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2,408,970
Patented Oct. 8, 1946
UNITED STATES PATENT OFFICE
2,408,970
BUTADIENE PURIFICATION
Thomas F. Doumani, Long Beach, and Davis A.
Skinner, Compton, Calif., assignors to Union
Oil Company of California, Los Angeles, Calif.,
a corporation of California
No Drawing. Application December 16, 1943,
Serial No. 514,546
5 Claims. (Cl. 260-6815)
1
This inventionrelates to the production of
butadiene, and especially to a method for puri?
cation of hydrocarbon mixtures containing buta~
diene and acetylene type hydrocarbons of the
same boiling range, whereby the acetylenes are
removed by a selective hydration process, with
out appreciable effect on the butadiene.
Butadiene has attained vital importance in
recent years as an ingredient of synthetic rub
her, and as a raw material for many other uses.
For many of these uses, such as in synthetic rub
ber manufacture, it is necessary or at least high
ly desirable that the butadiene be free from con
tamination with other, hydrocarbons, particular
2
the acetylenes are selectively converted to oxy
gen-containing compounds, While the butadiene
or other unsaturated hydrocarbons are substan
tially unaffected. The oxygen-containing com
pounds are then separated from the unreacted
unsaturated
hydrocarbons
by
conventional
methods such as distillation, solvent extraction,
azeotropic distillation, or the like.
As a speci?c example of our invention, the fol~
lowing process was carried out:
A naphthenic California crude gasoline frac
tion was cracked by vaporizing it and contacting
the vapors with hot ?ue gases at substantially
atmospheric pressure under such conditions that
1y acetylenic hydrocarbons. Since butadiene pro 15 an average temperature of about 1500° F. was
maintained for a period of about 0.02' second.
duced by pyrolysis of other organic compounds,
The C4 fraction recovered from the product by
particularly hydrocarbon mixtures such as pe
absorption and distillation contained about 54%
troleum fractions, generally contains large
butadiene, 5% acetylenes (largely vinyl acetylene,
amounts of such contaminating hydrocarbons,
the puri?cation of butadiene presents a serious 20 but also methyl and ethyl acetylenes), 3% bu
tanes, and the remaining approximately 38% bu
problem, and many processes have been devised
tenes, all per cents being molal.
as attempts to solve it. In most of these proc
The above C4 fraction was passed through a
esses, distillation is the ?rst step; but by this
tube containing 100 ml. of catalyst at a rate of 4
means, unless elaborate super~fractionation is
liters (atmospheric temperature and pressure)
employed, the product obtained is a so-called C4
per
hour, together with Water vapor introduced
out, which contains in addition to butadiene, other
hydrocarbons or azeotropic mixtures which boil in
the same range, including isobutane, normal bu-=
at a rate of 25 grams per hour. The temperature
of the catalyst bed was held at 300° C., and the
total pressure was substantially atmospheric.
tane, isobutene, the normal butenes, and methyl,
ethyl, and vinyl acetylenes. Azeotropic distilla 30 The product gas after removal by condensation
of substantially all of its oxygenated organic
tion, extractive distillation, and solvent extraction
compounds and water, was found to contain less
than about 0.01% of acetylenes, while the buta
diene ‘and other unsaturated hydrocarbons (bu
preciable proportion of them, remain with the 35 tenes) were substantially unaffected. The bulk
processes have been employed to separate the hu
tanes, and even the butenes from this mixture,
but in general the acetylenes, or at least an ap
butadiene, since their chemical characteristics
are quite similar,
We have now discovered a method whereby
acetylenes in mixtures with butadiene may be
of the oxygenated organic compounds produced
by the reaction of the acetylenes with the water
Were recovered as an oily upper layer in the liquid
condensate, although a small amount dissolved
quantitatively removed without appreciable loss 40 in the lower aqueous layer of condensate. The
oily upper layer contained a small amount of hy
of butadiene. This method not only effects puri
drocarbons,
apparently dimer and higher poly
?cation of the butadiene but also converts the
mers
of
butadiene,
but was predominantly com
acetylenes removed to by-products of great value
posed of oxygenated compounds, principally al
as solvents, perfumes, chemicals, etc. It is an
object of our invention therefore, to provide a 45 dehydes and ketones, including methyl vinyl ke
tone, methyl ethyl ketone, acetone, crotonalde
method for separating acetylenes from butadiene.
Further objects are to provide methods for sep
arating acetylenes from other diole?ns or from
hycle, butyraldehyde and propionaldehyde.
The catalyst employed in the above example
other unsaturated hydrocarbons such as mono
was a 12 to 20 mesh siliceous solid phosphoric
a hydrocarbon mixture containing acetylenes and
Company of Chicago, Illinois.
ole?ns and for converting acetylenes to valuable 50 acid commercially available as a polymerization
catalyst. It is known as Polymer Catalyst No 2,
aldehydes, ketones, and alcohols.
and is marketed by the Universal Oil Products
The above objects are accomplished by treating
Other catalysts
may be employed however, such as phosphoric
butadiene or other unsaturated hydrocarbons
with water in the presence of a catalyst, whereby 55 acid alone or partially neutralized, which may or
2,408,970
3
4
may not be deposited on carriers such as siliceous
but one of its most unusual aspects is that it will
materials, kieselguhr, clay, and the like. Oxides
take place selectively with the acetylenes even
or halides of heavy metals such as those of groups
I and II such as mercury, silver, copper, cadmium,
in the presence of other hydrocarbons in molal
excess over the acetylenes, i. e., in hydrocarbon
zinc, magnesium and the like, and mixtures of 5 mixtures containing acetylenes in admixture with
easily reducible oxides such as those of silver and
larger amounts of other unsaturated hydrocar
mercury with di?icultly reducible oxides such as
bons, especially when the other unsaturated hy
those of zinc, copper and the like, are also effec
drocarbons include diole?ns. It appears that
tive. The contact time employed in the process
either the acetylenes or their hydration products
will vary with the activity of the catalyst used, 10 act as inhibitors for the hydration of the buta
being shorter for the more active catalysts.
diene or other unsaturated hydrocarbons.
The process of this invention may be carried out
The oxygenated organic compounds formed in
with catalysts such as the above, at temperatures
the reaction are useful as chemicals, solvents,
between about 150° C. and 700° 0., although tem
perfumes, etc., as mentioned earlier, and may also
peratures between about 300° C. and about 500° C. 15 be used as azeotrope formers and as selective
are preferred. The total or overall pressure may
solvents for the separation, for example, of the
be as high as about 5 atmospheres, but the par
butanes and butenes from the butadiene and acet
tial pressure of the unsaturated hydrocarbons
ylenes of the C4 out. They are also useful as sol
should be below about 300 mm. of mercury and
vents for the dewaxing of oil and the deoiling
preferably below 100 mm. of mercury. In the 20 of wax, and for many other purposes.
above example it may be noted that the total
Other modi?cations‘ of this invention which
pressure was substantially one atmosphere and
would occur to one skilled in the art are to be in
the partial pressure of the unsaturated hydrocar
cluded in the scope of this invention as de?ned
bons (butadiene plus butenes plus acetylenes) was
in the following claims.
about 0.11 atmosphere or about 84 mm. of mer 25
We claim:
cury. Where the unsaturated hydrocarbons in
1. A process for the puri?cation of diole?ns
clude butadiene or other diole?ns, it is desirable
which are contaminated by the presence of rela
that the partial pressure of the diole?ns be below
tively small proportions of acetylenes of approxi
about 50 mm. of mercury. In the above example,
mately the same boiling points, which comprises
the butadiene partial pressure was 84><54/97= 30 reacting a hydrocarbon mixture containing said
4'? mm.
acetylenes and diole?ns with water in the vapor
The low partial pressures described above are
phase in the presence of a catalyst at a tempera
preferably attained by dilution with steam, but
ture above about 300° C. and a partial pressure of
dilution with other inert gases such as ?ue gases,
diole?ns below about 100 mm. of mercury, where
nitrogen, or saturated hydrocarbons may also be 35 by the acetylenes are converted to oxygenated
made, providing that there is at least one mol
derivatives, and the diole?ns are substantially
unchanged.
of water present to react with every mol of acet
ylenic hydro-carbon present. It is desirable, how
2. A process for the puri?cation of butadiene
ever, to have the molal ratio of water to acetylenes
which is contaminated with relatively small pro
100 or more to l. A ratio of water to total un 40 portions of acetylenes of similar boiling point,
saturates in the region of about 5 to 1 to 15 to 1
which comprises reacting a hydrocarbon mixture
appears to be desirable.
containing said acetylenes and butadiene with
The invention is not con?ned to the treatment
water in the vapor phase in the presence of a
of C4 fractions containing butadiene, although
catalyst at a temperature above about 300° C.
this is a preferred embodiment. Propylene and 45 and a partial pressure of diole?ns below about
ethylene fractions may also be freed of methyl
100 mm. of mercury, whereby the acetylenes are
acetylene and acetylene by this method; C5 frac
converted to oxygenated derivatives, and the bu
tions containing mono-ole?ns and diole?ns such
as cyclopentadiene, isoprene, and the like may be
tadiene is substantially unchanged.
3. A process according to claim 2 in which
freed of diacetylene, dimethyl acetylene, isopropyl 50 the catalyst is a siliceous solid phosphoric acid
catalyst.
and isopropenyl acetylenes, and the like; or
higher molecular weight fractions may also be
freed cf acetylenes. By the term acetylenes it is
meant to include any hydrocarbon compound
containing at least one triple bond. The reac
tion may be carried out in the liquid phase, es
pecially with the higher molecular weight frac
tions, but is preferably carried out in the vapor
phase. The reaction may also be carried out in
the absence of other unsaturated hydrocarbon, 60
4. A process according to claim 2 in which the
catalyst is an oxide of a heavy metal of groups
1 and 2 of the periodic system.
5. A process according to claim 2 in which the
catalyst is a halide of a heavy metal of groups
1 and 2 of the periodic system.
THOMAS F. DOUMANI.
DAVIS A. SKINNER.
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