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Patented Sept. 24, 1946
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2,408,131
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PATEiN'lT
1 Alexis Ycerhies, in, Baton Badge, La; assigleatie
"Standard‘Oil‘Dey lopment C
ration. ethdeware
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No Drawing. Application October 2_'1_, 1951,
~ "Serial. No- 415,903“
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(Cl. 260-6833)
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I have now vfound that a catalyst comprising
a major proportion of_ aluminum oxide and a
minorproportion of chromium oxide can bemade
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substantially" more heat'ijes'istant‘and
fébyI
. ,I .. I.. 'YJt'oi a sl'ubstant'ialfeI entj'wlien heated 5I retaIiIiji _its"ac_tivity 'atus'ubusta tially higher'teini
to‘témperatures“ at" which 'the' knowntypeswo'f
‘" peratures if approximately on I)
catalysts
firearm-these' " 1051,: their activity;
e an‘dwjith'the
~'
" ~ ‘ method
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mium.
re
arising.(aide
ahaiit.iterated
i 96%. altimeter;
tailed. ttat'arezeaiia
niqkel'bxidei
.QX
2% "9
bi
miuraexide and 2%
air Pit-ht. .
' tateniperataifesbetweee 'liitqaed l 00° F‘ with:
out. loses its aqtivitv to. art appreciable exitent
Wh¢17§ét§ a; ‘catalyst, camel: ?ne ‘2% eliminate
oiéide and 61% geranium 9X 6 loses. a tutti??
tial amount of itsaetiu. r
"
1600“ F.
.sieeheetss'l at}???
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a
»
-
inven
vert the nitrate to the oxide. In order to increase
the mechanical Str'eng'thand durability of the
catalyst it may be heated to a high temperature,
equal amounts.
say above 1000° F., at which temperature a sub-
.
These catalysts may be prepared by impreg
stantial amount of volatile matter and moisture
hating Activated Alumina, alumina gels, peptized
is driven off. In general it‘ may be said that the 25 alumina gels, bauxite, alumina lrlydraiiesv and
higher the temperature to which this type of
other forms of aluminum oxide with a mixture ‘
. Catalyst is heated, themore rugged it will become,
However, it is noted that as the temperature of
heating is increased, the catalyst tends to become “
less active.
30
The ability of a catalyst to retain its activity
when heated to high temperatures is important
not only in the preliminary heat treatment to
increase mechanical strength but also in the catalytic dehydrogenation reaction itself and in the 35
regeneration of the catalyst when its activity has
been reduced by the deposition of carbonaceous
contaminants thereupon. Thus it frequently
happens during the dehydrogenation reaction,
of solutions of chromium and nickel nitrates and
then heating the resulting mass to temperatures
between 600, and 800° F. The concentration of
chromium and nickel nitrates in the solution are
adjusted so that the ?nal heated mass will con
tain the desired quantities of Chromium and
nickel oxides. It Will be understood that soluble
salts 01" Chromium and nickel other than the
nitrates may be used for impregnating the alu
mimlm 0Xide~
The following experimental data indicate the
heat resistant pr?perties 0f the improved Cat
all/‘St in Comparison With those of the knOWn
and particularly during the regeneration, that 40 Catalyst!
'
' excessively high temperatures may be developed
T‘WO Catalysts are prepared, One Consisting of
in local spots in the catalyst mass and if these
96% Activated Alumina and 4% Chromium Oxide
temperatures are high enough to cause loss of
activity it can be seen that care must be taken
and the other consisting of ' 96% Activated
Alumina, 2% chromium oxide and 2% nickel
to prevent such local overheating. In regen- 45 oxide. Isobutane is passed over each catalyst at
crating the catalyst it is of great advantage to
a rate of 175 volumes of isobutane per volume of
be able to conduct the regeneration at as high
Catalyst liar hour at a temperature of 1075° F
a temperature as possible because this means
In the first experiment the Catalysts are not Dre
that the necessity for constant cooling. of~the '
heated to a high temperature- In the Second,
catalyst mass is greatly reduced, It can be Seen 50 third and fourth experiments the catalysts are
therefore that if the catalyst is one ‘which loses
heated to temperatures of 1600° F., 1800° F. and
its activity when heated to certain temperatures’,
care must be taken to prevent these temperatures
from being reached either during thereaction
period or during the regeneration period.
_
,
2000“ F. respectively. The following tables show
the results obtained. In the table the catalyst
containing 4% chromium oxide and no nickel
55 Oxide will be designated as Catalyst A, and the
2,408,131
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4
3
alyst which consists of about 96% by weight of
aluminum oxide, 2% by Weight of chromium
oxide and 2% by weight of nickel oxide, and
catalyst containing 2% chromium oxide and 2%
nickel oxide will be designated as catalyst B:
-
Experiment- #1
no preheating
A
B
Experiment #2
.
preheating to
16000 F_
A
which has been heated to a temperature between
5 1800° and 2000° F.
2. The process of dehydrogenatinghydrocar
bons having from 2 to 5 carbon atoms which com
B
prises passing the hydrocarbons at dehydrogen
ating temperatures and pressures over a catalyst
Per cent unsaturates in exit gas-_
Per cent isobutylene in unsatur
29
26
26
26
ates __________________________ _ _
89
89
94
9Q
which contains about 96% by Weight of alumi
num oxide, 2% by weight of chromium oxide
and 2% by weight of nickel oxide, and which
has been heated to a temperature between 1800°
Experiment #3 Experiment #4
preheating to
preheating to
1800° F.
2000° F.
A
B
A
and 2000° F., and regenerating the catalyst by
15 removing coke deposits at intervals substantially
at temperatures of the regeneration reaction
without constant cooling.
3. The process of dehydrogenating hydrocar
bons having from 2 to 5 carbon atoms which
B
Per cent unsaturates in exit gas._
Per. cent lsobutylene in unsatur
14
‘20
8
12
ates __________________________ _ _
64
88
65
82
genating temperatures and pressures over a
It will be noted that when the two catalysts
are heated to temperatures of 1600° F., they are
catalyst which consists of a major proportion
of aluminum oxide and minor substantially equal
proportions of chromium oxide and nickel oxide
substantially equivalent in activity as represented
by the fact that about the same amount of un
saturates are produced and about the same per
centage of the unsaturates consists of isobutylene.
However, when the catalysts are heated to 1800°
F., it will be noted that there is a marked de
crease in the percent of unsaturates and percent
comprises passing the hydrocarbons at dehydro
20
2%
4. The process of dehydrogenating hydrocar
bons having from 2 to 5 carbon atoms which
comprises passing the hydrocarbons at dehydro
genating temperatures and pressures over a cat
alyst which contains a major proportion of
aluminum oxide and minor substantially equal
proportions of chromium oxide and nickel oxide
of isobutylene produced with catalyst A, where
as the decrease with catalyst 13 is not nearly so
great. This tendency is even more marked when
both catalysts are heated to 2000° F.
_ and which has been heated to a temperature
35
I'claim:
l _1. The process of dehydrogenating hydro
carbons having from 2 to 5 carbon atoms which
comprises passing the hydrocarbons at dehydro- ‘
genating temperatures and pressures over a cat
and which has been heated to a temperature
between 1800° and 2000° F.
46
between 1800° and 2000° F., and regenerating
the catalyst by removing coke deposits at inter
vals substantially at temperatures of the regen
eration reaction without constant cooling.
ALEXIS VOORHIES, JR.
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