Kinetic study of alkaline hydrolysis of substituted phenyl tosylates. XXII. Variation of ortho substituent effect with solvent

Article abstract of DOI:10.1135/cccc20050198

The second-order rate constants k (dm³ mol^-1 s ^-1) for the alkaline hydrolysis of meta-, para-, and ortho-substituted phenyl tosylates 4-CH₃C₆H ₄SO₂OC₆H₄-X in aqueous 0.5 M Bu ₄NBr have been measured spectrophotometrically in a wide temperature range. The log k values for ortho-substituted derivatives at various temperatures together with meta- and para-substituted derivatives were analyzed using the modified Fujita-Nishioka equation log k_m,p,ortho = c ₀ + c_1(m,p,ortho)σ° + c _2(ortho)σ₁ + c₃(1/T) + c _4(m,p,ortho)(1/T)σ° + c_5(ortho)(1/T) σ_I. In order to study the dependence of substituent effects, especially ortho inductive and resonance terms on different solvent parameters, the following equation was used: Δlog k_m,p,ortho = c ₀ + c_1(m,p,ortho)σ° + c _2(ortho)σ_I + c₃ΔE + c ₄ΔY + c₅ΔP + c _6(m,p,ortho)ΔEσ° + + c _7(m,p,ortho)ΔYσ° + c _8(m,p,ortho)ΔPσ° + c _9(ortho)ΔEσ_I + c _10(ortho)ΔYσ_I + c _11(ortho)ΔPσ_I. Δlog k = log k ^X - log k^H, σ° and σ_I, are the Taft polar and inductive substituent constants, E, Y and P, are the solvent electrophilicity, polarity and polarizability parameters, respectively. In data treatment ΔE = E_S - E_H2O, ΔY = Y_S - Y_H2O, ΔP = P_S - P_H2O were used. The solvent electrophilicity was found to be the main factor responsible for changes in the ortho, para, and meta polar substituent effects with medium. The variation of the ortho inductive term with the solvent electrophilicity E _S was found to be twice smaller than that for para substituents, while the ortho resonance term appeared to vary with solvent nearly similarly to that for para substituents. The ortho effect caused by the supplementary inductive effect from ortho position was found to disappear in a solvent whose electrophilic solvating power is comparable to pure DMSO (E ≈ 4).

Full text of DOI:10.1135/cccc20050198

198
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
KINETIC STUDY OF ALKALINE HYDROLYSIS OF SUBSTITUTED
PHENYL TOSYLATES. XXII. VARIATION OF ORTHO SUBSTITUENT
EFFECT WITH SOLVENT
1,
2
Vilve NUMMERT, Mare PIIRSALU *, Marika LEPP, Vahur MÄEMETS and
Ilmar KOPPEL
3
Institute of Chemical Physics, Tartu University, Jakobi 2, 51014 Tartu, Estonia;
1
2
3
e-mail: mare.piirsalu@ut.ee, vahur.maemets@ut.ee, ilmar.koppel@ut.ee
Received Jun e 22, 2004
Accepted Novem ber 1, 2004
Dedicated to Professor Otto Exner on the occasion of his 80th birthday.
Th e secon d-order rate con stan ts k (dm 3 m ol–1 s–1) for th e alkalin e h ydrolysis of meta-, para-,
an d ortho-substituted ph en yl tosylates 4-CH3C6H4SO2OC6H4–X in aqueous 0.5 M Bu4NBr
h ave been m easured spectroph otom etrically in a wide tem perature ran ge. Th e log k values
for ortho-substituted derivatives at various tem peratures togeth er with meta- an d para-substi-
tuted derivatives were an alyzed usin g th e m odified Fujita–Nish ioka equation log km ,p,orth o
=
c0 + c1(m ,p,orth o)σ° + c2(orth o)σI + c3(1/T) + c4(m ,p,orth o)(1/T)σ° + c5(orth o)(1/T)σI. In order to study
th e depen den ce of substituen t effects, especially orth o in ductive an d reson an ce term s on
differen t solven t param eters, th e followin g equation was used: ∆log km ,p ,orth o = c0
+
c
1(m ,p ,orth o)σ° + c2(orth o)σI + c3∆E + c4∆Y + c5∆P + c6(m ,p ,orth o)∆Eσ° + + c7(m ,p ,orth o)∆Yσ° +
8(m ,p,orth o)∆Pσ° + c9(orth o)∆EσI + c10(orth o)∆YσI + c11(orth o)∆PσI. ∆log k = log kX – log kH, σ° an d
c
σI, are th e Taft polar an d in ductive substituen t con stan ts, E, Y an d P, are th e solven t
electroph ilicity, polarity an d polarizability param eters, respectively. In data treatm en t ∆E =
ES – EH2O, ∆Y = YS – YH2O, ∆P = PS – PH2O were used. Th e solven t electroph ilicity was foun d
to be th e m ain factor respon sible for ch an ges in th e orth o, para, an d m eta polar substituen t
effects with m edium . Th e variation of th e orth o in ductive term with th e solven t
electroph ilicity ES was foun d to be twice sm aller th an th at for para substituen ts, wh ile th e
orth o reson an ce term appeared to vary with solven t n early sim ilarly to th at for para sub-
stituen ts. Th e orth o effect caused by th e supplem en tary in ductive effect from orth o position
was foun d to disappear in a solven t wh ose electroph ilic solvatin g power is com parable to
pure DMSO (E ≈ 4).
Keyw ord s: Esters; Sulfon ates; Ph en yl tosylates; Alkalin e h ydrolysis; Substituen t effects;
Orth o effects; Solven t effects; Kin etics.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)
doi:10.1135/cccc20050198

Kinetic Study of Alkaline Hydrolysis
199
In previous papers, th e depen den ce of th e orth o, para, an d m eta substi-
tuen t effects in th e alkalin e h ydrolysis of substituted ph en yl tosylates,
4-CH3C6H4SO2OC6H4–X, an d ben zoates, C6H4CO2C6H4–X, in water, aque-
ous 2.25 M Bu4NBr, 80% (v/v) DMSO an d 5.3 M NaClO4 (see lit.1–3 an d refer-
en ces th erein ) depen den t on tem perature was studied.
On e purpose of th e presen t work was to exten d our study of substituen t
effects an d to obtain m ore in form ation about variation of th e in ductive
an d reson an ce effects of orth o substituen ts an d polar effect of m eta an d
para substituen ts with solven t an d tem perature in th e tran sition from water
to aqueous 0.5 M Bu4NBr. Th e electroph ilic solvatin g power of th e latter is
reduced com pared to water an d 5.3 M NaClO4, but h igh er th an th at of
aqueous 2.25 M Bu4NBr an d 80% (v/v) DMSO. With th at aim th e secon d-
order rate con stan ts of th e alkalin e h ydrolysis of ortho-, meta-, an d para-sub-
stituted ph en yl tosylates 4-CH3C6H4SO2OC6H4–X (X = H, 4-NO2, 4-CN,
3-NO2, 3-Cl, 4-Cl, 2-NO2, 2-CN, 2-F, 2-Cl, 2-CH3, 2-OCH3) in aqueous 0.5 M
Bu4NBr at various tem peratures, were determ in ed an d an alyzed (Sch em e 1).
3
4
2
O
S
O
S
12
9
0.5
M Bu4NBr
O
5
7
11
10
OH
+
+
1
O
6
X
O
HO
X
8
H3C
H3C
SCHEME 1
An oth er goal of th e presen t work was to study th e sign ifican ce of dif-
feren t solven t param eters for th e substituen t effects, in particular orth o
effects, in th e alkalin e h ydrolysis of substituted ph en yl tosylates,
4-CH3C6H4SO2OC6H4–X, on th e basis of our earlier kin etic data for various
m edia (water, aqueous 1 M Bu4NBr, 2.25 M Bu4NBr, 80% (v/v) DMSO, 5.3 M
NaClO4, 4.8 M NaCl, 30% EtOH, 60% EtOH, 80% EtOH, lit.1,2,4 an d refer-
en ces th erein ) an d kin etic data for aqueous 0.5 M Bu4NBr reported in th is
work.
Th e log k values for th e alkalin e h ydrolysis of substituted ph en yl tosylates
in th e case of m eta an d para substituen ts were foun d to be correlated with
σ° con stan ts. In water, th e in ductive in fluen ce from orth o position was
foun d to be 1.5-fold stron ger th an th at from para an d m eta position . In
tran sition from water to aqueous 2.25 M Bu4NBr an d 80% aqueous DMSO
m edia, th e electroph ilic solvatin g power of wh ich is reduced com pared
with water, th e polar effect of para an d m eta substituen ts was foun d to be
en h an ced by about 1.0 un its of th e ρ° scale (at 75 °C in water ρ° = 1.7, in
2.25 M Bu4NBr ρ° = 2.7). In th e alkalin e h ydrolysis of substituted ph en yl
ben zoates th e ρ° value ch an ged n early to th e sam e exten t wh en goin g from
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

200
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
water to aqueous 2.25 M Bu4NBr (at 50 °C in water ρ° = 1.01, in 2.25 M
Bu4NBr ρ° = 2.03)3. Th e variation of th e orth o in ductive term with solven t
an d tem perature appeared to be n early h alf of th at of para substituen ts.
Due to th e reduced variation of orth o in ductive effect with solven t, com -
pared to th at of para substituen ts, a con siderable decrease in th e orth o ef-
X
fect (i.e. th e differen ce log korth o – log kparaX) caused by th e in ductive in flu-
en ce, h as been observed wh ile goin g from water to less electroph ilic m edia
(aqueous 2.25 M Bu4NBr an d 80% DMSO). Th e orth o, m eta, an d para polar
substituen t effects were foun d to decrease an d th e orth o effect was observed
to in crease wh en goin g from water to an in organ ic salt solution like 5.3 M
1
aqueous NaClO4
.
Th e variation of th e substituen t effects (ρ) with solven t properties h as
been studied m ain ly in th e case of m eta an d para substituen ts. In th e study
of Koppel an d Karelson 5 th e depen den ce of ρ values on th e solven t param e-
ters h ave been studied for acid dissociation of ben zoic acids an d ph en ols in -
cludin g th e values for in dividual solven ts an d th e gas ph ase, accordin g to a
special varian t
A = A0 + yY + eE
of th e Koppel–Palm equation 6,7
(1)
A = A0+ yY + pP + eE + bB + δES .
(2)
In Eq. (2) A an d A0 are reactivities or ph ysico-ch em ical properties in a given
m edium an d in th e gas ph ase (stan dard m edium ), respectively; Y is th e po-
larity param eter of solven t as a fun ction of dielectric perm ittivity ε, usually
in th e form (ε – 1)/(ε + 2) or (ε – 1)/(2ε + 1); P is th e polarizability param eter
of solven t as a fun ction of refractive in dex n in th e form (n2 – 1)/(n2 + 2) or
(n2 – 1)/(2n2 + 1); E is th e electroph ilicity param eter based on ET(30) val-
ues6–8, corrected for th e in fluen ce of solven t polarity Y an d polarizability P;
B is th e n ucleoph ilicity param eter by Koppel an d Paju9. Th e steric param e-
ters Es, con structed on th e basis of isostericity prin ciple10 take in to accoun t
steric in teraction s of th e solven t m olecules with th e solute.
Wh en th e variation of substituen t effects on th e dissociation of som e
Brøn sted acids with solven t was con sidered5, solven t polarity was foun d to
be th e m ain in fluen cin g factor. Th e in fluen ce of electroph ilicity was foun d
to be som ewh at less im portan t, wh ereas th e in fluen ce of polarizability an d
basicity were n egligible. Later11, in differen t reaction series (acid dissocia-
tion of ben zoic acids, ph en ols, an ilin ium ion s, pyridin ium ion s; alkalin e
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
201
h ydrolysis of esters an d sovolysis of ben zyl ch lorides) th e solven t electro-
ph ilicity was foun d to be th e m ain factor th at in fluen ces polar effects of
substituen ts, wh ile solven t polarity appeared to be con siderably less im -
portan t.
Th e variation of th e orth o substituen t effects with solven t param eters
an d sim ultan eously with m eta an d para substituen ts is studied to an essen -
tially lesser exten t. In th e alkalin e h ydrolysis of substituted ph en yl
tosylates4, 4-CH3C6H4SO2OC6H4–X, th e orth o in ductive term was foun d to
in crease with decreasin g solven t electroph ilicity properties m ore th an twice
less th an th e in ductive term . In th e alkalin e h ydrolysis of substituted ph en -
yl tosylates, 4-CH3C6H4SO2OC6H4–X, th e data for ortho-substituted deriva-
tives sim ultan eously with meta- an d para-substituted derivatives h ave been
an alyzed accordin g to th e m odified Fujita an d Nish ioka12 equation (3) in -
cludin g th e data for various m edia (water, aqueous 80% DMSO, aqueous
5.3 M NaClO4, 4.8 M NaCl, 1 M Bu4NBr, 2.25 M Bu4NBr an d 30, 60, an d 80%
aqueous eth an ol) at 75 °C.
∆log km ,p,orth o = c0 + c1(m ,p,orth o)σ° + c2(orth o)σI + c3∆E +
+ c4(m ,p,orth o)∆Eσ° + c5(orth o)∆EσI .
(3)
In Eq. (3) ∆log k = log kX – log kH, th e differen ce in solven t electro-
ph ilicities, ∆E = ES – EH2O, was used as param eter of th e m edium . In Eq. (3)
th e reaction con stan ts c1 an d c4 are com m on for orth o, m eta, an d para sub-
stituen ts but c2 an d c5 refer on ly to orth o substituen ts. In Eq. (3) Fujita an d
Nish ioIka12 assum ed th at (σ°)orth o – (σ°)para. Th e term s c2(orth o)σI an d
c5(orth o)∆EσI are a m easure of th e addition al orth o in ductive effect (com -
pared to th e para in ductive effect) for water an d th e addition al orth o in duc-
tive effect depen den t on th e ∆E param eter in th e tran sition from pure water
to bin ary aqueous solution s, respectively.
In th e presen t work, th e supplem en tary kin etic data were available for
th e study variation of substituen t effects with solven t in th e alkalin e h ydro-
lysis of substituted ph en yl tosylates accordin g to th e m ultilin ear relation -
sh ip an d, in addition to th e solven t electroph ilicity (E) scale, th e solven t
polarity (Y), an d polarizability (P) scales were in cluded.
EXPERIMENTAL
Th e preparation procedure an d ch aracteristics of th e substituted ph en yl tosylates an d tech -
n ique of kin etic m easurem en ts are described in lit.1,2,4 an d referen ces th erein . 2-Cyan o- an d
4-cyan oph en yl tosylates were syn th esized by th e reaction of tosyl ch loride with th e corre-
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

202
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
spon din g cyan oph en ols in 1 M aqueous Na2CO3 solution 13 an d recrystallized from 60%
aqueous eth an ol. Both th e ph en yl tosylates were dried in a desiccator over P2O5. Th e esters
were iden tified by m eltin g poin ts an d NMR spectroscopy ch em ical sh ifts (see Sch em e 1). 1H
an d proton -decoupled 13C NMR spectra of com poun ds were m easured in CDCl3 at 300 K on
a Bruker AC-200 spectrom eter. Th e ch em ical sh ifts (δ, ppm ) are referen ced to an in tern al
TMS (δ 0). Couplin g con stan ts (J) are given in Hz.
2-Cyanophenyl tosylate: m .p. 88–89 °C. 1H NMR: 2.46 s, 3 H (CH3); 7.34–7.68 m , 6 H (H-3,
H-4, H-5, H-6, H-9, H-11); 7.72 d, 2 H, 3J = 8.5 (H-8, H-12). 13C NMR: 21.77 (CH3); 114.44
(CN); 150.38 (C-1); 107.91 (C-2); 138.77 (C-3); 127.36 (C-4); 134.26 (C-5); 123.81 (C-6);
146.36 (C-7); 128.84 (C-8, C-12); 130.10 (C-9, C-11); 131.80 (C-10).
4-Cyanophenyl tosylate: m .p. 90.4–90.9 °C. 1H NMR: 2.46 s, 3 H (CH3); 7.14 d, 2 H, 3J = 9.0
(H-2, H-6); 7.35 d, 2 H, 3J = 8.5 (H-9, H-11); 7.62 d, 2 H, 3J = 9.0 (H-3, H-5); 7.72 d, 2 H, 3J =
8.5 (H-8, H-12). 13C NMR: 21.73 (CH3); 117.00 (CN); 152.66 (C-1); 123.43 (C-2, C-6); 133.91
(C-3, C-5); 111.26 (C-4); 146.13 (C-7); 128.47 (C-8, C-12); 130.06 (C-9, C-11); 132.04 (C-10).
As th e reagen t, 0.0950 M tetrabutylam m on ium h ydroxide was used. A carbon dioxide-
free tetrabutylam m on ium h ydroxide solution was prepared from 10% aqueous Bu4NOH
(Ch em apol, reagen t for polarograph y) by passin g th e h ydroxide solution th rough an an -
ion -exch an ge colum n (Am berlite IRA-400) in argon atm osph ere. Th e salt, Bu4NBr (pure
grade, Reakh im , Moscow), was purified by triple recrystallization from aceton e, precipitated
with eth er an d dried in vacuum .
Th e kin etics was m easured spectroph otom etrically as described earlier1. To avoid salt ef-
fect on kin etic m easurem en ts, a n early con stan t alkali con cen tration was used. Th e pseudo-
first-order rate con stan ts, k1 (s–1), were determ in ed usin g a least-squares com puter program .
Th e secon d-order rate con stan ts k (dm 3 m ol–1 s–1) were calculated by dividin g th e pseudo-
first-order rate con stan ts k1 (s–1) by alkali con cen tration . Th e kin etic m easurem en ts were re-
peated m ore th an th ree tim es for each derivative an d th e average values of th e secon d-order
rate con stan ts k (dm 3 m ol–1 s–1) were calculated. Th e k values for substituted ph en yl
tosylates in aqueous 0.5 M Bu4NBr, th e n um ber of m easurem en ts an d th e wavelen gth λ used
in spectroph otom etric kin etic m easurem en ts are given in Table I.
DATA PROCESSING
For study of th e substituen t effects on a sin gle tem perature, th e log k values
of th e alkalin e h ydrolysis of substituted ph en yl tosylates were treated ac-
cordin g to th e Taft equation (4), th e m odified Fujita an d Nish ioka12 equa-
tion (5), an d th e Ch arton 14 equation (6):
T = con st., X is n ot con stan t
log km ,p = log k0 + (ρ°)m ,pσ°
(4)
(5)
(6)
log km ,p,orth o = log k0+ (ρ°)m ,p,orth oσ° + cI(orth o)σI
log korth o = log k0 + (ρ°I)orth oσI + (ρ°R)orth oσ°R .
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
203
TABLE I
Th e secon d-order rate con stan ts k (in dm 3 m ol–1 s–1) for alkalin e h ydrolysis of substituted
ph en yl tosylates, 4-CH3C6H4SO2OC6H4–X, in aqueous 0.5 M Bu4NBr at various tem peraturesa
λ b
n m
102 k c
λb
n m
102 k c
d
d
X
T, °C
n
X
T, °C
n
dm 3 m ol–1 s–1
dm 3 m ol–1 s–1
4-NO2 410
40
50
60
75
40
50
60
75
40
50
60
75
40
50
60
75
50
60
75
50
60
75
85
1.78 ± 0.01
3.75 ± 0.07
3
2-NO2
430
330
290
295
290
40
50
60
75
40
50
60
75
40
50
60
75
40
50
60
75
50
60
75
80
50
60
75
80
2.89 ± 0.05
6.03 ± 0.01
3
4
3
3
4
4
4
3
3
4
3
3
3
6
3
3
3
3
3
3
4
4
3
3
4
7
3
4
4
3
3
3
5
4
3
3
4
3
3
3
3
5
3
3
3
3
6.77 ± 0.19
9.80 ± 0.15
20.1 ± 2.4
26.2 ± 0.8
4-CN
295
0.807 ± 0.035
2.04 ± 0.01
2-CN
2-F
2.24 ± 0.02
4.49 ± 0.14
4.20 ± 0.53
7.55 ± 0.19
9.43 ± 0.33
21.6 ± 0.1
3-NO2 295
0.792 ± 0.039
1.95 ± 0.08
0.131 ± 0.004
0.317 ± 0.006
0.557 ± 0.068
2.09 ± 0.10
3.97 ± 0.21
10.7 ± 0.3
3-Cl
295
0.104 ± 0.013
0.252 ± 0.012
0.621 ± 0.026
1.80 ± 0.20
2-Cl
0.142 ± 0.001
0.294 ± 0.007
0.603 ± 0.037
2.07 ± 0.02
4-Cl
H
302
295
0.145 ± 0.007
0.334 ± 0.005
1.16 ± 0.02
2-CH3
0.00826 ± 0.00018
0.0178 ± 0.0005
0.0877 ± 0.0023
0.131 ± 0.014
0.0105 ± 0.0002
0.0294 ± 0.0059
0.120 ± 0.006
0.165 ± 0.015
0.0224 ± 0.0005
0.0650 ± 0.0021
0.208 ± 0.006
0.331 ± 0.003
2-OCH3 295
a
c
b
Aqueous 0.0950 M Bu4NOH was used. λ is th e wavelen gth used in kin etic m easurem en ts.
k is th e arith m etic m ean value of th e secon d-order rate con stan ts with value of stan dard
d
deviation of arith m etic m ean . n equals to th e n um ber of th e rem ain in g k values after ex-
clusion of sign ifican tly deviatin g rate con stan ts in th e calculation of th e arith m etic m ean
values.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

204
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
Th e activation param eters log A an d activation en ergy E values were cal-
culated accordin g to Eq. (7):
T ≠ con st., X is con stan t
log k = log A – (E/2.3RT) .
(7)
To study th e in fluen ce of th e substituen t effects depen den t on tem pera-
ture, th e log k values were subjected to a regression an alysis usin g Eq. (8):
T ≠ con st., X is n ot con stan t
log km ,p,orth o = c0 + c1(m ,p,orth o)σ° + c2(orth o)σI + c3(1/T) +
+ c4(m ,p,orth o)(1/T)σ° + c5(orth o)(1/T)σI .
(8)
To study th e in fluen ce of solven t effects on variation of substituen t ef-
fects th e ∆log k = log kX – log kH values for ortho-, meta-, an d para-substituted
derivatives at 75 °C in various m edia were correlated with Eqs (9) an d (10):
∆log km ,p,orth o = c0 + c1(m ,p,orth o)σ° + c2(orth o)σI + c3∆E + c4∆Y +
+ c5∆P + c6(m ,p,orth o)∆Eσ° + c7(m ,p,orth o)∆Yσ° +
+ c8(m ,p,orth o)∆Pσ° + c9(orth o)∆EσI + c10(orth o)∆YσI +
+ c11(orth o)∆PσI
(9)
∆log korth o = a0 + a1σI + a2σ°R + a3∆E + a4∆Y +
+ a5∆P + a6∆EσI + a7∆YσI + a8∆PσI +
+ a9∆Eσ°R + a10∆Yσ°R + a11∆Pσ°R .
(10)
Th e in ductive effect from th e orth o position , differen t from th at from th e
m eta an d para derivatives, was assum ed12,15. Sim ilarly, in th e case of orth o
substituen ts, th e variation of th e in ductive term with tem perature an d
solven t param eters, differen t from th at for m eta an d para derivatives, was
assum ed. As a m easure of th e orth o effect, th e addition al in ductive term
an d th e correspon din g cross-term s for orth o substituen ts were in cluded.
For orth o substituen ts, th e reson an ce term an d its variation with tem pera-
ture an d solven t param eters were con sidered to be equal to th ose for para
substituen ts.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
205
Equation s (4)–(6) an d (9) in clude data at a sin gle tem perature, Eq. (8) at
various tem peratures. Th e data for meta- an d para-substituted ph en yl es-
ters sim ultan eously with ortho-substituted esters were treated accordin g to
Eqs (5), (8), an d (9). Th e data for on ly ortho-substituted derivatives were
treated accordin g to Eqs (6) an d (10), an d for meta- an d para-substituted
esters with Eqs (4), (8), an d (9) to com pare th e susceptibilities obtain ed
with th ose determ in ed with th e sim ultan eous use of data for ortho-, meta-,
an d para-substituted derivatives. In processin g of data for ortho-substituted
derivatives with Eqs (6) an d (10), th e log k value for th e un substituted de-
rivative (X = H) as stan dard was in cluded besides th e ortho-substituted de-
rivatives.
18
The Taft polar σ° 16,17, inductive σI and resonance σ°R (σ°R = (σ°)para – σI)19
scales were used in th e data processin g (Table II). In th e data processin g
(σ°)orth o = (σ°)para were used. Th e previous statistical data treatm en t1,4
TABLE II
Substituen t param eters used for correlation an d values of log A an d activation en ergy E
(in kJ m ol–1) for alkalin e h ydrolysis of substituted ph en yl tosylates, 4-CH3C6H4SO2OC6H4–X,
in aqueous 0.5 M Bu4NBr, calculated usin g Eq. (7)
16,17
18
19
X
H
σo
σI
σo
log A
E, kJ m ol–1
R
s
n
R
0
0
0
9.856 ± 0.470 83.44 ± 3.05
9.486 ± 0.343 81.00 ± 2.18
8.617 ± 0.376 62.20 ± 2.36
8.523 ± 0.685 63.40 ± 4.39
9.089 ± 0.321 66.96 ± 2.01
9.417 ± 0.270 74.30 ± 1.70
9.771 ± 0.236 78.06 ± 1.51
7.822 ± 0.419 56.10 ± 2.64
8.005 ± 0.465 57.94 ± 2.93
8.691 ± 0.531 69.34 ± 3.33
8.842 ± 0.735 70.34 ± 4.64
0.998
0.999
0.998
0.993
0.999
0.999
0.999
0.997
0.996
0.997
0.994
0.995
0.999
0.033
0.034
0.029
0.053
0.025
0.021
0.012
0.033
0.036
0.041
0.057
0.056
0.027
4
5a
4
4
4
4
3
4
4
4
4
4
4
4-NO2
4-CN
3-NO2
3-Cl
0.81
0.72
0.71
0.37
0.28
0.81
0.72
0.28
0.21
–
–
–
–
–
–
–
–
–
4-Cl
–
2-NO2
2-CN
2-Cl
0.63
0.58
0.47
0.52
–0.05
0.25
0.19
0.11
–0.20
–0.35
2-F
2-CH3
–0.14
–0.10 10.411 ± 0.790 89.91 ± 5.11
–0.41 10.289 ± 0.383 88.21 ± 2.49
2-OCH3 –0.15
a
Th e log k = –4.001 value calculated with Eq. (4) at 40 °C, was in cluded in addition to th e
experim en tal log k values.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

206
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
con fim ed th at th ere was n o reson an ce in th e case of 2-N(CH3)2 substituen t
an d in th e com m on data treatm en t th e correction ρσ°R was added. In th e
case of ortho-substituted derivatives, th e σI scale was in cluded for takin g
in to con sideration th e addition al in ductive effect from orth o position .
Main ly th e followin g substituen ts were in cluded: X = H, 4-NO2, 3-NO2,
4-CN, 4-Cl, 3-Cl, 4-NH2, 3-NH2, 4-N(CH3)2, 3-N(CH3)2, 4-CH3, 3-CH3,
4-OCH3, 3-OCH3, 2-NO2, 2-CN, 2-F, 2-Cl, 2-CH3, 2-OCH3, 2-NH2,
2-N(CH3)2.
In th e data processin g accordin g to Eqs (4)–(8) th e secon d-order rate con -
stan ts k2 of th e alkalin e h ydrolysis of ortho-, meta-, an d para-substituted
ph en yl tosylates in 0.5 M aqueous Bu4NBr at various tem peratures, reported
in Table I, were used. In Eqs (9) an d (10) th e an alogous data for th e alkalin e
h ydrolysis of ortho-, meta-, an d para-substituted ph en yl tosylates at 75 °C in
pure water, aqueous 0.5 M Bu4NBr (presen t work), 1 M Bu4NBr, 2.25 M
Bu4NBr, 80% (v/v) DMSO, 5.3 M NaClO4, an d 4.8 M NaCl (lit.1,2,4 an d refer-
en ces th erein ) were in cluded. In Eq. (9) th e values of ∆E, ∆Y, an d ∆P are th e
differen ces in electroph ilicities, polarities an d polarizabilities on goin g from
pure water to th e correspon din g aqueous bin ary solution , ∆E = ES – EH2O
,
∆Y = YS – YH2O, an d ∆P = PS – PH2O, respectively. Th e stan dard m edium ,
wh ere ∆E, ∆Y, an d ∆P are equal to zero, is pure water an d th e stan dard
substituen t is X = H. Th e electroph ilicity E values of Koppel an d Palm 8,20–22
,
polarity Y calculated as fun ction of dielectric perm ittivity ε in th e form
(ε – 1)/(ε + 2) an d th e polarizability P as a fun ction of refractive in dex nD in
th e form (n2 – 1)/(n2 + 2) were used.
Th e data processin g was carried out usin g a m ultiple-param eter lin ear
least-squares (LLSQ) procedure23. Th e sign ifican tly deviatin g poin ts were
excluded usin g th e Studen t criterion . Th e exclusion of th e sign ifican tly de-
viatin g poin ts was perform ed on differen t con fiden ce level of th e t-test23
.
Results of th e data treatm en t in th e presen t work are given m ain ly on th e
con fiden ce level 0.99.
Th e substituen t param eters used in th e correlation s an d th e values of
log A an d activation en ergies, E (kJ m ol–1), for aqueous 0.5 M Bu4NBr calcu-
lated with th e Arrh en ius equation (7), are listed in Table II. Th e results of
th e data treatm en t with Eqs (4)–(6) at various tem peratures an d th ose in -
cludin g various tem peratures (Eq. (8)) are presen ted in Tables III an d IV, re-
spectively. Th e values of solven t ch aracteristics used in data treatm en t are
listed in Table V. Th e results of th e data treatm en t with Eq. (9) are collected
in Table VI. Th e depen den ce of (ρ°)m ,p an d (ρI)orth o on (1/T) an d on th e sol-
ven t electroph ilicity ∆E are sh own in Figs 1 an d 2.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
207
DISCUSSION
Influence of Substituents and Temperature in aqueous 0.5 M Bu4NBr
Th e
alkalin e
h ydrolysis
of
substituted
ph en yl
tosylates,
4-CH3C6H4SO2OC6H4–X, is con sidered to proceed by bim olecular n ucleo-
ph ilic substitution m ech an ism SN2 35–37, wh ich in volves th e attack of th e
n egatively ch arged h ydroxide ion on th e sulfur atom . Th e acyl-oxygen
bon dbreakin g h as been proved. Th e positive ρ values for th e alkalin e h y-
drolysis of substituted ph en yl tosylates in dicate th at electron -with drawin g
groups stabilize th e tran sition state by delocalization of th e fraction al n ega-
tive ch arge in th e tran sition com plex. Th e electron -don atin g groups de-
stabilize th e tran sition state with n egative ch arge or stabilize th e groun d
state of esters by decreasin g th e fraction al positive ch arge on th e sulfur
atom in esters of 4-m eth ylben zen e-1-sulfon ic acid.
For m ost substituted ph en yl tosylates th e tran sition s from pure water to
aqueous 0.5 M Bu4NBr solution result in a decrease in th e rate con stan ts of
alkalin e h ydrolysis. Th e retardation was foun d to be lower for esters with
TABLE III
Results of th e correlation with Eqs (4)–(6) for alkalin e h ydrolysis of substituted ph en yl
tosylates, 4-CH3C6H4SO2OC6H4–X, in aqueous 0.5 M Bu4NBr at various tem peraturesa
T
Equa-
log k0
(ρo)m ,p(orth o)
cI(orth o) or ρI(orth o)
(ρo
)
s0
n/n0
R
R
orth o
°C tion
75 (4)
(5)
–2.645 ± 0.043
–2.635 ± 0.083
–2.730 ± 0.106
–3.168 ± 0.019
–3.178 ± 0.048
–3.240 ± 0.107
–3.624 ± 0.019
–3.640 ± 0.038
–3.709 ± 0.130
–4.001 ± 0.089
–3.995 ± 0.079
2.356 ± 0.076
2.309 ± 0.084
–
–
–
–
0.997 0.07
0.994 0.11
6/6
12/12
7/7
0.543 ± 0.110
3.041 ± 0.203
–
(6)
1.922 ± 0.252 0.991 0.13
60 (4)
(5)
2.489 ± 0.033
2.482 ± 0.070
–
–
–
0.999 0.03
0.996 0.09
6/6
0.462 ± 0.094
3.092 ± 0.206
–
12/12
7/7
(6)
2.188 ± 0.252 0.992 0.013
50 (4)
(5)
2.709 ± 0.034
2.729 ± 0.055
–
–
–
0.999 0.024
6/6
0.495 ± 0.078
3.491 ± 0.250
–
0.998 0.058 11/12
(6)
2.278 ± 0.307 0.990 0.14
7/7
40 (4)
(5)
2.712 ± 0.160
2.694 ± 0.110
–
–
0.995 0.10
0.993 0.118 10/10b
4/4
0.682 ± 0.140
a
b
cI(orth o) is th e susceptibility to th e addition al orth o in ductive effect in Eq. (5). Th e log k =
–4.001 value for un substituted derivative calculated with Eq. (4) an d th e log k values for
2-OCH3- an d 2-CH3-derivatives calculated with Eq. (7) (–4.386 an d –4.584, respectively) were
in cluded in addition to th e experim en tal log k values.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

208
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
TABLE IV
Results of th e correlation of kin etic data with Eq. (8) for alkalin e h ydrolysis of substituted
ph en yl tosylates in 0.5 M Bu4NBr at various tem peratures
ortho-, meta- an d
meta- an d para-
Reaction con stan t
Weigh t
0.75
para-substituted
Weigh t
substituted derivatives
derivatives
c0
9.778 ± 0.373
–1.305 ± 0.416
–
9.433 ± 0.575
–0.853 ± 0.973
–1.128 ± 1.399
–4.210 ± 0.190
1.122 ± 0.322
0.566 ± 0.464
49/49a
c1(m ,p,orth o)
0.82
0.045
0.14
0.01
0.01
c2(orth o)
c3 × 10–3
–4.317 ± 0.126
1.271 ± 0.373
–
0.24
c4(m ,p,orth o) × 10–3
0.044
c5(orth o) × 10–3
n/n0
23/23a
R
s
0.999
0.995
0.037
0.098
s0
t
0.043
0.099
0.999
0.999
a
Th e log k = –4.001 value for un substituted derivative calculated with Eq. (4) at 40 °C was
b
in cluded in addition to th e experim en tal log k values.
Th e log k = –4.001 value for
un substituted derivative calculated with Eq. (4) at 40 °C an d th e log k values for 2-OCH3-de-
rivatives calculated with Eq. (7) (–4.386) were in cluded in addition to th e experim en tal log k
values.
TABLE V
Th e values of electroph ilicity E, dielectric perm ittivity ε, refractive in dex nD, polarizability
P = (n2 – 1)/(n2 + 2), an d polarity Y = (ε – 1)/(ε + 2) at 25 °C for aqueous solution s
20–22,23
20–23
Medium
E
nD
ε
P
Y
∆E
∆P
∆Y
24
Water
21.74
16.53
13.77
8.11
1.333
1.363
1.383
1.447
78.39
0.2057 0.9627
0.2223 0.9525
0.2333 0.9429
0
0
0
25
0.6 M Bu4NBra
1.0 M Bu4NBr
2.25 M Bu4NBr
5.3 M NaClO4
80% DMSO
4.8 M NaCl
30% EtOH
61.2
50.5
60.29
–5.21 0.0166 –0.0102
–7.97 0.0276 –0.0198
25
26
27
0.2672 0.9518 –13.63 0.00615 –0.0109
0.2272 0.9128 3.79 0.0215 –0.0499
0.2713 0.9544 –13.81 0.0656 –0.0083
28
25.53b 1.3719
32.4
63.8
29
30
32
7.93
22.34b 1.3757
1.455
31
31
31
31
43.33
0.2293 0.9338
0.2155 0.9543
0.2221 0.9384
0.2238 0.9183
0.60 0.0236 –0.0289
–5.07 0.0098 –0.0084
–8.30 0.0164 –0.0243
–9.22 0.0181 –0.0444
34
16.67
13.84
12.83
1.3506
1.3626
1.3657
63.6
46.7
34.7
34
34
60% EtOH
80% EtOH
a
In th e case of aqueous 0.5 M Bu4NBr solution th e ch aracteristics for 0.6 M Bu4NBr were
b
used as m uch as th e con cen tration of Bu4NOH was taken in to accoun t. Determ in ed for
m eth an olic solution .
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
209
TABLE VI
Results of th e correlation with Eqs (9) an d (10) for kin etic data of alkalin e h ydrolysis of sub-
stituted ph en yl tosylates, 4-CH3C6H4SO2OC6H4–X, in various m edia at 75 °C a,b,c. Solven t
electroph ilicity param eter, ∆E, was in cluded
Meta, para
substituen ts
Eq. (9)
Orth o, m eta, para
substituen ts
Eq. (9)
Orth o
substituen ts
Eq. (10)
Reaction
con stan t
Weigh t
Weigh t
Weigh t
c0(a0)
0.057 ± 0.039
0.047 ± 0.027
–0.019 ± 0.069
0.052 ± 0.033a
0.045 ± 0.025a
–0.037 ± 0.071a
c1(m ,p,orth o)
c2(orth o)
a1(orth o)
a2(orth o)
c3(a3)
1.806 ± 0.062
0.95
0.96
1.863 ± 0.015
0.91
0.93
0.06
0.05
–
–
–
1.818 ± 0.056a
1.806 ± 0.012a
–
–
–
–
–
–
0.853 ± 0.005
0.832 ± 0.003a
–
2.772 ± 0.124
2.802 ± 0.017a
1.704 ± 0.131
1.710 ± 0.019a
0.0037 ± 0.0060
0.0053 ± 0.0066a
–
–
–
–
–
0.63
0.64
0.34
0.35
0.001
0.004
0.025 ± 0.0036
0.04
0.0094 ± 0.0016
0.002
0.002
0.03
0.015
0.001
0.001
0.0033 ± 0.0001a 0.03
0.0051 ± 0.0022a
c6(m ,p,orth o) –0.656 ± 0.0077
0.003
–0.0699 ± 0.0046
–0.0698 ± 0.0069a 0.004
–0.0856 ± 0.0042a
–
–
–
c9(orth o)
–
–
–
–
–
0.0360 ± 0.0085
0.0480 ± 0.0070a
a6(orth o)
–
–
–
–
–0.0346 ± 0.0143
–0.0406 ± 0.0154a
–0.0751 ± 0.0151
–0.0747 ± 0.0163a
47/47
0.004
0.004
0.014
0.011
–
–
–
a9(orth o)
–
n/n0
45/45
60/60a
0.990
0.992a
0.119
0.112a
0.144
0.133a
0.999
0.999a
75/85
95/115a
0.995
0.996a
0.102
0.083a
0.105
0.088a
0.95
64/64a
R
s
0.989
0.987a
0.154
0.169a
s0
t
0.149
0.160a
0.999
0.95a
0.999a
a
Th e log k values for 30, 60, an d 80% aqueous EtOH at 60 °C as well as for pure water,
0.6 M Bu4NBr, 1.0 M Bu4NBr, 2.25 M Bu4NBr, 80% DMSO, 5.3 M NaClO4, 4.8 M NaCl at 75 °C
b
were in cluded. Th e program m akes it possible to treat data in four differen t ways: 1. Exclu-
sion of in sign ifican t argum en t scales was perform ed before excludin g con siderably deviatin g
poin ts. 2. Exclusion of sign ifican tly deviatin g poin ts was perform ed before excludin g in -
sign ifican t argum en t scales. Both ways of data treatm en t h ave two differen t m odes of form -
in g cross term s: (i) Cross term s can be form ed from cen tered basic argum en t scales. (ii) Cross
term s are form ed from n on -cen tered basic argum en t scales. Wh en th e values for in sign i-
fican t scales are sh own , th e cross term s were form ed from cen tered basic argum en t scales.
c
A table con tain in g th e results of th e correlation s with Eqs (9) an d (10) for kin etic data of
alkalin e h ydrolysis of substituted ph en yl tosylates, 4-CH3C6H4SO2OC6H4–X, in various m e-
dia at 75 °C wh en th ree solven t param eters, th e solven t electroph ilicity, ∆E, th e solven t po-
larity, ∆Y, an d th e solven t polarizability, ∆P, were in cluded, is available as supplem en tary
m aterial (Table SI).
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

210
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
electron -with drawin g substituen ts but h igh er in th e case of electron -
don atin g substituen ts. Wh en goin g from water to aqueous 0.5 M Bu4NBr
for 4-NO2-substituted derivative n o decrease in th e rate of alkalin e h ydro-
lysis at 75 °C was detected but for th e un substituted derivative th e decrease
in th e log k value was foun d to be about 0.5 un its com pared with th e corre-
spon din g values in water1.
4
3
2
1
0
–1
–2
–3
0
0.0005
0.0010 0.0015 0.0020
0.0025
1/T
0.0030 0.0035
FIG. 1
Depen den ce of (ρ°)m ,p an d (ρI)orth o on (1/T) for th e alkalin e h ydrolysis of substituted ph en yl
tosylates in 0.5 M aqueous Bu4NBr: ᭿ orth o substituen ts, ٗ m eta an d para substituen ts
4
3
2
1
0
–5
0
5
10
15
20
25
–∆E
FIG. 2
Depen den ce of (ρ°)m ,p an d (ρI)orth o on th e solven t electroph ilicity ∆E for th e alkalin e h ydroly-
sis of substituted ph en yl tosylates1,2,4 an d ben zoates3 in various m edia. Sh aded circles an d tri-
an gles den ote ortho-substituted derivatives
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
211
Earlier th e variation of th e reaction rates due to th e polar effect of sub-
stituen ts in th e alkalin e h ydrolysis of meta- an d para-substituted ph en yl
tosylates was described by σ° con stan ts. In th e case of orth o derivatives, th e
in fluen ce of substituen ts appeared to be well described wh en th e com ple-
m en tary in ductive scale was in cluded. For th e alkalin e h ydrolysis of substi-
tuted ph en yl tosylates in water, th e in ductive effect from orth o position
was foun d to exceed th at from para position , but th e reson an ce from orth o
position appeared to be equal to th at from para position .
In aqueous 0.5 M Bu4NBr th e log k values for meta- an d para-substituted
derivatives gave excellen t correlation with σ° con stan ts (Eq. (4), Table III)
as was foun d earlier1,2,4 for water, aqueous 2.25 M Bu4NBr, 5.3 M NaClO4,
80% DMSO as well as for 30, 60, an d 80% aqueous eth an ol. Wh en data
for ortho-substituted derivatives were treated sim ultan eously with m eta
an d para derivatives (Eq. (5)), th e addition al in ductive σI scale was in cluded
for orth o substituen ts. Wh en on ly ortho-substituted derivatives were trea-
ted, th e Ch arton equation (6) was used. Th e values of reaction con stan ts for
ortho-substituted derivatives (ρI)orth o, an d (ρR)orth o calculated with Eq. (6)
separately for ortho-substituted derivatives were approxim ately th e sam e
wh en calculated sim ultan eously with ortho-, meta-, an d para-substituted
derivatives: (ρI)orth o = (ρ°)m ,p,orth o + c1(orth o) an d (ρR)orth o = (ρ°)m ,p,orth o (see
Table III).
Th e (ρ°)m ,p an d (ρI)orth o for 0.5 M Bu4NBr at various tem peratures ran ged
between 2.3–2.7 an d 2.9–3.4, respectively. Earlier th e (ρ°)m ,p an d (ρI)orth o for
pure water were foun d in ran ges 1.75–1.88 an d 2.8–3.0 4. In tran sition from
pure water to aqueous 0.5 M Bu4NBr th e polar effect of m eta an d para sub-
stituen ts in creased by ca. 0.5–0.6 un its of (ρ°)m ,p. At th e sam e tim e th e
ch an ge in th e susceptibility to th e orth o in ductive effect, (ρI)orth o, was es-
sen tially lower, in ran ges 0.15–0.20 un its of (ρI)orth o. Earlier,3 on goin g from
pure water to aqueous 2.25 M Bu4NBr, th e ch an ge in th e (ρ°)m ,p, an d (ρI)orth o
values in th e alkalin e h ydrolysis of substituted ph en yl tosylates as in th e al-
kalin e h ydrolysis of ph en yl ben zoates occurred in ran ges 0.9–1.1 an d
0.4–0.5, respectively, th ough th e susceptibilities to th e polar in fluen ce of
orth o, m eta, an d para substituen ts in water differed two-fold. Th e an alysis
of data for alkalin e h ydrolysis of ph en yl tosylates in aqueous 0.5 M Bu4NBr
dem on strates on ce again th at th e orth o in ductive term varies with solven t
m ore th an twice less com pared with th e para in ductive term . In th e case
of alkalin e h ydrolysis of substituted ph en yl tosylates, th e orth o effect (i.e.
X
log korth o – log kparaX) of n early 1.0 un its of (ρI)orth o in pure water dim in -
ish es to 0.6 un its in 0.5 M Bu4NBr an d 0.45 un its in 2.25 M Bu4NBr. Wh en
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

212
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
th e in ductive term of para substituen ts reach es th e level of orth o substitu-
en ts, th e orth o effect caused by th e in duction effect disappears.
To study th e variation of th e orth o in ductive an d reson an ce effects as
well as th e m eta an d para polar effects with tem perature, th e kin etic data at
various tem peratures were processed accordin g to Eq. (8) (Table IV) in clud-
in g th e data sim ultan eously for ortho-, meta-, an d para-substituted deriva-
tives an d separately for m eta an d para derivatives. Wh en th e data for meta-
an d para-substituted derivatives were processed with Eq. (8), th e addition al
term s for orth o substituen ts were om itted.
Equation (8) is a m ultilin ear relation sh ips with cross term s. Accordin g to
Palm an d Istom in 20,38 th is kin d of equation s exh ibit a rem arkable property
called isoparam etricity. Th e ph en om en on of isoparam etrical relation sh ip is
possible if th ere are represen ted th e cross term s in correlation equation . Th e
isoparam etrical poin t for tem perature T is kn own as isokin etical (or iso-
equilibrium ) tem perature. At isokin etical tem perature all reaction s of th e
series in cludin g various substituen ts sh ould proceed with th e sam e rate.
It follows from th e results of th e statistical data processin g accordin g to
Eq. (8) (Table IV) th at th e log k values for th e alkalin e h ydrolysis of substi-
tuted ph en yl tosylates in 0.5 M Bu4NBr could be correlated quite well with
th e m odified Fujita an d Nish ioka equation (8). Th e con stan ts c0 an d c3 be-
lon g to un substituted derivatives an d th eir values do n ot depen d on sub-
stituen ts, in cludin g eith er th e data on ly for meta- an d para-substituted de-
rivatives or th e data set th at can em brace th e ortho-substituted derivatives
as well. Th e reaction con stan t c0 is n early equal to th e log A for un sub-
stituted derivative (for X = H, log A = 9.486, Table II). In Eq. (8) th e wh ole
en tropy term for ortho-substituted derivatives is expressed by th e sum c0 +
c1(m ,p,orth o)σ° + c2(orth o)σI. Th e sen sitivity of th e en tropy term to th e in ductive
in fluen ce of orth o substituen ts cI(orth o) could be written as cI(orth o)
=
c1(m ,p,orth o) + c2(orth o) wh ile th e sen sitivity of th e en tropy term to reson an ce
of orth o substituen ts cR(orth o) is con sidered to be th e sam e as in th e case of
para-substituted derivatives, i.e. cR(orth o) = c1(m ,p,orth o). Sim ilarly, th e suscepti-
bility of th e orth o in ductive effect to tem perature variation in Eq. (8) is ex-
pressed as sum cI(T)(orth o) = c4(m ,p,orth o) + c5(orth o)
.
For aqueous 0.5 M Bu4NBr we foun d th e cI(orth o) = –1.98 an d th e values of
c1(m ,p) in th e ran ge from –0.85 to –1.31 (Table IV). For pure water1 th e val-
ues of cI(orth o) were in th e ran ge from –1.45 to –2.2 an d c1(m ,p) = 0 (in aque-
ous 80% DMSO an d 2.25 M Bu4NBr c1(m ,p) ≈ –1.40).
Th e polar effect of m eta an d para substituen ts, th e in ductive an d reso-
n an ce effects of orth o substituen ts were foun d to decrease with in creasin g
tem perature. In th e case of m eta an d para substituen ts, th e susceptibility of
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
213
th e polar effect to th e tem perature variation of c4(m ,p,) was foun d to be in
th e ran ge 1.12 × 103–1.27 × 103 (Table IV). Wh en goin g from water to aque-
ous 0.5 M Bu4NBr th e depen den ce of th e m eta an d para polar effects on
tem perature in creased by ca. 0.6 un its of c4(m ,p) (c4(m ,p) is ca. 0.6 × 103 in
pure water1). In aqueous 0.5 M Bu4NBr th e tem perature depen den ce of th e
orth o in ductive effect appeared to be sligh tly greater, cI(T)(orth o) = 1.7 × 103
(= c4(m ,p,orth o) + c5(orth o)) (Table IV), th an th at for para substituen ts. Th e in -
crease in th e orth o in ductive effect with tem perature on goin g from pure
water to aqueous 0.5 M Bu4NBr is on ly 0.2 × 103 un its of cI(T)(orth o) (in water
cI(T)(orth o) was ca. 1.5 × 103). Con sequen tly, th e variation of th e orth o in duc-
tive term with tem perature was foun d to be about twice sm aller th an th e
polar effect of m eta an d para substituen ts. Sim ilarly, in th e alkalin e h ydro-
lysis of substituted ph en yl tosylates an d ben zoates1–3, in tran sition from
pure water to aqueous 2.25 M Bu4NBr an d 80% DMSO, th e variation of th e
orth o in ductive term with tem perature was foun d to be h alf th at for para
substituen ts, but by tran sfer from pure water to aqueous 5.3 M NaClO4 th e
depen den ce of th e orth o in ductive in fluen ce on tem perature was practi-
cally un ch an ged.
In tran sition from water to m edia, th e electroph ilic solvatin g power of
wh ich is reduced com pared with water, th e polar effect of substituen ts an d
th e sen sitivity to tem perature variation was en h an ced. In pure water th e
variation of th e orth o in ductive term with tem perature was foun d to be
m ore th an twice larger th an th at for para substituen ts. Due to a reduced
variation of th e orth o tem perature-depen den t in ductive term with solven t
an d tem perature, com pared to th at of para substituen ts, a con siderable de-
X
crease in th e orth o effect (i.e. log korth o – log kparaX), caused by an in ductive
in fluen ce, h as been observed wh en goin g from water to less electroph ilic
m edia.
Th e variation of th e reaction rates with th e substituen t an d tem perature
in alkalin e h ydrolysis of substituted ph en yl tosylates was well described by
Eq. (8) (Table IV).
(log kcalc m ,p,orth o = 9.433 – (0.853σ°)m ,p,orth o –
)
– (1.128σI)orth o – 4.210(103/T) +
+ [1.122(103/T)σ°]m ,p,orth o + [0.566(103/T)σI]orth o
(11)
R = 0.995, s = 0.098, s0 = 0.099, n/n0 = 49/49
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

214
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
Th e predicted log kcalc values calculated with Eq. (11) (Table IV) an d th e ex-
perim en tal log kobs values (Table I) for ortho-, meta-, an d para-substituted de-
rivatives were com pared.
(log kobs m ,p,orth o
)
= –(0.013 ± 0.035) +
+ (0.993 ± 0.015)(log kcalc m ,p,orth o
)
(12)
R = 0.995, s = 0.093, s0 = 0.102, n/n0 = 47/47
In th e alkalin e h ydrolysis of substituted ph en yl tosylates th e depen den ce
for th e polar effect of m eta an d para substituen ts as well as th e orth o reso-
n an ce term on tem perature in water was an isoen tropic relation sh ip (c1(m ,p)
=
0)2. We con sider th at in aqueous 0.5 M Bu4NBr, sim ilarly to pure water, th e
depen den ce of th e orth o in ductive term on tem perature for tosylates reac-
tion series correspon ds to an isoparam etric relation sh ip, i.e. belon gs to th e
isokin etic relation sh ip as m uch th e term s cI(orth o)σI an d cI(T)(orth o)(1/T)σI ap-
peared to be differen t from zero (cI(orth o) = –1.98, cI(T)(orth o) = 1.7 × 103)20,38
.
Th e depen den ce of th e m eta an d para polar effect term on tem perature in
tosylates reaction series turn ed to th e isokin etic relation sh ip series wh en
goin g from water to aqueous 0.5 M Bu4NBr as factors c1(m ,p)σ° an d
c
4(m ,p)(1/T)σ° appeared to be sign ifican t (c1(m ,p) is in th e ran ge from –0.85 to
–1.31), c4(m ,p) is ca. 1.2 × 103) (Table IV).
For com parison , th e m odels of an isoen tropic, isoen th alpic, an d iso-
kin etic relation sh ips were tested usin g special program developed by
Exn er39. Th e log k values for th e alkalin e h ydrolysis of substituted ph en yl
tosylates in aqueous 0.5 M Bu4NBr were subjected to th e statistical an alysis
separately for ortho-substituted derivatives, an d meta- an d para-substituted
derivatives. So, in th e case of orth o substituen ts as m eta an d para substitu-
en ts, th e isoen th alpic relation sh ip was rejected an d both th e isoen tropic
an d isokin etic relation sh ips appeared to be accepted. Accordin g to th e sta-
tistical criterion s th e isokin etic an d isoen tropic relation sh ips could be con -
sidered as in distin guish able on es. Due to th e relatively large deviation s, th e
reaction s con stan ts c1(m ,p) an d c2(orth o) (Table IV) could be con sidered as in -
distin guish able from zero an d th e reaction series could be con sidered as iso-
en tropic as well.
Assum in g th e isokin etic relation sh ip for th e alkalin e h ydrolysis of sub-
stituted ph en yl tosylates in aqueous 0.5 M Bu4NBr (Fig. 1), we calculated
th e isokin etic tem peratures β for th e orth o in ductive effect38: βI(orth o)
=
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
215
–cI(T)(orth o)/cI(orth o) = 852 K, an d for m eta an d para polar effect: βm ,p
=
–c4(m ,p)/c1(m ,p) = 974 K (Table IV). Approxim ately th e sam e values for
isokin etic tem peratures β were foun d from th e depen den ce of ρ on tem per-
ature ρT = c0 + c1(1/T) 40 (see Fiq. 1): βI(orth o) = 802 K [ρI(orth o) = (–2.154 ±
0.942) + (1.727 ± 0.309)(103/T)] an d βm ,p = 1066 K [ρ(m ,p) = (–1.144 ± 0.844) +
(1.220 ± 0.276)(103/T)]. Th e isokin etic tem perature for th e addition al orth o
in ductive effect β(orth o=para) = –c5(orth o)/(c2(orth o)σI = 566/1.128 = 502 K. Th e
sam e value for th e addition al orth o in ductive effect β(orth o=para) = 500 K was
earlier foun d for th e sam e reaction series in water1. At isokin etic tem pera-
ture β(orth o=para) th e addition al orth o in ductive in fluen ce from orth o posi-
tion disappears an d th e polar effect of orth o substituen ts becom e equal to
th at for para substituen ts.
Th e depen den ce of th e activation en ergies E on th e substituen t effects
in th e alkalin e h ydrolysis of meta- an d para-substituted as well as ortho-sub-
stituted ph en yl tosylates is en tirely caused by polar effects of substituen ts
(Table II). In th e alkalin e h ydrolysis of tosylates, th e electron -with drawin g
substituen ts stabilize th e tran sition state by delocalization of th e fraction al
n egative ch arge in th e tran sition com plex, an d, th erefore, decrease th e acti-
vation en ergy E. Th e electron -don atin g groups destabilize th e tran sition
state with n egative ch arge or stabilize th e groun d state of esters by decreas-
in g th e fraction al positive ch arge on th e sulfur atom in esters of
4-m eth ylben zen esulfon ic acid, so an in crease in th e activation en ergy could
be observed. Th e in fluen ce of th e orth o, m eta, an d para substituen t polar
effect on th e activation en ergy is greater in aqueous 0.5 M Bu4NBr com -
pared with th at in water. Th e activation en ergy for ortho-substituted deriva-
tives in aqueous 0.5 M Bu4NBr was foun d to be lower th an th ose for para-
substituted derivatives. However, in 0.5 M Bu4NBr th e decrease in th e dif-
X
X
feren ce Epara – Eorth o com pared to th at in pure water could be observed.
Wh ile th e ch an ge in th e tem perature-depen den t orth o polar effect is essen -
tially lower th an th at for para substituen ts on goin g from water to aqueous
0.5 M Bu4NBr, for ortho-substituted derivatives th e ch an ge in th e activation
en ergy is greater th an th at for para-substituted derivatives an d com parable
to th at for un substituted derivatives. Th e activation en ergy E for th e alka-
lin e h ydrolysis of substituted ph en yl tosylates (Table II) appeared to in -
crease for all substituen ts on goin g from water to aqueous 0.5 M Bu4NBr.
However, for esters with electron -don or substituen ts th e in crease in acti-
vation en ergies is greater th an in th e case of electron -with drawin g sub-
stituen ts. For in stan ce, th e ch an ge in activation en ergies on goin g from
pure water to aqueous 0.5 M Bu4NBr for un substituted derivative was ca.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

216
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
11 kJ m ol–1, wh ereas for 4-NO2 substituen t ca. 2 kJ m ol–1. Th e ch an ges in
th e activation en ergies for ortho-substituted derivatives were greater th an
th at for para-substituted on es: for 2-NO2 an d 4-NO2 substituen ts ca. 7 an d
2 kJ m ol–1, respectively (Table II). In aqueous solution s, th e activation en er-
gies for un substituted, 2-NO2 an d 4-NO2 derivatives were foun d to be
70.55, 48.69, an d 59.91 kJ m ol–1, respectively.
Th e log A values for orth o substituen ts in 0.5 M Bu4NBr appeared to be
sm aller th an th ose for para substituen ts due to th e addition al term c2(orth o)σI
(Table II).
Dependence of Substituent Effects on Solvent Parameters
In order to study th e in fluen ce of solven t param eters on substituen t effects
in th e alkalin e h ydrolysis of substituted ph en yl tosylates, th e ∆log k values
at 75 °C for various m edia (water, aqueous 0.5 M Bu4NBr, 1 M Bu4NBr,
2.25 M Bu4NBr, 80% DMSO, 5.3 M NaClO4, 4.8 M NaCl an d 30, 60, an d
80% EtOH) were subjected to th e m ultilin ear regression an alysis accordin g
to Eqs (9) an d (10) in two differen t ways: (i) on ly th e solven t electro-
ph ilicity, ∆E, or (ii) all th ree solven t param eters, th e solven t electro-
ph ilicity, ∆E, th e solven t polarity, ∆Y, an d th e solven t polarizability, ∆P,
were in cluded (Table VI). For com parison , th e data treatm en t is sh own
separately for meta- an d para-substituted derivatives (Eq. (9)) an d ortho-
substituted derivatives ((Eq. (10)) as well as sim ultan eously for ortho-, meta-,
an d para-substituted derivatives (Eq. (9), Table VI).
Th e reaction con stan ts c0, c1(m ,p,orth o), c2(orth o), an d a1(orth o) an d a2(orth o) as
in tercepts an d th e values of ch aracteristics of th e substituen t effects in pure
water appeared to be rath er con stan t values th at do n ot depen d sign ifi-
can tly on th e way used for data treatm en t; th e data in cluded eith er on ly for
meta- an d para-substituted derivatives or for ortho-substituted derivatives, or
th e data set can em brace th e data sim ultan eously for ortho-, meta-, an d para-
substituted derivatives. Th e in tercept values c0 an d a0 in all cases did n ot
exceed 0.1. Th e reaction con stan t c1(m ,p,orth o) is com m on for ortho-, meta-,
an d para-substituted derivatives. In th e case of m eta an d para derivatives it
sh ows th e susceptibility to th e polar effect of m eta an d para substituen ts in
stan dard solution , pure water at 75 °C (Table VI). Th e values of c1(m ,p,orth o)
foun d in differen t ways, appeared to vary in quite a n arrow ran ge, from
1.80 to 1.90. Earlier, th e (ρ°)m ,p value for th e alkalin e h ydrolysis of sub-
stituted ph en yl tosylates in water at 75 °C was foun d to be in ran ge
1.67–1.75 1,4. Th e reaction con stan ts c2(orth o), a1(orth o), an d a2(orth o) are th e
ch aracteristics of th e in ductive an d reson an ce effects in pure water for
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
217
orth o substiten ts on ly. Th e reaction con stan t c2(orth o) is th e ch aracteristic of
th e addition al orth o in ductive effect in pure water. Th e con stan ts a1(orth o)
an d a2(orth o) are th e total susceptibilities to th e orth o in ductive an d reso-
n an ce effects, respectively. Th e calculated susceptibility to th e orth o in duc-
tive effect for water at 75 °C appeared to be a rath er fixed value n ot depen d-
in g on wh eth er it could be calculated as sum of reaction con stan ts
c1(m ,p,orth o) + c2(orth o) for orth o, m eta, an d para derivatives in com m on data
treatm en t or calculated with Eq. (10) as reaction con stan t a1(orth o) for orth o
derivatives on ly. In Table VI th e sum of c1(m ,p,orth o) + c2(orth o) an d th e values
of a2(orth o) ran ges between 2.65 an d 2.80. Earlier4 th e correspon din g values
of (ρI)orth o for pure water at 75 °C were in th e ran ge 2.50–2.70. Th e value for
th e reson an ce con stan t a2(orth o), calculated separately for orth o substituen ts,
was n early equal to th e c1(m ,p,orth o) con stan t.
Th e solven t electroph ilicity was th e m ain factor respon sible for th e de-
pen den ce of th e substituen t effects on m edium as th e con tribution of cross
term s con tain in g th e solven t electroph ilicity (c6(m ,p,orth o)∆Eσ°, c9(orth o)∆EσI,
a
6(orth o)∆EσI, a9(orth o)∆Eσ°R) was sign ifican t wh en th e ∆log k values were pro-
cessed accordin g to Eqs (9) an d (10) (Table VI). Th erefore th e variation of
th e m eta, para polar effect, th e orth o in ductive an d orth o reson an ce effects
with solven t occurs m ain ly due to ch an ge in electroph ilicity properties of
th e m edium con sidered.
Th e cross term con tain in g th e solven t polarity c7(m ,p,orth o)∆Yσ° was differ-
en t from zero for th e sim ultan eous data treatm en t with Eq. (9) for orth o,
m eta, an d para derivatives. However, th e con tribution of solven t polarity
on th e polar effect of substituen ts could be con sidered as alm ost in sign ifi-
can t due to its very low relative weigh t. Besides, in th e separate data treat-
m en t for m eta, para, an d orth o derivatives th e term c7(m ,p,orth o)∆Yσ° was ex-
cluded as in sign ifican t. Th e term c8(m ,p)∆Pσ° was sign ifican t wh en th e data
for m eta an d para derivatives were processed with Eq. (9) an d th e data set
in volved 30, 60, and 80% aqueous EtOH at 60 °C as well. Due to very low
weight of the polarizability term , c8(m ,p)∆Pσ°, its effect could be con sidered
as n egligible.
Th e variation of th e m eta an d para polar effect with th e solven t electro-
ph ilicity was twice h igh er th an th at for th e orth o in ductive effect. Th e cor-
respon din g value for reaction con stan ts c6(m ,p) was in th e ran ge from –0.065
to –0.087. In th e case of orth o substituen ts, th e susceptibility of th e in duc-
tive effect to th e solven t electroph ilicity variation (i.e. in Eq. (9), th e sum
c6(m ,p,orth o) + c9(orth o) an d a6(orth o) in Eq. (10)) ran ge from –0.3 to –0.04. Ear-
lier4 n early th e sam e values for reaction con stan ts c6(m ,p) = –0.065 (con stan t
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

218
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
c4(m ,p,orth o) in Eq. (3)) an d a6(orth o) = –0.026 (differen ce c4(m ,p,orth o) – c5(orth o) in
Eq. (3)) were foun d wh en th e data for alkalin e h ydrolysis of substituted
ph en yl tosylates in a m ore n arrow solven t ran ge were studied. Th e orth o
reson an ce effect was foun d to vary with th e solven t electroph ilicity n early
to th e sam e exten t as th e polar effect of para substituen ts, a9 ≈ c6(m ,p,orth o)
.
It follows from Table VI th at in th e m edium con sidered th e total sub-
stituen t effect for alkalin e h ydrolysis of substituted ph en yl tosylates could
be expressed by Eqs (13) an d (14).
∆log km ,p,orth o = log kX – log kH = 0.045 + 0.0051∆E +
+ (1.806σ°)m ,p,orth o + (0.832σI)orth o – (0.0856∆Eσ°)m ,p,orth o
+
+ (0.0480∆EσI)orth o
(13)
R = 0.996, s = 0.083, s0 = 0.088, n/n0 = 95/115
∆log korth o = log kX – log kH = –0.037 + 0.0053∆E +
+ 2.802σI + 1.710σ°R – 0.0406∆EσI – 0.0747∆Eσ°R
(14)
R = 0.987, s = 0.169, s0 = 0.160, n/n0 = 64/64
Th e excellen t fit between th e experim en tal log k values (Table I an d lit.1,2,4
)
an d predicted log k values (log kcalc), calculated with Eq. (13) or (14), was
foun d.
(log kobs m ,p,orth o
)
= –(0.021 ± 0.011) + (1.010 ± 0.010)(log kcalc m ,p,orth o
)
(15)
(16)
R = 0.995, s = 0.096, s0 = 0.101, n/n0 = 102/115
(log kobs orth o = (0.034 ± 0.014) + (0.971 ± 0.013) (log kcalc)orth o
)
R = 0.996, s = 0.088, s0 = 0.090, n/n0 = 49/64
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
219
In th e alkalin e h ydrolysis of substituted ph en yl tosylates, th e in duction
factor from orth o position , 1.5-fold h igh er th an th at from para position in
water, varies twice less th an th e polar effect from para position with ch an g-
in g solven t. Wh en th e in ductive effect of para substituen ts reach es th e level
of orth o substituen ts, th e addition al in ductive in fluen ce from orth o posi-
tion disappears. From Eq. (13) could be calculated th e value of th e solven t
electroph ilicity, in wh ich th e orth o effect caused by th e addition al in duc-
tive effect from orth o position becom es zero.
(0.832σI)orth o + (0.0480∆EσI)orth o = 0
(17)
∆E[(ρI)orth o = (ρI)m ,p] = –0.832/0.048 = 17.3 an d E[(ρI)orth o = (ρI)m ,p] = 4.4
Con sequen tly, in alkalin e h ydrolysis of substituted ph en yl tosylates, th e
polar effects of orth o an d para substiuen ts becom e equal in solven t with
electroph ilic solvatin g power n early th e sam e as th at of pure DMSO (E =
3.2)8.
In Fig. 2 th e depen den ce of th e ρI(orth o) an d (ρ°)m ,p values on ∆E values is
sh own . On e can see th at in alkalin e h ydrolysis of substituted ph en yl
tosylates th e variation of th e polar effect of m eta an d para substituen ts, an d
th e orth o in ductive effect with th e solven t electroph ilicity is n early th e
sam e as in alkalin e h ydrolysis of substituted ph en yl ben zoates3 th ough th e
ratio of th e susceptibilities to polar effect of substituen ts in water differed
two-fold. Due to equal variation in substituen t effects wh en passin g from
water to an oth er solven t in th e two reaction series con sidered, th e sam e dif-
feren ce in polar substituen t effects (in cludin g th e addition al orth o in duc-
tion effect) foun d for water appears in oth er m edia. But th e ∆E[(ρI)orth o
=
(ρI)m ,p] value for th e alkalin e h ydrolysis of substituted ph en yl ben zoates is
n early twice sm aller (ca. 9–10) an d correspon ds approxim ately to aqueous
70% eth an ol or 1 M Bu4NBr (Table V).
As th e m edia in th e presen t work, pure water, aqueous organ ic salt solu-
tion s (0.5 M Bu4NBr, 1.0 M Bu4NBr, 2.25 M Bu4NBr), aqueous in organ ic salt
solution s (5.3 M NaClO4, 4.8 M NaCl), an d aqueous bin ary solution s (80%
DMSO, 30% EtOH, 60% EtOH, 80% EtOH) were used. In tran sition from
water to aqueous solution s of organ ic salts (0.5 M Bu4NBr, 1.0 M Bu4NBr,
2.25 M Bu4NBr) an d solution s in 80% DMSO an d aqueous EtOH th e
electroph ilic solvatin g power of wh ich is reduced com pared with water, th e
polar effects of orth o, m eta, an d para substituen ts were foun d to in crease.
On th e oth er h an d, th e polar effect of orth o, m eta, an d para substituen ts
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

220
Nummert, Piirsalu, Lepp, Mäemets, Koppel:
TABLE SI
Results of th e correlation with Eqs (9) an d (10) for kin etic data of alkalin e h ydrolysis of sub-
stituted ph en yl tosylates, 4-CH3C6H4SO2OC6H4–X, in various m edia at 75 °C a. Solven t
electroph ilicity, ∆E, polarity, ∆Y, an d polarizability, ∆P, param eters were in cludedb
Meta, para
substituen ts
Eq. (9)
Orth o, m eta, para
substituen ts
Eq. (9)
Orth o
substituen ts
Eq. (10)
Reaction
con stan t
Weigh t
Weigh t
Weigh t
c0
0.057 ± 0.039
0.051 ± 0.032
0.015 ± 0.046
0.014 ± 0.035a
0.058 ± 0.026a
–0.042 ± 0.058a
c1(m ,p,orth o)
c2(orth o)
a1(orth o)
a2(orth o)
c3
1.806 ± 0.062
0.96
0.95
1.900 ± 0.040
0.92
0.95
0.06
0.06
–
–
–
–
1.905 ± 0.049a
1.899 ± 0.037a
–
–
–
–
–
–
0.821 ± 0.067
0.824 ± 0.055a
–
–
–
–
2.767 ± 0.073
0.55
0.60
0.29
0.25
2.763 ± 0.086a
1.816 ± 0.080
1.710 ± 0.019a
0.0025 ± 0.0036
0.04
0.0093 ± 0.0016
0.002
0.002
0
0
–
–
–
–
–
–
0.0062 ± 0.0028a 0.03
0.0021 ± 0.0021a
c5
1.565 ± 0.589a
0.005
0.003
0
c6(m ,p,orth o) –0.0656 ± 0.0077
–0.0672 ± 0.0048
0.018
0.006
0.001
0.001
–0.0736 ± 0.0067a 0.003
–0.0762 ± 0.0045a
c7(m ,p,orth o)
–
–
1.00 ± 0.30
1.10 ± 0.30a
c8(m ,p,orth o)
c9(orth o)
–4.96 ± 1.86a
0.002
–
–
–
0.0329 ± 0.0081
0.002
0.005
–
–
0.0451 ± 0.0067a
a6(orth o)
–
–
–
–
–
–
–
–
–0.0298 ± 0.0075
–0.0423 ± 0.0088a
–0.0887 ± 0.0081
–0.0880 ± 0.0104a
42/47
0.027
0.005
0.012
0.010
a9(orth o)
n/n0
45/45
52/60a
0.990
0.995a
0.116
0.078a
0.141
0.098a
0.999
0.95a
79/85
93/115a
0.995
0.996a
0.099
0.080a
0.102
0.086a
0.95
59/64a
R
s
0.996
0.992a
0.096
0.129a
s0
t
0.094
0.128a
0.97
0.95a
0.97a
a
Th e log k values for 30, 60, an d 80% aqueous EtOH at 60 °C as well as for pure water,
0.6 M Bu4NBr, 1.0 M Bu4NBr, 2.25 M Bu4NBr, 80% DMSO, 5.3 M NaClO4, 4.8 M NaCl at 75 °C
b
were in cluded. Th e program m akes it possible to treat data in four differen t ways: 1. Exclu-
sion of in sign ifican t argum en t scales was perform ed before excludin g con siderably deviatin g
poin ts. 2. Exclusion of sign ifican tly deviatin g poin ts was perform ed before excludin g in -
sign ifican t argum en t scales. Both ways of data treatm en t h ave two differen t m odes of form -
in g cross term s: (i) Cross term s can be form ed from cen tered basic argum en t scales. (ii) Cross
term s are form ed from n on -cen tered basic argum en t scales. Wh en th e values for in sign ifi-
can t scales are sh own , th e cross term s were form ed from cen tered basic argum en t scales.
Wh en th ree differen t solven t param eters were in cluded, exclusion of in sign ifican t argum en t
scales was perform ed before excludin g con siderably deviatin g poin ts.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Kinetic Study of Alkaline Hydrolysis
221
decreased in tran sition from water to in organ ic salt solution s (5.3
M
NaClO4, 4.8 M NaCl) wh ose electroph ilic solvatin g power is h igh er from
th at of water (Table V).
In organ ic salt solution s an d 80% DMSO, th e tran sition state of th e
n ucleoph ilic substitution reaction SN2 in volvin g an d n egative ch arge could
be con sidered as rath er weakly electroph ilically solvated wh ich leads to es-
sen tially in creased ρ values com pared with pure water. In con cen trated
aqueous organ ic salt solution s sim ilarly th ose in 80% DMSO, very few ac-
tive water m olecules are assum ed to be able to form h ydrogen bon d an d th e
large Bu4N+ ion s are n ot able to com plex to th e partially n egatively ch arged
ph en olic oxygen in th e tran sition state as sm all cation s M+ do. In in organ ic
salt solution s, th e com plexation of sm all M+ cation s to n egatively ch arged
tran sition state sh ould decrease th e polar effect of substituen ts in con trast
with water.
SUPPLEMENTARY MATERIAL
Table SI con tain in g th e results of th e correlation s with Eqs (9) an d (10) for
kin etic data of alkalin e h ydrolysis of substituted ph en yl tosylates,
4-CH3C6H4SO2OC6H4–X, in various m edia at 75 °C wh en th ree solven t pa-
ram eters, th e solven t electroph ilicity, ∆E, th e solven t polarity, ∆Y, an d th e
solven t polarizability, ∆P, were in cluded, is available as supplem en tary m a-
terial.
This work was supported by the funding from the grants No. 5226 and No. 5254 of the Estonian
Science Foundation.
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