5702
T. Kamitanaka et al. / Tetrahedron 64 (2008) 5699–5702
alcohol forming reaction mainly proceeds via the route shown in
Scheme 5.
set to zero when the temperature reached the desired value. The
temperature in the autoclave reached 623 K in 20 min. After
a specific reaction time had elapsed, the autoclave was removed
from the furnace and cooled by a strong air stream to quench the
reaction.
3. Conclusions
The treatment of benzonitrile with supercritical methanol,
ethanol or 2-propanol resulted in the formations of the benzoate
ester or/and benzyl alcohol. The esterification of benzonitrile in
supercritical methanol and ethanol occurred in high (up to 93%)
and low (up to 20%) yields, respectively. On the other hand, no ester
generation was observed in supercritical 2-propanol. The rate of
ester formation may depend on the amount of the alkoxide ion in
the alcohol solution. The transformation of benzonitrile into esters
is explained on the basis of a mechanism analogous to that for
the Pinner reaction. The benzyl alcohol generation occurred in
supercritical 2-propanol and ethanol. The study under dehydrated
conditions and the deuterium tracing one suggested that
the transformation from benzonitrile to benzyl alcohol proceeded
via the route of C6H5C^N/C6H5CH]NH/C6H5CH]O/
C6H5CH2OH.
4.3. Analysis
A 25
ml portion of the reaction solution in the tube was poured
into a test tube and a 25
ml aliquot of the solution of bibenzyl (in-
ternal standard; 10 mmol dmꢀ3) was added to the tube. The solu-
tion was subjected to analysis by the gas chromatography
(Shimadzu GC-15A, capillary column, i.d. 0.32-mm, liquid phase
DB-17, film thickness 0.5-mm, length 30-m). The quantitative
analyses were performed by the internal standard method. The
identification of the products was performed by GC–MS and 1H
NMR analyses, if necessary.
Supplementary data
4. Experimental section
4.1. Materials
Supplementary data associated with this article can be found in
References and notes
Materials were purchased from Nacalai Tesque, Inc. and used
without further purification. Dehydrated 2-propanol was pur-
chased from Wako Pure Chemical Industry. The water content was
below 50 ppm.
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Supplementary data.