Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2003-03-17
2004-09-21
Nguyen, Cam N. (Department: 1754)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C562S531000, C562S532000, C562S534000, C502S104000, C502S110000, C502S111000, C502S113000, C502S117000, C502S311000, C502S312000, C502S318000, C502S321000
Reexamination Certificate
active
06794539
ABSTRACT:
The present invention relates to a process for preparing multimetal oxide compositions employed as active composition of catalysts, in particular for the catalytic oxidation of organic compounds in the gas phase, to the multimetal oxide compositions obtainable by means of this process and to a process for preparing acrylic acid using catalysts comprising these multimetal oxide compositions as active composition.
Multimetal oxide compositions containing delineated regions of a promoter phase whose chemical composition is different from its surroundings are known. They are prepared by separately preforming one or more promoter phases in finely divided form and mixing them with sources of the elemental constituents of a host phase. The mixture is then dried if appropriate and calcined. Thus, DE 198 15 281 and EP 0 756 894 state that (a) separately preformed promoter phase(s) can be mixed either dry or wet with the sources of the elemental constituents of the host phase. One possibility is thus to mix the separately preformed promoter phase dry with finely divided starting compounds of the host phase in the desired molar ratio in a mixer, kneader or in a mill. Alternatively, the separately preformed promoter phase can be stirred into an aqueous solution and/or suspension of starting compounds of the host phase and this mixture can subsequently be spray dried.
BACKGROUND OF INVENTION
It has been found that the known production processes are unsatisfactory, in particular for the industrial production of large quantities of catalyst. Thus, the dry mixing of the preformed promoter phase with the starting compounds of the host phase achieves only unsatisfactory mechanical bonding of the phases with one another. On the other hand, stirring the separately preformed promoter phase into an aqueous solution and/or suspension of the elemental constituents of the host phase makes it difficult to achieve a uniform distribution in the host phase because of the high density of the preformed promoter phase. Furthermore, the crystallites of the preformed promoter phase tend to be partly dissolved when stirred into an aqueous solution and/or suspension, particularly when allowed to stand for a prolonged period, as is unavoidable in the processing of large quantities, which blurs the phase boundary and leads to impaired catalyst performance.
SUMMARY OF INVENTION
It is an object of the present invention to provide a process for preparing multimetal oxide compositions comprising a host phase and at least one phase different from the host phase dispersed therein, which process does not have the abovementioned disadvantages. A further object of the invention is to provide a process for preparing multimetal oxide compositions which display improved selectivity in respect of the formation of acrylic acid when used as catalysts for the oxidation of acrolein.
We have found that this object is achieved by a process for preparing multimetal oxide compositions of the formula I
[A]
p
[B]
q
[C]
r
(I),
where A is a phase having the composition
Mo
12
V
a
X
1
b
X
2
c
X
3
d
X
4
e
X
5
f
X
6
g
O
x
,
B is a phase having the composition
X
7
1
Cu
h
H
i
O
y
and C is a phase having the composition
X
8
1
Sb
j
H
k
O
z
where the variables have the following meanings:
X
1
: W, Nb, Ta, Cr and/or Ce, preferably W, Nb and/or Cr,
X
2
: Cu, Ni, Co, Fe, Mn and/or Zn, preferably Cu, Ni, Co and/or Fe,
X
3
: Sb and/or Bi, preferably Sb,
X
4
: Li, Na, K, Rb, Cs and/or H, preferably Na and/or K,
X
5
: Mg, Ca, Sr and/or Ba, preferably Ca, Sr and/or Ba,
X
6
: Si, Al, Ti and/or Zr, preferably Si, Al and/or Ti,
X
7
: Mo, W, V, Nb and/or Ta, preferably Mo and/or W,
X
8
: Cu, Ni, Zn, Co, Fe, Cd, Mn, Mg, Ca, Sr and/or Ba, preferably Cu and/or Zn, particularly preferably Cu,
a: 1 to 8, preferably from 2 to 6,
b: 0.2 to 5, preferably from 0.5 to 2.5,
c: 0 to 23, preferably from 0 to 4,
d: 0 to 50, preferably from 0 to 3,
e: 0 to 2, preferably from 0 to 0.3,
f: 0 to 5, preferably from 0 to 2,
g: 0 to 50, preferably from 0 to 20,
h: 0.3 to 2.5, preferably from 0.5 to 2, particularly preferably from 0.75 to 1.5,
i: 0 to 2, preferably from 0 to 1,
j: 0.05 to 50, preferably from 0.2 to 20, particularly preferably from 0.2 to 5,
k: 0 to 50, preferably from 0 to 20, particularly preferably from 0 to 12,
x,y,z: numbers selected so that each phase is electrically neutral, and
p,q: positive numbers,
r: 0 or a positive number,
where the ratio p/(q+r)=20:1 to 1:20, preferably 5:1 to 1:14, and, when r is a positive number, the ratio q/r=20:1 to 1:20, preferably from 4:1 to 1:4, which comprises
i) preforming the phase B and optionally C in finely divided form,
ii) preparing a plastically deformable precursor composition for the phase A, and
iii) dispersing the preformed phase B and optionally C in the precursor composition for the phase A and drying and calcining the composition.
The term “phase” used for the purposes of the present invention refers to three-dimensional regions whose chemical composition is different from their surroundings. The phases are not necessarily X-ray-crystallographically homogeneous. In general, the phase A forms a continuous phase in which the particles of the phase B and optionally C are dispersed.
The finely divided phases B and optionally C advantageously comprise particles whose largest diameter, i.e. the longest line going through the center of gravity of the particle and connecting two points on the surface of the particle, is up to 300 &mgr;m, preferably from 0.1 to 200 &mgr;m, particularly preferably from 0.5 to 50 &mgr;m and very particularly preferably from 1 to 30 &mgr;m. However, particles having a largest diameter of from 10 to 80 &mgr;m or from 75 to 125 &mgr;m are also suitable.
In principle, the phases A, B and C in the multimetal oxide compositions prepared according to the present invention can be amorphous and/or crystalline. It is advantageous for the phase B to consist of crystallites of oxo metalates or comprise oxo metalate crystallites which have the X-ray diffraction pattern and thus the crystal structure type of at least one of the following copper molybdates. The place where the associated X-ray diffraction fingerprint is recorded is given in brackets.
Cu
4
Mo
6
O
20
[A. Moini et al., Inorg. Chem. 25 (21) (1986) 3782-3785],
Cu
4
Mo
5
O
17
[record card 39-181 of the JCPDS-ICDD card index (1991)],
&agr;-CuMoO
4
[record card 22-242 of the JCPDS-ICDD card index (1991)],
Cu
6
Mo
5
O
18
[record card 40-865 of the JCPCS-ICDD card index (1991)],
Cu
4−x
Mo
3
O
12
where x=0 to 0.25 [record card 24-56 and 26-547 of the JCPCS-ICDD card index (1991)],
Cu
6
Mo
4
O
15
[record card 35-17 of the JCPDS-ICDD card index (1991)],
Cu
3
(MoO
4
)
2
(OH)
2
[record card 36-405 of the JCPDS-ICDD card index (1991)],
Cu
3
Mo
2
O
9
[record card 24-55 and 34-637 of the JCPDS-ICDD card index (1991)],
Cu
2
MoO
5
[record card 22-607 of the JCPDS-ICDD card index (1991)].
The phase B preferably comprises oxo metalates which have the X-ray diffraction pattern and thus the crystal structure type of the following copper molybdate:
CuMoO
4
-III having a wolframite structure as described in Russian Journal of Inorganic Chemistry 36 (7) (1991) 927-928, Table 1.
Among these, preference is given to those having the stoichiometry II below:
CuMo
A
W
B
V
C
Nb
D
Ta
E
O
y
.(H
2
O)
F
(II)
where
1/(A+B+C+D+E): 0.7 to 1.3, preferably from 0.85 to 1.15, particularly preferably from 0.95 to 1.05 and very particularly preferably 1,
F: 0 to 1,
B+C+D+E: 0 to 1, preferably from 0 to 0.7, and
y a number determined by the valence and abundance of the elements different from oxygen.
Particular preference is given to compounds of this type which have the stoichiometry III, IV or V:
CuMo
A
W
B
V
C
O
y
(III)
where
1/(A+B+C): 0.7 to 1.3, preferably from 0.85 to 1.15, particularly preferably from 0.95 to 1.05 and very particularly
Arnold Heiko
Felder Raimund
Petzoldt Jochen
Unverricht Signe
BASF - Aktiengesellschaft
Nguyen Cam N.
LandOfFree
Method for producing multiple-phase multi-metal oxide materials does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing multiple-phase multi-metal oxide materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing multiple-phase multi-metal oxide materials will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3215684