Multimetal cyanide compounds

Details Multimetal cyanide compounds Multimetal cyanide compounds

2002-08-28

2004-07-20

Wood, Elizabeth D. (Department: 1755)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Inorganic carbon containing

C502S200000

Reexamination Certificate

active

06764978

ABSTRACT:

The invention relates to multimetal cyanide compounds which can be employed in particular as catalysts for the ring-opening polymerization of alkylene oxides, to a process for their preparation and to the use thereof as catalysts for the polymerization of alkylene oxides.
Multimetal cyanide catalysts, also referred to as DMC catalysts, are efficient catalysts for preparing polyetherols by ring-opening polymerization of alkylene oxides. Products of this type are used in industry for example as starting materials for preparing polyurethanes by reaction with polyisocyanates, as surface-active compounds or as base oils.
It is possible by using multimetal cyanide compounds as catalysts to prepare polyether alcohols with a reduced content of unsaturated byproducts. In addition, the rate of the addition of the alkylene oxides is distinctly higher compared with conventional basic catalysts, and thus the utilization of plants is distinctly greater.
The DMC catalysts also have disadvantages, however. Thus, initiation of the reaction may be retarded at the start of the reaction. This retardation is also frequently referred to as the induction period. A further disadvantage is the formation of very high molecular weight fractions in the polyether alcohol. These high molecular weight fractions may have very disadvantageous effects during the further processing to polyurethanes.
One possibility for overcoming these disadvantages is to improve the DMC catalysts. A large number of structures of DMC catalysts is described in the prior art.
WO 99/16775 describes crystalline monoclinic DMC catalysts which have higher catalytic activity than the amorphous DMC catalysts preferred until then. It has, however, emerged that these catalysts also have an induction period which is too long.
It is an object of the present invention to provide crystalline DMC catalysts which are distinguished by increased catalytic activity and with which, on use for the polymerization of alkylene oxides, the induction period is distinctly reduced.
We have found that this object is achieved by DMC catalysts which comprise at least 10% by weight of a crystalline monoclinic multimetal cyanide compound whose X-ray diffractogram shows sharp reflections at least at the d values of
11.4 ű0.5 Å
8.9 ű0.5 Å
6.3 ű0.5 Å
5.8 ű0.5 Å
5.5 ű0.5 Å
4.5 ű0.5 Å
4.4 ű0.5 Å
3.9 ű0.5 Å
3.7 ű0.5 Å
3.4 ű0.5 Å
and have a particularly high catalytic activity, and addition of alkylene oxides using such catalysts shows only a short induction period.
The invention accordingly relates to DMC catalysts which comprise at least 10% by weight, based on the weight of the DMC catalysts, of a crystalline multimetal cyanide compound whose X-ray diffractogram shows sharp reflections at least at the d values of
11.4 ű0.5 Å
8.9 ű0.5 Å
6.3 ű0.5 Å
5.8 ű0.5 Å
5.5 ű0.5 Å
4.5 ű0.5 Å
4.4 ű0.5 Å
3.9 ű0.4 Å
3.7 ű0.4 Å
3.4 ű0.4 Å.
The invention further relates to a process for preparing the DMC catalysts of the invention, and to the use thereof as catalysts for polymerizing alkylene oxides.
The X-ray diffractograms were determined at a wavelength of 1.5406Å at room temperature. The other multimetal cyanide compounds of the DMC catalysts of the invention may be crystalline or amorphous, preferably crystalline. They are, in particular, multimetal cyanide compounds having the same molecular formula as the multimetal cyanide compounds having the structure described above. In a particular embodiment of the invention, the other multimetal cyanide compounds are crystalline and monoclinic.
The DMC catalysts may also consist completely of the multimetal cyanide compound defined above. When the content of the multimetal cyanide compound characterized in detail above is below 10% by weight, the beneficial effect of the compound on the catalytic properties of the DMC catalysts is detectible to only a very small extent.
In an advantageous embodiment of the DMC catalysts of the invention, the multimetal cyanide compound characterized in detail above exhibits a triclinic crystal system. The unit cell of this triclinic crystal system preferably has the following lattice parameters:
a=13.3 ű0.5 Å
b=13.3 ű0.5 Å
c=9.3 ű0.5 Å
á=98.4°±1°
â=99.9°±1°
ã=116.2°±1°
In a particularly preferred embodiment of the DMC catalysts of the invention, the triclinic multimetal cyanide compounds show the following reflections:
11.4 ű0.5 Å
8.9 ű0.5 Å
6.3 ű0.5 Å
5.8 ű0.5 Å
5.5 ű0.5 Å
4.5 ű0.5 Å
4.4 ű0.5 Å
3.9 ű0.4 Å
3.7 ű0.4 Å
3.5 ű0.5 Å
3.4 ű0.4 Å
3.1 ű0.4 Å
2.9 ű0.3 Å
2.41 ű0.09 Å
2.37 ű0.09 Å
2.31 ű0.09 Å
2.25 ű0.09 Å.
The multimetal cyanide compounds of the invention preferably have the general formula (I)
M
1
a
[M
2
(CN)
b
(A)
c
]
d
.fM
1
g
X
n
.h(H
2
O).eL.kP  (I),
where
M
1
is a metal ion selected from the group comprising Zn
2+
, Fe
2+
, Co
3+
, Ni
2+
, Mn
2+
, Co
2+
, Sn
2+
, Sn
4+
, Pb
2+
, Mo
4+
, Mo
6+
, Al
3+
, V
4+
, V
5+
, Sr
2+
, W
4+
, W
6+
, Cr
2+
, Cr
3+
, Cd
2+
, Cu
2+
, La
3+
,
M
2
is a metal ion selected from the group comprising Fe
2+
, Fe
3+
, Co
2+
, Co
3+
, Mn
2+
, Mn
3+
, Ni
2+
, V
4+
, V
5+
, Cr
2+
, Cr
3+
, Rh
3+
, Ru
2+
, Ir
3+
,
and M
1
and M
2
are different,
A is an anion selected from the group comprising halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate or nitrate,
X is an anion selected from the group comprising halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate or nitrite (NO
2
−
), and the uncharged species CO, H
2
O and NO,
L is a water-miscible ligand selected from the group comprising alcohols, aldehydes, ketones, ethers, polyethers, esters, polyesters, polycarbonate, ureas, amides, nitrites and sulfides or mixtures thereof,
P is an organic additive selected from the group comprising polyethers, polyesters, polycarbonates, polyalkylene glycol sorbitan esters, polyalkylene glycol glycidyl ethers, polyacrylamide, poly(acrylamide-co-acrylic acid), polyacrylic acid, poly(acrylamide-co maleic acid), polyacrylonitrile, poly(alkyl acrylates), poly(alkyl methacrylates), polyvinyl methyl ethers, polyvinyl ethyl ethers, polyvinyl acetate, polyvinyl alcohol, poly-N-vinylpyrrolidone, poly(N-vinylpyrrolidone-co-acrylic acid), polyvinyl methyl ketone, poly(4-vinylphenol), poly(acrylic acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic acid and maleic anhydride copolymers, hydroxyethylcellulose, polyacetates, ionic surface-active compounds, bile acid or salts, esters or amides thereof, carboxylic esters of polyhydric alcohols and glycosides,
and
a, b, d, g and n are integral or fractional numbers greater than zero,
c, f, e, h and k are integral or fractional numbers greater than or equal to zero,
where
a, b, c, and d, and q and n, are selected so that electrical neutrality is ensured.
For preference, f and k may be zero only if c is not zero and A is exclusively carboxylate, oxalate or nitrate.
The multimetal cyanide compounds of the invention are prepared by combining an aqueous solution of a cyanomet

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