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Патент USA US2407815

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Patented Sept. 17, 1946
2,407,814
UNITED STATES PATENT OFFICE
' 2,407,814
CATALYSTS
Harry A. Cheney, Oakland, Calif., assignor to
Shell Development Company, San Francisco,‘
Calif., a corporation of Delaware
No Drawing. ‘ Application June 21, 1943,
Serial No. 491,724
‘
5 Claims. (01. 252-251)
1
2
and hexylene, respectively, materials highly de
This invention relates to the manufacture of
supported catalysts and relates more particularly
to the manufacture of catalysts} comprising at
sirable as starting materials in the production of
such products as synthetic rubber and aviation
least one metal of group VIII in combination
fuels, renders these catalysts exceedingly valu
able, Of these catalysts those comprising cobalt
with activated carbon which have been found to
be particularly effective in the conversion of ole
?nic hydrocarbons to the lower boiling of-the
and/ or nickel in combination with activated car
bon are particularly outstanding‘in their ability
to effect this desirable polymerization reaction.
Catalysts comprising cobalt are somewhat-pre
employed also in other types of hydrocarbon con
10 ferred over those comprising nickel since they
versions.
,
enable the conversion of ‘the ole?nic hydrocar
Catalysts comprising elements of group VIII
hop to the lower boiling of the linear‘ polymers
find application in a wide variety of processes,
thereof at temperatures below 250° C.‘ and pref
particularly those involving the conversion of
erably not substantially in excess of 150° 0.,
hydrocarbons such as, for example, hydrogena
whereas those comprising‘ nickel ‘generally ‘re
tion, polymerization, dehydrogenation, “isomeri;
quire somewhat‘higher temperatures, for exam;
zation, gas pyrolysis, aromatization, etc; These
ple, up to about 350° 0., to attain equivalent
metals in a limited number of cases are used per
se in relatively large fragments, pieces or chunks.
Methods heretofore generally employed in the’
Most catalytic processes, however, require‘their
usage in dispersed or ?nely-divided form depos~ 20 preparation of these catalysts comprise‘tihe im
pregnation of the carrier material with a solu-‘
ited upon suitable support‘ materials. Support
tion of ‘a compound of an element of group‘ VIII
' materials which may be employed, comprise ma
linear polymers thereof, although they can be
results.
'
‘
"
’
‘
‘
and subsequently heating the resulting mixture‘
terials of porous structure such as activated car
at atmospheric pressure to e?ect decomposition
bon, pumice, ?re brick, as well as synthetically
prepared or naturally-occurring siliceous or alui 25 of the ‘deposited compound. Though variations‘
in the‘ method of preparing these “catalysts have
been‘ disclosed, such methods have generally been
ruinous materials such as, for example, clays,
bentonite. bauxite, diatomaceous earth, silica ‘gel,
handicapped by serious disadvantages. ' There
Activated Alumina, active or activated blends or
sulting catalysts are generally" lacking injg'u‘ni- '
compounds of silica and alumina, etc. “"These
various types of carrier materials, though indi; 30 formity with respect to activity. Another disad
vantage is the often total absence of a particular
vidualiy applicable as supports for the catalyst as:
characteristic such as, for example,‘ in the‘ case
used in the execution of a number ofreactions,
of catalysts comprising an element of group VIII
are, however, not equivalent. It has been found
and activated carbon, the ability to catalyze the
that characteristics of the catalysts are‘often
dependent upon the nature of the particular ‘1 ‘ conversion of ole?ns to a product predominating
in the lower boiling of the linear polymers there
upport material employed and that the catalytic
eifect of the elements of group VIII may be modi
?ed or changed by judicious selection of a par
of,
‘
‘
‘
The particular characteristic of the resultant
catalyst, it has been found, is dependent not only
ticular support material combined therewith.
It has been found that catalysts comprising 4-0 upon the particular element of group VIII and
the particular support material chosen but also
upon the particular compound of the element of
an element of group VIII in combination with
activated carbon possess the ability of catalyz
ing the conversion of ole?nic hydrocarbons to a
group VIII used as a starting material.
product which can be made to predominate in
catalysts comprisingcobalt and/or nickel pre
pared by combining an activated carbon with a
one or several of the lower boiling‘ of the linear
polymers thereof at temperatures below about
350° C. A particularly advantageous character
istic of this catalyst combination is the ability to
convert even the lower boiling of the ole?nic
hydrocarbons, such as ethylene and propylene,
to the lower boiling 'of‘=the linear polymers there
of to a degree irlot‘prlo'ssessed by other types of
available polymerizatibra catalysts. Their ability
to promote the eoiiversion of ethylene and proa
pylene to prodl?’ct'sfl predominating in- butylene
l
l
.
Thus,
salt such as the acetate and chloride of these
L". C.
metals,v the subsequent reduction of these com-'
pounds, produces a catalyst possessing little, if
any, ability to promote the conversion of ethyl
one to the lower boiling of the linear polymers
thereof. On the other hand, when utilizing a
salt‘ such as, for example, a salt obtained by the
interaction of an element of group VIII with an‘
oxygen-containing mineral acid, for example,
cobalt nitrate, nickel nitrate, etc., as starting,
2,407,814 -
3
4
materials, the resulting catalysts possess these
use of others comprising stationary vessels is
comprised within the scope of the invention. The
rotating type of apparatus is preferred not ‘only
because it enables the uniform distribution of the
desirable characteristics to a surprising degree.
However, the production of the catalyst from
salts particularly prone to undergo spontaneous
ignition during heating, such as 'the nitrates,
especially when conducted on a large scale by
methods utilized heretofore, often results in a
spontaneous decomposition to varying degrees of
the salt, therebynot only producing materials
ineffective as catalysts but presenting serious 10
metallic element throughout the porous mass but
because it enables the attainment of more effec
tive mixing of the components Without attrition
of the porous material to any substantial degree.
It furthermore enables more uniform heating of
the mixture thereby providing more effective con
When the production of some mate
trolof the rate of decomposition as well as more
rial in the absence of marked spontaneous de
efficient removal of decomposition‘ products and
hazards.
composition is attained by such methods, the
resulting product nevertheless generally consists
volatilized materials from the mass under treat
. ment.
In preparing the catalyst in accordance with
of a substantial proportion which is lacking in 15
the invention a suitable inorganic porous mate
the desired characteristic activity and a remain
rial, for example, a porous granular carbon such
ing portion which is devoid to a marked degree
of uniformity with respect to composition and
as activated vegetable or animal charcoals as pre
catalytic activity. This, it is found, is due to at
least a substantial degree to overheating of por
20
pared and activated by various commercial sup
pliers, is introduced into a closed vessel prefer
ably of the rotating type. Suction is thereupon
applied to reduce the pressure within the vessel
to subatmospheric, for example,~in the range of
tions of the catalyst resulting from spontaneous
ignition which, though present to a lesser'and
localized degree is, nevertheless. often unavoid
from about 1 to about 25 mm. of mercury. While
ably encountered to an undesirable extent in
methods of catalyst preparation resorted to here 25 maintaining the subatmospheric pressure a solu
tion of the metal nitrate is introduced into the
tofore.
'
vessel.
It is an object of the present invention to pro
The salt is preferably introduced into the drum
vide an improved method for the more e?icient
preparation of catalytic materials comprising co
dissolved in a suitable solvent of relatively low
volatility. The particular solvent used may vary
balt and/or nickel and activated carbon wherein
and will depend upon the solubility of the par
the above disadvantages are obviated to at least
ticular salt therein. When utilizing cobalt ni
a substantial degree. Another object of the in
trate as a starting material water is found to
vention is the provision of an improvedmethcd
‘for the ‘more 'e?icientmanufacture of catalysts
be a suitable solvent. The amount of the salt
comprising cobalt and/or nickel in combination 35 introduced into the vessel is dependent upon the
nature of the particular catalyst to be prepared.
with activated carbon having greater'uniformity
with ‘respect to composition and catalytic activity
In the preparation of catalysts, comprising co
balt in combination with carbon, particularly ef
fective for the conversion of ole?ns, it is preferred
to add a suf?cient amount of the cobalt salt to
the carbon to obtain a ?nished catalyst contain
ing from about 3% to about 35% and preferably
than those obtained by methods available here
tofore. A still further object of ‘the invention is
theprovision of an improved vmethod for the
more efficient production, of catalysts comprising
cobalt and/or nickel in combination with acti
vated carbon. particularly effective in the con
version of ole?nic hydrocarbons to the lower boils
ing‘of the linear polymers/thereof. Other objects
and advantagesof the‘ invention will become ap
parent from. the following description thereof.
7 Inaccordance with ‘the present invention an
from about 5% to 25% of cobalt. ' Catalytic
materials comprising higher or lower concentra
45
tions of cobalt, depending upon the particular
characteristics desired of the catalyst to be ob
tained may, however, be prepared in accordance
with the process of the invention.
The concentration of the cobalt nitrate in the’
activated carbon is admixed in a suitable vessel
with an aqueoussolution of a nitrate of cobalt 50 solution used as a starting material may vary
and/or nickel. The-"resulting mixture is heated
within the scope of the invention. In general,
' under conditionsassuring a slow and'gradual in
it is preferred to employ a su?icient amount of
crease in temperature of the‘ mixture to a maxi
solvent for the cobalt nitrate to immerse the
mum temperature not substantially in excess of
greater. part of the mass of charcoal.
, _
that enabling the maintenance of at least a part 55
The mixture is then agitated, for example, by
of the solvent in the'vessel. Additional solvent
rotation of the drum until intimate contact be
is intermittently or continuously added to the»
tween the solution and charcoal has been estab
vessel during the heating operation until at least
lished. The pressure in the drum is then in
partial decomposition of the greater part of the
nitrate has been effected. Thereafter the addi
tion of solvent is stopped and the temperature
slowly increased to a temperature not substan
creased ‘to at least atmospheric pressure. By this’
procedure impregnation of the cobalt nitrate into
the inorganic. porous material is obtained to the
degree essential to the‘ attainment of a catalyst
possessing sufficiently high activity as well as
tially in excess of and preferably below the maxi
mum temperature required to bring about the
the characteristics essential for its use in such
decomposition of the remaining portion of the 65 processes as the conversion of ole?nic hydrocar
nitrate. When generation of decomposition
bons to the lower boiling of the linear polymers
products to any susbtantial degree has ceased,
thereof. The invention is, however, not neces-~
the heating is discontinued. The catalyst is
sarily limited to this particular method of im
cooled and removed from the Vessel.
pregnating the porous support materialand other
In a preferred method of executing the inven 70 methods such as impregnation at atmospheric or
tion the catalyst is prepared in a sealed rotating
higher pressures before, proceeding with the
drum provided ‘with means for heating and cool
preparation in accordance with the invention
ing its contents, removing volatilized material
may be resorted to.
'
therefrom and for varying the pressure therein.
After impregnating the charcoal with the soluél
Although this type of apparatus is preferred, the 75 tion'of cobalt nitrate heatis applied to the drum, 1
2,407,814
6
5
which is preferably rotated during the process,
to attain a gradual increase in .the temperature of
the contents therein without occasioning any
sudden substantial increase in temperature. Dur
ing the heating water vapor is continuously re
moved from the drum, preferably by the apD1i~
cation of suction thereon.
‘The cobalt nitrate
will undergo gradual decomposition even before
the greater part of the water has been removed
from the mixture in .t 1e drum.
Resulting de
composition products, comprising oxides of nitro
gen, are removed from the drum together with
the water vapor. The heating is continued for a
period of time, and up to a. maximum tempera
When at least the greater part of the salt
charged to the drum has undergone substantial
decomposition, which in the case of cobalt nitrate
will be, for example, when at least 50% and pref~
erably about 70% or more of the combined nitro- '
gen has been removed from the mixture, the
heating is continued at the maximum tempera
ture prescribed for this phase of the process
until substantially all of the water is removed
10 from the drum.
The temperature of the con
tents of the drum is then gradually increased, in
the absence of any further addition of water, to
a temperature not substantially in excess of about
400° C. and preferably not substantially in excess
ture, not exceeding that assuring the presence of 15 of about 300° C. During this second heating
period, decomposition products are removed from
at least a part, for example about 20% of the
the drum substantially as rapidly as formed.
water in the drum. When utilizing cobalt nitrate
The heating is continued, while maintaining the
as the starting material a maximum temperature
temperature of the contents in the drum within
of, for example, about 110° C. and preferably of
the prescribed temperature range, until no fur
about 105° C. is not exceeded. When the greater
ther generation of substantial amounts of decom
part of the water has been removed from the mix
position products is evidenced. The contents of
ture, but prior to its complete removal, an addi
the drum are then cooled and removed therefrom.
tional amount of water is introduced into the
Although the pressure Within the drum during
drum and the heating operation is continued
within the prescribed limited temperature range 25 the heating steps may be maintained at substan
tially atmospheric, it is preferred to maintain the
until the greater part of the water has‘ again been
drum under partial vacuum to further the decom
removed from the drum. The intermittent addi~
position of the cobalt nitrate and facilitate re
tion of solvent is repeated until at least 50% and
moval of vaporized solvent and decomposition
preferably 70% or more of the combined nitro
gen has been removed from the drum.
30 products therefrom. It has been found that par
ticularly active catalysts are produced by em
The amount of water added during the con
ploying a subatmospheric pressure during that
secutive additions may vary within the scope of
phase of the heating process conducted after
the invention. It has been found suitable to add
removal of the solvent. Suitable reduced pres
‘an amount equal to about one half of the amount
?rst required to effect submersion of the catalyst. 35 sures comprise, for example, from about 25 mm.
to about 250 mm. mercury pressure.
The extent to Which it is removed prior to fur
ther additions may also vary Within the scope
of the invention. In general, it is preferred to
add the additional amounts when about 89% of
the water within the drum, comprising water of
crystallization of the cobalt nitrate, has been
removed therefrom.
The amount of water re
In a modification of the process of the inven
tion the addition of the cobalt and/or nickel
nitrate, for example cobalt nitrate, to the acti
vated carbon is effected in successive steps. A
part of the total amount of the cobalt nitrate to
be added is initially introduced into the drum
containing the carbon prior to beginning the
moved prior to each successive addition may be
heating. Successive‘ additions of cobalt nitrate
progressively increased during the course of the
operation, care being taken however, during this 43 are then made simultaneously with the subse
quent additions of solvent during the heating
phase of the process that all of the water be
operation until the requisite amount of cobalt
not removed.
’
nitrate has been added to produce the catalyst of
The process may be modi?ed by effecting the
the-desired composition. This, it has been found,
addition of the solvent continuously instead of
intermittently during this ?rst or decomposition L’ O often leads to more efficient catalyst production
resulting in catalysts of unusually high activity.
stage of the process. Under such conditions it is
found advantageous, particularly when solvents
Furthermore, it enables the production of active
vent, optionally comprising the re?uxing of the
avoided.
catalysts containing higher proportions of the
other than water are used, to provide condensing
metallic element than methods wherein the ad~
means to which the eilluence from the drum may
be passed and vaporized solvent condensed there 55 dition is effected in a single step.
In preparing the catalyst in accordance ‘with
in under conditions effecting the removal of de
the invention, it has been found that sponta
composition products therefrom in the gaseous
neous ignition to any substantial degree of even
state, and to return the condensed and cooled
ich compounds as cobalt nitrate, so deleterious
solvent to the drum. Under these conditions the
temperature is, however, controlled in such man 60 to the activity of the ?nished catalyst, and which
effect is inherent to a degree often preventing
ner as not to exceed the maximum temperature
economical production of such catalysts by
of the permissible temperature range in the drum.
methods available heretofore, is completely
When utilizing the continuous addition of sol
The resulting catalysts unlike those
solvent, it is preferred to maintain a gradual in 65 produced by many other processes are not sub
ject to wide variations in activity due to minor
crease in the temperature gradient, up to the
?uctuations in the method of manufacture and
maximum permissible temperature, during the
are not only exceedingly uniform
composition
entire period of this phase of the process.
but unusually stable upon contact with the atmos
The solvent added subsequently to the primary
impregnation need not necessarily be the same 70 phere and under storage conditions. The exact
composition of the catalysts thus prepared com
as that originally used .to introduced the salt into
prising the cobalt and/or nickel in combination
the drum. Under certain conditions it is found
with carbon and which are particularly effective
advantageous to utilize different solvents in the
for the conversion or treatment of ole?nic hy
impregnation step and in the subsequent solvent
drocarbons is not readily determined. The co
addition steps.
2,407,814
7
8
balt and/or nickel ‘may be present therein in the
elementary form, in combination with oxygen, in
400 grams of water was added and the heating
resumed for a period of 2 hours until the tem
combination with carbon, or in a mixture or"
perature again reached 105° C. Approximately
these various forms. The carbon, in the partic
50% of the nitrogen had then been removed from
the contents of the drum which still contained
about 180 grams of Water. 400 grams of water
was then again injected into the drum and heat
ular catalysts comprising this material in com
bination with cobalt and/or nickel prepared in
accordance with the method of the invention, is
not merely a diluent or support material but an
active component of the catalyst in the absence
ing continued for a period of 1/2 hour until the
temperature of the contents was again gradu
of which the catalytic e?ect upon such reactions 10 ally raised to 105° C. About 100 grams of Water
as the conversion of normally gaseous ole?nic
then remained in the mixture in the drum along
hydrocarbons, particularly ethylene, to the lower
boiling of the linear polymers thereof is only
negligible if not completely absent.
with about 30% of the combinednitrcgen. The
heat was then adjusted to give a temperature rise
of about 1° C. per minute until the temperature
Materials capable of promoting or otherwise
reached 300° C. After cooling, the catalyst, which
modifying the activity of the ?nished. catalyst
was almost identical in appearance with the orig
inal charcoal, was removed from the drum and
may be added thereto. Such materials compris
ing, for example, elements other than cobalt
charged to a reaction chamber.
‘ ‘
and/or ‘nickel, or compounds thereof, may be
140 cc. of catalyst prepared by the above pro
added in relatively small amounts to the mate 20 cedure was charged to a stainless steel reaction
rials in the catalyst drum during the course of
tube. The catalyst was swept with Hz for 3 hours
manufacture. The porous materials need not _
at 300° C. Ethylene was polymerized over the
consist of a ‘material of but one type and may‘
catalyst at 100° C. under 800 pounds pressure.
comprise a mixture of two or more inorganic
The ethylene flow rate averaged 633 grams per
materials of porous structure. Thus in the prep
liter of catalyst per hour. In 70.9 hours the cat
aration of catalysts comprising cobalt and/or
alyst produced 18,600 grams of polymer per liter
nickel in combination with carbon, inorganic
of catalyst, 66% of which was butylene. The av-,
material inert with respect to behavior of the
erage conversion of ethylene to polymer was 42%.
catalysts, such as, for example, pumice, crushed
The catalyst was then regeneratedby sweep
ing with Hz for 3 hours at 300° C. Polymeriza
brick, bauxite, clays, etc., may be admixed with
the charcoal prior to preparation of the catalyst
or even during the course of its preparation.
tion of ethylene was resumed under the above
The additional incorporation of a porous mate»
rial of more rugged structure enables the utiliza
tion of carbon of smaller particle size and even
in powdered form; the resultant catalyst then
comprising an admixture of cobalt and/or nickel
average flow rate of 794 grams of ethylene per
liter of catalyst per hour. In 64.8 hours-21,200
and ?nely-divided carbon deposited upon a cen
tral core of the added porous inert material.
conditions of temperature and pressure and an
grams of polymer were produced per liter of cat
alyst, 59% of which was butylene. The average
conversion of ethylene to polymer was 42%.
I claim as my invention:
a
1. In the preparation of catalysts comprising
Catalysts prepared in accordance with the 40 cobalt and activated carbon particularly effective
in the conversion of ole?nic hydrocarbons to the
method of ‘the invention possess appreciable ac
tivity and are ready to be utilized as such. It de--'
lower boiling of the linear polymers thereof, the
method of obtaining catalysts of substantially
sired, however, the catalyst may be subjected to
improved uniformity with respect to composition
additional treatments culminating in still greater
activity of the catalysts thus produced. Such
and catalytic activity which comprises heating
additional treatments may comprise subjecting
‘of the catalysts to higher temperatures in the
order oi‘, for example, about 500° C., while sweep
ing them with a gas consisting of or compris
ing hydrogen, nitrogen, carbon dioxide, normally
gaseous paraf?nic hydrocarbons such as methane,
ethane, propane, or mixtures thereof.
A method
particularly, effective for further increasing the
activity of catalysts of this type comprises their
subjection to an elevated temperature up to, for
example, about 500° C., while maintaining them
at a subatmo'spheric pressure, preferably below
about 10 mm. mercury.
an admixture of an aqueous solution of cobalt ‘
nitrate and activated carbon in a closed vessel
under conditions of progressively increasing “tem
perature not substantially exceeding about 110°
C., removing volatilized material and. gaseous de
composition products from the vessel, introduc
ing water in successively decreasing amounts into
the vessel to assure the presence of water therein
throughout said heating, continuing said heating
in the presence of added water until at least‘a
substantial part of the cobalt nitrate has under- .
gone decomposition, and thereafter heating the’
contents of the vessel without further water ade '
dition at a higher temperature not substantially
Example I
60 in excess of about 400° C. until evolution of sub
stantial amounts of decomposition products has
1800 grams of 6-14 mesh granular cocoanut
ceased.
charcoal was introduced into arotating drum
and the pressure therein reduced to 30 mm. of
2. In the preparation of catalysts comprising
mercury. While rotating, a solution of 1800
cobalt and activated carbon particularly effective
grams of cobalt nitrate hexahydrate in 800 65 in the conversion of ole?nic hydrocarbons to the
grams of water was introduced into the drum.
lower boiling of the linear polymers thereof, the
Heat was applied to the rotating vessel while
method of obtaining catalysts of substantially im
maintaining the subatmospheric pressure.
The
proved uniformity with respect to composition
heating was continued during a period of 3
and catalytic activity which comprises heating
hours until a maximum temperature of 105° C. 70 an admixture of an aqueous solution of cobalt
was attained. Approximately 80% of the Water ‘ nitrate and activated carbon in a closed vessel
initially present (including water of crystalliza
under conditions of‘ progressively increasing tem
tion) was removed during this treatment along
perature not substantially exceeding about 110°‘
with about 20% of the combined nitrogen,
C., said cobalt nitrate solution containing insuf
chiefly in the form of nitric oxide. At this point 75 ?cient cobalt nitrate to. provide the necessary
2,407,814
10
taining catalysts of improved uniformity with re
spect to composition and catalytic activity which
concentration of cobalt in the ?nished catalyst,
removing volatilized material and gaseous decom
position products from the vessel, introducing
water in successively decreasing amounts into said
comprises heating an admixture of activated car
vessel to assure the presence of water ‘therein
metal selected from the group consisting of co
balt and'nickel in a closed vessel under condi
throughout said heating, dissolving sui?cient co
bon and an aqueous solution of a nitrate of a
balt nitrate in at least a portion of the water so
tions of progressively increasing temperature, re
introduced during said heating to provide the
moving volatilized material and gaseous decom
position products from the vessel, introducing
catalyst, continuing said heating in the presence 10 water into the vessel to assure the presence of
water therein throughout said heating, continuing
of added water until at least a substantial part
said heating in the presence of added water until
of‘ the cobalt nitrate has undergone decomposi
at least a substantial part of the metal nitrate
tion, and thereafter heating the contents of the
has undergone decomposition, and thereafter
vessel without further water addition at a higher
temperature not substantially in excess of about 15 heating the contents of the vessel without further
water addition at a higher temperature not sub
400° C. until evolution of substantial amounts
stantially in excess of that required to effect de-'
of decomposition products has ceased.
composition of the remaining nitrate.
3. In the preparation of catalysts comprising
5. In the preparation of catalysts comprising
cobalt and activated carbon particularly effective
in the conversion of ole?nic hydrocarbons to the 20 activated carbon and a metal selected from the
group consisting of cobalt and nickel, the method
lower boiling of the linear polymers thereof, the ‘
of obtaining catalysts of improved uniformity
method of obtaining catalysts of substantially
necessary concentration of cobalt in the ?nished
improved uniformity with respect to composition
and catalytic activity which comprises heating
with respect to composition and catalytic activity
which comprises forming an admixture compris
an admixture of an aqueous solution of cobalt 25 ing an activated carbon and a solution of a nitrate
of a metal selected from the group‘c'onsisting of
nitrate and activated carbon in a closed vessel
cobalt and nickel in an aqueous solvent, heating
said admixture in a closed vessel under conditions
of progressively increasing temperature, remov
troducing water into the vessel to assure the pres 30 ing volatilized material and gaseous decomposi
tion products from the vessel, introducing Water
ence of Water therein throughout said heating,
into the vessel to assure the presence of water
continuing said heating in the presence of added
therein throughout said heating, continuing said
water until at least a substantial part of the
heating in the presence of added water until at
cobalt nitrate has undergone decomposition, and
thereafter heating the contents of the vessel with 35 least the larger part of the metal nitrate has
undergone decomposition, and thereafter heating‘
out further water addition at a higher tempera
the contents of the vessel without further addi
ture not substantially in excess of about 400° C.
tion of water to a higher temperature not sub
until evolution of substantial amounts of decom
stantially in excess of 400° C. until evolution ‘of
position products has ceased.
substantial amounts of decomposition products
4. In the preparation of catalysts comprising
under conditions of progressively increasing tem
perature, removing volatilized material and gas
eous decomposition products from the vessel, in
activated carbon and a metal of the group con
sisting of cobalt and nickel, the method of ob
has ceased.
'
HARRY A. CHENEY.
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