Catalytic alkylation of cresols with propanol-1

Article abstract of DOI:10.1134/S1070427213080168

Study of the reaction of alkylation of ortho-, meta-, and para-cresols with propanol-1 in the presence of ferrite cobalt and manganese catalysts is reported. The effect of the catalyst composition and reaction conditions on the yield and isomeric composit

Full text of DOI:10.1134/S1070427213080168

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 8, pp. 1252−1255. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © D.B. Tagiev, N.A. Agaeva, M.K. Nazarova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 8, pp. 1278−1281.
CATALYSIS
Catalytic Alkylation of Cresols with Propanol-1
D. B. Tagiev, N. A. Agaeva, and M. K. Nazarova
Sumgait State University, Sumgait, Republic of Azerbaijan
e-mail: irapon.sdu@mail.ru
Received July 19, 2013
Abstract—Study of the reaction of alkylation of ortho-, meta-, and para-cresols with propanol-1 in the presence
of ferrite cobalt and manganese catalysts is reported. The effect of the catalyst composition and reaction conditions
on the yield and isomeric composition of the resulting propyl derivatives of cresol was examined and the main
and side conversions occurring in the catalysis were determined.
DOI: 10.1134/S1070427213080168
Propylderivativesofcresolarevaluablehalf-products
in manufacture of antioxidants, stabilizers, medicinal
preparations, and vitamins [1, 2]. These derivatives
are produced by alkylation of cresols with propene or
propanol in the presence of various catalysts [3, 4];
however, these catalytic systems have low activity and
selectivity in syntheses of propyl derivatives of ortho-,
meta-, and para-cresols.
analyzed by gas-liquid chromatography on a Khrom-5
instrument. As the liquid phase was used Apiezon M
deposited in an amount of 12 wt % on Chromaton N.
Isomeric propyl-cresols were also separated by fractional
distillation of the reaction mixture at 0.010 MPa.
We synthesized five mixtures of ferrite catalysts
Co Mn Fe O ·γAl O (x = 0.3, 0.6, 0.9, 1.0) and
x
1–x
2
4
2
3
studied their catalytic properties in the reaction of
alkylation of ortho-, meta-, and para-cresols with
propanol-1. It can be seen in the figure that an increase
in the fraction of cobalt in a mixture with manganese
makes higher the conversion of all the three isomers
of cresol in the alkylation reaction and improves the
formation selectivity of the main propyl isomers of
cresol: 2-propyl-6-methylphenol (1) in the case of
ortho-cresol, 2-propyl-5-methylphenol (2) in alkylation
of meta-cresol, and 2-propyl-4-methylphenol (3) in the
interaction with para-cresol with propanol-1.
Our communication presents results of a study of
the reaction of alkylation of of ortho-, meta-, and para-
cresols with propanol-1 in the presence of ferrite cobalt
and manganese catalysts.
Cobalt- and manganese-ferrite catalysts were
synthesized by joint deposition of nitrate salts of
iron(III) and cobalt(II) and(or) manganese onto γ-Al O ,
2
3
followed by drying and calcination. The atomic ratio
between a divalent metal and iron, M : Fe, is 1 : (2–2.3).
The preliminarily found optimal content of MFe O
2
4
As regards the formation selectivity of the above
propyl derivatives of cresol, ortho-cresol surpasses the
other isomers, whereas the highest conversion of cresol
is observed for meta-cresol. Interestingly, the yield and
formation selectivity of the target products of the reaction
of alkylation of ortho-, meta-, and para-cresols with
propanol are at a maximum at x = 0.9. In addition, the
cobalt-ferrite catalyst largely surpasses in activity that of
the manganese-ferrite type in the reaction of propylation
of cresols. For example, the formation selectivities of
in the catalyst is 22 wt %. Improvement of the high-
temperature method for synthesis of ferrite catalyst
makes it possible to obtain chemically homogeneous
and finely porous ferrite particles having good catalytic
properties.
Experiments were performed on a flow-through
laboratory installation in a flow of hydrogen. The
volume of the fixed bed of a ferrite catalyst in the reactor
3
was 10 cm . Liquid and gaseous reaction products were
`
1
252

CATALYTIC ALKYLATION OF CRESOLS WITH PROPANOL-1
1253
1
in the presence of manganese- and cobalt-ferrite
S, %
C, %
catalysts are, respectively, 69.7 and 85.0%. The yields
of compound 2 in terms of the reacted meta-cresol for
these catalysts are, respectively, 63.5 and 67.5%. In the
case of alkylation of para-cresol with propanol-1, the
formation selectivity of 3 over the cobalt-ferrite catalyst
is 83.0%, and that in the presence of the manganese-
ferrite catalyst is 70.0%.
1'
2'
3'
The table lists the results obtained in the reaction
of alkylation of ortho-, meta-, and para-cresols with
propanol-1 in the presence of a manganese-containing
cobalt-ferrite catalyst (x = 0.1). In this case, low
temperatures preferably promote the O-alkylation,
whereas an increase in temperature enhances the
propylation of cresols into a ring. Analysis of the data
obtained shows that alkylation of cresols with propanol-1
occurs by the parallel-consecutive mechanism, namely,
simultaneous O-alkylation and propylation in the cresol
molecule are observed.
In the case of alkylation of ortho-cresol with
propanol-1, the main reaction products are n-propyl ether
of 2-methylphenol, (1), and n-propyl ether of compound
Effect of the atomic fraction x of a divalent metal (Co, Mn) in
the ferrite catalyst Co Mn Fe O γ-Al O on the conversion
C of (1) ortho-, (2) meta-, and (3) para-cresols and also on
the formation selectivity S of (1'–3') main products formed
in the reaction of alkylation of cresols with propanol-1. (1')
x
1–x
2
4
2
3
1
. At high temperatures (360°C), 2,4-dipropyl-6-
2
-Propyl-6-methylphenol, (2') 2-propyl-5-methylphenol, and
methylphenol is also formed in a noticeable amount.
Alkylation of 3-methylphenol with propanol-1 mostly
yields product 2, propyl ether 3, methylphenol, propyl
ether 2, and 2,6-dipropyl-3-methylphenol. At low
temperatures (300°C) an alternating parallel-consecutive
mechanism is more noticeable. At higher temperatures
(3') 2-propyl-4-methylphenol.
The resulting propyl ethers of 2-methylphenol and
products 1–3 undergo under mild conditions a partial
intramolecular migration of propyl groups into a ring
Scheme 1).
(
≥330°C), predominance of the carbon-propylation is
observed.
The main products formed in the reaction of
alkylation of para-cresol with propanol-1 are compound
(
Under the catalyzate conditions, there presumably
occurs a rearrangement of propyl groups (Scheme 2).
An increase in the temperature of alkylation of
cresols with propanol-1 (>360°C) enhances a number
of side reactions, specifically, the dealkylation and
isomerization of propyl derivatives of cresol. The
concentrations of xylenol, ethylphenol, and a variety
of isomeric propyl cresols in the catalyzates obtained
grows.
3
, propyl ether of 4-methylphenol, propyl ether 3, and
2
,6-dipropyl-4-methylphenol. It can be seen that cresol
undergoes in this reaction depper conversion than other
cresol isomers, with the result that the concentration
of dipropylcresol and, in particular, 2,6-dipropyl-4-
methylphenol in the reaction mixture increases. In all
cases, an increase in the partial pressure of the alcohol
in the raw material makes lower the yield of target
products 1–3 in terms of the reacted cresol and enhances
the conversion of al the three isomers of cresol.
The absence of arenes, diaryl ethers, and high-boiling
alkylphenols in the reaction products indicates that the
reaction of dehydration of cresol with the subsequent
auto-hydrocracking of the resulting aromatic ethers
does not occur.
The concentration of high-boiling propyl derivatives
of cresol and alcohol gasification products in the
catalyzates grows.
Interestingly, the gaseous reaction products contain
no propylene, and only trace amounts of this alkene
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 8 2013

1254
TAGIEV et al.
Scheme 1.
CH2
CH3
O
CH2
OH
CH2
CH3
CH2
;
CH3
CH2
CH2
CH3
CH2
CH2
O
CH
3
OH
H
C
CH2
2
H C
CH3
CH3
3
H C
CH2
2
CH3
CH3
Scheme 2.
CH2
CH2
CH2
CH3
CH2
CH2
CH3
CH3
O
CH2
O
OH
2
+
CH3
CH3
CH3
–
1
Alkylation of cresols with propanol-1 in the presence of Co Mn Fe O γ-Al O (x = 0.9). Reaction conditions: ν = 0.8 h
x
1–x
2
4
2
3
Run conditions
Yield in terms of the reacted cresol, %
Conversion
of cresol, %
HOC H CH :
propyl ether of
1-methylphenol
2,4-dipropyl-6-
methylphenol
6
4
3
Т, °С
1
propyl ether (1)
n-C H OH, mol/mol
3
7
ortho-Cresol–propanol-1
300
330
360
330
1 : 1
1 : 1
1 : 1
1 : 2
35.0
52.0
61.5
60.0
30.0
48.0
85.5
76.0
81.0
18.0
8.0
7.0
4.0
2.5
3.0
3.0
1.0
10.0
5.6
2.5
meta-Cresol–propanol-1
propyl ether of
2,6-dipropyl-3-
methylphenol
2
propyl ether (2)
3
-methylphenol
300
330
360
330
1 : 1
1 : 1
1 : 1
1 : 2
39.0
53.0
64.0
59.0
28.0
12.0
3.0
51.0
73.0
70.0
71.0
14.0
10.0
8.0
2.0
4.0
14.0
4.5
3.6
6.0
para-Cresol–propanol-1
propyl ether of
2,6-dipropyl-4-
methylphenol
3
propyl ether (3)
4
-methylphenol
300
330
360
330
1 : 1
1 : 1
1 : 1
1 : 2
40.0
57.5
66.0
63.5
34.0
4.0
1.0
5.0
43.0
80.5
72.5
75.0
20.0
8.5
1.5
6.5
8.0
15.8
7.6
10.0
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 8 2013

CATALYTIC ALKYLATION OF CRESOLS WITH PROPANOL-1
1255
are observed at temperatures T ≤ 330°C. Presumably,
the alkylation of cresols with propanol-1 occurs via the
stage of olefin formation. As evidence in favor of this
mechanism also serves the absence of macromolecular
compounds in the catalyzates obtained. In addition, it
was shown that alkylation does not occur in the reaction
of ortho-cresol with propylene under the conditions
specified above over a ferrite catalyst. This can be
attributed to the catalytic properties of the ferrite catalyst
having an MFe O active paste of spinel structure.
propyl derivatives of cresols and undesirable products
synthesized on the basis of propylene would be observed.
CONCLUSIONS
(1) The cobalt-ferrite catalyst modified with
manganese exhibits a selective ortho-propylating
capacity in the reaction of interaction of ortho-, meta-,
and para-cresols with propanol-1.
(2) Under the reaction conditions found in the study
2
4
(
1
T = 330°C, ν = 0.8 h–1, HOC H CH : C H OH = 1 :
mol mol ), the formation selectivity of target propyl
6 4 3 3 7
The ferrite systems under study possess mixed spinel
structures and are bifunctional, i.e., they have basic and
oxidative catalytic properties.
–
1
derivatives of cresols is 73.0–85.5%, and the conversion
of monomethylphenols is 52.0–57.5%.
The mechanism of the selective ortho-alkylation
of cresols with propanol-1 differs only slightly from a
similar reaction of cresols with methanol and ethanol
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