig. 4. Effect of catalyst loading. p-Toluenesulfonyl chloride, 0.02 mol; KF,
0.04 mol; speed, 1500 rpm; acetonitrile, 46 ml; temperature, 30 8C; time,
90 min.
Fig. 7. Validation of the model. p-Toluenesulfonylchloride, 0.02 mol;
PEG-, 0.8 g; speed, 1500 rpm; Acetonitrile, 46 ml; Temperature, 30 8C,
Time, 90 min.

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G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
Fig. 8. Effect of temperature. p-Toluenesulfonyl chloride, 0.02 mol; KF,
0.04 mol; PEG-400, 0.8 g; speed, 1500 rpm; Acetonitrile, 46 ml; Time,
90 min.
Fig. 10. Arrhenius plot for activation energy.
subsequent reactions were carried out with 1500 rpm while
assessing the effect of other variables on the rate of reaction.
The observed initial rate of reaction for a typical
experiment was equal to 1.6667 Â 10ꢀ7 mol cmꢀ3 sꢀ1
whereas the rate of mass transfer was estimated from the
knowledge of solid–liquid mass transfer coefficient (kSL–A),
particle surface area (aP = 611.20 cmꢀ1) and the solubility
of potassium fluoride in acetonitrile was measured as
2.62 Â 10ꢀ5 mol/cm3. The solid–liquid mass transfer
coefficient (kSL–A = 0.199 cm/s) which was found from
Sherwood number (kSL–AdP/DA = 2). A limiting value of
Sherwood number was taken as 2 since the particles were
very fine. The Wilke–Chang equation was used to calculate
the bulk diffusivity. The mass transfer rate was equal to
3.201 Â 10ꢀ3 mol cmꢀ3 sꢀ1 which is 1.996 Â 104 times
greater than the rate of reaction. Thus, the observed reaction
rate was much smaller than the mass transfer rate. Therefore,
there was no mass transfer resistance associated with the
reaction and the reaction would be kinetically controlled.
2.4. Effect of catalyst loading
The concentration of the catalyst was varied from
2.1739 Â 10ꢀ5 to 6.521 Â 10ꢀ5 mol/cm3 org (Fig. 4). It was
observed that as the concentration was increased, the
conversion increased, but above a concentration of
4.3447 Â 10ꢀ5 mol/cm3 org, there was no further increase
in the conversion. The validity of Eq. (13) was tested.
Appropriate plots were made for M = 2 as shown in Fig. 5.
There is an excellent fit for different values of catalyst
concentration. The average values of kr and Ke were obtained
as 77.1 cm3 molꢀ1 minꢀ1 and 0.11, respectively.
2.5. Effect of mole ratio
Mole ratio of p-toluenesulfonyl chloride to potassium
fluoride (KF) was varied from 1:1 to 1:3. (Fig. 6) The
catalyst loading was kept at 4.3447 Â 10ꢀ5 mol/cm3 org.
The reaction rate was found to increase at the mole ratio of
p-toluenesulfonyl chloride to KF from 1:1 to 1:1.5. It was
observed that there is insignificant increase in the conversion
at mole ratio of 1:2–1:3. This is because of the saturation of
the binding sites available in PEG. So further addition of
potassium fluoride does not help in enhancement of the rate
of reaction. The average values of kr and Ke were obtained as
73.216 cm3 molꢀ1 minꢀ1 and 0.0257, respectively. There is
an excellent fit of the proposed model with the experimental
data. (Fig. 7)
2.6. Effect of temperature
The effect of temperature was studied under otherwise
similar reaction conditions from 30 to 60 8C (Fig. 8). It was
found that the conversion increased substantially with
increase in temperature. However, there was a marginal
increase in conversion at 60 8C over than that at 50 8C. The
same theory was again validated at all temperatures (Fig. 9).
Thus, Arrhenius plot was made and the activation energy
calculated as 36.59 kJ/mol (Fig. 10), which suggested that
Fig. 9. Validation of model at different temperatures. p-Toluenesulfonyl
chloride, 0.02 mol; KF, 0.04 mol; PEG-400, 0.8 g; speed, 1500 rpm; Acet-
onitrile, 46 ml; Time, 90 min. kr = 78.34 cm3 molꢀ1 minꢀ1, Ke = 0.019 at
30 8C; kr = 115.2 cm3 molꢀ1 minꢀ1, Ke = 0.0018 at 40 8C; kr = 165.09 cm3
molꢀ1 minꢀ1
,
Ke = 0.0044 at 50 8C; kr = 299.03 cm3 molꢀ1 minꢀ1
,
Ke = 0.1324 at 60 8C.

G.D. Yadav, P.M. Paranjape / Journal of Fluorine Chemistry 126 (2005) 289–295
295
achieved. (Without employing these procedures reproduci-
ble data were difficult to achieve.)
After stirring for an hour, p-toluenesulfonyl chloride
(0.02 mol) dissolved in 21 ml of acetonitrile was added and
the mixture was stirred. A zero time sample was collected
and sampling was done periodically to get concentration–
time profiles of reactants and products.
4.2. Chemicals and catalysts
p-Toluenesulfonyl chloride, acetonitrile, diphenyl ether,
all of A.R. grade, were procured from M/s E. Merck Ltd.,
Mumbai. Potassium fluoride, (Anhydrous L.R. grade) was
purchased by M/s s.d. Fine Chemicals, Mumbai. PEG-400,
was obtained from S-D Fine Chemicals, Mumbai. All other
PTCs were gift samples from M/s Dishman Pharmaceuticals
and Chemicals Ltd. Ahmedabad, India.
Fig. 11. Gibbs free energy plot.
the reaction was kinetically controlled. Ke is a sort of combi-
nation of solubility and distribution constant of ion pairs. The
Gibbs free energy value was calculated as 185.01 kJ/mol,
which shows that the equilibrium exchange of ions and
solubility are thermodynamically feasible (Fig. 11).
4.3. Analysis
Analysis was performed on GC (Chemito Gas Chroma-
tograph, model 8610) by using a 2 m  3.175 mm stainless
steel column packed with 10% OV-17 on Chromosorb WHP,
coupled with a flame ionization detector. Synthetic mixtures
of the reactant and internal standard were used to calibrate
the chromatograms and quantify the data. The product was
confirmed by GC–MS.
3. Conclusion
p-Toluenesulfonyl fluoride is used as peroxygen bleach
activator. It also finds use in the treatment of Alzheimer’s
disease. The synthesis of this compound was undertaken by
using a variety of catalysts amongst which PEG-400 was
found to be the best catalyst. A complete theoretical analysis
of the process was carried out to explain the observed rate
data. Both equilibrium constant and rate constant could be
calculated from the same set of data. The apparent activation
energy is 36.59 kJ/mol.
Acknowledgement
G.D. Yadav acknowledges Darbari Seth Endowment for
supporting the Chair. Priyanvada Paranjape acknowledges
UGC, New Delhi for an award of JRF, which enabled this
work to be carried out.
References
4. Experimental details
[1] T.A. Binachi, L.A. Cate, J. Org. Chem. 42 (1977) 2031–2032.
[2] C.M. Starks, C.M. Liotta, M. Halpern, Phase Transfer Catalysis:
Fundamentals, Applications, and Perspectives, Chapman and Hall,
New York, 1994.
4.1. Experimental procedure
The reaction was studied in 5 cm i.d. fully baffled
mechanically agitated glass reactor of 100 cm3 total
capacity which was equipped with a six-blade pitched
turbine impeller (1 cm diameter).The impeller was located
at a distance of 2 cm from the bottom. This arrangement
ensured excellent solid–liquid mixing for high mass transfer
rates. The assembly was kept in a water bath to maintain the
desired temperature and mechanically stirred at a known
speed with an electric motor.
[3] Y. Sasson, R. Neumann (Eds.), Handbook of Phase Transfer Catalysis,
Blackie Academic and Professional, London, 1997.
[4] E.V. Dehmlow, S.S. Dehmlow, Phase Transfer Catalysis, third ed.
VCH Weinheim, New York, 1993.
[5] G.D. Yadav, M.M. Sharma, Ind. Eng. Chem. Process Res. Dev. 20
(1981) 385–390.
[6] S.D. Naik, L.K. Doraiswamy, Chem. Eng. Sci. 52 (1997) 4533–4546.
[7] G.D. Yadav, S.S. Naik, Org. Process Res. Dev. 3 (1999) 83–91.
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[9] G.D. Yadav, Y.B. Jadhav, Langmuir 18 (2002) 5995–6002.
[10] R. Vladea, T. Simandan, Rev. Chim. (Bucharest) 41 (1990) 421–425
(CA: 114:229413).
Typically the reaction was carried out as follows: initially
potassium fluoride (0.04 mol) along with PEG-400
(0.002 mol) and diphenyl ether (0.004 mol, used as an
internal standard) in 25 ml acetonitrile was stirred at 30 8C
for 1 h. This procedure allowed the salts to be continually
solubilized and precipitated until a constant particle size was
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