Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
The present lnvention relates to the high temper-
ature vapor phase dimerization of acrylonitrile to form
~someric 1,4-dlcyanobutenes and adiponitrile.
P~uch work has been recently done on the catalytic
dimerization and hydrodimerizaticn of acrylonitrile to 1,4~
dicyanobutenes and adiponitrlle. See, for example, the
following Japanese and German patent publications: JA
077686, JA 7115494, JA 7125726, JA 7121369, JA 7127729, JA
7115485, DT 1945780, JA 7139330 and DT 2446641. As disclosed
in these patents, acrylonitrile can be dimerized into 1,4-
dicyanobutenes and/or adiponitrile by contacting acrylonitrile
in the gaseous phase optionally together with hydrogen with
a catalyst selected from a wide variety of dif~erent materials.
In many of these references, ~t is necessary or preferable
to sub;ect the catalys~ pri.or to use to reduction in hydrogen
gas so that the metallic components of the catalyst are
present essentially in elemental form. Alternatively, the
metallic catalyst can be employed ln some of the processes
in the form o~ a chloride, sulfate, nitrate, acetate or
Gther organic compound.
~ .
5~
s-~Jr~ o~ ~}1E I~J~ I0~
Against this background, it has been discovered
tha~ a catalyst co~.prising actlvated alumi~a containing
inorganic su].fide lon exhibits a substantial and unexpected
activity in the catalytlc vapor phase dimerization of acrylo-
nitrile.
Therefore, in accordance with the present invention,
a process for the vapor phase catalytic dimer~.ation of
acrylonitrile to 1,4-dicyanobutenes and adiponitrile is
provided, the process comprising contacting gaseous acrylo-
nitrile with a catalyst comprising activated alumina contain-
lng inorganic sulfide ion. More specifically, the present
invention provides a process for the vapor phase catalytic
dimeri~ation of acrylonitrile to l,4-dicyanobutenes and
adiponitrile in which acrylonitrile in the gas phase is
contacted with an inorganic sulfide ion-containing activated
alumina catalyst formed by contacting activated alumina at
an elevated temperature of at least about 500F with a
material capable of decomposing to liberate inorganic sulfide
ion at the elevated temperature. In another embodiment, the
present lnvention also provides a process for the vapor
phase catalytic dimerization of acry~onitrile to 1,4-dicyano-
butenes in which acrylonitrile in the gas phase is contacted
with a catalyst comprising an activated alumina carrier
having supported thereon a catalytically effective amount of
a sulfide of a metal or metalloid, the metal or metalloid
being selected from Groups IA, IIA, IVB, VB, VIB, VIIB,
VIII, IB, IIB, IIA, and IVA of the Period1c Table, the rare
earth metals, scandium and hafnium.
754~
DETAI_~3 ~SCR~PTIOtJ
Process Conditions
In carrying out the inventive process, acrylo-
nitrile in the vapor phase is contacted with a catalyst zs
described below for effecting the dimerization reaction.
The reaction can be carried out either in the batch mode or
continuously and either with a fixed bed or a fluidized bed.
he reaction temperature is generally between 500 and 1100F,
800 to 1000~ being preferred. The reaction pressure is
normally maintained between 1 and lO0 atmospheres with a
reaction pressure of 2 to 50 atmospheres being preferred.
The apparent contact time between the catalyst and the
reactant may vary from about 0.1 second to about 30 seconds.
In general, lower reaction temperatures tend to benefit from
longer contact times, and at higher temperature shorter
contact times tend to be optimum.
Preferably, the gaseous acrylonitrile feed fed to
the reactor contains a carrier gas for sweeping the rela-
tively heavy reac~ion products out of the reactor. Hydrogen,
nitrogen or any gas inert to the reaction can be employed as
the carrier gas. Preferably, the amount of carrier gas
mixed with the acrylonitrile feed is such that the acrylo-
nitr~le/carrier gas ratio in the feed is 0.5:1 to 25:1. If
desired~ hydrogen sulfide in a molar ratio of gr eater than
zero to 30 mole ,ol ~ preferably 2 to 20 mole ~0, and optimally
30. 15 mole %, with respect to the total amount o~ carrier gas
--3--
,
5~3
~e~, can be include~' in ~hc carr'er gas to insure that t~lP
~ r~ir.a ca~alJ~st of thC ~PsPn~ r.ven~ion rera~ns ricn ~n
sul~lde ion during ~he di~erization reaction. ~he preferrPd
ca~rier ~as is hydro~en since hydrogen insures th2t the
metal or metallo~d in the catalyst remains in a reduced
sta~e.
he reaction product obtained upon comple'ion of
the reaction is composed prlmarily o~ propionitrile, adipo-
nitrile, cis- and trans-1,4-d~cyanobutene-1, cis and
trans-1,4-dicyanobutene-2 and unreacted acrylonitrile. Also
present may ~e small amounts Or succinonitrile, acetonitrile
and pyridine. The reaction product can be subjected to
suitable known separation techniques to yield the desired
end products, namely the 1,4-dicyanobutenes and adiponitrile.
As is well known ln the art, adiponitrile can be readily
con~erted into either hexamethylenediamine or adipic acid,
which are both starting materials for nylon 66, by simple
and straightforward procedures. See U. S. Patents 3,056,837,
3,272,866 and 3,272,867. Also, 1,4-dicyanobutenes can be
converted into adiponitrile by known hydrogenation proce-
dures. See, for example, M. J. .~stle, Chemistry of Petro-
che~icals, Reinhold Chemical Co., copyright 1956, pp. 240,
247 and 256; and U. S. Patent 2,518,608 and U. S. Patent
2,451,386.
Catalyst
The catalyst employed in the inventive process ~or
the high temperature vapor phase catalytic dimerization of
acrylonitrile comprises activated alumina containing the
inorganic sulfide ion, the alumina being used alone or in
combination with a metal or metalloid promo~er. Thus, in
one embodiment of the present invention, unpromoted
--4--
~17~
activated a'~l~ira ,lhen acti~ated SG as to contain inorganic
sullide ion can be used as the catalyst in the i~ventive
process. In this embodi,~.ent, activated aliu.nina is sulfur-
activated by contacting the alumina at an elevated tempera-
ture, normally at least about 500F, with a materi21 capableof decomposing in the presence of activated alumina at the
elevated temperature to liberate sul~ide ion (hereinafter
referred to as a "sulfide ion-yielding material"j. ~ny
material which is capable of decomposing in the presence o
activated alumina to liberate sulfide ion at a temperature
of at least about 500F is useful for this purpose. For
example, hydrogen sulfide, carbon disulf~de and organic
sulfur-containing molecules decomposing at a temperature of
at least about 500F to llberate sulfide ions can be used.
Good examples of such organic sulfur containing molecules
are the mercaptans, specifically alkyl mercaptans in which
the alkyl group has 1 to 12 carbon atoms (iOe. methyl
mercaptan, ethyl mercaptan, propyl mercaptan, etc.). In
this embodiment, the use of hydrogen sulfide or carbon
disulfide is pre~erred while the use of hydrogen sulfide is
most preferred.
In order to sulfur activate the activated alumina
catalyst in this embodiment of the invention so that it
contains inorganic sulfide ion, activated alumina is heated
to an elevated temperature at or above about 500F and
contacted with the sulfide ion-yielding material. The
activated alumina can be heated to the elevated temperature
prior to or simulaneously with contacting the sulfide lon-
yielding material. ~lternately, the sulfide ion-yielding
material can be heated to the elevated temperature. The
time period over which the activated al~nina must be
~'7~
contacted wlth the sul~ide ion-yielding material is the time
necessary ~or the sulfide ion-yielding material to react
with the ~lu~in~ and ~o~m si~ni~icant inorg~nic sulfide
ion. Normally this takes about 0.1 to 5 hours.
In accordance with another embodiment o~ the
present invention, the activated alu~ina support can be
promoted with a suitable metal or metalloid promoker ele-
ment. In accordance with the present invention, it has ~een
found that sul,ur-activated activated alumina promoted ~Jith
a wide variety of different metals or metalloids will also
exhibit a significant catalytic effect in the catalytic
dimerization of acrylonitrile to 1,4-dicyanobutenes and
adiponitrile. In accordance with this embodiment of the
invention, elements found useful in exhibiting a promoter
effect are metals and metalloids of Groups IA, IIA, IVB, VB,
VIB, VIIB, VIII, IB, IIB, IIIA5 and IVA of the Periodic
Table, rare earth metal, scandium and hafnium. A broadly
preferred class of promoter metal or metalloids is lithium,
sodium, potassium, rubidium, cesium, magnesium, calcium,
- 20 strontium, barium, chromium, molybdenum, manganese, iron,
cobalt, nickel, pallad~um, platinum, copper, silver, zinc,
cadmium, tellurium, tin and lead. A more preferred class of
metal or metalloid promoters is composed of those of the
foregoing elements in Groups IA, IIA, IB and IIB of the
Periodic Table and lead, namely lithium, sodium, potassium,
rubidium, cesium, manganese, calcium, strontium, barium,
copper, silver, zinc, cadmium and lead. ~ost preferred
metal or metalloid promoters are sodium, strontium, and
silver. In each of the above-noted classes, the indicated
metals and metalloid can be used individually or in ad-
mixture with one another.
--6--
3 ~L75~
~e s~ ur-ac~iva~ed ac~l~ated alu~n~ ca~'ysts
o2 ~his emboc~ment ol ~h~ preser~.t invention can contain from
a creat de~l to a ver~ llttle metal or metallold promo~Pr.
The m~nlmal amount Or pro~.oter is that amount nece~sary for
the presence of~ the promoter to exert an influence on the
catalytic activ~ty o~ the sulfur-activated catalyst. The
ma~lmum zmount is approximately 90 ~Jeight percent, based on
the total weight of the catalyst. Normally, the amount of
metal or metalloid promoter is greater than zero percent to
90 weight percent, preferably 0.1 to 50 weight percent,
while the most preferred amount is about 1 to 10 weight
percent.
The catalyst o~ this embodiment o~ the p~esent
invent~on can be prepared by depositing the metal or metal-
loid promoter in elemental form or in the form o~ an oxide~
hydroxide or salt on an activated alumina support or carrier
and thereafter subjecting the composites ~ormed to sulfur-
activating conditions as described above. Promoter metals
or metalloids can be deposited on an activated alumina
support by depositing on the activated alumina support a
reducible or irreducible salt, hydroxlde or oxide of the
metal or metalloid and thereafter reducing the salt or oxide
by contact with elemental hydrogen. Examples of compounds
useful for this purpose are Ni(No3)2~6H2o, P205-24MoO3-48H20
(for Mo), CetN03)3~6H20, CrO3, Cu(N03)2 3H20, ( 3 3 2
MntN3)2~6H2~ KOH~ Uo2(No3?2'6H20~ Mg(No3)2~6H2o~ ~lN03,
AgN03~ and PdC12. Techniques ~or depositing metals or
metalloids on supports are well known in the art and thoroughly
described ln the various Japanese patents listed above.
4~
~ ice the ~e~a or r~etalloid ~o~o~er ~ de~osited
cn the support, t~e co~pos~tes so rormed can be sub~ected to
sul~ur-activatlrlg cor.ditions as described above. As in the
previous e~.bodiment, the composite c~n be activ~ted by
contacting the composite wlth a material capable of decomposing
in the presence of the activated alumina composite to liberate
sul~ide ~on at an elevated tem~erature, preferably at least
about 500F. Such materials as hydrogen sulflde~ carbon
disulfide and decomposable organic sulfur-containing molecules,
such as the mercaptans mentioned above, are also use~ul in
this embodiment o~ the invent~on. Moreover, the contact
time should, in general, also be about 0.1 to 5 hours.
In this connection, in this embodiment of the
~nvention the sulfur activation procedure is accomplished
for a time and at a temperature sufficient so that the
metal or metalloid in the composite is converted to the
corresponding ~norganic sulfide. Accordingly, in this
embodiment of the present invention the catalyst can be
characterized as comprisin~ an activated alumina support
having thereon a metal or metalloid promoter in the form of
an inorganic sulflde.
From the foregoing, it will be appreciated that
the present invention provides a novel process for the
catalytic dimerization of acrylonitrile to 1,4-dlcyano-
butenes and adiponitrile. An important aspect of thisprocess is that the cakalyst employed is activated alumin~
either alone or in combination with a suitable metal or
metalloid promoter which has been subjected to a sulfur-
activation treatment. Although not wishing to be bound to
3 any theory, it is believed that the novel catalytic
-
75i~
e~ect re~'iz~d ir. accor~a~ce wi~h the pre~ent invention
occurs when sulfur is present in the activated all~mina
catalyst in the form of inorganic s~lfide ion. In the
second embodiment of the present invention in which the
activated alumina is promoted with a metal or metalloid
promoter, sul~ur-activation of the alumina/promoter com-
posite has the effect of causing the metal or metalloid in
the composite to take the form of a sulfide. Therefore, in
this embodiment sulfide ion is present as part of the metal
compound containing the metal promoter.
In a similar manner, it is believed that small but
significant amounts of sulfide ion are present in the
activated alumina catalyst of the first embodiment of the
present invention in which no metal or metalloid promoter is
combined with the activated alumlna support. Thermodynamic
studies tend to show that alumina, A12O3, will not be trans-
formed in major amount to aluminum sulfide by contact with
hydrogen sulfide. However, such studies are based on
macroscopic analysis. It is believed that although the
entire body of an alumina mass sub~ected to sulfiding
conditions may not form aluminum sulfide, small but signif-
icant amounts of aluminum sulfide are formed on the surfaces
of the alumina body. It i5 believed, therefore, that in-
organic sulfide ion is also present in the activated alumina
catalyst of the first embodiment of the present invention in
which no metal or metalloid promoter is added to the alu~.ina.
To further support the view that it is the pres-
ence of inorganic sulfide ion in the alumina catalyst of the
present invention which provides the novel catalytic effects
3o herein described, it has also been found in accordance with
the present invention that sulfide ion can be introduced
5a~9
into the alumina cava~yst c,f the p~esen~ invent~on b~
technlques other than the sulfur~activation treatment
discussed above. For exar.~le, it has been ~ound that an
e~. ective catalyst can also be obtained by introducin~
sulfide ion during the wet chemistry stage o~ preparir.g the
catalyst. This may be accompl~shed by bubbling H2S g2s
through an aqueous slurry o~ activated alumina particles and
a salt of the metal or metalloid promoter, whereby a sulfide
of the metal or metalloid forms on the activated alumina
particles. Still another way of producing an effective
catalyst comprises m~xing elemental sulfur with a composite
comprising the metal or metalloid promoter in reduced or ele-
mental form on an activated alumina support and thereafter
heating the mixture to calcining temperatures (e.g. above
500F) in an inert atmosphere.
Any activated alumina having a surface area of 0.5
to 800 m2/g can be employed as the starting material to form
the sulfide ion-containing catalyst em~loyed in the inventive
process. For example, activated alumina having a surface
,~ 20 area of 2 to 500 m2/g can be used to advantage in the
present invention. As a practical matter, the most common
surface area of commercially available alumina is about 200
m /g, and therefore the activated alumina used in the
inventive process preferably has a surface area of 2 to 200
m2/g. The particle size of the activated alumina starting
material used to make the catalyst of the inventive process
as well as the particle size of the catalyst itself is
unimportant, any particle size being effective. When the
inventive process is carried out in a fixed-bed reactor on a
commercial scale, the particle size of the catalyst
--10--
~75~
ca~. be the CGn~ention~ par~icle size for fi~ed-bed com-
mercial cara1ytic reactors, namel~ 1/16 inch to 1/2 inch in
diameter. Similarly, w-hen the in~entive ~rocess is carried
out in a fluid-bed, the particle size of the catalyst is
advantageously the conventional particle size ~or cor~mercial
fluid-bed reactor~, namely 20 to 300 mi crons. In the
following workin~ examples the catalyst had a particle size
of 9 to 40 mesh, Tyler, since this is a convenient size for
laboratory scale testing.
Examples
In order to more thoroughly describe the present
invention, the following working examples are presented. In
each o~ these examples, acrylonitrile was dimerized in a
reactor constructed of an 8.0 mm inside diameter stainless
steel tube. The reactor had a 10 cc reaction zone, an inlet
for reactants and an outlet for products. The reactor was
heated in a salt bath to give the desired reaction tempera-
ture. In ~eneral, the experimental method consisted of pre
reducing a supported metal oxide catalyst with hydrogen and
then passing a mixture of hydrogen and acrylonitrile over
the catalyst at 800F at one atmosphere total pressure.
Standard run conditions in all the examples unless otherwise
indicated comprised a feed rate of 40 STP cc/min. H2, 0.2
cc liquid acrylontrile per minute and a run time of 5
minutes. In a large number of runs, the used catalyst was
sulfided with a mixture of 15% H2S in H2 and a second run
was made with an acrylonitrile/hydrogen mixture.
In all runs, the off-gas was scrubbed in 11.0 cc
of acetone at ice temperature and an aliquot was analyzed by
~2S liquid chromotography and mass spectroscopy for the
degree of acrylonitrile conversion and the composition of
the converted product.
3L13L75q~
For the ?urDoses of th1s applicat~srl, the fol-
lo~ir,E definitions are used:
moles of acrYlni ri e reacted ~ 100
% Yield = moles of acrylonitrile converted to a s~ecific product x 100
moles of acrylonitrile reacted
The following experiments, some of which represent
the ~resent invention and others of which are outside the
scope of the invention and presented for the purposes of
comparison, were conducted:
Exam
An aqueous solution of NH4OH was added to an
aqueous copper nitrate solution to produce a preci~itate of
hydrous CuO. The precipitate was recovered, filtered,
washed, dried, crushed, screened, calcined and reduced at
800F in H2 to produce 9 to 40 mesh (Tyler) copper particles.
The reactor was charged with 3 cc of copper particles, and
the charge was ~ulfided by passing a 20% H2S in H2 stream
through the reactor for one hour at 800F. A total of 1.0
oc acrylonitrile was then fed through the reactor over a
period of fi~e minutes. Along with the acrylonitrile,
H2 was ~ed through the reactor at a rate of 40 STP cc/min.
The reaction temperature was maintained at 800F. The
reaction product was recovered and analyzed wlth the following
results:
acrylonitrile conversion = 0%
propionitrile yield = 0%
adiponitrile yield = 0,~
1,4-dicyanobutene-1 yield = 0%
1,4 dicyanobutene-2 yield = 0%
-12-
7~i49
_xam ~_
4 cc ~amma activated alumina having a surface area
of 180 to 200 m2/g and a particle size of 9 -to 40 rnesh ~as
fed .into the reactor and the reactor heated to a ternperature
o~ 800F. A gas mixture comprisiny 15% H2S in H2 was fed to
the reactor to effect sulfiding of the alumina catalyst.
After 15 minutes, acrylonitrile was also fed to the rèactor,
a total of 1 cc acrylonitrile being uniformly fed to the
reactor over a period of 5 minutes. The reaction product
10 was recovered and analyzed with the following results:
acrylonitrile conversion = 35.2%
propionitrile yield = 1.1%
adiponitrile yield = 0%
1,4-dicyanobutene-1 yield = 5.6%
1,4-dicyanobutene-2 yield = 0%
_ample 3
Example 2 was repeated except that the reactor was
charged with 4 cc of 14 to 2~ mesh (Tyler) Alundum ~ (Alcoa
T-61). The following results were obtained:
acrylonitrile conversion = 0%
propionitrile yield = 0%
adiponitrile yield = 0%
1,4-dicyanobutene-1 yield = 0%
1,4-dicyanobutene-2 yield = 0%
material balance 100%
Example 4
___ _
2.47 g. Co(NO3)2 6H20 was dissolved in S cc water,
and the solution obtained thereby was used to impregnate 5
- 13 -
5~9
,-c-a~s Or 9 ~o 4fS rr,esh activate~ r,ina having a surface
rea of 180 to 200 ~2/g The resultant corr.posite was dried
at 2 ~emDeratUre o~ 153C, heated in air for one hour at
500C and then c~ar~e~ into the reactor. ~2 was fed to the
reactor for a period of one hour at 800F to reduce the
cobalt in the composite. Thereafter, the com~osite was
sulfided by passing a mixture of 15% H2S in H2 ~hrough the
reactor for 30 minutes at 800F. The dimerization reaction
was accomplished by passing 1.0 cc acrylonitrile through the
reactor uniformly over a period of five minutes~ Along with
the acrylonitrile a carrier gas comprising 15% H2S in H2 was
fed to the reactor at a rate of 40-STP cc/min. The reaction
temperature was 800F. mhe reaction product was recovered
and the ~ollowing results were obta~ned:
acrylonitrile conversion =31.5%
propionitrile yield =13.8%
adiponitrile yield = 0%
1,4-dicyanobutene-1 yield =7.5%
1,4-dicyanobutene-2 yield = 0%
After completion of ~xample 4, the catalyst was
left in the reactor and stripped with H2 for one hour at
800F. After the stripping operation, 1.0 cc acrylonitrile
was fed to the reactor uniformly over a period of five
minutes. Along with the acrylonitrile, 40 STP cc/min H2 was
fed to the reactor. The reaction temperature was maintained
at 800F. The reaction product was r-ecovered and the
following results were obtained:
-14-
75~3
2crylon1lr le conversion = 12.9~
?ro?ionitrile yield ~ 35.5%
adiponitrile yield = 0
19 4-dicyanobutene-1 yield = 12.5~
1,4-dicyanobutene-2 yield a 0%
Exam~le 6
Example 4 was repeated except that the catalyst in
the reactor was not sub~ected to sulfiding condltions with
15% H2S in H2 after cobalt was reduced. Also, H2S was not
10 included in the carrier gas. The following results were
obtained:
acrylonitrile conversion = 5~.9%
propionitrile yield = 23. 8/o
adiponitrile yield = 0%
1,4-dicyanobutene-1 yield - 1.7%
1~4-dicyanobutene-2 yield = 0,0
Example_7
5.0 grams of 9 to 40 mesh (Tyler) high surface
area (180 to 200 m2~g~ gamma alumina particles were impreg-
nated with 0.97 grams P2o5~24MoO3~48H20 in sufficient amount
of water to ~us~ wet the surface of the alumina particles.
The alumina particles so impregnated were dried ~or two
hours at 150C and calcined in air at 500C for one hour
to yield activated alumina particles having thereon 9.1%
Mo in the ~orm of molydena. 3 cc of the catalyst were
charged into the reactor and sub~ected to hydrogen reduction
conditions at 800F for two hours. 1.0 cc acrylonitrile
was uniformly fed to the reactor over a period of five
minutes, H2 also being ~ed to the reactor during the reaction
-15-
~7~
at 40 STP cc/min. The reaction tem~erature ~las ~OO~F. The
reactlon product was recovered and the ~ollowing recults
were obtained:
acrylonitrile converslon = 49.0
pro~ionitrile yield ~ 58.5~
adiponi~rile yield ~ 0%
1,4-d~cyanobutene-1 yield = 2.0%
1,4-dicyanobutene-2 yield = 0%
Example 8
After the completion of Example 7, the catalyst in
the reactor was sulfided by passing 15~ H2S in H2 over the
catalyst for two hours at 800F. 1.0 cc acrylonitrile was
then fed to the reactor uniformly over a period of five
minutes, H2 at a rate of 40 STP cc/min also being fed to the
reactor during this period. The reaction temperature was
800F. The reaction product was recovered and the following
results were obtained:
acrylonitrile ccnversion = 70.1
propionitrile yield = 96.3~
adiponitrile yield = o%
1,4-dicyanobutene-1 yield = 2.3%
1,4-dicyanobutène-2 yield - 0%
The foregoing general procedure was repeated with
many di~ferent catalysts, and the results of these experi-
ments are set forth in the following Table 1. In most of
these experiments, a starting material comprising a support
and an amount of decomposable salt, decomposable hydroxide
-16-
or oxide thereon was first procluced, and then the starting
material was calcined in air at elevated temperakure so that
-the metal or metalloid was present in -the composite in oxide
form. The composite was then subjected to an atmosphere of
hydrogen at 800F to reduce the metal or metalloid oxide.
The catalyst so produced was used in a first dimerization
reaction. After completion of the first dimerization
reaction, the catalyst remaining in the reactor was subjected
to sulfiding with H2S at elevated temperature and used in a
second dimerization reaction. Unless-otherwise indicated in
Table 1:
-~ the catalyst support was 9 to 40 mesh, Tyler;
-- activated alumina was a gamma activated alumina
having a surface area of 180 to 200 m2/g;
-- activated carbon supports were about 10 mesh,
Tyler (Nitco ~3 Grade 718);
-- in those cases in which the support was silica,
the usual method of preparation was by forming
a solutior~ of decomposable metal salt in a
silica sol (Nalco ~ 1034 A), gelling with ammonium
nitrate and calcining the dry gel in air at a
temperature o~ 350 to 500C;
-- in those experiments in which the catalyst
contained more than one promoter and the
support was other than silica, the promotors
were applied individually by aqueous solution
in the order noted in the table, the composite
being dried after each promoter application;
!~
~i~75~
-- irl those exrseriments in which the catal~st
con~a~.~e~ ~ore than one pro~.oter and the sup~ort
was si.li.ca, an aqueous solution contalnin~
all Or the indicate~ lmpregnan~ materials was
made and mlxed ~ith a sllica sol, ~hich in
turn was gelled and dried as described above;
-- in the column labeled "Starting ~aterial1'
the indicated percent is the weight percent
of the metal or metalloid in the catalyst
ultimately obtained, with the weig~t of the
metal or metallold plus the wei~ht of the
support being taken as 100~ (for exam~le,
in Example 4 the catalyst ultimately produced
contained 9.1 weight % Co and 90.9 wei~ht ~0
A12O3);
-- calcination was done in air;
-- hydrogen reduction was done at 800~ with
100 mole percent H2i
-- the total amount of catalyst char~ed into
the reactor was 3 cc;
-- sulfiding of the catalyst wàs done at 800F
with a gas comprisin~ 15 mole percent H2S
and 85 mole percent H2;
-- a total of 1.0 cc liauld acrylonitrile was
fe~ to the reactor uniformly over a period
of flve minutes so that the acrylonitrile
feed rate was 0.2 cc/min;
--- 40 STP cc/min. H2 was also fed to the reactor
during the dimerization reaction; and
-- the ~ndicated percents ~or gases are mole
percents.
l7~
Also, in ~able 1 the fcllowing abbrcviations are
used:
"AN" reans 'acrylonitrile"
"propio" means "~ropionitrile"
"adipo" means "adiponitrile"
"1,4-~CB-l" means "1~4-dic~yanobutene-1"
"1,4-~CB-2" reans "1,4-dicyanobutene-2"
"succino" r.eans "succinonitrile"
"aceto" means "acetorlitrile"
"act" means "activated"
"TR" means "trace"
"RT" means - "retention time"
Also, the term "Ex 7 catalyst" as in, for example
Example ~, means "the catalyst obtained from Example 7 a~ter
the experiment of Example 7 was finished."
--19--
.
'g 9 ( !1 ~f O )
E t~
~ U
:rJ ~, 5
~ J~
~ . g oO O
~ O O O O O O C O C O
_l
l l O U~ C 1~
O
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t~j - 29a
7~'3
In many of t:he runs the yield fiyures fall far short
of totaling 100~. In these cases it rnay be assumed that losses
to gas and particularly coke were extensive. Chemical analysis
for yas and coke ~as not performed but rniCroscopiC exa~rlination
of spent catalysts confirmed the presence of carbon in cases of
low material balance.
From the foregoing examples it ca~ be seen that
catalysts comprising activated alumina which have been sulfided
so as to contain inorganic sulfide ion exhibit a significant
activity in the catalytic dimerization of acrylonitrile to
1,4-dicyanobutenes and adiponitrile. Moreover, it will further
be noted that in most instances sulfided activated alumina
catalysts containing a metal or metalloid promoter exhibit
catalytic activity superior to unsul~ided catalysts made from
the same support and promoter.
Although only a few embodiments of the present
invention have been specifically described above, it should be
appreciated that many additions and modifications can be made
without departing from the spirit and scope of the invention.
For example, it has been found that in some instances sulfiding
of the promoted or unpromoted activated alumina support to
produce the inorganic sulfide ion-containing catalyst used
in the inventive process can be conducted
- 30 -
75~
simul-taneously with rather than prior to the dimerization
reaction. In such instances, hydroyen sulfide, carbon
disulfide or other sulEiding gas as discussed above is
included in the carrier yas in sui-table amount (preferably
15%) and fed to the reac-tor along with acryloni-trile,
whereby the support is sulfided simultaneously with the
commencement of the dimerization reaction. This and all
other modifications are intended to be included within the
scope of the present invention, which is to be limited only
by the following claims:
- 31 -
