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Патент USA US3098891

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United States Patent 0 " ice
Patented July 23, 1963
1
2
3,098,882
catalyst and method which are capable of hydrogenating
small amounts of acetylenic compounds in dry gaseous
SELECTIVE HYDROGENATION PROCEDURE
AND CATALYST THEREFGR
Melvin R. Arnold, Louisville, Ky., assignor to Chemetron
Corporation, Chicago, llh, a corporation of Delaware
No Drawing. Filed Nov. 24, 1961, Ser. No. 154,840
4 Claims. (Cl. 260-677)
mixtures containing ole?ns or diole?ns in such manner
that the hydrogenation of the acetylenic compounds to
ole?ns proceeds virtually to completion at a relatively
low temperature ‘and with a low stoichiometric excess of
hydrogen to reduce the concentration of the acetylenic
compounds to a few parts per mill-ion without substantial
This invention relates generally to the hydrogenation
ly a?ecting the ole?ns or diole?ns. A related object is
of highly unsaturated hydrocarbons and especially to the 10 to provide a catalyst and method for reducing diole?ns to
selective hydrogenation of acetylenes and diole?ns in
monoole?ns without affecting the latter. Another object
gas mixtures containing high concentrations of ole?ns.
is to provide a hydrogenation catalyst which is relatively
More particularly, the invention involves an improved
active in promoting the hydrogenation of acetylene hy
noble metal catalyst for such reactions and selective hy
drocarbons but relatively inactive in promoting the hydro
drogenation reactions using the catalyst.
15 genation of ole?ns even in mixtures containing a major
This application is a continuation-in-part ‘of my co
pnoport-ion of ole?ns. A further object is to provide a
pending ‘application, Serial No. 817,975, ?led June 4,
method of purifying ole?n gas streams by removing
1959, now abandoned.
acetylenes and/ or di'ole?ns by selective hydrogenation in
Acetylen-ic hydrocarbons, as well as diole?nic hydnocar
the presence of a relatively inexpensive noble metal cata
bons, ‘because of their relative reactivity, may be hydro 20 lyst on an alumina carrier. These and other objects are
genated more readily than hydrocarbons containing one
apparent ‘from and are achieved in accordance with the
double bond (ole?ns). Therefore, preferential hydro
following disclosure.
genation (which is sometimes referred to as selective
hydrogenation) of acetylenes and diole?ns in a gas mix
I have discovered a palladium on alumina catalyst con
taining a small amount of chromium which is some-what
ture containing ole?ns is possible in the presence of an 25 less active as hydrogenation catalyst for the saturation
active catalyst by limiting the amount of hydrogen added.
of ole?ns than ordinary palladium. catalysts and is there
Such selective hydrogenation poses a di?icult problem,
however, when only small amounts of lacetylenic or di
ole?nc impurities are present in the .gasmixture and when
fore more selective in the hydrogenation of acetylenes
to 'ole?ns in the presence of ole?ns and diole?ns and in
the hydrogenation of diole?ns to ole?ns in the presence
it is necessary to effect substantially complete hydrogena 30 of ole?ns, without any substantial hydrogenation of the
tion of the acetylenes and diole?ns without appreciably
'ole?ns and diole?ns to saturated hydrocarbons. When
lowering the ole?n content in order to produce gas suitable
for use as a synthetic intermediate. By way of example,
used (as a selective hydrogenation catalyst in a gas stream
containing a major proportion of ole?n ‘as the unsaturated
hydrocarbon and a relatively minor proportion of acety
gas mixtures consisting essentially of ethylene for the
production of polyethylene should not, in general, con 35 lenes ‘and diole?ns with an excess of hydrogen over the
theoretical amount required to reduce acetylenes and di
tain more than about 25 parts per million of such highly
unsaturated impurities as acetylene, methylacetylene, pro
ole?ns to ole?ns, the catalyst of this invention has an
activity such that the excess of hydrogen is not consumed
padiene and other diole?ns of low molecular weight. For
in reducing 'ole?ns to saturated hydrocarbons and the
use in some of the newer polymerization processes it has
been found that the concentration of acetylenes and di 40 ef?ciency of the selective hydrogenation procedure is
thereby enhanced.
ole?ns in the puri?ed ole?n gases should preferably not
exceed 10 parts per million.
‘
The catalyst is prepared by spraying, dipping or other
wise applying to an alumina carrier :a solution of a pal
It is known that a superior selective hydrogenation
ladium compound and.v a chromium compound. The
catalyst may be made by incorporating palladium on an
alumina carrier in accordance with the disclosure of the 45 palladium compound and the chromium compound may
be applied from the same solution or separate solutions
Likins et a1. Patent No. 2,946,829‘, July 26, 1960. Such
of chromium compound and palladium compound may
catalyst is su?iciently active to completely hydrogenate
be used. The catalyst contains 0.01% to 0.5% palladium
highly unsaturated hydrocarbons at a commercially fea
by weight Iand 0.01% to 0.5% chromium by weight.
sible rate and does not lose activity under process condi~
Catalysts with palladium contents greater than 0.5% by
tions of long periods of time. While this catalyst is an
weight are operative (e.g., 1% P‘d) but the increase in
excellent catalyst for the puri?cation of ole?n streams
e?iciency of the catalyst is usually not great enough to
under most operating conditions, it has been found under
justify the increase in the cost of palladium, the latter
certain circumstances to be more active than may be de
being a precious metal in the platinum class. In most in
sired. In all commercial selective hydrogenation processes
an excess of hydrogen over that stoichiometrically re 55 stances, it is pre?erred that the weight ratio of palladium
to chromium be not substantially greater than unity. The
quired for the reduction of acetylenes and diole?ns to
maximum weight ratio of palladium to chromium is about
ole?ns is required and with highly ‘active catalysts the
2:1 and the maximum weight ratio of chromium to pal
excess of hydrogen is consumed in reducing the ole?ns
to saturated hydrocarbons, thereby reducing the ole?n
ladium is about 1.5 :1.
content of the stream with attendant disadvantages. Con
sumption of less hydrogen, in addition to providing a
better yield of the desired ole?n, would result in a smaller
The combination of chromium and palladium on the
alumina carrier tends to temper or lower the activity of
’
the highly active palladium hydrogenation catalyst and
at the same time to stabilize the catalyst against poison
temperature rise with attendant improved control and
ing and inactivation. Consequently, the palladium
selectivity. It is desirable to produce a selective hydro
genation catalyst having all of the advantages of the 65 chromium combination on alumina is less easily inacti
vated under the conditions employed for the commercial
Likins et ‘a1. catalyst but having slightly less hydrogena
hydrogenation of acetylenes in ole?n streams. The cat
tion activity so that more selective hydrogenation of high
alyst is active as a selective hydrogenation catalyst in the
ly unsatunated vhydrocarbons may be ‘accomplished in
ole?n streams without substantially hydrogenation of the
temperature range from about 100° F. to about 400° F.
and at pressures of about 50 to 500 p.s.i.g. The space
70
ole?ns.
.
velocity (volume of gas per volume of catalyst per hour
An important object of this invention is to provide a
at standard conditions of 60° F. and 1 atmosphere pres
3,098,882
3
4
pared by mixing 22 liters of 0.05 molar palladium chlo
ride solution and 22 liters of 0.1 molar chromic anhydride
(CrO3) solution and spraying the resulting mixture onto
400 kilos of :>716 inch tablets of Filtrol grade 90 alumina
PART B.—-0.033% Pd AND 0.036% Cr ON A1205
same gas stream, but with lower molar hydrogen/C3H4
sure) can vary from 50 to 2000. The amount of hydro
ratio. The results are given in Table II.
gen may vary from- -1.2 to 4- times the quantity required
to hydrogenate the acetylenes to ole?ns or \diole?ns to
Table 11
ole?ns.
PART A.—-0.046% Pd ON A1203
The following examples will further illustrate the na
ture and scope of the invention. It will be apparent that
numerous modi?cations in conditions may be made with
Temp, ° F.
mole ratio leakage,
leakage,
p.p.m.
p.p.m.
in the ranges discussed herein without departing from the
invention.
2
174
0
EXAMPLE 1
10 150 _____________________________ __
200 _____________________________ __
2
514
0
A palladium-chromium catalyst on alumina was pre
which had been calcined for 8 hours at 950° .F.
2
2
2
The
18
11
81
844
61
0
spraying operation was carried out while the alumina
It is seen thatall the hydrogen was consumed, indicat
tablets were motated in a revolving drum to insure uni
form distribution of the ingredients on the surface of the 20 ing hydrogenation of ole?n, in part A. However, with
the palladium-chromiurn-alumina catalyst in part B, there
carrier. The tablets were then calcined for 8 hours at
was substantial hydrogen leakage, indicating selectivity of
950° F. The catalyst so prepared contained 0.033% ‘Pd
the catalyst.
and 0.036% Cr (ratio of palladium to chromium sub
EXAMPLE 3
stantially unity).
The catalyst prepared as above was compared to a 25
The palladium-chromium-alumina catalyst prepared in
catalyst containing 0.046% Pd 'on the same alumina car
Example '1 was tested under various conditions, as shown
rier prepared in accordance with the disclosure of Likins
in Table III, with high ratios of hydrogen to C3H4 and
et al. Patent No. 2,946,829‘, by spraying 44 liters of 0.05
temperatures in the range of 150° F. to 300° F.
molar palladium chloride solution onto 400 kilos of 5716
Table 111
inch Filtrol grade 90 alumina tablets and calcining the 30
0.033%
Pd
AND
0.036% Cr ON A1203
sprayed tablets 8 hours at 950° F.
The two catalyst were tested in the same reactor under
the same conditions. The reactor contained 25 cc. of
catalyst and was operated at a temperature from 125° F.
to 250° F. at a pressure of 350 p-.s.i.g. and an hourly 35
space velocity of 1000. The‘gas stream had a nominal
Temp., ° F.
>
H2/C3H4
C3114
H2
mole ratio
leakage,
p.p.m.
leakage,
p.p.m.
3. 8
3. 8
3. 8
composition as follows:
Percent
Propadiene
_____, _____________________ __
Methylacetylene
1.0
_______________________ _ _
1 .0
Propylene
50
960
6, 000
7
51
4.
40
80.0
Propane ______________________________ __
Hydrogen _____________________________ __
10
22
60
EXAMPLE 4
A palladium-chromium-alumina catalyst, prepared ac
1.5
2.5-7.0
cording to the method described in Example 1 and con
taining 0.026% Pd and'0.031% C-r, underwent a life test
Methane
14.0—9.5
of two months without observable loss of activity or selec
The comparative results are given in the following 45 tivity. The conditions were as described in Example 1
with the following exceptions:
table:
7
'
Table I
Space velocity, hourly __________________ __
800
H2/C3H4 mole ratio ____________________ __ 1.6 to 2.0
PART A.—0.04e% Pd ON A1203
Temp., ° F.
H2/C3H4
mole ratio
3.5
C3114
leakage,
p.p.m.
50 Propadiene, inlet __________ ___.__.__percent__
Methylacetylene, inlet ____________ __do____
Ha
leakage,
p.p.m.
30
0.5
1.5
After gaining full activity in two days at 160° F., the
oatalystperformed'for 60 days at 130° F. with consistently
3.5
80
0
2,000 55
3.5
100
0
V 3.5
250
0
less than 10 p.p.m. leakage of high unsaturates as shown
in Table IV. The catalyst was removed at the end of
the run and was found to be exceptionally free of car
bonaceous deposit.
Table IV
PART B.——0.033% Pd AND 0.036% Cr ON A1203
3. 5
50
8, 000
3. 5
3. 5
40
10
150
65
0.026% Pd AND 0.031% Cr ON A1203
Days on Stream
The palladium-ohromium-alumina catalyst showed
better selectivity than the palladium-alumina catalyst
throughout the temperature range of 150° .F. to 250° F.
as evidenced by the low C3H4 ‘leakage and the reasonable
H2 leakage. The palladium-alumina catalyst appears to
be too active in that it used up allof the hydrogen at 150°
F. even at a hydrogen to C3H4 ratio of 3.5, without ade
quate removal of all the methylacetylene andpropadiene.
Temp.,
H2/C3H4
OHH4
Hz
° F.
Mole Ratio
leakage,
p.p.m.
leakage,
p.p.m.
160
2. 0
33
4,080
130
130
130
130
130
130
1. 9
1. 9
1.8
1. 6
1. 7
1. 7
l8
32
9
5
2
2
0
0
217
50
0
30
EXAMPLE 5
EXAMPLE 2
The e?iect of chromium as amod-i?er of the selective
hydrogenation activity of palladium was demonstrated
In another operation, the catalysts described in Ex
ample 1 were compared at 150° F. to 250° F. on the 75 by a series of three runs on catalysts containing about
3,098,882
5
6
0.03% Pd and 0, 0.03 and 0.06% Cr, respectively. Use
of 0.06% Cr produced an obvious inactivating in?uence
on the catalyst. The catalyst containing no chromium
performed fairly well at 140° F., but showed poor selec
tivity at 175° F. The use of appnoximately equal amounts
of palladium and chromium produced a highly selective
study the activity and selectivity of the catalyst in selec
hydrogenation catalyst which was less sensitive to tem
tively hydrogenating acetylenes in the presence of a
Although the acetylene removal was the same at 150
and 200° F., catalyst selectivity was higher at the lower
temperature. Pressure did not appreciably affect the re
action.
This example was oonducted as a differential test to
perature changes than the chromium-free catalyst. This
large proportion of butadiene. The test was designed to
catalyst possesses obvious advantages in operation of a
compare 'butadiene loss at different conditions rather than
commercial selective hydrogenation reactor. Results of 10 to demonstrate acetylene removal. No e?ort was made
the evaluation of the eifect of chromium are shown in
to remove substantially all of the acetylenes, but the
Table V. The tests were conducted under the same condi
removal thereof would be greatly increased by the use
tions as described in Example 4.
of lower space velocities.
What is claimed as new and is desired to be secured by
15 Letters Patent of ‘the United States is:
Table V
1. A method of selectively hydrogenating ace-tylenic
PART A.—0.027% Pd ON A1203
hydrocarbons in a gas wherein the major proportion of the
Temperature, ° F.
140 _____________________________ __
175 _____________________________ __
Mole Ratio
2.0
2.0
leakage,
leakage,
ppm.
ppm.
2
70
113
26
175 _____________________________ __
2
39
2. 0
2. 0
with a palladium and chromium on alumina catalyst
which comprises from 0.01% to 0.5% by weight of palla
dium metal and from 0.01% to 0.5% by weight of chro
mium metal on lan alumina carrier, at a temperature in
25 the range of 100° F. to 400° F. at an hourly space velocity
44
34
PART ~C.—0.028% Pd AND 0.062% 01‘ ON A1203
140 _____________________________ __
contacting said gas, admixed with a quantity of hydrogen
20 su?icient to reduce the acetylenic hydrocarbons to ole?ns,
PART B.—0.027% Pd AND 0.030% Cr ON A1203
2.0
2.0
unsaturated hydrocarbons is ol-e'?nic, which comprises
10
497
408
38
of 50 to 2000 volumes of gas per volume of catalyst.
2. A method of selectively hydrogenating the acetylenes
in an ole?n ‘gas stream without reducing substantially the
ole?n content of said gas stream which comprises con
30 tacting said gas stream, admixed with a quantity of hy
drogen in excess of that stoichiometrically equivalent to
the quantity of acetylenes and diole?ns in the gas stream,
with a palladium-chromium catalyst supported on alumina
EXAMPLE 6
which comprises from 0.01% to 0.5% by weight of palla
This example illustrates the selective hydrogenation of 35 dium metal and from 0.01% to 0.5% by weight of chro
mium metal on an alumina carrier, at a temperature in
vinylacetylene in the presence of 1,3-butadiene without
the range of 100° F. to 400° F. at an hourly space velocity
hydrogenation of the latter. This is ‘an extremely di?i
of 200 to 2000 volumes of gas per volume of catalyst.
cult reaction to conduct since both vinylacetylene and
3. A method of selectively hydrogenating methylacet
butadiene are very active compounds and both absorb 40
ylene and propadiene in a gas stream containing propylene
hydrogen very readily to produce butene. This example
as the major unsaturated constituent without substantially
therefore illustrates the selective nature of the catalyst
reducing the propylene content of said gas stream which
of this application.
comprises contacting said gas stream, admixed with at
A pvalladium-chromium-alumina catalyst prepared ac
cording to the method described in Example 1 and con 45 least 2 moles of hydrogen. per mole of methylacetylene
and propadiene, with a palladium-chnomium catalyst sup
taining 0.33% Pd and 0.24% Cr was found to be effec
ported on alumina which comprises from 0.01% to 0.5%
tive for the removal of C4 acetylenes in the presence of
by weight of palladium metal and from 0.01% to 0.5 % by
weight of chromium metal on an alumina carrier, at a
A feed material containing approximately 0.05% of
vinylacetylene and 0.05% ethylacetylene in GP. 1,3-buta 50 temperature in the range of 100° F. to 400° F. at an
hourly space velocity of 200 to 2000 volumes of gas per
diene was passed over 50 cc. of the catalyst. A total
volume of catalyst.
acetylene removal (approximately equal percentages of
4. A method of selectively hydrogenating C4 acetylenes
each) of 35-37% was accomplished without signi?cant
a diole?n.
loss of butadiene.
in a mixture containing a major proportion of 1,3-buta—
'
0.33% Pd AND 0.24% Cr ON A1203
[Pressure, 15 p.s.i.g.; space velocity, 200; Mole ratio of hydrogen
to acetylenes, 3.5:1]
Percent
Acetylene
Temp, ° F.
Removal
Hz Leak~
age
Maximum
Butadiene
Loss Com
puted,
p.p.1n.
55 diene without reducing substantially the content of 1,3
butadiene in said mixture which comprises contacting said
mixture, admixed with a quantity of hydrogen in excess
of that stoichiometrically equivalent to the quantity of
C4 acetylenes in the mixture, with a palladium-chromium
60 catalyst which comprises from 0.01% to 0.5% by weight
of palladium metal and from 0.01% to 0.5% by weight
of chromium metal on an alumina carrier, at a tem
perature in the range of 100-200° F. at an hourly space
150 _____________________________ __
200 _____________________________ __
87
37
1, 910
0
1, 220
3, 130
[Pressure, 50 p.s.i.g.; space velocity, 430; mole ratio of hydrogen
to acetylenes, 35:1]
150. ____________________________ __
35
1, 370
1, 780
velocity of 50-500 volumes of gas per volume of catalyst.
65
References Cited in the ?le of this patent
UNITED STATES PATENTS
11,836,927
2,317,683
2,946,829
Linckh et al. _________ __ Dec. 15, 1931
Greensfelde-r _________ __ Apr. 27, 1943
Likins et a1. __________ __ July 26, 1960
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