Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2000-10-05
2004-09-28
Nguyen, Cam N. (Department: 1754)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C562S534000, C562S535000, C502S104000, C502S110000, C502S113000, C502S117000, C502S255000, C502S305000, C502S306000, C502S307000, C502S308000, C502S309000, C502S310000, C502S311000, C502S312000, C502S313000, C502S314000, C502S315000, C502S316000, C502S317000, C502S318000, C502S321000, C502S322000, C502S323000, C502S335000, C502S337000
Reexamination Certificate
active
06797839
ABSTRACT:
The present invention relates to multimetal oxide materials of the formula I
(A)
p
(B)
q
(I),
where
A is 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 X
7
1
Sb
h
H
i
O
y
,
X
1
is W, Nb, Ta, Cr and/or Ce, preferably W, Nb and/or Cr,
X
2
is Cu, Ni, Co, Fe, Mn and/or Zn, preferably Cu, Ni, Co and/or Fe,
X
3
is Sb and/or Bi, preferably Sb,
X
4
is Li, Na, K, Rb, Cs and/or H, preferably Na and/or K,
X
5
is Mg, Ca, Sr and/or Ba, preferably Ca, Sr and/or Ba,
X
6
is Si, Al, Ti and/or Zr, preferably Si, Al and/or Ti,
X
7
is Ni and, if required, one or more of the elements selected from the group consisting of Cu, Zn, Co, Fe, Cd, Mn, Mg, Ca, Sr and Ba,
a is 1 to 8, preferably from 2 to 6,
b is 0.2 to 5, preferably from 0.5 to 2.5,
c is 0 to 23, preferably from 0 to 4,
d is 0 to 50, preferably from 0 to 3,
e is 0 to 2, preferably from 0 to 0.3,
f is 0 to 5, preferably from 0 to 2,
g is 0 to 50, preferably from 0 to 20,
h is 0.1 to 50, preferably from 0.2 to 20, particularly preferably from 0.2 to 5,
i is 0 to 50, preferably from 0 to 20, particularly preferably from 0 to 12,
x and y are each numbers which are determined by the valency and frequency of the elements in (I) other than oxygen and
p and q are each numbers which differ from zero and whose ratio p/q is from 20:1 to 1:80, preferably from 10:1 to 1:35, particularly preferably from 2:1 to 1:3,
which contain the moiety (A)p in the form of three-dimensional regions A having the chemical composition
A: Mo
12
V
a
X
1
b
X
2
c
X
3
d
X
4
e
X
5
f
X
6
g
O
x
and the moiety (B)q in the form of three-dimensional regions B having the chemical composition
B: X
7
1
Sb
h
H
i
O
y
,
the regions A, B being distributed relative to one another as in a mixture of finely divided A and finely divided B, with the proviso that, for the preparation of the multimetal oxide materials (I), at least one separately preformed oxometallate B,
X
7
1
Sb
h
H
i
O
y
,
is present, which is obtainable by preparing a dry blend from suitable sources of the elemental constituents of the oxometallate B which contain at least a part of the antimony in oxidation stage +5 and calcining said dry blend at from 200 to <600° C., preferably from 200 to ≦580° C. particularly preferably from 250 to ≦550° C.
The present invention furthermore relates to processes for the preparation of multimetal oxide materials (I) and their use as catalysts for the gas-phase catalytic oxidation of acrolein to acrylic acid.
WO 96/27437 relates to multimetal oxide materials which contain the elements Mo, V, Cu and Sb as essential components and whose X-ray diffraction pattern has the line of strongest intensity at a 2&thgr; value of 22.2°. WO 96/27437 recommends these multimetal oxide materials as suitable catalysts for the gas-phase catalytic oxidation of acrolein to acrylic acid. Furthermore, WO 96/27437 recommends using Sb
2
O
3
as an antimony source for the preparation of these multimetal oxide materials. Prior preparation of an Sb-containing component is not disclosed in WO 96/27437.
EP-B 235760 relates to a process for the preparation of Sb, Mo, V and/or Nb-containing multimetal oxide materials which are suitable as catalysts for the gas-phase catalytic oxidation of acrolein to acrylic acid. EP-B 235760 recommends using an antimony prepared beforehand and calcined at from 600 to 900° C. as an antimony source for the preparation of these multimetal oxide materials.
The disadvantage of the multimetal oxide materials of the prior art is that, when they are used as catalysts for the gas-phase catalytic oxidation of acrolein to acrylic acid, their activity and the selectivity of the acrylic acid formation are not completely satisfactory.
It is an object of the present invention to provide novel multimetal oxide materials which, when used as catalysts for the gas-phase catalytic oxidation of acrolein to acrylic acid, have the disadvantages of the catalysts of the prior art to a reduced extent, if at all.
We have found that this object is achieved by the multimetal oxide materials (I) defined at the outset.
Very particularly preferred materials (I) are those whose regions A have a composition of the following formula (II)
Mo
12
V
a
,X
1
b
,X
2
c
,X
5
f
,X
6
g
,O
x
, (II),
where
X
1
is W and/or Nb,
X
2
is Cu and/or Ni,
X
5
is Ca and/or Sr,
X
6
is Si and/or Al,
a′ is from 2 to 6,
b′ is from 0.5 to 2.5,
c′ is from 0 to 4,
f′ is from 0 to 2,
g′ is from 0 to 2 and
x′ is a number which is determined by the valency and frequency of the elements in (II) other than oxygen.
It is also advantageous if at least one of the moieties (A)
p
, (B)
q
of the novel multimetal oxide materials (I) is contained in the latter in the form of three-dimensional regions having the chemical composition A or B, respectively, the maximum diameters d
A
and d
B
, respectively, of which regions (longest connecting line between two points present on the surface (interface) of the region and passing through the center of gravity of the region) are from >0 to 300 &mgr;m, preferably from 0.01 to 100 &mgr;m, particularly preferably from 0.05 to 50 &mgr;m, very particularly preferably from 0.05 to 20 &mgr;m.
Of course, the maximum diameters can also be from 0.05 to 1.0 &mgr;m or from 75 to 125 &mgr;m (the experimental determination of the maximum diameters permits, for example, a microstructure analysis by means of a scanning electron microscope (SEM)).
As a rule, the moiety (B)
q
is present in the multimetal oxide materials according to the invention essentially in crystalline form, i.e. as a rule the regions B essentially comprise small crystallites whose maximum dimension is typically from 0.05 to 20 &mgr;m. However, the moiety (B)
q
can of course also be present in amorphous and/or crystalline form.
Particularly preferred multimetal oxide materials are those whose regions B essentially comprise crystallites which have the trirutile structure type of &agr;- and/or &bgr;-copper antimonate CuSb
2
O
6
. &agr;-CuSb
2
O
6
crystallizes in a tetragonal trirutile structure (E. -O. Giere et al., J. Solid State Chem. 131 (1997) 263-274), whereas &bgr;-CuSb
2
O
6
has a monoclinically distorted trirutile structure (A. Nakua et al., J. Solid State Chem. 91 (1991) 105-112 or reference diffraction pattern in index card 17-284 in the JCPDS-ICDD index 1989). Regions B which are also preferred are those which have the pyrochlore structure of the mineral partzite, a copper antimony copper hydroxide, having the variable composition Cu
y
Sb
2-x
(O, OH, H
2
O)
6-7
(y≦2.0≦x≦1) (B. Mason et al., Mineral. Mag. 30 (1953) 100-112 or reference pattern in index card 7-303 of the JCPDS-ICDD index 1996).
Furthermore, the regions B may consist of crystallites which have the structure of copper antimonate Cu
9
Sb
4
O
19
(S. Shimada et al., Chem. Lett. 1983, 1875-1876 or S. Shimada et al., Thermochim. Acta 133 (1988) 73-77 or reference pattern in index card 45-54 of the JCPDS-ICDD index) and/or the structure of Cu
4
SbO
4.5
(S. Shimada et al., Thermochim. Acta 56 (1982) 73-82 or S. Shimada et al., Thermochim. Acta 133 (1988) 73-77 or reference pattern in index card 36-1106 of the JCPDS-ICDD index).
Of course, the regions B may also consist of crystallites which are a mixture of the abovementioned structures.
The novel materials (I) are obtainable in a simple manner, for example by first separately preforming oxometallates B
X
7
1
Sb
h
H
i
O
y
,
in finely divided form as starting material 1. The oxometallates B can be prepared by preparing a preferably intimate, advantageously finely divided dry blend from suitable sources of their elemental constituents and calcining said dry blend at from 200 to 1200° C., preferably from 200 to 850° C., particularly preferably from 250 to <600° C., frequently is ≦550° C. (as a rule for from 10 minutes to several hours). All that is essential to the invention is that at least a part of the oxometallates B of the starting material 1 (referred to below as oxometallates B*) is obtainable by preparing a preferably intimate,
Hibst Hartmut
Unverricht Signe
BASF - Aktiengesellschaft
Nguyen Cam N.
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