ORGANIC SYNTHESIS AND INDUSTRIAL
Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 12, pp. 2100−2105.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © S.T. Rustamov, R.K. Azimova, F.A. Nabiev, A.G. Azizov, Ch.K. Rasulov, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84,
No. 12, pp. 1216−1221.
Reaction of Phenols with Methylcycloalkenes
in the Presence of KU-23 Catalyst
S. T. Rustamov, R. K. Azimova, F. A. Nabiev, A. G. Azizov, and Ch. K. Rasulov
Institute of Petrochemical Processes, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan
Received April 8, 2011
Abstract—Cycloalkylation of phenol, p-methylphenol, and p-hexylphenol with 1-methylcyclopentene and 1- and
3-methylcyclohexenes in the presence of KU-23 catalyst in the H form was studied.
Chemical additives of various destinations and
chemical structures are steadily demanded in the world.
Among them, phenolic compounds occupy an important
place owing to their valuable properties, primarily to
extremely wide spectrum of antioxidant activity [1–5].
The performance of alkylphenol antioxidants mainly
depends on the stability of the phenoxyl radical formed
in the course of oxidation and on the degree of polarity
of the hydroxy group. The stability of phenoxyl radicals
grows with their shielding with alkyl substituents. The
shielding ability of alkyl substituents increases with their
size. The polarity of the hydroxy group in alkylphenols
also depends on the character of alkyl substituents in the
p-position. It is known that the electron-donor power of
alkyl substituents in the p-position increases with chain
lengthening (e.g., in going from methyl to tert-octyl
substituent) . However, at high temperatures the octyl
substituent is unstable. Antioxidants based on alkylphenols
are not fully compatible with the substance being tested
and dissolve incompletely. Chemical additives based on
alkylphenols are volatile. Some alkylphenols volatilize
already in the course of processing. This problem is solved
by introducing a cycloalkyl radical into the aromatic
ring of phenol. Cycloalkylphenols are readily soluble in
polymeric materials, rubber, oil, and fuel and are stable
at high temperatures.
In this study we performed cycloalkylation of
phenol, p-methylphenol, and p-hexylphenol with
1-methylcyclopentene and 1- and 3-methylcyclohexenes
in the presence of KU-23 catalyst in the H form.
As starting compounds we used phenol, p-cresol,
p-hexylphenol (p-HP), 1-methylcyclopentene (1-MCP),
1-methylcyclohexene (1-MCH), and 3-methylcyclohexene
(3-MCH), which were prepared by the Diels–Alder
reaction, namely, by thermal cycloaddition of ethylene
to dienes (isoprene or piperylene).
1-MCH, bp 110–111°С, n
M 96; 3-MCH, bp 103–104°С, n
1-MCP was prepared by dehydration of cyclohexanol;
bp 75°С, n
0.7782, M 82.
Samples of all the methylcycloalkenes studied were
isolated from the corresponding condensates by sharp
fractional distillation on a 1-m column with metal pack-
ing at a reﬂ ux ratio of 10. The chromatographic purity of
methylcycloalkenes was 99.6–99.8%. Phenol and p-cresol
of reagent grade were used.
p-Hexylphenol was prepared by the reaction of phenol
with propylene dimer in the presence of acid catalysts; bp
138–140°С (at 1333 Pa), n
1.0182, M 178.
As catalyst we used KU-23 10/60 cation exchanger
[GOST (State Standard 20298–74] with high degree of
porosity and high mean effective pore radius. The sorbed