Kinetics of osmium(VIII) catalyzed oxidation of allyl alcohol by potassium bromate in aqueous acidic medium-autocatalysis in catalysis

Article abstract of DOI:10.1002/(SICI)1097-4601(1999)31:8<583::AID-KIN8>3.0.CO;2-S

The kinetics of oxidation of allyl alcohol with potassium bromate in the presence of osmium(VIII) catalyst in aqueous acid medium has been studied under varying conditions. The active species of oxidant and catalyst in the reaction were understood to be Bro₃^- and H₂OsO₅, respectively. The autocatalysis exhibited by one of the products, that is, Br^-, was attributed to complex formation between bromide and osmium(VIII). A composite scheme and rate law were possible. Some reaction constants involved in the mechanism have been evaluated.

Full text of DOI:10.1002/(SICI)1097-4601(1999)31:8<583::AID-KIN8>3.0.CO;2-S

Kinetics of Osmium(VIII)
Catalyzed Oxidation of Allyl
Alcohol by Potassium
Bromate in Aqueous Acidic
Medium-Autocatalysis in
Catalysis
S. M. DESAI, N. N. HALLIGUDI, S. T. NANDIBEWOOR
P. G. Department of Studies in Chemistry, Karnatak University, Dharwad-580 003, India
Received 5 October 1998; accepted 7 April 1999
ABSTRACT: The kinetics of oxidation of allyl alcohol with potassium bromate in the presence
of osmium(VIII) catalyst in aqueous acid medium has been studied under varying conditions.
Ϫ
The active species of oxidant and catalyst in the reaction were understood to be Bro3 and
Ϫ
H OsO , respectively. The autocatalysis exhibited by one of the products, that is, Br , was
2
5
attributed to complex formation between bromide and osmium(VIII). A composite scheme and
rate law were possible. Some reaction constants involved in the mechanism have been eval-
uated. ᭧ 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 583–589, 1999
INTRODUCTION
not disproportionate but, in fact, it accumulates by an
autocatalytic reaction. Therefore, in the presence of
acid and excess bromide ions, bromate can exclusively
act as bromine generator and the resulted bromine can
either brominate or oxidize the organic compound un-
der study depending on its nature [5]. Bromate oxi-
dations of organic and inorganic reactions usually in-
volve the complications such as induction period [6]
or involvement of two portions [7]. Even bromate ox-
idations sometimes involve oscillation reactions [8,9].
Hence, the chemistry of bromate ion in aqueous acid
medium is of considerable interest due to its impor-
tance in mechanistic chemistry [10–17].
Allyl alcohol finds a number of industrial applications
in the preparation of resins, plasticizers, pharmaceu-
ticals and many organic compounds. Kinetic studies
on the oxidation of allyl alcohol with different oxi-
dants such as potassium permanganate, chromic acid,
vanadium(V), chloramine-T, diperiodatonickelate(IV)
and so on have been reported [1–3]. Bromate, Br(V),
is known to be a powerful oxidizing agent with redox
potentials [4] of 1.44V in acid medium and 0.61V in
basic medium. The potentials show that Br in basic
2
solutions can disproportionate spontaneously to
Ϫ
Ϫ
BrO and Br . However, in acidic solutions Br does
Osmium(VIII) acts as a catalyst in the oxidation of
many organic and inorganic substrates [18,19] but
very few studies are available in acid medium.
Os(VIII) catalysis in redox reactions involve different
complexities, due to the formation of different inter-
2
Correspondence to: S. T. Nandibewoor (unikard@renback.
delhi.nic.in)
᭧
1999 John Wiley & Sons, Inc.
CCC 0538-8066/99/080583-07

5
84
DESAI, HALLIGUDI, AND NANDIBEWOOR
mediate complexes, free radicals, and different oxi-
dation states of osmium. The oxidation of allyl alcohol
by cerium(IV) in aqueous acid medium yielded acrylic
acid as the end product. But the use of different cata-
lysts gave different oxidation products [20]. Acrolein
is the main product of Os(VIII) catalyzed reaction and
acrylic acid is the product for palladium(II) catalyst.
In view of various possibilities of mechanism and ac-
tive species of bromate and osmium(VIII), we have
sought to study the title reaction.
against standard sodium thiosulphate solution using
starch as an indicator. The rate constants, k were
obs
Ϫ
3
obtained from the slopes of the log [BrO ] versus
time plots which were linear to about 70% completion
of reaction. Most of the kinetic runs were followed to
more than 80% completion of the reaction and the rate
constants kobs were reproducible within Ϯ5%.
RESULTS
Stoichiometry
EXPERIMENTAL
Materials
Different sets of reaction mixtures containing excess
concentration of allyl alcohol over bromate in HClO4
at constant ionic strength and with a constant amount
of catalyst were kept for 12 hours at 27ЊC in an inert
atmosphere and then analyzed. The remaining allyl al-
cohol was assayed iodometrically, as mentioned ear-
lier [23]. Acrylic acid formed as the main product was
detected by the method [25] and another product bro-
Reagent grade chemicals and doubly distilled water
were used throughout the experiment. The second dis-
tillation of water was from permanganate in a glass
still. Stock solution of the oxidant, bromate was pre-
pared by dissolving the potassium bromate (Riedel) in
water and the concentration was ascertained [21] by
iodometric titration. Bromide was prepared by dis-
solving a known amount of potassium bromide
mide was estimated by adding AgNO solution re-
3
sulting in the formation of precipitate. Test for acrolein
was negative [26]. The results proved the consumption
ratio of reductant to oxidant as 3 : 2, shown in equation
(BDH). The allyl alcohol (Koch Light) was purified
(
1).
CH "CH–CH OH ϩ 2KBrO 99 :
Os(VIII)
by the reported method [22] and used to prepare the
stock solution. It was standardized by addition of an
excess chloramine-T, followed by iodometric titration
HClO
4
3
2
2
3
[23]. Osmium(VIII) solution was made by dissolving
3
CH "CH–COOH ϩ 2KBr ϩ 3H O
(1)
2
2
a known mass of osmium tetroxide(OsO )(Johnson
4
Ϫ3
Matthey) in 0.50 mol dm sodium hydroxide and
standardized [24]. Perchloric acid (Merck) and sodium
perchlorate were used to provide the required acidity
and to maintain the ionic strength, respectively. The
stock solutions were used within two days and fresh
solutions were used during each kinetic run.
Reaction Order
The order of the reaction was determined from log-log
plots of kobs versus concentration at a constant acidity
Ϫ3
of 0.20 mol dm and ionic strength of 0.30 mol
Ϫ3
dm . At a fixed concentration of osmium(VIII) of
Ϫ
5
Ϫ3
5
.0 ϫ 10 mol dm the apparent order in [bromate]
KINETIC STUDIES
Ϫ4
Ϫ3
Ϫ3
in the range of 2.0 ϫ 10 to 2.0 ϫ 10 mol dm
was unity and the order in [allyl alcohol] in the range
The reaction was carried out under pseudo-first-order
conditions, where allyl alcohol was always in ten- or
more fold excess over the potassium bromate at con-
stant temperature of 27.0 Ϯ 0.1ЊC. The reaction was
initiated by mixing the previously thermostatted re-
actant solutions of bromate, allyl alcohol which also
contained the required amount of osmium(VIII), so-
dium perchlorate, perchloric acid, and doubly distilled
water (to keep the total volume constant for all runs).
Aliquotes (5 ml) of reaction mixture were pipetted out
at regular intervals of time and poured into an iodine
flask containing 5% of KI and a suitable amount of
sulphuric acid. The liberated iodine was titrated
Ϫ2
Ϫ1
Ϫ3
1
.0 ϫ 10 to 1.0 ϫ 10 mol dm was unity (Table
I). The order in [catalyst] was unity in the range of
Ϫ5
Ϫ4
Ϫ3
1
.0 ϫ 10 to 1.0 ϫ 10 mol dm . With all other
reactant concentrations and conditions being constant
Table I), with increasing concentration of acid, the
(
rate decreased (Table I). The uncatalyzed reaction un-
der the given conditions of concentrations is very
slow.
Effect of Added Products
Initially added product, acrylic acid did not affect the
reaction significantly. However, the initial addition of

OSMIUM(VIII) CATALYZED OXIDATION OF ALLYL ALCOHOL
585
Ϫ
ϩ
Table I Effect of [BrO ], [AA], [H ], and [Os(VIII)] on Os(VIII) Catalyzed Oxidation of Allyl Alcohol by Bromate in
3
Ϫ2
Ϫ3
Ϫ3
Acid Medium at 300 K; [Hg(OAc) ] ϭ 1.0 ϫ 10 mol dm , I ϭ 0.30/mol dm
2
4
kobs ϫ 10
Ϫ
1
s
Ϫ
3
2
ϩ
5
[
BrO ] ϫ 10
[AA] ϫ 10
mol dm
[H ]
[Os(VIII)] ϫ 10
3
Ϫ3
Ϫ
3
Ϫ3
Ϫ3
mol dm
mol dm
mol dm
Expt.*
Calcd.*
0
0
0
0
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
.2
.3
.5
.8
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
4.0
4.0
4.0
4.0
4.0
4.0
1.0
2.0
4.0
6.0
8.0
10.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.02
0.03
0.05
0.10
0.15
0.20
0.20
0.20
0.20
0.20
0.20
0.20
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
1.0
2.0
3.0
5.0
7.0
10
3.15
3.13
3.10
3.14
3.18
3.12
0.78
1.58
3.18
5.40
7.00
8.10
6.25
5.83
5.40
4.34
3.68
3.18
0.60
1.28
1.75
3.18
5.12
6.80
3.27
3.27
3.27
3.27
3.27
3.27
0.80
1.63
3.27
4.91
6.60
8.20
6.22
5.92
5.41
4.44
3.70
3.27
0.65
1.30
1.96
3.27
4.60
6.60
*
Experimental and calculated.
the other product, that is, KBr in the range 1.0 ϫ
varying the acetic acid-water content in the reaction
mixture with all other conditions being constant. At-
Ϫ3
Ϫ2
Ϫ3
1
0
to 1.0 ϫ 10 mol dm , other conditions being
constant, increased the rate of reaction with an order
of around (0.3). This illustrates the autocatalytic nature
of the product (Table II) which is also evident from
the concentration versus time plots (Fig. 1) and a linear
plot of kexpt versus kcal for bromide variation (Fig. 1,
Inset).
Ϫ
Table II Effect of Product, [Br ] on Os(VIII) Catalyzed
Ϫ
Oxidation of Allyl Alcohol by BrO in Acid Medium at
3
Ϫ2
Ϫ
Ϫ3
300 K [AA] ϭ 4.0 ϫ 10 ; [BrO ] ϭ 1.0 ϫ 10 ;
3
Ϫ5
ϩ
Ϫ3
[
Os(VIII)] ϭ 5.0 ϫ 10 ; [H ] ϭ 0.20, I ϭ 0.30/mol dm
4
kobs ϫ 10
Ϫ
1
s
Effect of Ionic Strength and Solvent
Polarity
Ϫ
3
[
Br ] ϫ 10
Ϫ3
mol dm
Expt.*
Calcd.*
The effect of ionic strength of the reaction medium
1.0
2.0
3.0
4.12
4.84
5.60
6.40
7.20
8.40
4.13
4.91
5.57
6.62
7.40
8.30
Ϫ3
was varied from 0.20 to 2.0 mol dm with sodium
perchlorate at constant concentrations of oxidant, re-
ductant, acid, and catalyst. It was found that ionic
strength has negligible effect on the rate of the reac-
tion.
5
7
0
.0
.0
1
The relative permittivity effect (D) was studied by
*Experimental and calculated.

5
86
DESAI, HALLIGUDI, AND NANDIBEWOOR
DISCUSSION
The reaction exhibits 2 : 3 stoichiometry between bro-
mate and allyl alcohol in presence of Os(VIII) catalyst
and the orders are found to be unity each in allyl al-
cohol, bromate and osmium(VIII) concentrations,
ϩ
whereas negative fractional order in [H ]. The pres-
ence of Mercuric acetate (more than that of bromate
concentration) simply means that Br oxidation has
2
been completely suppressed, which otherwise would
Ϫ
have formed by interaction of Br and bromate as fol-
lows
Ϫ
Ϫ
ϩ
BrO3 ϩ Br ϩ 6 H EF Br ϩ 3 H O
2
2
It is necessary to clarify that in the present study no
free radicals were obtained and rates were independent
with different concentration of mercuric acetate. These
considerations confirm only the complex forming abil-
Figure 1 Concentration versus time plots. [AA] ϭ 4.0 ϫ
Ϫ
ity of Hg(II) with Br ion in this reaction. Mercuric
Ϫ2
Ϫ3
ϩ
1
0 ; [HBrO ] ϭ 1.0 ϫ 10 ; [H ] ϭ 0.20; I ϭ 0.30/mol
Ϫ
3
acetate acts as a scavenger [30–32] for any Br
formed in the reaction as HgBr4
Ϫ3
Ϫ5
Ϫ3
dm . (a) [Os(VIII)] ϭ 7.0 ϫ 10
mol dm ; (b)
2
Ϫ
or unionised HgBr2
Ϫ4
Ϫ3
[Os(VIII)] ϭ 1.0 ϫ 10 mol dm . Inset: Plot of k vs.
expt
and thus ensuring that oxidation takes place purely
through bromate. The reported rate constants therefore
1
1
ϩ
Ϫ0.32
Ϫ 0.3
kЈ ϭ [AA] [Os(VIII)] [H ]
cal
[Br ] for variation of
bromide (Table II).
2ϩ
stand for pure bromate oxidation. At zero [Hg ], the
reaction is probably a mixed oxidation by bromate and
Br2.
tempts to measure the relative permittivity of the me-
dia were failed. However, they were computed from
the values of pure liquids as in earlier work [27–29].
The inertness of the solvent towards oxidant has earlier
been tested. It was found that the rate constants kobs
increased with decreasing dielectric constant of the
medium. The plot of log kobs versus 1/D was linear
with positive slope.
The important point in bromate oxidations is to es-
tablish the reactive species that participates in a given
reaction. In acid solution of bromate, the reactive spe-
Ϫ
cies are likely to be BrO and protonated bromate
3
ϩ
ϩ
[
HBrO or H BrO (BrO )]. Hence, the oxidation
3 2 3 2
reaction may be a reaction involving one of the oxidant
ϩ
species. Amis et al. [33] proposed BrO2 as an oxi-
dizing species. Amber and Guttmann [34], Wright and
Barton [35], on the other hand, suggested that in mod-
ϩ
erately strong acid solutions H XO is the existing
2
3
Test for Free Radicals
ϩ
form of halate ion and in case of bromate, H BrO is
2
3
the existing form. Beck and co-workers [36], however,
To test for free radicals, the reaction mixture contain-
ing acrylonitrile was kept for 24 hours and on dilution
with methanol, no precipitate resulted, indicating the
absence of free radical intervention in the reaction.
ϩ
have shown that both HBrO and H BrO are the ac-
3
2
3
tive form of bromate in moderately strong acid solu-
tions. However, in the present study, the decrease of
ϩ
rate with increase in [H ] is observed which can be
Ϫ
understood due to formation of BrO3 from HBrO in
3
the prior equilibrium in scheme I. The order of less
than unity (negative) in [H ] may also be understood
Effect of Temperature
ϩ
The rate constants were evaluated at four different
temperatures and were used for the calculation of ac-
in terms of the predominant species of bromate as
Ϫ
BrO . The orders in oxidant and osmium(VIII) results
3
Ϫ1
tivation parameters. The values of k
(s ) are
presumably from a complex formation between the
oxidant and catalyst which further reacts with allyl al-
cohol in a slow step to give the products. Os-
mium(VIII) is known to form complex [37–39] with
other species in view of its vacant d-orbital. The os-
mium(VIII) species in acid media is understood
obs
Ϫ4
Ϫ4
Ϫ4
3
1
⌬
.18 ϫ 10 , 4.92 ϫ 10 , 6.55 ϫ 10 , and 9.25 ϫ
Ϫ4
0
at 300, 305, 310, and 315 K, respectively. E ,
a
#
#
#
H , ⌬G , and ⌬S were calculated to be 57.4 Ϯ
Ϫ1
Ϫ1
Ϫ1
3
.0 kJ mol , 54.8 Ϯ 3.0 kJ mol , 64 Ϯ 3 kJ mol ,
Ϫ1
Ϫ1
and Ϫ30.8 Ϯ 2.0 J K mol , respectively.

OSMIUM(VIII) CATALYZED OXIDATION OF ALLYL ALCOHOL
587
[
40–42] as H OsO with very low dissociation con-
stant.
d[HBrO3] kK K [A A][HBrO ][Os(VIII)]
1 2 3
2
5
Ϫ
ϭ
(3)
ϩ
dt
[H ] ϩ K
1
In accordance with the experimental results, the
possible mechanism as shown in scheme I is proposed.
Rate law (3) accommodates all the experimental re-
sults except autocatalysis by bromide. The mechanism
of scheme I and rate law (3) may be verified by rear-
ranging it in the form of (4).
K
1
Ϫ
ϩ
HBrO ERF BrO ϩ H
3
3
K
2
Ϫ
BrO3 ϩ H OsO ERF Complex (C1)
2
5
k
C ϩ CH "CH–CH OH 9
9
:
ϩ
1
2
2
[AA] [OS(VIII)]
[H ]
1
Slow
ϭ
ϩ
(4)
Ϫ
2
CH "CH–CHO ϩ H OsO ϩ H O ϩ BrO
k
obs
kK
1
K
2
kK
2
2
2
5
2
fast
99 :
Ϫ
CH "CH–CHO ϩ BrO
2
2
Ϫ
The plot of [AA] [Os(VIII)]/kobs vs. [H
ϩ
] is linear, the
slope and intercept of which lead to values of K and
kK as 0.18 Ϯ 0.01 mol dm and 345.7 Ϯ 17.0 dm6
CH "CH–COOH ϩ OBr ϩ H O
2
2
fast
1
Ϫ
CH "CH–CH OH ϩ OBr 9
9
:
Ϫ3
2
2
2
Ϫ
CH "CH–CHO ϩ Br ϩ H O
Ϫ2
Ϫ1
2
2
mol s , respectively. From these values, rate con-
stants for several experimental conditions may be cal-
culated from equation (3) and compared with experi-
mentally found data. Such a comparison is made in
Table I and shows good agreement between the cal-
culated and experimental rate constants, which forti-
fies the proposed scheme I.
The ionic strength has negligible effect on the rate
of reaction which is in the right direction, since an ion
and a neutral molecule are involved [45] in scheme I.
However, increase in the content of acetic acid in the
reaction medium leads to the increase in the reaction
rate, contrary to the expected slower reaction between
dipole and a negative ion in the media of lower relative
permittivity. This might be due to the solvation of
complex in low relative permittivity media [46].
Hence, the net increase in rate with increase in acetic
acid content in the medium.
fast
99 :
Ϫ
3
CH "CH–CHO ϩ BrO
2
Ϫ
CH "CH–COOH ϩ BrO
2
2
fast
99 :
Ϫ
CH "CH–CH OH ϩ BrO
2
2
2
Ϫ
CH "CH–CHO ϩ OBr ϩ H O
2
2
fast
Ϫ
CH "CH–CHO ϩ OBr 99 :
2
Ϫ
CH "CH–COOH ϩ Br
2
Scheme I
The complex (C ) might have the following structure.
1
Ϫ
O
O
OH
O"Os9O9Br
OH
O
O
In order to understand the role of metal in binding
with the olefinic double bond and its impact on oxi-
dation, the corresponding saturated alcohol, n-pro-
panol, was oxidized by bromate under identical con-
ditions, and did not show any appreciable oxidation
even after the period of 24 hours. This indicates that
binding of the metal with the olefinic double bond in
allyl alcohol is of crucial importance in the oxidation
of this substrate which might reduce the energy of ac-
tivation of reaction path. A similar role of the olefinic
bond has been observed in the case of oxidation of
allyl alcohol with Ce(IV) [47,48].
Evidence for the complex formation was obtained
from absorption spectra of both Os(VIII) and Os(VIII)
and BrO3 mixture, which indicate a hypsochromic
shift of about 20 nm due to the participation of d-elec-
trons of Os(VIII) species in bonding which clearly
supports complex formation. Kinetic evidence for
complex formation is also obtained. Such complex
formation between the catalyst and oxidant has also
been observed in other studies [43,44].
Ϫ
Thus, scheme I leads to the rate law (2)
The autocatalysis by one of the products, bromide,
is interesting. The apparent order of less than unity in
bromide concentration when bromide is initially
present, may be attributed to complex formation be-
tween osmium(VIII) and bromide. The complex (C2)
is then subsequently involved in the interaction with
bromate. These steps shown in scheme II will form
part of scheme I.
d[HBrO3] kK K [A A][HBrO ][Os(VIII)]
1
2
3
Ϫ
ϭ
(2)
ϩ
dt
[H ] ϩ K ϩ K K [Os(VIII)]
1 1 2
In view of low concentration of osmium(VIII) used,
the term such as K K [Os(VIII)] is negligible com-
1
2
ϩ
pared to [H ] and therefore is neglected. Thus, equa-
tion (2) becomes (3).

5
88
DESAI, HALLIGUDI, AND NANDIBEWOOR
K
3
Ϫ
kgross ϭ kcat ϩ kautocat
H OsO ϩ Br E
R
F Complex (C2)
(6b)
2
5
k
1
kgross Ϫ kcat ϭ kautocat
Ϫ
ϩ
C ϩ HBrO 9
9
: 2BrO ϩ H OsO ϩ H
2
3
2
2
4
fast
Ϫ
Ϫ
Ϫ
BrO2 ϩ H OsO 9
9
: H OsO ϩ OBr
K k [Os(VIII)][Br ]
2
4
2
5
3 1
ϭ
(6c)
(7)
fast
Ϫ
ϩ K [Br ]
3
1
Ϫ
CH "CH–CH OH ϩ OBr 99 :
2
2
Ϫ
CH "CH–CHO ϩ Br ϩ H O
2
2
[
Os(VIII)]
1
1
fast
9
Ϫ
ϭ
ϩ
Ϫ
CH "CH–CHO ϩ BrO 9
:
2
3
kgross Ϫ kcat K k [Br ] k1
3 1
Ϫ
CH "CH–COOH ϩ BrO
2
2
fast
99 :
Ϫ
CH "CH–CH OH ϩ BrO
2
2
2
Ϫ
At a constant concentration of oxidant and catalyst, a
plot of left hand side of equation (7) vs. 1/[Br ] should
be linear, and this was found to be so (Fig. 2). Indeed,
it is to be noted that the plot shows an intercept which
is in agreement with the complex formation as in
scheme II. From the slope and intercept, the values of
CH "CH–CHO ϩ OBr ϩ H O
2
2
Ϫ
fast
Ϫ
CH "CH–CHO ϩ OBr 99 :
2
Ϫ
CH "CH–COOH ϩ Br
2
fast
99 :
Ϫ
CH "CH–CH OH ϩ BrO
2
2
2
Ϫ
CH "CH–CHO ϩ OBr ϩ H O
2
2
3
Ϫ1
K and k are obtained as 105 Ϯ 5 dm mol and
3
1
fast
Ϫ
3
Ϫ1
Ϫ1
CH "CH–CHO ϩ OBr 9
9
:
20 Ϯ 1 dm mol s , respectively. Using these val-
ues the experimental rate constants can be regenerated
(Table II).
2
Ϫ
CH "CH–COOH ϩ Br
Scheme II
2
The structure of the complex (C ) might be as given
below
2
CONCLUSION
Ϫ
O
The osmium(VIII) catalyzed bromate oxidation of al-
lyl alcohol, which involves the autocatalytic nature has
been studied and the overall mechanistic sequence de-
scribed here is consistent with product studies, mech-
anistic studies, and kinetic studies. We have shown
that in the catalyzed reaction, autocatalysis has also
taken place and a composite rate law is possible. The
OH
O"Os9Br
OH
O
The evidence for complex (C ) formation was also ob-
2
tained from UV-vis spectra of both Os(VIII) and
Ϫ
Os(VIII) and Br mixture, which indicate a batho-
chromic shift of about 5 nm and also an increase in
Ϫ
intensity for the mixture of Os(VIII) and Br . Indeed,
Ϫ
such complex formation between Os(VIII) and Br
have been observed in the literature [49,50]. From
scheme II the rate law (5) is obtained.
Ϫ
K k [HBrO ][Os(VIII)][Br ]
3
1
3
Rateautocat
ϭ
(5)
Ϫ
1
ϩ K [Br ]
3
Thus, when bromide is initially present, a composite
scheme involving all the steps of scheme I and II op-
erates and rate law (6a) and then (6b) and (6c) may be
derived and rearranged to the form (7).
kK K [A A] [Os(VIII)]
1
2
kgross
ϭ
ϩ
[
H ] ϩ K
1
Ϫ
K k [Os(VIII)][Br ]
3
1
Figure 2 Verification of rate law (6) in the form of (7)
(Conditions as in Table II).
ϩ
(6a)
Ϫ
1
ϩ K [Br ]
3

OSMIUM(VIII) CATALYZED OXIDATION OF ALLYL ALCOHOL
589
acid dissociation constant of HBrO has been obtained
with the complex rate law.
25. Feigl, F.; Anger, V. Spot Tests in Organic Analysis
975, Elsevier, London, 212.
6. Feigl, F.; Anger, V. Spot Tests in Organic Analysis
975, Elsevier, London, 416.
7. Hodgman, C. D. Hand Book of Chemistry and Physics;
Rubber Publishing Company: Ohio, 41st ed., 1960; p
3
1
2
2
1
BIBLIOGRAPHY
2
513.
1
2
3
4
5
6
7
. Bhat, K.; Nand, K. C. Z Phys Chem (Leipzig) 1983,
64, 1195.
. Hiremath, G. A.; Timmanagoudar, P. L.; Nandibewoor,
S. T. J Phys Org Chem 1998, 11, 31.
. Chougale, R. B.; Kamble, D. L.; Nandibewoor, S. T.
Polish J Chem 1997, 71, 986.
. Latimer, W. A. Oxidation Potentials, 2nd ed.; Prentice
Hall: New York, 1952.
28. Radhakrishnamurthy, P. S.; Pati, S. C. Indian J Chem
1969, 7, 687.
2
29. Timmanagoudar, P. L.; Hiremath, G. A.; Nandibewoor,
S. T. J Chem Soc, Dalton Trans 1995, 3623.
30. Bailar, J. C. The Chemistry of Coordination Com-
pounds; Reinhold: New York, 1955, p 4.
31. Venkatasubramanian N.; Thiagarajan, V. Can J Chem
1969, 47, 694.
32. Koros, E.; Varga, M.; Gyorgyi, L. J Phys Chem 1984,
88, 4116.
33. Amis, E. S.; Nolen, G.; Iondelli, A. J Am Chem Soc
1960, 82, 3233.
. Reddy, C. S.; Sundaram, E. V. Tetrahedron 1989, 45,
7
, 2126.
. Simoyi, R. H.; Epstein, I. R.; Kustin, K. J Phys Chem
994, 98, 551.
1
. Sanjeevareddy, C.; Vijayakumar, T. Indian J Chem,
Sect A 1996, 35, 408.
34. Amber, M.; Guttmann, S. G. J Am Chem Soc 1961, 83,
4741.
8
9
. Rabai, G.; Hanazaki, I. J Phys Chem 1996, 100, 10615.
. Gyorgyi, L.; Field, R. J. J Phys Chem 1992, 96,
35. Wright, C. A.; Barton, A. F. M. J Chem Soc (A) 1968,
1747.
1
221.
0. Simoyi, R. H.; Epstein, I. R.; Kustin, K. J Phys Chem
994, 98, 551.
36. Beck, M. T.; Rabai, G.; Bazsa, G. Int J Chem Kinet
1980, 13, 1277.
37. Nandibewoor, S. T.; Morab, V. A. J Chem Soc, Dalton
Trans 1985, 483.
1
1
1
1
1. Young, H. A. J Am Chem Soc 1950, 72, 3310.
2. Avasthi, V.; Chatterji, A. C. Z Phys Chem (Leipzig)
38. Agrawal, M. C.; Singhal, R. K.; Mushran, S. P. Z Phys
Chem 1963, 62, 112.
1
970, 245, 154, 161; 1972, 249, 17.
1
3. Natarajan, R.; Venkatasubramanian, N. Tetrahedron
Lett 1969, 57, 5021; Tetrahedron 1974, 30, 2785; Int J
Chem Kinet 1976, 8, 205.
4. Char, P. N.; Sondu, S.; Sethuram, B.; Rao, T. N. Indian
J Chem, Sect A 1988, 27, 31; 1989, 28, 670.
39. El-Tantawy, Y. A.; Abu-Shady, A. I.; Ezzat, I. I. J Inorg
Nucl Chem 1978, 40, 1683.
40. Kampli, S. R.; Nandibewoor, S. T. Proc Indian Acad
Sci (Chem Sci) 1994, 106, 837.
41. Mehrotra, U. S.; Mushran, S. P. Can J Chem 1970, 48,
1148.
42. Tuwar, S. M.; Nandibewoor, S. T.; Raju, J. R. Trans
Met Chem 1991, 16, 196.
43. Kamble, D. L.; Nandibewoor, S. T. Int J Chem Kinet
1996, 28, 673.
44. Morab, V. A.; Nandibewoor, S. T. J Chem Soc, Dalton
Trans 1995, 483.
45. Laidler, K. J. Chemical Kinetics, 2nd ed.; McGraw Hill,
Inc.: New York, 1976; p 230.
46. Glasstone, S. Text Book of Physical Chemistry, 2nd ed.;
Nostrand Co. Inc.: U.S.A. 1974; p 1113.
47. Bhat, K.; Nand, K. C. Z Phys Chem (Leipzig) 1983,
264, 1195.
1
1
1
1
1
1
2
2
2
2
2
5. Reddy, C. S.; Sundaram, E. V. Indian J Chem, Sect A
1
984, 23, 911.
6. Krishnamurthy, N.; Reddy, C. S.; Sundaram, E. V. In-
dian J Chem, Sect A 1989, 28, 288.
7. Jonnalagadda, S. B.; Simoyi, R. H.; Muthakia, G. K. J
Chem Soc, Perkin Trans 1988, 2, 1111.
8. Agrawal, M. D.; Upadhyay, S. K. J Sci Ind Res 1983,
1
12, 508.
9. Kamble, D. L.; Nandibewoor, S. T. J Phys Org Chem
998, 11, 171.
1
0. Tuwar, S. M.; Morab, V. A.; Nandibewoor, S. T.; Raju,
J. R. Transition Met Chem 1991, 16, 430.
1. Vogel, A. I. Text Book of Quantitative Chemical Anal-
ysis, 5th ed.; ELBS, Longman, 1989; 407.
2. Vogel, A. I. A Text Book of Practical Organic Chem-
istry, 3rd ed.; ELBS, Longman, 1973; 459.
3. Mahadevappa, D. S.; Naidu, H. M. K. Talanta 1973, 20,
48. Sethuram, B. Current Sci (India) 1966, 35, 254.
49. Livingstone, S. E. Texts in Inorganic Chemistry, Vol-
ume 25, 1st ed.; Pergamon Press: Oxford, 1973; p 1232.
50. Cotton, F. A.; Wilkinson, G. Advanced Inorganic
Chemistry, 5th ed.; Wiley Interscience: New York,
1988; p 886.
3
49.
4. Saxena, O. C. Microchem J 1967, 12, 609.