Russian Journal of Organic Chemistry, Vol. 39, No. 10, 2003, pp. 1415 1417. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 10, 2003,
pp. 1487 1489.
Original Russian Text Copyright
2003 by Postnova, S. Koshel’, Lebedeva, Kuznetsova, G. Koshel’.
Synthesis of Cyclohexylphenols
M. V. Postnova, S. G. Koshel’, N. V. Lebedeva,
E. A. Kuznetsova, and G. N. Koshel’
Yaroslavl State Technical University, Moskovskii pr. 88, Yaroslavl, 150023 Russia
e-mail: koshel@polytech.yaroslavl.su
Received December 18, 2002
Abstract Catalytic alkylation of phenols with cyclohexanol gives o- and p-cyclohexylphenols as the major
products. The effect of temperature, catalyst nature, and reactant concentration on the reaction outcome was
studied.
Cyclohexylation of aromatic hydrocarbons and
their functional derivatives underlies an efficient
procedure [1, 2] which was developed by us for the
preparation of functionalized biphenyls and terphenyls
as initial compounds and intermediate products in the
synthesis of liquid crystalline thermotropic polymers,
biologically active substances, photographic materials,
etc. [3]. On the other hand, an analogous reaction
with phenols was studied insufficiently. Therefore,
in the present work we determined optimal conditions
for the reaction of phenol (I) with cyclohexanol (II)
sponding cyclohexyl-substituted derivatives were
68 70% (calculated on the initial cyclohexanol). The
products were identified by IR and H NMR spec-
troscopy and GLC data. Their properties are given
in Table 2.
1
EXPERIMENTAL
The IR spectra were recorded on a Specord 75IR
spectrophotometer from samples prepared as thin
1
films. The H NMR spectra were obtained on a Tesla
(Table 1). The major reaction products are o-cyclo-
BS-467 instrument from solutions in acetone-d using
6
hexylphenol (III) and p-cyclohexylphenol (IV). Also,
relatively small amounts of cyclohexyl phenyl ether
HMDS as internal reference. GLC analysis was per-
formed on a Khrom-4 chromatograph equipped with
a flame-ionization detector; steel column, 2.5 m;
stationary phase 10% of SKTFT-50Kh on Chromaton
N-AW-DMCS; carrier gas nitrogen, flow rate
(
V) and dicyclohexylphenols VI were formed as
by-products (Scheme 1).
As follows from the data in Table 1, the most
favorable conditions include the use of orthophos-
phoric acid, reactant ratio H PO :II:I 4.20:1.0:1.5,
3
0 ml/min; oven temperature programming from 80
to 200 C at a rate of 8 deg/min.
3
4
temperature 130 C, and reaction time 2.5 3 h. In this
case the conversion of phenol I and alcohol II is
almost quantitative, and the yield of compounds III
and IV is 34 and 26%, respectively (calculated on the
reacted cyclohexanol; overall yield 77%).
Under the same conditions we performed alkylation
with cyclohexanol of p-cresol, resorcinol, hydro-
quinone, and pyrocatechol. The yields of the corre-
Alkylation of phenol and its derivatives with
cyclohexanol. Cyclohexanol, 100.16 g, was added
over a period of 1 h to a mixture of 141.17 g of
phenol (I) and 411.6 g of 85% phosphoric acid,
maintaining the temperature at 130 C. The mixture
was kept for 2 h at that temperature, and the organic
phase (upper layer) was separated. The acid layer
(bottom) was extracted at 100 C with three portions
Scheme 1.
1
070-4280/03/3910-1415$25.00 2003 MAIK Nauka/Interperiodica
Postnova
