Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 8, pp. 1428−1430.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
E.V. Pyatnitsyna, M.M. El’chaninov, A.P. Savost’yanov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 8,
AND INDUSTRIAL ORGANIC CHEMISTRY
Procedures for Recovery of Crystalline 2-Butyne-1,4-diol
from Industrial Aqueous Solutions and for Its Puriﬁ cation
E. V. Pyatnitsyna, M. M. El’chaninov, and A. P. Savost’yanov
South-Russian State Technical University (Novocherkassk Polytechnic Institute), Novocherkassk, Rostov oblast, Russia
Received December 22, 2008
Abstract—Four procedures for recovery of crystalline 2-butyne-1,4-diol from aqueous solutions and for its
purification were examined. Samples of crystalline 2-butyne-1,4-diol containing 98.5 to 99.9 wt % target
product were obtained.
1,4-Butynediol (BYD) is a valuable compound
for electroplating and for synthesis of widely used
polymeric materials, medicines, and household chemical
products. The commercial procedure for BYD production
(Reppe method) is based on condensation of acetylene
with formaldehyde on a copper–bismuth catalyst .
Commercial BYD is produced as solution containing no
more than 60% main substance. It also contains impurities
of intermediates and by-products of the alkynol synthesis
and tars (the ﬁ gure a, Table 1).
Because of stringent requirements imposed upon
the quality of BYD-based monomers, it seemed topical
to check various procedures for BYD recovery and
puriﬁ cation with the aim of their subsequent use in
commercial or laboratory processes.
Let us consider four procedures for preparing puriﬁ ed
BYD from aqueous solutions containing condensation
products of acetylene and formaldehyde (Table 2).
(1) Extraction with organic solvents. To recover
BYD, we used organic solvents immiscible with water.
With respect to the extraction efﬁ ciency, they can be
ranked in the following order: ethyl acetate > chloroform
> benzene > carbon tetrachloride. The extraction allows
the formaldehyde content in the product to be decreased
by an order of magnitude (the ﬁ gure b), but the amounts
of methanol and propargyl alcohol remain virtually
unchanged. The other drawbacks of this method are
considerable (50–70 ml g
BYD) consumption of the
organic solvent for the product recovery and low yield
of BYD due to its high solubility in water.
(2) Vacuum distillation. The process is performed
in two steps. In the ﬁ rst step, water and low-boiling
impurities are removed in a vacuum, and the second step
involves vacuum distillation of BYD. Analysis of the
product obtained shows that distillation allows removal of
major amounts of formaldehyde, methanol, and propargyl
alcohol (the ﬁ gure c, Table 1). Apparently, formaldehyde
and propargyl alcohol may be formed in certain amounts
at the end of distillation, owing to partial decomposition
of the bottom residue. The advantages of this process are
low (d 3 wt %) total loss of BYD with the water fraction
and due to tarring, and also the possibility of preparing
the product without using organic solvents.
When performing the process, it should be taken into
account that BYD can decompose with explosion in the
presence of alkaline impurities and heavy metal salts
[2, 3]. Therefore, exhaustive distillation of the product
should be avoided.
(3) Distillation–recrystallization. To prepare
samples of increased quality, vacuum-distilled BYD was
recrystallized from ethyl acetate–ether. Instead of ether,
other compounds poorly dissolving BYD can be used, in
particular, benzene, chloroform, methylene chloride, and
other chlorinated hydrocarbons. Recrystallization allows
the product quality to be improved (the ﬁ gure d, Table 2).
In particular, the content of formaldehyde and propargyl
alcohol is decreased, and methanol is fully removed.