Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
BACKGROUND OF THE INVENTION
. ~atal~sts for the oxidation, ammoxldation and
oxvdeh~dro~enatlon Or olefins are well known. See t f~r
example, U.S. 3~642,930 and U. S. 3,414,631. Although
these catalysts of the art are very desirable, the ca$alysts
10~ of the present invention have significant advantages over
these other ~atalysts~
~ .
.,
SU~IARY AN3 DE~AIL~D DESCRIP~IO~ O~ THE I~ IO~J
The present lnvention is based on the discovery
~hat certain oxldztion catalysts based on iron, bismuth and
~olybde~um and contalnin~ additiona~ speclfied promoter
elements exhiblt excellent catalytic activlty for a variety
o~ ole~ln oxidatlon, ammoxldatlon, dehydrogenation and
oxydehydrogenatlon reactlons. In particular, lt has been
round that speci~ic catalytlc compositions as descrlbed
`
~ ~ 3 ~ (5-_7~
below are es~e~i211y suited for use in prcducln~ acr~'-o-
nitrile and m~thacrylonitrlle by the amms~ld2tion Or propyl-
ene and isobutylene, resDectively. In addition to being
excellent am~oxidation ca~alysts for the production of
acrylonitrile or methacrylonitrile, these catalysts aiso
exhibit excellent catalytic activity for the conversion of
olerins having four or more contiguous carbon 2toms to the
corresponding dioiefins, and in the oxydehydro~enatior. of
ole~ins to diolefins.
l~ In accordance with the present invention, novel
catalysts having improved catalytic propert~es are repre-
sented by the following empirical formula
a~b7~cFe~DeMol2ox
wherein J is an alkali metal, thallium, silver or
mixtures thereof;
Q is ~o, Ni, Zn, Cd, Be, r~, Ca, Sr, Ba, ~a
or mixtures thereof;
Z is a two-or-more element system selected
from the group consisting o~ ~7e T Sb, Cu + W~
Cu + Sn, Ce + W, Pr + ~n, Sn + r'n, ~'r + t~
W + Sb, Cr ~ Sn, W + Sn, Ge + Sn, Sb + Sn,
W ~ P, Sb ~ P, Cr + Cu, Mn + Cu, Sb + Cu,
~n + P or mlxtures thereof, with the proviso
that said catalyst is free of Tl ~then Z is
Mn + P;
C ~ is Bi or Te; and
wherei~ a is 0.01 to 5
b is 0~1 t~ 20
c is 0.1 to ~0
d is 0.1 to 20
e ls 0.1 to 20; and
x ls a value such that the valence requlre-
ment of the elements in the catalyst for
oxy~en are satisfied.
Tn this catalyst compositlon, the Z comDonent is
com?osed of systems o~ two or more speclried elements. In
these systems as described above, each element of the system
is present ir. an amount of at least l atom percent, pre~er-
-2-
: -- (5~27~
ably at least 5 a'om percent, based on the atoms in the
I particular system selected. In this ca~alyst, ~ is prefer-
ably Bi.
Preferably, the catalysts of this invention con-
tains the above-indicated elements in the following amounts:
a is 0.01 to 0.5,
b is 0.1 to 20,
:~ c is 0.1 to 9,
d is 0.1 to 20, and
e is 0.1 to 20.
Optimally the elements are present in the following amourlts:
a is 0.03 to 0.5,
b is 4 to 10,
c is 0.5 to 7,
d is 0.5 to 5, and
e is 0.5 to 5.
In a particularly preferred embodiment, the fore-
: going preferred and optimal catalysts contain K. Rb and/or
~; Cs and optionally r~i and/or Co.
-.~ 20 Also, lt is desirable if Z is selected so that the
C ratio of the amount of ~he first element of each system as
described above to the amount of second element in the
sy3tem is 1:0.25 to 1:0.75.
Of the foregoing catalysts, catalyst in which the
Z component ls selected from the following combinations of
elements are of special interest: Ge + Sb, Cu + W, Cu + Sn,
Ce + W, Pr + Mn, Sn + Mn and Mn + W; while those catalysts
in which Z is one of Ge + Sb, Cu + W, Cu + Sn, Ce I W and Pr
- f Mn are particularly noteworthy.
3 ~he catalysts of this invention can be prepared in
any conventional manner known in the art, such as ~or
example the various techniques shown in the patents and
-3- .
~,~27
applications referred to in the 3ACXGROU~IJ~ OF T:i~ IN~_}TQI5l7~
~or exam?le, the catalysts can be made by ~orming an aqueou-
com~osition of decomposable salts and/or oxides of the
metals to be incorporated into the catalyst, evapora inO the
water from the aqueous composition to form ~ thick pas~e,
drying the thick paste and then calcining the thick ~as e at
elevated temperature in an oxidizing atmosphere. mechniques
for forming catalysts of the type described herein are well
Xnown in the art, and those skilled in the art should have
no difficulty in making catalysts of the invention.
The catalysts of the present invention may be used
unsup~orted or supported on various conventional carriers
such as SiO2, A1203, 7r~2~ T~02~ ~ 4
morillonite, or the like. They may be used in fixed-bed or
fluid-bed reactors as desired. When using these catalysts,
they are simply substituted for the catalysts previously
employed, and the reaction is conducted under substantially
the same conditions.
For example~ when the inventive catalysts are used
in the ammoxidation o~ propylene or isobutylene to form
acrylonitrile or methacrylonitrile, respectively, the olefin
C to be reacted together with oxygen and ammonia in conven-
tlonal proportions are contacted with the catalyst at an
elevated temperature, usually about 200-60ac, in a ~ixed or
fluid-bed reactor for a time sufficient to e~fect the
appro~riate ammoxidation reaction. Similarly, when the
inventive catalysts are employed to catalyze other well
known reactions, the reaction conditions employed are those
which are conventional.
SPECIFIC EMBODIMENTS
Comparat~ve E~amDle A
80~ Ko lNi2 sC4 sFe33iPo.5M0l20x 2
. .
A sol~tion of 127.1 g. ammonium heptamolybd2te
~ 4)6r~io7~24-4.~20 2nd wa er W25 prepa~ed. To tnis solut~on
w2s added 6.9 b of a 42.5~ solutlon of H3PO4 and 102.7 g.
of ~lco 40~ silica sol to form a slu~ry. Serarately, an
aqueous solu~ion containing 72.7 g. ferric nitra'e, ~e(~!03)~ -
9~2i 29.1 g. bismuth nitrate, Bi~N03)3 5.~20: 78-6 g. cobalt
nitrate Co(.~03)2 c:~20; 43.6 g. nickel nitrate ~ 03)2-~.2C:
and 6.1 g. of a 10~ potass~um nitrate solution was orep2red.
The solution of metal nitrates was slowly added tc the
slurry. The resulting slurry was evaporated to dryness, and
the solid obtzined was heat treated at 290C for three
hours, at 425C for three hours and at 550C for 16 hou~s.
Examrles 1 to 7
In the same manner as discussed in Compara~ive
Example A, catalysts listed in the following ~ABLE I were
prepared. Each of these catalysts as well as Comparative
Catalyst A W2S tested for its catalytic activity in the
ammoxidation of propylene to acrylonitrile. In carrying out
this test, each of the catalysts was charged into a 5 cc.
flxed-bed reactor. A reed of propylene/ammonia/oxygen/
nitrogen/steam in amounts of 1.8/2.2/3.6/2.4/6 was fed to
the reactor such that the l~WH was 0.1 g. propylene per gram
; catalyst per hour and the contact time was three seconds.
The reaction tem~erature was maintained at 420C. lhe
results obtained as well as the results obtained when
Comparative Catalyst A was employed was se~ forth in the
; following TABLE I.
. ~
u
-~
u~ * ;:
~ C~
c r~
~O
0
h
~ e ~ o o
_1 tO ~ 0~) C~ ~ ~ ~ r~
r~ ~ I` X O` I` I~ r~
u
C cO~
Y
.~ .
^l
O~ J
,/ X ^ ^ ^ ^ ,_ ~ ~
O X ~
C
e o 9 1:~
G ,.,
u C~ .
LJ O U~
9 0 G O
~ ~ ~ O O
Ei C~
O _, o u~
C; ~r, ~; ~ 0
. ~ _I
U~ 0 ~ Z _
C ~
t~ C
v u . ~ ~ ~' ~
e
Z . . . ~ C ~
~ --I ~O O O ~ C . U
O 3 c~ 3 3 ~ E: o "~
~, Y ~ C~ c4 ~ E
w
~1
C~ ¢
= ~.
s~ _ ~
X ~
0~73
The parentheses used in -TABLE I as well as tAe follo~,Ji~g
TABLr TI have no signific2nce other than to clarlry the
difference betwe-n the various catalysts.
_xam~les 8 to lQ
.
Using the various catalysts prepared in the m_nner
described above, additional examples in which propylene was
ammoxidized to acrylonitrile were conducted. These addi-
tional experi~ents were conducted in accordance with the
same procedure used in F.xamples 1 to 7, except that the
reaction temDerature was 430~ the contact time was 6
seconds and the catal,yst support was 50~ Si~2. The results
obtained are set forth in the following TABLE II.
c
~ t3,~
.j_,
U~ *
. ~ ~ o
r~ 0
.~.j
cl
0
P~
C;
~ ~o ~J o o o 5~
0 ~ 0 0 4
~rl L r~ I~I~ C~ Cl? --
U
'~ C
: o G
: .
e
,
X ^ ~ 'I
: ~ OX cX C~l ~
O C X ~
V ~ ~ . ~
.,, V o o . -
O o .~ ~' 0
C C~
ci _i CJ
U V:
' V V U~ U~ .z
U~ ~ ~-
;` C C
~, ~,
U~ ~ . o
' ~ ~ . K", ,
31 c c o
X 0~ 0-- C~
W ~ *
