Formation and properties of a catalyst based on sodium and potassium hydroxides in the reaction of 2,6-di-tert-butylphenol with methyl acrylate

Article abstract of DOI:10.1023/A:1022170915654

The nature of the cation (K⁺ or Na⁺) in hydroxides affects the temperature plot of the equilibrium constant of the reaction of KOH and NaOH with 2,6-di-tert-butylphenol (ArOH) and the conversion of KOH and (or) NaOH to potassium or sodium 2,6-di-tert-butyl phenoxides, which are catalysts for the alkylation of ArOH by methyl acrylate. The kinetic method for determination of the composition of the catalyst formed from NaOH and ArOH was proposed. The nature of the cation in phenoxides ArOK or ArONa is a factor determining the kinetics of the reaction of ArOH with methyl acrylate. Two different kinetic schemes were proposed to describe the transformation of ArOH in the presence of ArONa or ArOK.

Full text of DOI:10.1023/A:1022170915654

Russian Chemical Bulletin, International Edition, Vol. 51, No. 12, pp. 2189—2195, December, 2002
2189
Formation and properties of a catalyst based on sodium and potassium
hydroxides in the reaction of 2,6ꢀdiꢀtertꢀbutylphenol with methyl acrylate
ꢀ
A. A. Volod´kin and G. E. Zaikov
N. M. Emanuel´ Institute of Biochemical Physics, Russian Academy of Sciences,
4 ul. Kosygina, 119991 Moscow, Russian Federation.
Fax: +7 (095) 137 4101. Eꢀmail: chembio@glasnet.ru
The nature of the cation (К+ or Na+) in hydroxides affects the temperature plot of the
equilibrium constant of the reaction of KOH and NaOH with 2,6ꢀdiꢀtertꢀbutylphenol (ArOH)
and the conversion of КОН and (or) NaOH to potassium or sodium 2,6ꢀdiꢀtertꢀbutyl phenoxꢀ
ides, which are catalysts for the alkylation of ArOH by methyl acrylate. The kinetic method for
determination of the composition of the catalyst formed from NaOH and ArOH was proposed.
The nature of the cation in phenoxides ArOK or ArONa is a factor determining the kinetics of
the reaction of ArOH with methyl acrylate. Two different kinetic schemes were proposed to
describe the transformation of ArOH in the presence of ArONa or ArOK.
Key words: 2,6ꢀdiꢀtertꢀbutylphenol, potassium hydroxide, sodium hydroxide, potassium
and sodium 2,6ꢀdiꢀtertꢀbutyl phenoxides, kinetics, alkylation, methyl acrylate, methylꢀ
3ꢀ(4ꢀhydroxyꢀ3,5ꢀdiꢀtertꢀbutylphenyl) propionate.
The catalytic alkylation of 2,6ꢀdialkylphenols in the
liquid phase in the presence of 2,6ꢀdialkyl phenoxides
depends on the nature of the alkaline metal and the
method of preparation of the catalyst by the interaction of
2,6ꢀdialkylphenol with an alkaline agent.1—6 The most
promising alkaline agents are sodium and potassium
hydroxides or their compositions, which found use in
the synthesis of methylꢀ3ꢀ(4ꢀhydroxyꢀ3,5ꢀdiꢀtertꢀbutylꢀ
phenyl) propionate (R1OH).2 The reactions of 2,6ꢀdiꢀ
tertꢀbutylphenol (ArOH) with KOH or NaOH are reversꢀ
ible and were studied only at the qualitative level.
In this work, we obtained quantitative data on the
reactions of ArOH with KOH (NaOH) and of ArOK
(ArONa) with H2O in the temperature interval from 70 to
144 °С. When the process occurs in the gas—liquid sysꢀ
tem, water vapors diffuse from the liquid phase but, in
authors´ opinion, diffusion has no substantial effect on
the regularities of the reaction in the liquid phase.
The kinetics of the reaction of ArOH with methyl
acrylate in the presence of the compositions containing
ArONa and NaOH was studied. It was shown that only
ArONa was the catalyst. The method for determination of
the catalyst composition (contents of ArONa and NaOH)
and the mechanism of the reaction of ArOH with methyl
acrylate in the presence of ArONa or ArOK was proposed.
In the presence of ArONa, sodium 4ꢀ(βꢀmethoxycarboxyꢀ
ethyl)ꢀ2,6ꢀdiꢀtertꢀbutyl phenoxide is formed, which makes
it possible to interpret the reaction mechanism in the
framework of the scheme different from that described
previously.7 The results of this work substantiate the use
of the NaOH and KOH mixtures as initial alkaline agents
for the preparation of the catalyst for ArOH alkylation by
methyl acrylate.
Experimental
A Bruker LCꢀ31 instrument with an IBM Cyano column
was used for HPLC (hexane—isopropyl alcohol—ethyl acetate
(8 : 1 : 1, v/v/v) as an eluent, working pressure 57 atm, rate
0.4 mL min–1). IR spectra were recorded using a Beckman DUꢀ8
spectrometer. 1H NMR spectra were obtained with a Bruker
WMꢀ400 instrument (400 MHz, a solution in CDCl3, Me4Si as
an internal standard).
Synthesis of sodium 4ꢀ(βꢀmethoxycarboxyethyl)ꢀ2,6ꢀdiꢀ
tertꢀbutyl phenoxide (R1ONa). In an argon flow R1OH (0.01 mol)
was added to MeONa (0.01 mol) in MeOH (30 mL). The soluꢀ
tion was refluxed for 30 min, then MeОН was distilled off in
vacuo. The crystalline residue was twice washed with hexane
and separated by filtration. The crystals decompose upon heatꢀ
ing above 220 °С. Found (%): C, 68.55; H, 8.40; Na, 7.85.
C18H27O3Na. Calculated (%): C, 68.76; H, 8.66; Na, 7.32.
IR (KBr), ν/cm–1: 1568 (C—O); 1736 (С=О).
Kinetic and analytical measurements were carried out using a
known procedure.7 Individual ArOK and ArONa were obtained
by the addition of calculated amounts of ButOK in ButOH (or
MeONa in MeOH) to ArOH followed by the removal of aliꢀ
phatic alcohol by evacuation.
The equilibrium ArOH + MOH
ArOM + H2O
(M = K, Na) was studied as follows. A weighed sample of melted
2,6ꢀdiꢀtertꢀbutylphenol was placed in a cylindrical vessel with a
plunger and a pipeꢀbend in the bottom part for the connection
of a needle. The plunger was removed, a weighed sample of
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2031—2037, December, 2002.
1066ꢀ5285/02/5112ꢀ2189 $27.00 © 2002 Plenum Publishing Corporation

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Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Volod´kin and Zaikov
ArOK (ArONa) and a measured volume of water were introꢀ
duced into the cylinder, the plunger was connected, air was
removed from the cylinder, and the needle was replaced by a
plug. The reaction mixture thus prepared was stirred by shaking,
placed in a thermostat, and stored at a specified temperature for
a needed time. Then the plug was replaced by the needle, benꢀ
zene (10—12 mL) was placed in the cylinder (reactor), and the
precipitate formed was filtered off. The cylinder was filled with
benzene (2—3 mL) three times more, and the precipitate on the
filter was washed with benzene. The concentration of phenol in
a benzene solution was determined by HPLC. Benzene with
water was distilled off from phenol, and the content of water in a
benzene solution was determined by the Fischer method. The
filter with the alkali and phenoxide residue was placed in a flask,
toluene (30 mL) was added, and residues of H2O and ArOH
with toluene were distilled off in vacuo. After cooling, a meaꢀ
sured volume of H2SO4 with a known concentration was added
to the residue, and the total concentration of alkali and phenoxꢀ
ide was determined by "inverse" titration using phenolphthalein
as an indicator. Benzene (5 mL) was added to the same flask,
phenol formed was extracted, and the amount of ArOH was
determined by HPLC using solutions with the known concenꢀ
tration of ArOH. The concentration of ArOK or ArONa was
calculated from the results of this analysis. The concentration of
alkali in the reaction solution was determined from the differꢀ
ence between the total amount of bases found by titration and
the amount of phenoxide calculated using the results of HPLC
analysis. The results of studying the equilibrium are presented in
Table 1.
The influence of the gaseous phase in the reactor was checked
by a special experiment, during which nitrogen was introduced
into the cylinder after removal of air (Table 2). The results are
discussed further.
The reaction of ArONa with R1OH was studied using a
similar procedure.
A mixture of ArONa (0.024 mol) and R1OH (0.065 mol) was
boiled for 20—40 min at 116 °С. The yield of R1ONa remained
unchanged and was 0.014 mol (58% calculated on the basis of
Table 1. Initial (I) and equilibrium (II) concentrations (mol kg–1) of the reactants and effective equilibrium
constants (Keeff) of the reaction of ArOH with MOH (M = K, Na) in the condensed phase at different temperaꢀ
tures
eff
T/°C
ArOH
MOH
ArOM
H2O
Ke
I
II
I
II
I
II
I
II
M = K
—
—
144
116
100
70
4.718
4.667
4.349
4.495
4.111
4.374
0.467
0.657
—
0.0486
0.0808
0.0342
0.447
0.555
0.325
—
—
0.479
0.428
0.566
0.436
0.91
0.94
0.95
0.93
0.33
0.26
0.31
0.3
0.099
0.068
0.13
0.089
0.014
0.009
0.011
0.359
4.312
4.748
4.654
4.398
4.448
4.119
—
0.358
0.703
0.0687
0.0596
0.208
0.395
—
—
0.326
0.248
0.511
0.376
—
—
0.309
0.278
0.519
4.719
4.261
2.167
4.449
4.492
3.624
0.463
—
—
0.203
0.2147
1.457
—
0.429
1.745
0.28
0.248
0.249
—
0.462
5.36
0.318
0,264
2.704
4.719
4.329
4.575
4.649
0.463
—
0.338
0.302
—
0.373
0.145
0.071
—
0.497
0.145
0.195
M = Na
—
0.206
0.527
144
116
100
70
4.741
4.316
4.171
4.487
4.451
4.372
0.538
—
—
0.205
0.222
0.201
0.225
0.278
0.345
—
0.222
0.541
0.332
0.293
0.355
0.081
0.082
0.13
0.1
4.634
4.162
4.089
4.178
4.321
4.406
1.089
—
—
0.574
0.171
0.243
—
0.547
0.597
0.416
0.402
0.355
—
0.369
0.523
0.475
0.145
0.299
0.082
0.079
0.099
0.086
0.067
0.073
0.068
0.069
0.034
0.038
0.034
0.035
4.768
4.447
4.114
4.544
4.593
4.316
0.391
—
—
0.128
0.118
0.186
—
0.289
0.598
0.175
0.165
0.396
—
0.369
0.226
0.293
0.243
0.137
4.725
4.171
4.651
4.519
4.425
4.721
0.619
—
—
0.356
0.271
0.077
—
0.534
0.145
0.216
0.254
0.068
—
0.459
0.239
0.253
0.181
0.181

Catalyst based on hydroxides for 2,6ꢀdiꢀtertꢀbutylphenol Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2191
Table 2. Initial (I) and equilibrium (II) concentrations (mol kg–1) of the reactants of the reaction of ArOH with
MOH (M = K, Na) in the condensed phase (liquid—vapor) at 100 °C
τ/min
ArOH
MOH
ArOM,
II
Yield of
ArOM (%) [ArOH]•[MOH]
[ArOM]2
I
II
I
II
M = K
0.437
1.224
0.548
0.589
M = Na
0.448
0.499
0.619
0.429
0.584
0.334
10
20
30
60
4.727
4.513
4.696
4.685
4.588
4.011
4.308
4.353
0.266
0.723
0.238
0.258
0.138
0.501
0.303
0.341
32
41
55
58
0.016
0.087
0.09
0.103
10
20
30
40
60
90
4.758
5.012
4.725
4.762
4.731
6.781
4.669
4.694
4.509
4.379
4.372
4.565
0.348
0.219
0.356
0.138
0.277
0.129
0.109
0.098
0.216
0.155
0.287
0.205
24
31
35
36
49
61
0.007
0.009
0.029
0.039
0.068
0.071
ArONa consumed). According to the data of calculation, the
equilibrium constant is Ke = 0.41.
and the plot in the coordinates of van´t Hoff equation
(Fig. 1). A series of experiments in the condensed
phase—gas (vapor) phase system was performed to eluꢀ
cidate the role of diffusion under static conditions.
The results of determination of the concentrations of
the initial and formed compounds at 100 °С and the
[ArOK]2/([ArOH]•[KOH]) ratios, which depend on the
time of the reaction of ArOH with KOH, are presented in
Table 2. After 30 min of the reaction of ArOH with KOH,
this value becomes equal to Keeff determined for the reacꢀ
tion of ArOH with KOH in the liquid phase without a
gaseous phase, and it remains virtually unchanged for
60 min in the condensed phase—vapor phase system. A
similar result was obtained for the reaction of ArOH with
NaOH. It follows from these data that diffusion has no
substantial effect on the ratio of the concentrations of the
formed and initial components.
The catalyst based on KOH and/or NaOH was synthesized
by the addition of calculated amounts of KOH and/or NaOH to
ArOH followed by the removal of H2O by evacuation at
100—105 °С. The calculated amount of methyl acrylate was
added to thus obtained catalytic mixture, the reaction was carꢀ
ried out at 116—118 °С in an argon atmosphere, and samples of
the liquid phase for HPLC analysis were taken after 5, 10, 15,
20, and 30 min.
For example, NaOH (0.12 g, 0.003 mol) was added to ArOH
(20.6 g, 0.1 mol) in an argon flow, and water was distilled off
upon stirring for 60 min in vacuo (20 µbar). Methyl acrylate
(9.8 g, 0.14 mol) was added to the reaction mixture, and the
reaction was carried out at 116 °С. After 75 min, the yield of
R1OH was 92%.
The catalytic activity of R1ONa in the reaction of ArOH with
methyl acrylate was determined similarly. R1ONa (0.006 mol)
and methyl acrylate (0.14 mol) were added to ArOH (0.1 mol).
The reaction was carried out at 116 °С with sampling for analyꢀ
sis. The yield of R1OH after 75 min was 94%.
lnK
Results and Discussion
The quantitative data characterizing the change in the
composition of a solution during the reaction of ArOH
with alkaline metal hydroxides made it possible to examꢀ
ine in detail this reaction. The equilibrium concentraꢀ
tions of the components at 100 °С in the reaction of
ArOH with KOH are established within 25—30 min after
mixing the reactants at a constant temperature of the
solution. The reaction of ArOH with NaOH occurs with a
lower rate, and the equilibrium is established within
55—65 min. In a series of experiments (see Table 1),
ArOK (ArONa) and Н2О with different initial concentraꢀ
tions were also used as the starting components. The proꢀ
cessing of the results gave the equilibrium rate constants
(Keeff) for the reactions of ArOH with KOH and NaOH
4
3
2
1
2
1
2.6
2.8
T –1•103/K–1
Fig. 1. Temperature plots of the equilibrium constant (K) of the
reaction of ArOH with NaОН (1) and KOH (2).

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Volod´kin and Zaikov
Phenoxide ArONa is involved in the exchange reacꢀ
tion with R1OH to form R1ONa, whereas ArOK does not
react with R1OH.7,8 The satisfactory coincidence of the
experimental and calculated kinetic data for the reaction
of ArOH with methyl acrylate in the presence of ArONa
became possible if one takes into account the reaction of
ArOH with R1ONa, which affords the 2,6ꢀdiꢀtertꢀbutyl
phenoxide ion (ArO–) and a compound with the cycloꢀ
hexadienone structure (R2ONa+) in which the Na+ catꢀ
ion is coordinated to three O atoms and is surrounded by
two But groups (Scheme 1, Fig. 2). The effective radius of
the Na+ cation is optimal for the isomerization of the
aromatic system of bonds to form the cyclohexadienone
system. The effective radius of the K+ cation is larger than
that of the Na+ cation. This is most likely related to the
instability of a similar structure with the K+ cation in the
reaction of ArOK with R1OH. According to Scheme 1,
R1ONa accepts a proton from ArOH and simultaneously
retains the Na+ cation in a chelate complex to produce
the protonated form of a new R2ONa+ catalyst (autocaꢀ
talysis). Therefore, now the nonassociated phenoxide ion
(ArO–) can interact with the methyl acrylate molecule to
produce the A anion (see Scheme 1) followed by the
protonation of this anion by the R2ONa+ cation or ArOH.
The reaction of methyl acrylate with 2,6ꢀdiꢀtertꢀbutylꢀ
phenol deuterated at the phenolic OH group in the presꢀ
ence of ArONa or R1ONa affords R1OH and an analog of
R1OH with deuterium labels at the phenolic OH group
Scheme 1

Catalyst based on hydroxides for 2,6ꢀdiꢀtertꢀbutylphenol Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2193
[ArOH]/mol kg–1
3.0
1
1´
2.5
2
2´
2.0
3
3´
1.5
4
4´
5
1.0
5´
Fig. 2. Molecular model of R1ONa.
0.5
and at the Cβ atom in the lateral chain. The presence of
the deuterium label at the phenolic OH group in the final
product is attributed to the deuterium exchange between
ArOD and R1OH. The mechanism of the reaction of meꢀ
thyl acrylate with ArOD (40% enrichment) is interpreted
on the basis of the data on the integral intensity of signals
in the 1H NMR spectrum of the partially deuterated anaꢀ
log of R1OH. The signals are assigned to the H atom of
the phenolic OH group (δ 5.10) and H atom at the
Cβ atom (δ 2.89).
10
20
τ/min
Fig. 3. Kinetics of the reaction of ArOH with methyl acrylate
(MA) at [ArONa]0 = 0.1 (1), 0.08 (2), 0.06 (3), 0.04 (4), and
0.02 (5). [R1ONa]0 = 0.1 (1´); [ArONa]0 = 0.08, [NaOH]0 =
0.02 (2´); [ArONa]0 = 0.06, [NaOH]0 = 0.04 (3´); [ArONa]0 =
0.04, [NaOH]0 = 0.06 (4´); [ArONa]0 = 0.02, and [NaOH]0 =
0.08 mol kg–1 (5´). Lines are calculation, points are experiment;
116 °С; [ArOH]0 = 3.29, [MA]0 = 3.75 mol kg–1
.
It should also be noted that the IR spectrum repeatꢀ
edly detected after the reaction of H2O with R1ONa in a
pellet with KBr exhibited an increase in the intensity of
the peak at ν = 1660 cm–1, which is characteristic of the
conjugated carbonyl group of quinolide compounds.9 This
is most likely related to the formation of a compound with
the cyclohexadienone structure.
The results of the kinetic studies of the reaction of
ArOH with methyl acrylate in the presence of individual
ArONa (or R1ONa) show that the reaction between
ArONa and R1OH is fast because the kinetic curves obꢀ
tained using ArONa and R1ONa coincide completely
(Fig. 3, curves 1 and 1´).
reactions (Table 3). The first set (Eqs. (1)—(8)) represent
the reactions involving the R1ONa catalyst (the numbers
of constants correspond to the numbers of reactions in
Table 3).
The second set contains three reactions involving
the ArONa catalyst. The third set is composed of
reactions (12)—(15) involving NaOH and yielding
ArONa and byꢀproducts. The fourth and fifth sets consist
of Eqs. (16)—(22) describing the irreversible conꢀ
Scheme 2
Based on Scheme 1, we performed the mathematical
simulation of the experimental kinetic data of the reacꢀ
tion at different initial concentrations of ArOH, methyl
acrylate, ArONa, and NaOH taking into account the forꢀ
mation of R1OH and byꢀproducts: the product of alkylaꢀ
tion of 4ꢀhydroxyꢀ3,5ꢀdiꢀtertꢀbutylphenol by two methyl
acrylate molecules (Scheme 2), sodium salt of βꢀ(4ꢀhydrꢀ
oxyꢀ3,5ꢀdiꢀtertꢀbutylphenol)propionic acid (R4ONa), and
methyl acrylate polymers (oligomers).
Mathematical simulation was performed using the proꢀ
gram of calculation of the reaction kinetics on the basis of
the solution of the "rigid system" of ordinary differential
equations.10 The kinetic scheme consists of five sets of

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Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Volod´kin and Zaikov
Table 3. Kinetic scheme of the reaction of ArOH with methyl
acrylate in the presence of ArONa, R1ONa, and NaOH at 116 °С
Scheme 3
Reaction
k a
ArOH + R1ONa → R1OH + ArONa (1)
ArONa + R1OH → ArOH + R1ONa (2)
ArOH + R1ONa → R2ONa+ + ArO– (3)
ArO– + R2ONa+ → R1ONa + ArОН (4)
ArO– + MA → ArO–•MA (5)
2.5•10–2 b
1•10–2 b
6•10–3 b
1•10–3 b
8•10–2 b
4•10–3 c
2•10–2 b
1.8•10–2 b
2•10–2 b
1•10–3 c
ArO–•MA → ArO– + MA (6)
ArO–•MA + R2ONa+ → R1ONa + R1OH (7)
ArO–•MA + ArOH → ArO– + R1OH (8)
ArONa + MA → ArONa•MA (9)
ArONa•MA → ArONa + MA (10)
ArONa•MA + ArOH →
→ ArONa + R1OH (11)
8•10–2 b
1.7•10–3 b
2•10–2 b
1•10–1 b
5•10–3 b
2•10–3 b
ArOH + NaOH → ArONa + H2O (12)
ArONa + H2O → ArOH + NaOH (13)
R1OH + NaOH → R4ONa + MeOH (14)
ArONa•MA + H2O → R1OH + NaOH (15)
R1ONa + MeOH → R1OH + MeONa (16)
ArONa•MA + MeOH →
→ R1OH + MeONa (17)
7•10–3 b
4•10–5 b
1•10–4 b
ArONa•MA + MA → ArONa•2MA (18)
ArO–•MA + MA → ArO–•2MA (19)
ArO–•2MA + ArOH →
→ R3COOMe + ArO– (20)
1•10–4 b
8•10–3 d
NaOH + MA + MA → МА (oligomer) (21)
МА (oligomer) + МА + МА →
→ MA (polymer) (22)
5•10 d
a Calculated reaction rate constants, dimensionality
b kg mol–1 s–1
c s–1
d kg2 mol2 s–1
,
,
acrylate in the presence of the sodium compounds showed
that the presence of NaOH in amounts comparable with
concentrations of ArONa had no effect on the rate of the
reaction of ArOH with methyl acrylate (see Fig. 3,
curves 2, 2´, 3, 3´, 4, 4´, 5, and 5´). The above data also
show that the yield of ArONa in the reversible reaction of
ArOH with NaOH in the temperature interval from 80 to
140 °С does not exceed several percents. However, the
yield of ArONa can be enhanced by the removal of water
.
sumption of the active forms of the catalyst and side
processes. Reactions (14)—(22) are included to take
into account the formation of byꢀproducts: R4ONa,
R3(CH2CH2COOMe)2, and methyl acrylate oligomers.
In the presence of ArOK, the mechanism of the reacꢀ
tion of ArOH with methyl acrylate differs from that conꢀ
sidered above due to the formation of a contact pair of the
ArO– ion with the K+ cation and the possibility of particiꢀ
pation of the K+ cation in the elementary act of interacꢀ
tion of the reacting species. It can be assumed that the
methyl acrylate yields an intermediate product with the
weakly bonded ion pair (ArOK•MA), which affords R1OH
due to the proton transfer from the ArOH (or methyl
acrylate) molecule (Scheme 3).
During phenoxide formation, the reaction of ArOH
with KOH produces a gelꢀlike mixture, whose properties
affect the kinetics of the reaction of ArOH with methyl
acrylate. Monomeric ArOK yields agglomerates in the
form of dimeric associates, which decreases the efficiency
of ArOK as a catalyst of the reaction.10,11
from the reaction mixture (for example, by evacuation1—5
)
but, in this case, a catalytic mixture is obtained. Thereꢀ
fore, the analytical determination of the composition of
this catalytic mixture is an important problem.
The quantitative data considered above allow the use
of mixtures of KOH and NaOH to obtain ArONa and
ArOK simultaneously and to apply them as catalysts for
the alkylation of ArOH by methyl acrylate. The present
study made it possible to develop the kinetic method for
analysis of the ArONa content in the reaction system
under the conditions of partial distillation of water. The
method is based on the determination of the rate of the
reaction of ArOH with methyl acrylate and is espeꢀ
cially suitable for systems with a low content of alkali
(0.1—5 mol.% of the initial amount of ArOH).
A comparison of the experimental results and calculaꢀ
tion of the kinetics of the reaction of ArOH with methyl

Catalyst based on hydroxides for 2,6ꢀdiꢀtertꢀbutylphenol Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2195
[ArOH]/mol kg–1
mation of a composition of ArONa, ArOK, and NаОН
due to the separation of water during the interaction of
NaOH and КОН with ArOH. This assumption is based
3.0
on the known data that NaOH prevents the agglomeraꢀ
tion of ArOK (by analogy to the effect of KOH).7 In fact,
2.5
as follows from Fig. 5 (curve 2), the addition of 30% KOH
to the starting NaOH is sufficient to obtain the catalyst, in
the presence of which the initial rate of ArOH alkylation
by methyl acrylate corresponds to the rate of the same
reaction in the presence of individual ArONa (see Fig. 3,
curve 1). In this case, the final yield of R1OH increases.
The obtained result seems to be related to the stageꢀtoꢀ
stage effect of ArONa and ArOK + NaOH, depending on
the time of the interaction of ArOH with methyl acrylate.
Thus, the use of potassium and sodium hydroxides as
initial alkaline components provides the catalyst for the
alkylation of 2,6ꢀdiꢀtertꢀbutylphenol by methyl acrylate,
which is more efficient than individual ArOK or ArONa
even in the case of the partial conversion of alkaline metꢀ
als to the corresponding phenoxides. The analysis of the
experimental and calculated data shows that the basic
difference in the reactivity and catalysis by ArONa and
ArOK is related to the form of participation of the metal
ion in the reaction of ArOH with methyl acrylate.
2.0
1.5
1.0
10
20
τ/min
Fig. 4. Kinetics of the reaction of ArOH with methyl acrylate at
116 °С; [ArOH]0 = 3.29, [MA]0 = 3.75 mol kg–1; line is calculaꢀ
tion; points are the experiment with the unknown composition
of the ArONa + NaOH catalyst, [NaOH]0 = 0.1 mol kg–1. The
calculated data coincided with the points at [ArONa]0
0.048 mol kg–1
=
.
The good coincidence of the results of calculation and
experiment (Fig. 4) indicates the efficiency of the proꢀ
cedure.
It would be reasonable to elucidate the role of two
different in nature components of the catalyst in their
combined effect in the reaction of ArOH with methyl
acrylate. The role of NaOH could be positive in the forꢀ
References
1. A. A. Volod´kin and G. E. Zaikov, Ros. Khim. Zh., 2000, 44,
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Popov, Khim. Promꢀst´ [Chem. Industry], 1988, No. 12, 7 (in
Russian).
[ArOH]/mol kg–1
1
3.0
2
4. US Pat. 5177247; Сhem. Abstrs., 1991, 116, 6249.
5. Jpn. Pat. 81ꢀ161350; Chem. Abstrs., 1981, 96, 162344.
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[Russ. Chem. Bull., 1994, 43, 769 (Engl. Transl.)].
7. A. A. Volod´kin, A. S. Zaitsev, V. L. Rubailo, V. A. Belyakov,
and G. E. Zaikov, Izv. Akad. Nauk SSSR, Ser. Khim., 1989,
1829 [Bull. Acad. Sci. USSR, Div. Chem. Sci., 1989, 38, 1677
(Engl. Transl.)].
8. A. A. Volod´kin, Izv. Akad. Nauk, Ser. Khim., 1991, 989
[Bull. Acad. Sci. USSR, Div. Chem. Sci., 1991, 40, 877 (Engl.
Transl.)].
9. V. V. Ershov, G. A. Nikiforov, and A. A. Volod´kin,
Prostranstvennoꢀzatrudnennye fenoly [Sterically Hindered
Phenols], Khimiya, Moscow, 1972, 351 pp. (in Russian).
10. С. W. Gear, in Numerical Initial Value Problems in Ordinary
Differential Equations, Prentice Hall, New York, 1971, 158.
11. A. A. Volod´kin, G. E. Zaikov, and A. S. Deev, Polymer
Degradation and Stability, 1992, 36, 125.
2.5
3
4
2.0
1.5
1.0
0.5
0
20
40
τ/min
Fig. 5. Kinetics of the reaction of ArOH with methyl acrylate
in the presence of ArONa, ArOK, and NaOH at 116 °C,
[ArOH]0 = 3.29, and [MA]0 = 3.75 mol kg–1: [ArONa]0 = 0.06,
[ArOK]0 = 0.06, [NaOH]0 = 0.04 mol kg–1 (1); [ArONa]0 = 0.06,
[ArOK]0 = 0.02, [NaOH]0 = 0.04 mol kg–1 (2); [ArONa]0 = 0.06,
12. A. A. Volod´kin, A. S. Zaitsev, and G. E. Zaikov, Polymer
Degradation and Stability, 1989, 26, 89.
[ArOK]0
= 0, [NaOH]0 =
0.04 mol kg–1 (3); and
[ArONa]0 = 0.02, [ArOK]0 = 0.12 mol kg–1 (4). Lines are calcuꢀ
Received February 9, 2001;
in revised form April 10, 2002
lation; points are experiment.