Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From heterocyclic reactant containing as ring atoms oxygen,...
Reexamination Certificate
2002-02-04
2004-07-13
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From heterocyclic reactant containing as ring atoms oxygen,...
C528S411000, C528S412000, C528S415000, C528S419000, C528S421000, C521S172000
Reexamination Certificate
active
06762278
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improved process for the copolymerization of alkylene oxides and carbon dioxide using multimetal cyanide compounds as catalysts. The present invention permits one to efficiently form polyethercarbonate polyols with better incorporation of carbon dioxide into the polyol.
BACKGROUND OF THE INVENTION
Polyethercarbonate polyols are the polymerization reaction product of an initiator, at least one alkylene oxide and carbon dioxide. The carbon dioxide is incorporated into the backbone of the polyol chain. A number of catalyst systems have been used to form polyethercarbonate polyols with varying degrees of success. One difficulty has been the generally low reactivity of carbon dioxide in the catalytic systems to date, in particular the generally observed decreasing rate of reaction with increasing CO
2
pressure (L Chen, Rate of regulated copolymerization involving CO
2
, J Natural Gas Chemistry, 1998, 7, 149-156), thus requiring very high levels of catalyst to produce any product having incorporation of a significant amount of carbon dioxide into the polyol. A second difficulty is the generally high rate of formation of cyclic by products such as propylene carbonate. Finally, most procedures produce a very viscous product having a large degree of polydispersity.
In an attempt to better control the reaction and to increase the carbon dioxide incorporation, several forms of double metal cyanide (DMC) complexes have been used in the past. These are disclosed in the following U.S. Pat. Nos. 4,472,560; 4,500,704; 4,826,887; 4,826,952; and 4,826,953. These DMC procedures, however, still suffer from slow reaction rates, required high catalyst concentrations and have high levels of by-product formation. Polyethercarbonate polyols produced using these DMC catalysts also have high viscosities and high degrees of polydispersity. Thus there is a need for an improved catalyst system for polyethercarbonate polyol formation.
Most double metal cyanide complexes are amorphous structures and are used in the form of powders. In the present invention it has been found that much better results are obtained using crystalline multimetal cyanide compounds in a form which gives them a very high catalytic activity. In a preferred embodiment crystalline multimetal cyanide compounds are suspended in organic or inorganic liquids and used as catalysts in this form. It is particularly advantageous for the suspended multimetal cyanide compound to have a platelet-like morphology.
SUMMARY OF THE INVENTION
In one embodiment, the present invention is a method of forming a polyethercarbonate polyol comprising the steps of: providing a multimetal cyanide compound having a crystalline structure and a content of platelet-shaped particles of preferably at least 30% by weight, based on the weight of the multimetal cyanide compound and further comprising at least two of the following: an organic complexing agent, water, a polyether, and a surface-active substance; and reacting an alcohol initiator with at least one alkylene oxide and carbon dioxide under a positive pressure in the presence of the multimetal cyanide compound, thereby forming the polyethercarbonate polyol.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the present invention a unique multimetal cyanide compound is used. The compound is crystalline and preferably has a platelet-like morphology. In addition, the catalyst is preferably used in the form of a suspension, which gives it unique activity. The multimetal cyanide compound of the present invention provides different activity than past DMC complexes.
The multimetal compound of the present invention comprises at least three components. First, at least one multimetal cyanide compound having a crystalline structure and a content of platelet-shaped particles of at least 30% by weight, based on the multimetal cyanide compound. Second the compound includes at least two of the following components: an organic complexing agent, water, a polyether, and a surface-active substance.
The organic complexing agent comprises, in particular, one of the following: alcohols, ethers, esters, ketones, aldehydes, carboxylic acids, amides, nitrites, sulfides and mixtures thereof.
As polyethers, use is made, in particular, of polyether alcohols, preferably hydroxyl-containing polyaddition products of ethylene oxide, propylene oxide, butylene oxide, vinyloxirane, tetrahydrofuran, 1,1,2-trimethylethylene oxide, 1,1,2,2-tetramethylethylene oxide, 2,2-dimethyloxetane, diisobutylene oxide, &agr;-methylstyrene oxide and mixtures thereof.
As the surface-active substance, use is made, in particular, of compounds selected from the group comprising C
4
-C
60
-alcohol alkoxylates, block copolymers of alkylene oxides of differing hydrophilicity, alkoxylates of fatty acids and fatty acid glycerides, block copolymers of alkylene oxides and polymerizable acids and esters.
The crystalline multimetal cyanide compounds used according to the present invention are preferably prepared by the following method. First, addition of an aqueous solution of a water-soluble metal salt of the formula M
1
m
(X)
n
to an aqueous solution of cyanometalate compound of the formula H
a
M
2
(CN)
b
(A)
c
. Wherein for the formula M
1
m
(X)
n
: M
1
is at least one metal ion selected from the group consisting of Zn
2+
, Fe
2+
, Co
3+
, Ni
2+
, Mn
2+
, Co
2+
, Sn
2+
, Pb
2+
, Fe
3+
, Mo
4+
, Mo
6+
, Al
3+
, V
5+
, Sr
2+
, W
4+
, W
6+
, Cu
2+
, Cr
2+
, Cr
3+
, Cd
2+
, Hg
2+
, Pd
2+
, Pt
2+
, Vt
2+
, Mg
2+
, Ca
2+
, Ba
2+
, and mixtures thereof; X is at least one anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, carboxylate, in particular formate, acetate, propionate or oxalate; and nitrate and m and n are integers which satisfy the valence of M
1
, and X. Wherein for the formula H
a
M
2
(CN)
b
(A)
c
,: M
2
is at least one metal ion selected from the group consisting of Fe
2+
, Fe
3+
, Co
3+
, Cr
3+
, Mn
2+
, Mn
3+
, Rh
3+
, Ru
2+
, Ru
3+
, V
4+
, V
5+
, Co
2+
, Ir
3+
, and Cr
2+
and M
2
can be identical to or different from M
1
; H is hydrogen or a metal ion, usually an alkali metal ion, an alkaline earth metal ion or an ammonium ion; A is at least one anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanate, thiocyanide, isocyanate, carboxylate and nitrate, in particular cyanide, where A can be identical to or different from X; and a, b and c are integers selected so that the cyanide compound is electrically neutral.
In an alternative, one or both aqueous solutions may, if desired, comprise at least one water-miscible, heteroatom-containing ligand selected from the group comprising alcohols, ethers, esters, ketones, aldehydes, carboxylic acids, amides, sulfides or mixtures of at least two of the components mentioned, and at least one of the two solutions comprises a surface-active substance.
Also if desired, combination of the aqueous suspension formed in the first step above can be made with a water-miscible, heteroatom-containing ligand selected from the above-described group which can be identical to or different from the ligand in the first step.
In a second step, if desired, the multimetal cyanide compound can be separated from the suspension.
The procedure produces platelet-like shaped crystalline multimetal cyanide compounds. The compounds can have a cubic, tetragonal, trigonal, orthorhombic, hexagonal, monoclinic or triclinic crystal structure. The definition of the crystal systems describing these structures and the space groups belonging to the abovementioned crystal systems may be found in “International tables for crystallography”, Volume A, editor: Theor Hahn, (1995).
For the preparation of multimetal cyanide compounds which are used for the suspensions of the present invention, it is advantageous,
Bohres Edward
Dexheimer Edward Michael
Grosch Georg Heinrich
Hinz Werner
BASF Corporation
Borrego Fernando A.
Buttner David J.
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