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Kinetics of oxidation of ketoglutaric acids by alkaline chloramine-t solution
Terrd~~dwnVol. 42, No. 3. pp. 857 to 861. 1986 Rioted in C&at Britain.
KINETICS OF OXIDATION OF KETOCLUTARIC ACIDS BY ALKALINE CHLORAHINE-T SOLUTION
BHARAT SINCH', A.K. SAMANT, B.B.L. SAXENA and M.B. SINGH
Chemical Laboratories. University OP Allahabad, Allahabad - 211002, India (Receivedin UKU) Seprember 1985) Abstract - Kinetics of the oxidation of a-ketoglutarlc and B-ketonlutaric acids by chloramine-T (CAT) have been The reactions show investigated in highly-alkaline media. first order dependence in chloramine-T and fractional order in substrates. The order in hydroxide ions has been Pound to be second but shows a slight decrease at high concentration of No effect of p-toluene-sulphonamidewas evident. alkali. Observed stoichiometry, positive effects of ionic strength and dielectric constant point to a mechanism involving formation of an intermediate in a termolecular rate determining slowest step among hypochlorlte ion. hydroxide ion and enollc anion of keto acids followed by a Past step leading to products. Activation parameters have been computed and formaldehyde and formic acid were identified as end-products.
INTRODUCTION The present communication reports the complex kinetics in oxidation of ketoglutaric acids by alkaline solution of chloramlne-T in contrast to very simple kinetic observations, so Par, obtained in chloramine-T oxidation of aldehydes,'r2 ketones,3,4 and aldoses5 in alkaline media. In order to shed some further light on chloramine-T oxidations, the kinetic observations o$ the present invesigatlon have been discussed and a suitable mechanism has been presented.
MATERIALS AND METHODS All the reagents used were of highest purity available. Chloramine-T (E. Merck proanalysis) was used and stored in black coated bottles. Koch-Light (England) sample of D-toluene-SulDhOnamidewas used. All other reanents were of anaiar grade.‘ The solutions of h-ketoglutaric acid (E. Merck) and 8-ketoglutaric acid (Loba Chemle) Were prepared by direct weighing and dissolving in double distilled water. The reaction stllls were blackened Prom outside to avoid any photochemical influence. All reactants except keto acid were allowed to mix and the reaction was initiated by adding subsequently appropriate amount of ketoglutaric acid. The progress of the reaction was monitored by estimating unconsumed CAT iodometrically using starch as indicator. All the rate studies were carried out at constant temperature (i 0.1). Stoichiometry and product analysis Reaction mixture containing excess of CAT over ketoglutaric acid was allowed to equilibrate at 35OC Por 48 hours in presence of 2.00 x 10-l H NaOH. Excess oP CAT left was estimated. The results showed that two moles of CAT were consumed per mole oxidation oP ketoglutarlc acid (Table 1) and accordingly the Pollowing stoichlometric equation could be formulated, where R represents -CH2. CO.COOH and -CO.CH COOH groups in the substrate molecule. The end products formic acid (tes2ed by chgomatographlc technique) and formaldehyde uere tested by conventional methods. R.CH2COOH + 2 CH3C6H4SO2N.NaCl + 4 OH- 2 CH3CgH4.S02NH2 + 2 NaCl + 4 HCOO- + HCHO ...............(l)
851
B.
858
Kinetics
of
Investigated strength.
Initial
concentrations
Owing to the high
possible
to
use a buffer.
chloramlne-T of
the
reaction
the
of
the
plot
slope
The most chloramine-T show that
the
the of
of
second-order
are
log
of
ionic
sodium
perchlorate
negligible
and effect
of
Average
activation
(AS+)
Were calculated
(30-45O)
respectively
(a-ketoglutaric
acid)
respectively
(B-ketoglutaric
acid).
recorded appear
here, to
acids
have
clearly
In the
and were found
oxidation
R’\C-O
ii’/
l
to
of
that
that
process
OH-
the
and not
their
*\
where R’ - -COOH and R’-
be 7.54
+ H20
follow while
oxidation
at
of
suitable
addition
of
ethanol
(the
(AE))
rate
Kcal
(5-305) product
of
and -40.60
and -35.89
of
form
Identical oxidation
temperature of
e.u.,
e.u., acids,
kinetics of
ketoglutarlc
of
at four
and B-ketoglutaric have
of and
and entropy
constants
mol-’
mol-’
positive amounts
reduction
The effect
of
Kcal
of
4 records
addition
and thus
ketoglutaric
acids
is
involved
by chloramine-T.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . (2)
-CH2CH2COOHIn a-ketoglutaric
CH2COOHin B-ketoglutaric
acid
and R”’
and R--W -CHCOOH (B-ketoglutaric In aqueous
alkaline
sulphochloramide
_)
acid
and R’-
R’-
-CHCH2COOH(a-ketoglutaric
acid)
acid).
solutions,
chloramine-T
(CATI
(CAT*) and p-toluenesulphonamide
CH3C6H4S02N.NaC1+H20
CH3C6H4S02N.HCl +
hydrolyses
to p-toluene-
(TSA) as follows: NaOH
. . . . . . . . . . . . . . . . . (3)
CAT*
CAT CH3C6H4S02N.HCl*NaOH
CH3C6H4S02NH2+NaC10
CAT*
. . . . . . . . . . . . . . . . . . . . (4)
TSA
Chloramine-T dichloramine-T
of
activation
values
keto
slope
reactions
(s-1
(S)
CAT Itself,
of
anion
the
Table
Base catalysed
fl,C_=O
e
of
reactions
enolic
(Table
Prom the
concentrations
rate
a-ketoglutaric
the
a common mechanism. indicates
the
and 9.15
the oxidation
have revealed
by
energy
by
The results
In alkalinity
that
of’ temperature.
from
temperatures
of
studied.
of
1) from
acids
oxidation.
p-toluenesulphonamide
values
(Fig.
2).
2).
on the
variation
marked.
as 0.54
was calculated
factors
effect
(Table
ketoglutaric of
alkali
(Fig.
In
acid].
was observed
(affected
of
dependence
to a change Ions
at lower
negative
addition
rate
Ionic
was not
concentration
of
the
was also
variation
was quite
The results
ions
other
solution), of
It
decreases
by chloramine-T
strength
effect
chloramlne-T)
several
order
oxidation of
[OH-].
It
was found
susceptible
In hydroxide of
acids
the
(pH > 12)
Cketoglutaric
In hydroxide
the order
The Influence effect
highly
kl ~9 log
kinetics
of
were
at constant
acid
acids log
acids
reactants
alkali
show first
on alkali
reaction
concentrations
ketoglutaric
Peature
the
the
In ketoglutaric
kl agalnst
dependence
reactions
The order
higher
log
interesting is
plots
order
of
in ketoglutaric
of
of
concentration
The results
and fractional
The order
3). of the
RESULTS AND DISCUSSION of a-ketoglutaric and B-ketoglutaric
the oxidation
at several
SINGHI et al.
in aqueous
CAT*, hypochlorite acting
solution
thus
provides
four
Ion and dichloramine-T.
as main oxidising
species
Is
oxidizing
species
The possibility ruled
out,
-viz. of
as in alkaline
Kinetics of oxidation of ketoghtaric acids
media it oxidlslng second
does not species
order
dependence
of
effect
of
involved
In the
rate-determining
acids
all
ionic
the
posltive Considering
experimental
H20
l
data,
TSA
on hydroxide
the
ClO-
ion
of
steps.
not
left
and
is
to
hypochlorite
of
(ii)
as
to
be expected
is
oxidation
Step
assumed
conform
concentration cannot
choice
mechanism
be
ion.
ketoglutaric
slow.
. . . . . . . . . . . . . . . . . . . . . . . . . . (1)
Na+
l
does
species
The only
following
l
CAT or CAT* is
law obtained
Hence these step.
by the
2 _
rate
reactions
strength.
may be summarised
CAT
When either
exist even in traces. of chloramlne-T. the
859
k-l fast k2
S + OH-
+ OH- + OCl’
S’
Slowest x
l
but not
the
titre
step
disappearance
value
2 k2k3
is
well
fairly
large
ion
the
the
and the
concentrations
the
will
decrease.
with
respect
consistent
with
reactions
order
observed
be two.
law
according
hold (Fig.
of
conform
to.the
rate
may be ascribed
thank
U.G.C.
New Delhi
for
the
on
of
alkali
and the
alkali
order
and are,
order to the
in alkali
due to
in order
therefore, 0.54)
(i.e. first
law (6).
providing
determining
2) show a decrease
order
with
dependence
The decrease
decrease
constant of the medium on increasing the concentration of The rate determining step (iii) involves an Interaction charged ions which would require a positive effect of ionic positive effect of ionic strength has been observed and is the rate determining step (iii). The values of energy of activation and positive effect of dielectric constant also controlling step (iii) in the proposed mechanism. The authors
dependence
low concentrations
At higher
The fractional not
for
for
strictly
concentration
(6).
to substrates
constant
observations
1) does
order
rate
will
(Fig.
first
(6)
the
be valid
rate
formation
>> k3 CCATICOHI.
will
at higher
both
in the
on OH when k_2 [H20]
being
not
to
only
as eqn (6).
small,
on substrates respect
with
will
by eqn (5).
.....................
dependence
in alkali
given
corresponds consumed
approximation
order
alkali the
is
may be written
in agreement
approximation
to substrates
mixture
k3 [CATJCOHT
l
The experimental to
reaction
steady-state
is
. . . . . . . . . . . . . . . . ...(5)
and chloramine-T
and k3 is above
Applying
hypochlorite
[Sl[CATl[OH-I2
and a second
and thus
with
for
k_2 [H201
law (6)
(iii).
of
+ k3 CClO-ICOH-1
Thus eqn (5) _
chloramine-T
order
of
and hypochlorite
dt
the
rate-determining
rate
k_2 [H201
-d[CATl
respect
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (iv)
2 k2k3[S~[C10-~~OH-~2
hydroxide
. . . . . . . . . . . . . . . . . . . . . . . . (iii)
(X)
[ClO-1
hypochlorite.
step
Intermediate
dt
chloramine-T
k_2 is
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (ii)
Products
as the
to S,
The iodometrlc
The rate
-%
k4 ___) fast
oc1as slow
-d
+ H20
and rate-determining
conditions
of
S-
of
in
in dielectric
ketoglutaric acids. between similarly strength. In fact, thus consistent with activation, entropy of confirm the rate
financial
assistance.
B.
860
1
I
I
I
I
1.0
1.2
1.4
1.6
3+logt[S]/M) Fig. 1:
SINOH~ el a/.
c
0.8 1.0 I-2 1.4 2 t LogC[Otf]/M>-
-
Plot of log kl against log KGAI [Chloramlne-T] = 2.00 x 10' 4 ; p = 0.20 M [NaOH] = 8.00 x 10S2M, Temp. 35"
Fig. 2:
~~~tl~~_:oagtkj5~gainst [chloramine-Tl = 2.00 x 10_3M, p = 0.20 M
-
a== w acid]
TABLE Stoichiometry
CKGAI i03r4
1
of the Oxidation of Ketoglutaric Acids (KGA)
[CAT] io2n
1.00
(a - Ketoglutaric 2.00 x lo-2 M (6 - Xetoglutaric = 2.00 x 1O-2 M
Unconsum d [CAT] lo!I M
Consume CCATI lo4M
Stoichiometry [CAT] [KGAI
consumed
2.00
2.00 2.00
17.98 15.80
2.00 1.00
1.00 1.00
6.04 7.94
2.02 4.20 3.96 2.06
1.00 2.00
2.00 2.00
la.04 15.76
1.96
l.96b
4.24
2.12b
a
--
a-ketoglutaric
acid
and
b ---
2.02a 2.10a
1 .9aa 2.06b
B-ketoglutarlc
acid
TABLE 2 Effect of Concentrations [NaOHl - 8.00
103M
[CAT1
0.80 1.00 1.34 1.60 2.67 4.00 2.00 2.00 2.00 2.00 2.00
CAT ----
of Reactants on the Rate at 35OC x
10S2
M;
IJ -
0.20 M
k,xlO'
set -'
a-KGA
B-KGA
1.92 1.93 1.95 1.97 2.00 2.07 1.62 1.73
1.42 1.43 1.43 1.50 1.52 1.53 1.25 1.33 1.43 1.57
DOOM CKGAI
2.00 2.00 2.00 2.00 2.00 2.00 1.00 1.25 1.67 2.50 4.00
Chloramine-T and KGA ----
I .a7 2.13 2.50
i .a7
Ketoglutarlc
acid
Kinetics ofoxidation ofkctoglutaricacids
861
TABLE 3 EfPect of Concentration CCATI
-
2.00 x 10-3M,
of Alkali on Rate at 35O
CKGAl - 2.00 x 10-2M;
and p - 0.20 M
kl x lo4 set-' [NaOH] x 102M
5.00 6.25 8.00 10.00 12.50 20.00 KGA ----
a-KGA
B-KGA
1.02 1.38 1.97 2.27
0.85 1.10 1.50 2.37
Ketoglutaric acid
TABLE 4 p), Ethanol Concentrat..on and Temperature Varii?)tionon Effect of Ionic Strength [NaOH] - 8.00 x lo- M. Rate. CCATI - 2.00 x lo- 4M; CKGAI - 2.00 x 10 M;
Temperature
OC
u
Ethanol % (v/v)
0.80 0.20 0.30 0.40 0.50
0.20 0.20 0.20 0.30 0.20 0.20
5.00
10.00 20.00 30.00
0.20 KGA ----
kl x lo4 set-' ______________ a-KGA B-KGA 1.33 1.97 2.83 3.52
1.12 1.50 2.12 2.75
z: 1:30
1.25 1.07 0.85 0.75 1.17 1.87 2.32
1.00 0.82 1.60 2.30 2.82
3.40
Ketoglutaric acid
REFERENCES 1. 2. 3.
4. 65: 7.
R. Sanehi, M.C. Agrawal and S.P. Mushran, Indian J. Chem.. 12. 311 (1974). S.P. Mushran and M.C. Agrawal, Z. Naturforscn., 2;Tq-mT (1972): S.P. Mushran. R. Sanehi and A.K. Bose, Acta Chim. Acad. Sci., Hungaricae, 84(2), 135 (1975). 2591 (1982:). Bharat Singh, A.K. Samant and B.B.L. Saxena. Tetrahedron, 38, M.C. Agrawal and S.P. Hushran, J. Chem. Sot. ?!Yerkin If), 762 (1973). F. Feinl. Spot Tests In 0raanic-X nalysis, 5th edn. (Elsevier, Amsterdam), pi331 Tl956j. R. Dietzel and K. Taufel, Apoth.-Ztg.. 44, 989 (1929:).
KINETICS OF OXIDATION OF KETOCLUTARIC ACIDS BY ALKALINE CHLORAHINE-T SOLUTION
BHARAT SINCH', A.K. SAMANT, B.B.L. SAXENA and M.B. SINGH
Chemical Laboratories. University OP Allahabad, Allahabad - 211002, India (Receivedin UKU) Seprember 1985) Abstract - Kinetics of the oxidation of a-ketoglutarlc and B-ketonlutaric acids by chloramine-T (CAT) have been The reactions show investigated in highly-alkaline media. first order dependence in chloramine-T and fractional order in substrates. The order in hydroxide ions has been Pound to be second but shows a slight decrease at high concentration of No effect of p-toluene-sulphonamidewas evident. alkali. Observed stoichiometry, positive effects of ionic strength and dielectric constant point to a mechanism involving formation of an intermediate in a termolecular rate determining slowest step among hypochlorlte ion. hydroxide ion and enollc anion of keto acids followed by a Past step leading to products. Activation parameters have been computed and formaldehyde and formic acid were identified as end-products.
INTRODUCTION The present communication reports the complex kinetics in oxidation of ketoglutaric acids by alkaline solution of chloramlne-T in contrast to very simple kinetic observations, so Par, obtained in chloramine-T oxidation of aldehydes,'r2 ketones,3,4 and aldoses5 in alkaline media. In order to shed some further light on chloramine-T oxidations, the kinetic observations o$ the present invesigatlon have been discussed and a suitable mechanism has been presented.
MATERIALS AND METHODS All the reagents used were of highest purity available. Chloramine-T (E. Merck proanalysis) was used and stored in black coated bottles. Koch-Light (England) sample of D-toluene-SulDhOnamidewas used. All other reanents were of anaiar grade.‘ The solutions of h-ketoglutaric acid (E. Merck) and 8-ketoglutaric acid (Loba Chemle) Were prepared by direct weighing and dissolving in double distilled water. The reaction stllls were blackened Prom outside to avoid any photochemical influence. All reactants except keto acid were allowed to mix and the reaction was initiated by adding subsequently appropriate amount of ketoglutaric acid. The progress of the reaction was monitored by estimating unconsumed CAT iodometrically using starch as indicator. All the rate studies were carried out at constant temperature (i 0.1). Stoichiometry and product analysis Reaction mixture containing excess of CAT over ketoglutaric acid was allowed to equilibrate at 35OC Por 48 hours in presence of 2.00 x 10-l H NaOH. Excess oP CAT left was estimated. The results showed that two moles of CAT were consumed per mole oxidation oP ketoglutarlc acid (Table 1) and accordingly the Pollowing stoichlometric equation could be formulated, where R represents -CH2. CO.COOH and -CO.CH COOH groups in the substrate molecule. The end products formic acid (tes2ed by chgomatographlc technique) and formaldehyde uere tested by conventional methods. R.CH2COOH + 2 CH3C6H4SO2N.NaCl + 4 OH- 2 CH3CgH4.S02NH2 + 2 NaCl + 4 HCOO- + HCHO ...............(l)
851
B.
858
Kinetics
of
Investigated strength.
Initial
concentrations
Owing to the high
possible
to
use a buffer.
chloramlne-T of
the
reaction
the
of
the
plot
slope
The most chloramine-T show that
the
the of
of
second-order
are
log
of
ionic
sodium
perchlorate
negligible
and effect
of
Average
activation
(AS+)
Were calculated
(30-45O)
respectively
(a-ketoglutaric
acid)
respectively
(B-ketoglutaric
acid).
recorded appear
here, to
acids
have
clearly
In the
and were found
oxidation
R’\C-O
ii’/
l
to
of
that
that
process
OH-
the
and not
their
*\
where R’ - -COOH and R’-
be 7.54
+ H20
follow while
oxidation
at
of
suitable
addition
of
ethanol
(the
(AE))
rate
Kcal
(5-305) product
of
and -40.60
and -35.89
of
form
Identical oxidation
temperature of
e.u.,
e.u., acids,
kinetics of
ketoglutarlc
of
at four
and B-ketoglutaric have
of and
and entropy
constants
mol-’
mol-’
positive amounts
reduction
The effect
of
Kcal
of
4 records
addition
and thus
ketoglutaric
acids
is
involved
by chloramine-T.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . (2)
-CH2CH2COOHIn a-ketoglutaric
CH2COOHin B-ketoglutaric
acid
and R”’
and R--W -CHCOOH (B-ketoglutaric In aqueous
alkaline
sulphochloramide
_)
acid
and R’-
R’-
-CHCH2COOH(a-ketoglutaric
acid)
acid).
solutions,
chloramine-T
(CATI
(CAT*) and p-toluenesulphonamide
CH3C6H4S02N.NaC1+H20
CH3C6H4S02N.HCl +
hydrolyses
to p-toluene-
(TSA) as follows: NaOH
. . . . . . . . . . . . . . . . . (3)
CAT*
CAT CH3C6H4S02N.HCl*NaOH
CH3C6H4S02NH2+NaC10
CAT*
. . . . . . . . . . . . . . . . . . . . (4)
TSA
Chloramine-T dichloramine-T
of
activation
values
keto
slope
reactions
(s-1
(S)
CAT Itself,
of
anion
the
Table
Base catalysed
fl,C_=O
e
of
reactions
enolic
(Table
Prom the
concentrations
rate
a-ketoglutaric
the
a common mechanism. indicates
the
and 9.15
the oxidation
have revealed
by
energy
by
The results
In alkalinity
that
of’ temperature.
from
temperatures
of
studied.
of
1) from
acids
oxidation.
p-toluenesulphonamide
values
(Fig.
2).
2).
on the
variation
marked.
as 0.54
was calculated
factors
effect
(Table
ketoglutaric of
alkali
(Fig.
In
acid].
was observed
(affected
of
dependence
to a change Ions
at lower
negative
addition
rate
Ionic
was not
concentration
of
the
was also
variation
was quite
The results
ions
other
solution), of
It
decreases
by chloramine-T
strength
effect
chloramlne-T)
several
order
oxidation of
[OH-].
It
was found
susceptible
In hydroxide of
acids
the
(pH > 12)
Cketoglutaric
In hydroxide
the order
The Influence effect
highly
kl ~9 log
kinetics
of
were
at constant
acid
acids log
acids
reactants
alkali
show first
on alkali
reaction
concentrations
ketoglutaric
Peature
the
the
In ketoglutaric
kl agalnst
dependence
reactions
The order
higher
log
interesting is
plots
order
of
in ketoglutaric
of
of
concentration
The results
and fractional
The order
3). of the
RESULTS AND DISCUSSION of a-ketoglutaric and B-ketoglutaric
the oxidation
at several
SINGHI et al.
in aqueous
CAT*, hypochlorite acting
solution
thus
provides
four
Ion and dichloramine-T.
as main oxidising
species
Is
oxidizing
species
The possibility ruled
out,
-viz. of
as in alkaline
Kinetics of oxidation of ketoghtaric acids
media it oxidlslng second
does not species
order
dependence
of
effect
of
involved
In the
rate-determining
acids
all
ionic
the
posltive Considering
experimental
H20
l
data,
TSA
on hydroxide
the
ClO-
ion
of
steps.
not
left
and
is
to
hypochlorite
of
(ii)
as
to
be expected
is
oxidation
Step
assumed
conform
concentration cannot
choice
mechanism
be
ion.
ketoglutaric
slow.
. . . . . . . . . . . . . . . . . . . . . . . . . . (1)
Na+
l
does
species
The only
following
l
CAT or CAT* is
law obtained
Hence these step.
by the
2 _
rate
reactions
strength.
may be summarised
CAT
When either
exist even in traces. of chloramlne-T. the
859
k-l fast k2
S + OH-
+ OH- + OCl’
S’
Slowest x
l
but not
the
titre
step
disappearance
value
2 k2k3
is
well
fairly
large
ion
the
the
and the
concentrations
the
will
decrease.
with
respect
consistent
with
reactions
order
observed
be two.
law
according
hold (Fig.
of
conform
to.the
rate
may be ascribed
thank
U.G.C.
New Delhi
for
the
on
of
alkali
and the
alkali
order
and are,
order to the
in alkali
due to
in order
therefore, 0.54)
(i.e. first
law (6).
providing
determining
2) show a decrease
order
with
dependence
The decrease
decrease
constant of the medium on increasing the concentration of The rate determining step (iii) involves an Interaction charged ions which would require a positive effect of ionic positive effect of ionic strength has been observed and is the rate determining step (iii). The values of energy of activation and positive effect of dielectric constant also controlling step (iii) in the proposed mechanism. The authors
dependence
low concentrations
At higher
The fractional not
for
for
strictly
concentration
(6).
to substrates
constant
observations
1) does
order
rate
will
(Fig.
first
(6)
the
be valid
rate
formation
>> k3 CCATICOHI.
will
at higher
both
in the
on OH when k_2 [H20]
being
not
to
only
as eqn (6).
small,
on substrates respect
with
will
by eqn (5).
.....................
dependence
in alkali
given
corresponds consumed
approximation
order
alkali the
is
may be written
in agreement
approximation
to substrates
mixture
k3 [CATJCOHT
l
The experimental to
reaction
steady-state
is
. . . . . . . . . . . . . . . . ...(5)
and chloramine-T
and k3 is above
Applying
hypochlorite
[Sl[CATl[OH-I2
and a second
and thus
with
for
k_2 [H201
law (6)
(iii).
of
+ k3 CClO-ICOH-1
Thus eqn (5) _
chloramine-T
order
of
and hypochlorite
dt
the
rate-determining
rate
k_2 [H201
-d[CATl
respect
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (iv)
2 k2k3[S~[C10-~~OH-~2
hydroxide
. . . . . . . . . . . . . . . . . . . . . . . . (iii)
(X)
[ClO-1
hypochlorite.
step
Intermediate
dt
chloramine-T
k_2 is
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (ii)
Products
as the
to S,
The iodometrlc
The rate
-%
k4 ___) fast
oc1as slow
-d
+ H20
and rate-determining
conditions
of
S-
of
in
in dielectric
ketoglutaric acids. between similarly strength. In fact, thus consistent with activation, entropy of confirm the rate
financial
assistance.
B.
860
1
I
I
I
I
1.0
1.2
1.4
1.6
3+logt[S]/M) Fig. 1:
SINOH~ el a/.
c
0.8 1.0 I-2 1.4 2 t LogC[Otf]/M>-
-
Plot of log kl against log KGAI [Chloramlne-T] = 2.00 x 10' 4 ; p = 0.20 M [NaOH] = 8.00 x 10S2M, Temp. 35"
Fig. 2:
~~~tl~~_:oagtkj5~gainst [chloramine-Tl = 2.00 x 10_3M, p = 0.20 M
-
a== w acid]
TABLE Stoichiometry
CKGAI i03r4
1
of the Oxidation of Ketoglutaric Acids (KGA)
[CAT] io2n
1.00
(a - Ketoglutaric 2.00 x lo-2 M (6 - Xetoglutaric = 2.00 x 1O-2 M
Unconsum d [CAT] lo!I M
Consume CCATI lo4M
Stoichiometry [CAT] [KGAI
consumed
2.00
2.00 2.00
17.98 15.80
2.00 1.00
1.00 1.00
6.04 7.94
2.02 4.20 3.96 2.06
1.00 2.00
2.00 2.00
la.04 15.76
1.96
l.96b
4.24
2.12b
a
--
a-ketoglutaric
acid
and
b ---
2.02a 2.10a
1 .9aa 2.06b
B-ketoglutarlc
acid
TABLE 2 Effect of Concentrations [NaOHl - 8.00
103M
[CAT1
0.80 1.00 1.34 1.60 2.67 4.00 2.00 2.00 2.00 2.00 2.00
CAT ----
of Reactants on the Rate at 35OC x
10S2
M;
IJ -
0.20 M
k,xlO'
set -'
a-KGA
B-KGA
1.92 1.93 1.95 1.97 2.00 2.07 1.62 1.73
1.42 1.43 1.43 1.50 1.52 1.53 1.25 1.33 1.43 1.57
DOOM CKGAI
2.00 2.00 2.00 2.00 2.00 2.00 1.00 1.25 1.67 2.50 4.00
Chloramine-T and KGA ----
I .a7 2.13 2.50
i .a7
Ketoglutarlc
acid
Kinetics ofoxidation ofkctoglutaricacids
861
TABLE 3 EfPect of Concentration CCATI
-
2.00 x 10-3M,
of Alkali on Rate at 35O
CKGAl - 2.00 x 10-2M;
and p - 0.20 M
kl x lo4 set-' [NaOH] x 102M
5.00 6.25 8.00 10.00 12.50 20.00 KGA ----
a-KGA
B-KGA
1.02 1.38 1.97 2.27
0.85 1.10 1.50 2.37
Ketoglutaric acid
TABLE 4 p), Ethanol Concentrat..on and Temperature Varii?)tionon Effect of Ionic Strength [NaOH] - 8.00 x lo- M. Rate. CCATI - 2.00 x lo- 4M; CKGAI - 2.00 x 10 M;
Temperature
OC
u
Ethanol % (v/v)
0.80 0.20 0.30 0.40 0.50
0.20 0.20 0.20 0.30 0.20 0.20
5.00
10.00 20.00 30.00
0.20 KGA ----
kl x lo4 set-' ______________ a-KGA B-KGA 1.33 1.97 2.83 3.52
1.12 1.50 2.12 2.75
z: 1:30
1.25 1.07 0.85 0.75 1.17 1.87 2.32
1.00 0.82 1.60 2.30 2.82
3.40
Ketoglutaric acid
REFERENCES 1. 2. 3.
4. 65: 7.
R. Sanehi, M.C. Agrawal and S.P. Mushran, Indian J. Chem.. 12. 311 (1974). S.P. Mushran and M.C. Agrawal, Z. Naturforscn., 2;Tq-mT (1972): S.P. Mushran. R. Sanehi and A.K. Bose, Acta Chim. Acad. Sci., Hungaricae, 84(2), 135 (1975). 2591 (1982:). Bharat Singh, A.K. Samant and B.B.L. Saxena. Tetrahedron, 38, M.C. Agrawal and S.P. Hushran, J. Chem. Sot. ?!Yerkin If), 762 (1973). F. Feinl. Spot Tests In 0raanic-X nalysis, 5th edn. (Elsevier, Amsterdam), pi331 Tl956j. R. Dietzel and K. Taufel, Apoth.-Ztg.. 44, 989 (1929:).