Polymerizing alkylene oxide with sound or radiation treated DMC

Details Polymerizing alkylene oxide with sound or radiation treated DMC Polymerizing alkylene oxide with sound or radiation treated DMC

2001-08-31

2003-07-22

Sellers, Robert E. L. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From heterocyclic reactant containing as ring atoms oxygen,...

C502S104000, C502S111000

Reexamination Certificate

active

06596842

ABSTRACT:

The present invention relates to a process for polymerization alkylene oxides with the help of a double metal cyanide complex catalyst, to a process for treating double metal cyanide complex catalyst and to a double metal cyanide complex catalyst per se.
BACKGROUND OF THE INVENTION
Double metal cyanide (DMC) compounds are well known catalysts for epoxide polymerization, i.e. for polymerizing alkylene oxides like propylene oxide and ethylene oxide to yield poly(alkylene oxide) polymers, also referred to as polyether polyols. The catalysts are highly active, and give polyether polyols that have low unsaturation compared with similar polyols made using strong basic catalysts like potassium hydroxide. Besides for the preparation of polyether polyols the catalysts can be used to make a variety of polymer products, including polyester polyols and polyetherester polyols. The polyols can be used for preparing polyurethanes by reacting them with polyisocyanates under appropriate conditions. Polyurethane products that can be made include polyurethane coatings, elastomers, sealants, foams, and adhesives.
Although highly active catalysts can be prepared with the help of the prior art processes, there still is interest in increasing the activity further.
SUMMARY OF THE INVENTION
It has now surprisingly been found that the activity of DMC catalysts can be increased further by treating the catalyst with sound waves and/or electromagnetic radiation.
Therefore, the present invention relates to a process for polymerization of alkylene oxides, which process comprises polymerising alkylene oxide in the presence of a double metal cyanide complex catalyst and a hydroxyl group-containing initiator, at least part of which double metal cyanide complex catalyst has been treated with sound waves and/or electromagnetic radiation.
Further, the present invention relates to a process comprising treating a double metal cyanide complex catalyst with sound waves and/or electromagnetic radiation, and to a catalyst containing a double metal cyanide complex, which catalyst has been treated with sound waves and/or electromagnetic radiation.
Sound waves include not only waves having a frequency which can be heard, but also waves having either a higher or a lower frequency.
DETAILED DESCRIPTION OF THE INVENTION
As mentioned above, DMC catalysts are well known in the art. It has been found that in principle any DMC catalyst can be used in the present invention.
Generally, DMC catalysts prepared according to the prior art and suitable for use in polymerization of alkylene oxides, exhibits a powder x-ray diffraction pattern exhibiting no detectable signals corresponding to highly crystalline zinc hexacyanocobaltate at about (d-spacing, angstroms) 5.07. More specifically, such DMC 30 catalysts generally exhibit a powder x-ray diffraction pattern of (d-spacing, angstroms): 4.82 (br), 3.76 (br) and exhibits no detectable signals corresponding to highly crystalline zinc hexacyanocobaltate at about (d-spacing, angstroms): 5.07, 3.59, 2.54 and 2.28.
A process by which the DMC catalyst for use in the present invention can be prepared, has been described in Japanese application 4-145123. The catalyst which is prepared is a bimetallic cyanide complex having tertiary butanol coordinated as organic ligand. The bimetallic cyanide complex catalyst is prepared by mixing together aqueous solutions, or solutions in water and organic solvent mixtures, of a metal salt, preferably a salt of Zn(II) or Fe(II), and a polycyanometallate (salt), preferably containing Fe(III) or Co(III), and bringing tertiary butanol into contact with the bimetallic cyanide complex so obtained and removing the surplus solvent and tertiary butanol. In Reference Example 1, the surplus solvent and tertiary butanol are removed by suction filtration. The filter-cake obtained is washed with a 30% wt tertiary butanol aqueous solution and filtered, and this procedure is repeated with 100% t-butanol. The filter cake is dried at 40° C. under reduced pressure and then pulverized.
Another process by which the DMC catalyst for use in the present invention can be made, has been described in EP-A-555053. EP-A-555053 describes a process in which the DMC catalysts are prepared by (a) adding an aqueous solution of at least 100% stoichiometric excess of a first metal salt to an aqueous solution of an alkali metal cyano-metallate while maintaining the temperature of the latter in the range 30 to 75° C., and in which either or both the first and the second aqueous solutions contain a water-miscible heteroatom-containing organic ligand selected from alcohols, aldehydes, ketones, ethers, esters, ureas, amides, nitrites and sulphides, to form an aqueous slurry of particulate metal cyanide complex catalyst; and (b) combining the aqueous slurry with a second water-miscible heteroatom-containing organic ligand, which may be the same as or different from the first organic ligand and is selected from alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitrites, or sulphides, said combining step being optional unless neither the first nor the second aqueous solution contained any water-miscible heteroatom-containing organic ligand; and (c) recovering the particulate metal cyanide complex catalyst from the aqueous slurry by filtration.
Another process by which the DMC catalyst can be prepared, has been described in PCT patent application PCT/EP01/03498 by Shell. The process described comprises the steps of
(a) combining an aqueous solution of a metal salt with an aqueous solution of a metal cyanide salt and reacting these solutions, wherein at least part of this reaction takes place in the presence of an organic complexing agent, thereby forming a dispersion of a solid DMC complex in an aqueous medium;
(b) combining the dispersion obtained in step (a) with a liquid, which is essentially insoluble in water and which is capable of extracting the solid DMC complex formed in step (a) from the aqueous medium, and allowing a two-phase system to be formed consisting of a first aqueous layer and a layer containing the DMC complex and the liquid added;
(c) removing the first aqueous layer; and
(d) recovering the DMC catalyst from the layer containing the DMC catalyst.
Preferably, the extracting liquid used comprises a compound of the general formula (I):
wherein:
R
1
represents hydrogen, an aryl group, a substituted or unsubstituted C1-C10 alkyl group or a group R
3—
NH—,
R
2
represents hydrogen, an optionally halogenated C
1
-C
10
alkyl group, a group R
3
—NH—, a group —R
4
—C(O)O—R
5
or a cyanide group,
R
3
represents hydrogen or a C
1
-C
10
alkyl group,
R
4
represents a substituted or unsubstituted alkylene group having 2 to 15 carbon atoms,
R
5
represents hydrogen, a substituted or unsubstituted C
1
-C
10
alkyl group, and
n and m independently are 0 or 1.
Most preferred extracting liquids are 2-butyl-2-ethyl-1,3-propanediol, methyl tert-butyl ether, ethyl formiate, ethyl acetate, ethyl-2-ethyl-3-methyl butanoate, di-ethyl id malonate, di-ethyl-2-cyclohexyl-2-propyl malonate, heptane, benzonitrile, pivalonitrile (tert-butylnitrile), butyl carbamate, dibutyl carbate and propyl carbamate, dichloromethane, 1,2-dichloroethane and tetrachloroethane.
Typically, the DMC catalyst according to PCT patent application PCT/EP01/03498 will have the formula
Zn
2
[Co(CN)
6
]Cl.nC.mH
2
O.pA
wherein C is the ligand used and A is the compound of general formula (I) used. Preferably, C is tert-butyl alcohol and A is methyl tert-butyl ether, di-ethyl ether, di-isopropyl ether, tert-amyl methyl ether or di-butyl ether. Preferably, n is from 0 to 10, m is from 0 to 20 and p is from 0 to 10.
In DMC catalyst preparation processes in general, and more specifically in the DMC catalyst preparation processes mentioned above, a metal salt solution is combined with a metal cyanide salt solution.
Suitable metal salts and metal cyanide salts which can be used in DMC preparation processes in general comprise water-soluble salts suitably having the formula M(X)n, in which M is selected from the group

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