Alkylation of acetylene by tert-butyl alcohol

Article abstract of DOI:10.1023/A:1021640700304

A reaction of acetylene with tert-butyl alcohol in the presence of sulfuric acid leads to tert-butylacetylene.

Full text of DOI:10.1023/A:1021640700304

2134
Russian Chemical Bulletin, International Edition, Vol. 51, No. 11, pp. 2134—2135, November, 2002
Brief Communications
Alkylation of acetylene by tertꢀbutyl alcohol
ꢀ
P. V. Kazakov, E. I. Demina
State Scientific Research Institute of Organic Chemistry and Technology,
23 Shosse Entuziastov, 111024 Moscow, Russian Federation.
Fax: +7 (095) 273 2218
A reaction of acetylene with tertꢀbutyl alcohol in the presence of sulfuric acid leads to
tertꢀbutylacetylene.
Key words: tertꢀbutyl alcohol, tertꢀbutyl hydrogen sulfate, acetylene, tertꢀbutylacetylene,
nickel sulfate, 2,2,4ꢀtrimethylpentꢀ2ꢀene.
tertꢀButylacetylene (1) is widely used in the preparaꢀ
and rising in the content of diisobutylene in the reaction
products. The main product of the reaction at 40—45 °C
is diisobutylene (2).
tive organic synthesis, for example for the introduction of
tertꢀbutylethynyl group and a synthesis of diverse comꢀ
pounds (propargyl alcohols, ketones, etc.1). However, the
practical use of tertꢀbutylacetylene is limited due to the
absence of a convenient method for its preparation.
By now essentially the only way of preparation of this
compound is the laborious and expensive synthesis from
pinacolin and phosphorus pentachloride followed by deꢀ
hydrochlorination2 of formed dichloride.
The condensation of acetylene with lower alkenes in
sulfuric acid in the presence of mercury salts was previꢀ
ously reported,3 but the nature of products was not deꢀ
fined.
We investigated a reaction of acetylene with tertꢀbutyl
alcohol in the presence of 70% sulfuric acid. It was found
that at low temperature (0—5 °C) the reaction gives
tertꢀbutylacetylene (1) in ∼0.8% yield (based on starting
tertꢀbutyl alcohol), while diisobutylene (2) is practically
absent. Increasing the temperature to 25—30 °C leads to a
slight decreasing in the yield of tertꢀbutylacetylene (∼0.5%)
The formation of tertꢀbutylacetylene (1) can be exꢀ
plained by the addition of tertꢀbutyl cation (3) to acetyꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1978—1979, November, 2002.
1066ꢀ5285/02/5111ꢀ2134 $27.00 © 2002 Plenum Publishing Corporation

Alkylation of acetylene by tertꢀbutyl alcohol
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 11, November, 2002 2135
retention time was 1.3 min (isothermal mode, column temperaꢀ
ture 120 °C).
lene, which leads to the tertꢀbutylvinyl carbocation (4),
followed by the rejection of the proton from the latter.
Since the use of mercury salts as a catalysts has no
prospects for industrial application we investigated the
influence of zinc and nickel sulfates on this process. It
was shown that ZnSO4 practically does not affect the
reaction at 25—30 °C (the yield of tertꢀbutylacetylene
is ∼0.6%). Meanwhile the presence of NiSO4 rises the
yield of tertꢀbutylacetylene up to ∼2% based on the startꢀ
ing tertꢀbutyl alcohol. The increase in the yield can be
explained by the increase in the solubility of acetylene in
the reaction mixture which is due to the formation of
πꢀcomplex of acetylene with the catalyst.
Thus, we have shown for the first time the fundamenꢀ
tal possibility of the formation of tertꢀbutylacetylene by
the reaction of tertꢀbutyl alcohol with acetylene. In spite
of the low yield of tertꢀbutylacetylene, this previously unꢀ
known reaction may become a base of technological
method for the preparation of tertꢀbutylacetylene, since
the reaction provides easy isolation of the target product,
does not need implementation of complicated devices,
and furthermore it does not give nonutilizable waste.
tertꢀButylacetylene (1). Acetylene (3 L) was bubbled through
a mixture of 70% H2SO4 (30 mL, 47.8 g, 0.34 mol), ButOH
(30 mL, 23.57 g, 0.32 mol), and NiSO4 (1 g) at 25—30 °C during
2 h. Gases from the reactor were condensed in a trap, cooled to
–5 °C (totally 0.8 g of liquid was collected in the trap). Then the
reaction mixture was poured onto ice (40 g) and distilled. The
fraction 1 collected (0.84 g, b.p. 37—40 °C) was combined with
the condensate from the trap to give 1.64 g of a liquid (according
to the GLC data the united fraction 1 contains tertꢀbutylacetylene
(28%), tertꢀbutyl alcohol (21%), diisobutylene (51%)). The fracꢀ
tion 2 (26.8 g, b.p. 85 °C) contains 81% of tertꢀbutyl alcohol.
The united fractions 1 (14.5 g) from the several experiments
(obtained from 141.42 g (1.909 mol) of ButOH) were comꢀ
bined and distilled to give tertꢀbutylacetylene (3.3 g, 5.0 mL,
0.04 mol), b.p. 37—38 °C, nD20 1.3750 (cf. Ref. 2: b.p. 39—40 °C,
nD 1.3738). H NMR (CCl4), δ: 1.23 (s, 9 H, But); 1.91 (s,
1 H, C≡CH). Similarly, fractions 2 gave 134.2 g (1.813 mol)
of unreacted ButOH. tertꢀButylacetylene was obtained in
∼2.1% yield based on initial ButOH and 42% based on reꢀ
acted ButOH.
20
1
References
Experimental
1. W. L. Collier and R. S. Macomber, J. Org. Chem., 1973,
38, 1367.
1
The H NMR spectra were recorded on a Bruker AMꢀ370
2. P. D. Bartlett and L. J. Rosen, J. Am. Chem. Soc., 1942,
64, 544.
3. J. Nieuwland and R. Vogt, Chemistry of Acetylene, Reinhold
Publishing Corporation, New York, 1945.
spectrometer (360.13 MHz) with Me4Si as the internal stanꢀ
dard. tertꢀButylacetylene was identified in the distillate by GLC
on a LKhMꢀ80M chromatograph (katharometer as detector,
helium as the carrier gas, 20 L min–1, 2 m columns packed with
10% SKTFꢀ100 on Chromaton, evaporator temperature 240 °C,
detector temperature 190 °C). A specimen of tertꢀbutylacetylene
obtained by the known method2 was used as a standard. The
Received July 29, 2001;
in revised form April 22, 2002