152
TOLKACHEVA et al.
Table 2. Variation of selectivity with time of
hydrogenation of compound Ia on type 1 catalyst (23
27 C, 16 20 at)
for 2 h (in 0.5 h the catalyst turned black). Then the
2-propanol was decanted, and the catalyst was dried
at 80 C.
(2) Preparation of the catalyst poisoned with zinc
acetate (type 1). To 100 g of the catalyst prepared as
above was added 0.5 l of 15% solution of Zn(OAc)2,
and the mixture was boiled at reflux for 2.5 h, then
the catalyst was filtered off, washed with distilled
water, and dried at 80 100 C.
Yield of compound, % Selectivity,
Time, Conversion,
%
h
%
IIa
IIIa
1.5
18.6
27.0
48.6
74.7
90.9
98.2
17.9
25.8
46.5
71.2
85.5
91.4
0.7
1.2
2.1
3.5
5.4
6.8
96.2
95.5
95.7
95.3
94.1
93.1
4.5
8
(3) Preparation of the catalyst poisoned with
ammonia (type 2). The catalyst prepared along proce-
dure 2 was placed into a desiccator and evacuated by
a water-jet pump. Then ammonia was introduced into
the desiccator to atmospheric pressure, and the vessel
was left standing for 10 h. The catalyst thus treated
was flushed with air and put into the reactor.
12
14.5
16
At exhaustive hydrogenation of farnesylacetone
(IV) into phyton (V) the problem of selectivity is
lacking, and the catalyst ShPAK-0.5 can be used
without modification. Phyton (V) was obtained with
the help of unmodified catalyst ShPAK-0.5 in 97.8%
yield.
General method of hydrogenation in a reactor
with a fixed-bed catalyst. Into the reactor of 10 l
capacity was charged a cell with 120 g of granular
catalyst, then in a vacuum through the bottom dis-
charge valve was charged into the vessel 7 l of liquid
[2,2-dimethyl-3-butyn-2-ol (Ia) and dehydrolinalool
(Ib) were used without dilution, 3.5 l of dehydro-
nerolidol (Ic) or dehydroisophytol (Id) for hydrogen-
ation were diluted with 3.5 l of 2-propanol]. The flow
of hydrogen was passed into the reactor, the agitator
was switched on, and the reactor was heated to the
required temperature (the catalyst type, temperature
of the process, and hydrogen pressure are listed in
Table 1). As the hydrogen was consumed, it was
added to the initial pressure value. The reaction
mixture in the reactor was sampled through a capil-
lary and analyzed every hour. On completion of the
process the reactor was cooled to room temperature,
and the reaction product was discharged under hydro-
gen pressure. The compound obtained was analyzed
by GLC and subjected to rectification.
EXPERIMENTAL
Chromatographic analysis of compounds IIa d,
IIIa d, IV was carried out on chromatograph
LKhM-8MD (capillary column 25 m, stationary
phase SE-30, 22 C).
REFERENCES
Catalyst preparation. (1) Catalyst on alumina
support for exhaustive hydrogenation. Commercial
catalyst ShPAK-0.5 (0.5% of Pd on -Al2O3) was
placed in a porcelain dish and calcined in a muffle for
2 h at 350 450 C. The catalyst was cooled, placed
into a round-bottom flask equipped with a reflux
condenser and a capillary for hydrogen input. To the
catalyst was poured 2-propanol, the flask was heated
to 70 C, and a hydrogen flow through it was passed
1. Sul,man, E.M., Usp. Khim., 1994, vol. 63, no. 11,
p. 981.
2. Esteruelas, M.A., Lopes, A.M., Oro, L.A., Perez, A.,
Schulz, M., and Werner, H., Organometallics, 1993,
vol. 12, no. 8, p. 1823.
3. Shuikina, A.P., Ednatanova, A.I., Kovaleva, L.S.,
Parenago, O.P., and Frolova, V.M., Kinetika i kata-
liz, 1981, vol. 22, no. 1, p. 177.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 2 2002