Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From heterocyclic reactant containing as ring atoms oxygen,...
Reexamination Certificate
1997-07-30
2001-04-03
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From heterocyclic reactant containing as ring atoms oxygen,...
C528S410000, C528S411000, C528S412000, C528S415000
Reexamination Certificate
active
06211330
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to double metal cyanide (DMC) catalysts useful for epoxide polymerization. In particular, the invention relates to DMC catalysts that have high activity and that give very low unsaturation polyols even at relatively high epoxide polymerization temperatures.
BACKGROUND OF THE INVENTION
Double metal cyanide complexes are well-known catalysts for epoxide polymerization. These active catalysts give polyether polyols that have low unsaturation compared with similar polyols made using basic (KOH) catalysis. The catalysts can be used to make many polymer products, including polyether, polyester, and polyetherester polyols. The polyols can be used in polyurethane coatings, elastomers, sealants, foams, and adhesives.
DMC catalysts are usually made by reacting aqueous solutions of metal salts and metal cyanide salts to form a precipitate of the DMC compound. A low molecular weight organic complexing agent, typically an ether or an alcohol is included in the catalyst preparation. The organic complexing agent is needed for favorable catalyst activity. Preparation of typical DMC catalysts is described, for example, in U.S. Pat. Nos. 3,427,256, 3,829,505, and 5,158,922.
We recently described substantially amorphous DMC catalysts that have exceptional activity for polymerizing epoxides (see U.S. Pat. No. 5,470,813). We also described highly active DMC catalysts that include, in addition to a low molecular weight organic complexing agent, from about 5 to about 80 wt. % of a polyether such as a polyoxypropylene polyol (see U.S. Pat. No. 5,482,908). Compared with earlier DMC catalysts, the DMC catalysts described in U.S. Pat. Nos. 5,470,813 and 5,482,908 have excellent activity and give polyether polyols with very low unsaturation. The catalysts are active enough to allow their use at very low concentrations, often low enough to overcome any need to remove the catalyst from the polyol. Catalysts with even higher activity are desirable because reduced catalyst levels could be used.
One drawback of DMC catalysts now known is that polyol unsaturations increase with epoxide polymerization temperature. Thus, polyols prepared at higher reaction temperatures (usually to achieve higher reaction rates) tend to have increased unsaturation levels. This sensitivity of unsaturation to increases in epoxide polymerization temperature is preferably minimized or eliminated.
Matsumoto et al. (Jap. Pat. Appl. Kokai No. H6-184297) teach to use an organophosphine oxide as a cocatalyst in a KOH-catalyzed epoxide polymerization to enable increased reaction rates without an increase in polyol unsaturation. The use of the organophosphine oxide is only taught in connection with alkali metal and alkaline earth metal (basic) catalysts; the reference is silent regarding the potential impact of using an organophosphine oxide with a coordination catalyst such as a double metal cyanide catalyst.
An ideal catalyst would give polyether polyols with low unsaturation and would be active enough to use at very low concentrations, preferably at concentrations low enough to overcome any need to remove the catalyst from the polyol. Particularly valuable would be a catalyst that can produce polyether polyols having very low unsaturation levels over a broad range of epoxide polymerization temperatures.
SUMMARY OF THE INVENTION
The invention is a double metal cyanide (DMC) catalyst useful for epoxide polymerizations. The catalyst comprises a DMC compound, an organic complexing agent, an organophosphine oxide, and optionally, a polyether. The catalyst contains from about 0.1 to about 10 wt. % of the organophosphine oxide. When a polyether is included, the catalyst contains from about 5 to about 80 wt. % of the polyether. The invention also includes a method for making the catalysts, and processes for making epoxide polymers.
I surprisingly found that DMC catalysts that include an organophosphine oxide have improved activities compared with similar catalysts made in the absence of the organophosphine oxide. In addition, the catalysts of the invention give polyols having very low unsaturations even at relatively high epoxide polymerization temperatures. The reduced sensitivity of unsaturation to reaction temperature allows for efficient production of polyether polyols while maintaining high product quality.
DETAILED DESCRIPTION OF THE INVENTION
Catalysts of the invention comprise a double metal cyanide (DMC) compound, an organic complexing agent, an organophosphine oxide, and optionally, a polyether.
Double metal cyanide compounds useful in the invention are the reaction products of a water-soluble metal salt and a water-soluble metal cyanide salt. The water-soluble metal salt preferably has the general formula M(X)
n
in which M is selected from the group consisting of Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sn(II), Pb(II), Fe(III), Mo(IV), Mo(VI), Al(III), V(V), V(IV), Sr(II), W(IV), W(VI), Cu(II), and Cr(III). More preferably, M is selected from the group consisting of Zn(II), Fe(II), Co(II), and Ni(II). In the formula, X is preferably an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, carboxylate, and nitrate. The value of n is from 1 to 3 and satisfies the valency state of M. Examples of suitable metal salts include, but are not limited to, zinc chloride, zinc bromide, zinc acetate, zinc acetonylacetate, zinc benzoate, zinc nitrate, iron(II) sulfate, iron(II) bromide, cobalt(II) chloride, cobalt(II) thiocyanate, nickel(II) formate, nickel(II) nitrate, and the like, and mixtures thereof.
The water-soluble metal cyanide salts used to make the double metal cyanide compounds useful in the invention preferably have the general formula (Y)
a
M′(CN)
b
(A)
c
in which M′ is selected from the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV), and V(V). More preferably, M′ is selected from the group consisting of Co(II), Co(III), Fe(II), Fe(III), Cr(III), Ir(III), and Ni(II). The water-soluble metal cyanide salt can contain one or more of these metals. In the formula, Y is an alkali metal ion or alkaline earth metal ion. A is an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, carboxylate, and nitrate. Both a and b are integers greater than or equal to 1; the sum of the charges of a, b, and c balances the charge of M′. Suitable water-soluble metal cyanide salts include, but are not limited to, potassium hexacyanocobaltate(III), potassium hexacyanoferrate(II), potassium hexacyanoferrate(III), calcium hexacyanocobaltate(III), lithium hexacyanoiridate(III), and the like.
Examples of double metal cyanide compounds that can be used in the invention include, for example, zinc hexacyanocobaltate(III), zinc hexacyanoferrate(III), zinc hexacyanoferrate(II), nickel(II) hexacyanoferrate(II), cobalt(II) hexacyanocobaltate(III), and the like. Further examples of suitable double metal cyanide compounds are listed in U.S. Patent No. 5,158,922, the teachings of which are incorporated herein by reference.
The DMC catalysts of the invention include an organic complexing agent. Generally, the complexing agent must be relatively soluble in water. Suitable complexing agents are those commonly known in the art, as taught, for example, in U.S. Pat. No. 5,158,922. The complexing agent is added either during preparation or immediately following precipitation of the catalyst. Usually, an excess amount of the complexing agent is used. Preferred complexing agents are water-soluble heteroatom-containing organic compounds that can complex with the double metal cyanide compound. Suitable complexing agents include, but are not limited to, alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides, and mixtures thereof. Preferred complexing agents are water-soluble aliphatic alcohols selected from the group consisting of ethanol
Bayer Antwerp N.V.
Dawson Robert
Gil Joseph C.
Whalen Lyndanne M.
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