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PYATNITSYNA, EL’CHANINOV
BAD due to a growth in the content of n-butanol.
The dependence of the yield of the reaction products
on time was examined at the exhaustive hydrogenation
of BYD (wt %). The data were obtained at 40°C in the
presence of catalysts Pd/C-2 and Ni-Raney. Analysis
of the kinetic curves of BYD consumption in presence
of a palladium contact (Fig. 1) shows that initially one
π-bond is hydrogenated, the highest concentrations of
BED is observed at the time of the BYD disappearance,
then its transformation into BAD start. Isomerization and
dehydration occur simultaneously with BED appearance,
but after the exhausting of BYD the BED concentration
increases dramatically. A similar situation occurs in the
case of hydrogenation on skeletal Ni catalyst (Fig. 2), but
the selectivity of the process relative to BAD is provided
by the formation of n-butanol, which is three time less,
and hydrogenation of HBA to BAD.
Fig. 1. Kinetic curves of BYD consumption and accumulation
of reaction products at 40°С, catalyst Pd/C-2. (с) Concentration
(wt %), (τ) time (min); the same for Fig. 2. (1) NBT, (2) HBA,
3) BED, (4) BAD, (5) BYD; the same for Fig. 2.
(
The results of the exhaustive BYD hydrogenation on
suspended Ni-Raney catalyst at atmospheric pressure due
to the high selectivity of BAD formation and relatively
low content of by-products allowed offering a laboratory
method for BAD synthesis. 2-Butyne-1,4-diol (TU 64-
5
-52-79), distilled water (GOST 6709-72), commercial
hydrogen (GOST 3022-80), the catalyst Ni-Raney may
be recommended as starting materials for the process
performance.
3
In a three-necked flask of 2 dm equipped with
a stirrer, bubbler, and tube connected to Vial Wolf, which
Fig. 2. Kinetic curves of BYD consumption and accumulation
of reaction products at 40°С, catalyst Ni-Raney.
is used to control the gas release, 75 g of catalyst and
3
1
.5 dm of BYD aqueous solution (25 wt%) were charged.
was even its reducing that was likely due to an increase
in the partial pressure of water vapor.
Hydrogenation on Ni-Raney proceeds more slowly,
but with greater selectivity relative to the target product
87–92%), especially at 40–50°C. In smaller amounts
2-fold) n-butanol is formed but HBA, which is upon
reaction hydrogenated likely to BAD, is virtually
nonexistent. The latter assumption is confirmed by the
reduction on skeletal Ni-contact of 5% aqueous solution
of HBA, which is quantitatively converted to BAD. The
influence of the weight fraction of the catalyst in the
reaction mixture on the composition of hydrogenation
products was studied at 50°C. The analysis of the data
revealed that for the Ni-Raney catalyst its weight fractions
of 10 to 20% are the most effective for the target product
yield.An increase in its content up to 50–100% promotes
accelerating of the process but reduces the selectivity of
The reaction mixture was heated to 50–60°C, then after
switching on the stirrer bubbling of hydrogen was started.
Monitoring of catalysate composition was performed
chromatographically. Disappearing of BED peak on the
chromatogram was assumed for the time of the reaction
completion. Then the flask content was filtered from
the catalyst on a Buchner funnel. Water from the filtrate
was removed on water bath by a vacuum jet pump. The
residue was distilled using a reflux condenser and vacuum
pump RVN-20 with a residual pressure of 3 mm Hg. The
BAD yield was 349 g (89%), boiling point 227–228°C
at 760 mm Hg.
(
(
CONCLUSIONS
(
1) The higher selectivity of Ni-Raney was dem-
onstrated compared with the palladium catalyst in the
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013