WO2001004177A1

WO2001004177A1 - Metal cyanide catalysts on inorganic supports

Info

Publication number: WO2001004177A1
Application number: PCT/US2000/018618
Authority: WO
Inventors: Richard M. Wehmeyer
Original assignee: The Dow Chemical Company
Priority date: 1999-07-09
Filing date: 2000-07-07
Publication date: 2001-01-18
Also published as: AU5920700A; AR024679A1

Abstract

Metal cyanide polymerization catalysts are supported on a zeolite that is capable of engaging in cation exchange reactions. The supported catalysts are active polymerization catalysts for alkylene oxides. They are easily separated from the polymerization product and recycled.

Description

METAL CYANIDE CATALYSTS ON INORGANIC SUPPORTS

This invention relates to metal cyanide complexes. More particularly, it relates to heterogeneous metal cyanide catalysts and to methods for polymerizing alkylene oxides in the presence of a metal cyanide catalyst.

Polyethers are prepared in large commercial quantities through the polymerization of alkylene oxides such as propylene oxide and ethylene oxide. The polymerization is usually conducted in the presence of an initiator compound and a catalyst. The initiator compound usually determines the functionality (number of hydroxyl groups per molecule) of the polymer and in some instances incorporates some desired functional groups into the product. The catalyst is used to provide an economical rate of polymerization.

Metal cyanide complexes are becoming increasingly important alkylene oxide polymerization catalysts. These complexes are often referred to as "double metal cyanide" or "DMC" catalysts, and are the subject of a number of patents. Those patents include, for example, U. S. Patent Nos. 3,278,457, 3,278,458, 3,278,459, 3,404,109, 3,427,256, 3,427,334, 3,427,335 and 5,470,813, among many others. In some instances, these metal cyanide complexes provide the benefit of fast polymerization rates and narrow polydispersities. Additionally, these catalysts sometimes are associated with the production of polyethers having very low levels of monofunctional unsaturated compounds. The most common of these metal cyanide complexes, zinc hexacyanocobaltate

(together with the proper complexing agent and an amount of a poly(propylene oxide)), has the advantages of being active and of forming polypropylene oxide) having very low unsaturation. However, the catalyst is quite difficult to remove from the product polyether. Because of this difficulty and because the catalyst can be used in small amounts, the usual practice is to simply leave the catalyst in the product. However, this means that the catalyst must be replaced. In addition, the presence of the residual catalyst in the polyether product has been reported to cause certain performance problems. These include poor storage stability and, in some instances, interference with downstream processes. In order to reduce catalyst expense and to avoid these problems, it would be desirable to provide a catalyst that can be recovered easily from the product polyether.

In one aspect, this invention is a metal cyanide catalyst supported on a zeolite capable of engaging in cation exchange reactions.

In a second aspect, this invention is a method of polymerizing an alkylene oxide comprising contacting said alkylene oxide with an initiator compound under polymerization conditions in the presence of a metal cyanide catalyst supported on a zeolite capable of engaging in cation exchange reactions. This invention provides a method whereby a relatively inexpensive heterogeneous metal cyanide catalyst can be made and used. Because the catalyst is heterogeneous, it is easily recovered from a polymer made using the catalyst. The recovered catalyst can be recycled into further polymerization reactions. The supported catalyst complex of the invention includes a water insoluble metal cyanide catalyst. These metal cyanide catalysts are well known and are often referred to as

"double metal cyanide" or "DMC" catalysts because in most instances these complexes include two different metal ions. The metal cyanide catalysts can be represented by the general formula M^CN WJ M^XU • nM³ _xA , wherein M is a metal ion that forms an insoluble precipitate with the M¹(CN)_r(X)_t group and which has at least one water soluble salt;

M¹ and M² are transition metal ions that may be the same or different; each X independently represents a group other than cyanide that coordinates with an M¹ or M² ion;

M³ _xA represents a water-soluble salt of metal ion M³ and anion A, wherein M³ is the same as or different than M; b and c are positive numbers that, together with d, reflect an electrostatically neutral complex; d is zero or a positive number; x and y are numbers that reflect an electrostatically neutral salt; r is from 4 to 6; t is from 0 to 2; and n is a positive number (which may be a fraction) indicating the relative quantity of M³ _xA_y.

The X groups in any M²(X)₆ do not have to be all the same. The molar ratio of c:d is advantageously from 100:0 to 20:80, more preferably from 100:0 to 50:50, and even more preferably from 100:0 to 80:20.

The term "metal salt" is used herein to refer to a salt of the formula M_xA_y or M³ _xA_y, where M, M³, x, A and y are as defined above.

M and M³ are preferably metal ions selected from iZn⁺², Fe⁺², Co⁺², Ni⁺², Mo⁴⁴, Mo^*6, Al⁺³, V^*4, V⁺⁵, Sr⁺², W ⁴, W^*6, Mn⁺², Sn⁺², Sn^*4, Pb⁺², Cu⁺², La⁺³ and Cr⁺³. M and M³ are more preferably Zn⁺², Fe⁺², Co⁺², Ni⁺², La⁺³ and Cr⁺³. M is most preferably Zn⁺².

M¹ and M² are preferably Fe⁺³, Fe^t2, Co⁺³, Co⁺², Cr⁺², Cr⁺³, Mn⁺², Mn⁺³, lr⁺³, Ni⁺², Rh⁺³,

Ru⁺², V^*4 and V⁺⁵. Among the foregoing, those in the plus-three oxidation state are more preferred. Co^*3 and Fe⁺³ are even more preferred and Co^*3 is most preferred. M¹ and M² may be the same or different.

Preferred groups X include anions such as halide (especially chloride), hydroxide, sulfate, carbonate, oxalate, thiocyanate, isocyanate, isothiocyanate, C, ₄ carboxylate and nitrate, and uncharged species such as CO, H₂0 and NO. Particularly preferred groups X are NO, N0₂ ^"and CO. r is preferably 5 or 6, most preferably 6 and t is preferably 0 or 1 , most preferably 0. In many cases, r + 1 will equal 6.

Suitable anions A include halides such as chloride and bromide, nitrate, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, perchlorate, an alkanesulfonate such as methanesulfonate, an arylenesulfonate, such as p-toluenesulfonate, trifluoromethanesulfonate (triflate) and C,_.4 carboxylate. Chloride ion is especially preferred. Among the catalysts of particular interest are:

Zinc hexacyanocobaltate • nZnCI₂;

Zn[Co(CN)₅NO]^» nZnCI₂;

Zn_s[Co(CN) _o[Fe(CN)₅NO]_p ^» nZnC (o, p = positive numbers, s=1.5o + p);

Zn_s[Co(CN)₆]_o[Co(N0₂) _p[Fe(CN)₅NO]_q • nZnCI₂ (o, p, q = positive numbers, s=1.5(o+p)+q); Zinc hexacyanocobaltate • nLaCI₃;

Zn[Co(CN)₅NO]^» nLaCI₃;

Zn[Co(CN)₆]_o[Fe(CN)₅NO]_p ^» nLaCI₃ (o, p = positive numbers, s=1.5o + p);

Zn_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nLaCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q);

Zinc hexacyanocobaltate • nCrCI₃; Zn[Co(CN)₅NO] nCrCI₃;

Zn_s[Co(CN)₆]_o[Fe(CN)₅NO]_p ^» nCrCI₃ (o, p = positive numbers, s=1.5o + p);

Zn_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nCrCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nZnCI₂;

Mg[Co(CN)₅NO] • nZnCL; Mg_s[Co(CN)₆]_o[Fe(CN)₅NO]_p ^» nZnCI₂ (o, p = positive numbers,s=1.5o + p);

Mg_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nZnCI₂ (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nLaCI₃;

Mg[Co(CN)₅NO]^« nLaCI₃;

Mg_s[Co(CN) _o[Fe(CN)₅NO]_p ^» nLaCI₃ (o, p = positive numbers, s=1.5o + p); Mg_s[Co(CN)₆]_o[Co(N0₂)J_p[Fe(CN)₅NO]_q • nLaCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nCrCI₃;

Mg[Co(CN)₅NO] • nCrCI₃;

Mg_s[Co(CN)₆]_o[Fe(CN)₅NO]_p ^» nCrCI₃ (o, p = positive numbers, s=1.5o + p);

Mg_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nCrCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q); as well as the various complexes such as are described at column 3 of U. S. Patent No.

3,404,109. By "zeolite", it is meant a crystalline structure having well-defined pores, composed of one or more different types of so-called "T-atoms", i.e. ions surrounded by four oxygen atoms in an approximately tetrahedral array. The most common T-atoms are silicon and aluminum, although a great number of other atoms, such as phosphorus, germanium, beryllium, boron, titanium, copper, iron, gallium, can also be present. Suitable zeolite materials have alkali metal or alkaline earth atoms that can be exchanged for an M atom. Suitable zeolites include those having structure types ABW, AEI, AEL, AET, AFG, AFI, AFO, AFR, AFR, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ATN, ATO, ATS, ATT, ATV, AWW, BEA, BIK, BOG, BPH, BRE, CAN, CAS, CGF, CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DOH, EAB, EDI, DMT, EPI, ERI, EUO, FAU (zeolite Y), FER, GIS, GME, GOO, HEU, IFR, ITE, JBW, KFI, LAU, LEV, LIO, LOS, LOV, LTA, LTL, LTN, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MTN, MTT, MTW, MWW, NAT, NEW, NON, OFF, OSI, PART, PAU, PHI, RHO, RON, RSN, RTE, RTH, RUT, SAU, SAT, SGT, SOD, STI, TER, THO, TON, VET, VFI, VNI, VSV, WEI, WEN, YUG, ZON, and which are capable of exchanging a metal cation for an M atom.

Generally, the catalyst is complexed with an organic complexing agent. A great number of complexing agents are potentially useful, although catalyst activity may vary according to the selection of a particular complexing agent. Examples of such complexing agents include alcohols, aldehydes, ketones, ethers, amides, nitriles, and sulfides. Suitable alcohols include monoalcohols and polyalcohols. Suitable monoalcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, octanol, octadecanol, 3-butyn-1-ol, 3-butene-1-ol, propargyl alcohol, 2-methyl-2-propanol, 2-methyl-3- butyn-2-ol, 2-methyl-3-butene-2-ol, 3-butyn-1 -ol, 3-butene-1 -ol, 1 -t-butoxy-2-propanol. Suitable monoalcohols also include halogenated alcohols such as 2-chloroethanol, 2- bromoethanol, 2-chloro-1 -propanol, 3-chloro-1-propanol, 3-bromo-1-propanol, 1 ,3-dichloro-2- propanol, 1-chloro-2-methyl-2-propanol as well as nitroalcohols, keto-alcohols, ester- alcohols, cyanoalcohols, and other inertly substituted alcohols.

Suitable polyalcohols include ethylene glycol, propylene glycol, glycerine, 1 ,1 ,1- trimethylol propane, 1 ,1 ,1 -trimethylol ethane, 1 ,2,3-trihydroxybutane, pentaerythritol, xylitol, arabitol, mannitol, 2,5-dimethyl-3-hexyn-2,5-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, sucrose, sorbitol, alkyl glucosides such as methyl glucoside and ethyl glucoside. Low molecular weight polyether polyols, particular those having an equivalent weight of 350 or less, more preferably 125-250, are also useful complexing agents.

Suitable aldehydes include formaldehyde, acetaldehyde, butyraldehyde, valeric aldehyde, glyoxal, benzaldehyde, and toluic aldehyde. Suitable ketones include acetone, methyl ethyl ketone, 3-pentanone, 2-hexanone. Suitable ethers include cyclic ethers such as dioxane, trioxymethylene and paraformaldehyde as well as acyclic ethers such as diethyl ether, 1 -ethoxy pentane, bis(betachloro ethyl) ether, methyl propyl ether, diethoxy methane, dialkyl ethers of alkylene or polyalkylene glycols (such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether and octaethylene glycol dimethyl ether).

Amides such as formamide, acetamide, propionamide, butyramide and valeramide are useful complexing agents. Esters such as amyl formate, ethyl formate, hexyl formate, propyl formate, ethyl acetate, methyl acetate, triethylene glycol diacetate can be used as well. Suitable nitriles include acetonitrile, proprionitrile. Suitable sulfides include dimethyl sulfide, diethyl sulfide, dibutyl sulfide, and diamyl sulfide.

Compounds having an S=0 group, such as dimethyl sulfoxide and sulfolane, are also useful complexing agents.

Preferred complexing agents are 1-t-butoxy-2-propanol, t-butanol, polyether polyols having an equivalent weight of 75-350, DMSO, sulfolane and dialkyl ethers of alkylene and polyalkylene glycols. Especially preferred complexing agents are 1-t-butoxy-2-propanol, t- butanol, polyether polyols having an equivalent weight of 125-250, DMSO and a dimethyl ether of mono-, di- or triethylene glycol. 1 -t-Butoxy-2-propanol, t-butanol, DMSO and glyme (1 ,2-dimethoxy ethane) are especially preferred.

In addition, the catalyst complex is believed to contain a quantity of water that is bound into the crystalline lattice of the complex.

The catalyst complex is conveniently made by precipitating the catalyst in the presence of the zeolite. This can be done by first forming a slurry of the zeolite in a solution of a metallic cyanide compound of the form B_u[M¹(CN)_r(X)J_v, where B is hydrogen or a metal that forms a water-soluble salt with the M¹(CN)_r(X)_t ion, u and v are integers that reflect an electrostatically neutral compound, and M¹, X, r and t are as before. If it is desired to include M²(X)₆ groups in the complex, a B_u[M²(X)₆]_v compound can also be dissolved into the slurry, where B, M², X, u and v are as defined before. The slurry can be made by adding the zeolite to a solution containing the dissolved B M^CN^X)^ compound and any desired B_u[M²(X)₆]„ compound, or the zeolite may be first slurried into water and the compound(s) then added and caused to dissolve.

Then, a solution of one or more salts of the form M_xA_y is added. At least a stoichiometric amount of M_xA salt is added based on the combined number of equivalents of the B_u[M¹(CN)_r(X)_t]_v and B_u[M²(X)₆]_v compounds plus the number of equivalents of cation exchange groups on the zeolite. Preferably, at least a 10 equivalent-percent excess, more preferably a 20-100 percent stoichiometric excess of M_xA_y salt is added. The M_xA_y solution is preferably added slowly over a period of from 1 to 20 minutes, with agitation. The temperature of mixing is not critical provided that the starting materials remain in solution until the mixing is performed. Temperatures of 10°C to the boiling temperature of the solution, particularly 15-35°C, are most suitable. The mixing can be done with rapid agitation. Intimate mixing techniques as are described in U. S. Patent No. 5,470,813 can be used, but are not necessary.

Especially suitable M_xA_y salts include zinc halides, zinc hydroxide, zinc sulfate, zinc carbonate, zinc cyanide, zinc oxalate, zinc thiocyanate, zinc isocyanate, zinc C_{1 4} carboxylates, zinc methanesulfonate, zinc p-toluenesulfonate, zinc trifluoromethanesulfonate and zinc nitrate. Zinc chloride, zinc acetate and zinc nitrate are most preferred. When the M_xA_y solution is added, a catalyst precipitates having the form

M_b[M¹(CN)_r(X)_t]_c[M²(X)₆]_d, where d is zero or a positive number and b, c and d together reflect an electrostatically neutral complex. Although this invention is not limited to any theory, it is believed that some the M ions react with an M¹(CN)_r(X)_t ion as well as an anionic group on the zeolite, thereby forming a bridge between the zeolite and the catalyst complex. In the preferred case where the catalyst complex is treated with a complexing agent, the complexing agent is advantageously present as the catalyst complex is precipitating. This can be accomplished by including the complexing agent in one or both of the starting solutions, or by adding the complexing agent immediately after precipitation of the catalyst begins. If only a stoichiometric equivalent of M A salt is used in the precipitation step, additional metal salt of the form M³ _xA_y is added in a later step. This is conveniently done by forming a solution of the M³ _xA_y compound in water, complexing agent, or both, and reslurrying the precipitated catalyst in the solution. In one variation of this technique, the precipitated catalyst is combined with a small amount of a solution of the M³ _xA compound in complexing agent or a complexing agent/water mixture so that the M³ _xA_y solution is essentially completely absorbed by the precipitated catalyst. This method permits an active catalyst to be made using reduced quantities of M³ _xA_y compound and complexing agent.

The resulting precipitated catalyst complex is then recovered by a suitable technique such as filtration. Preferably, the catalyst complex is subjected to one or more subsequent washings with water, complexing agent or some combination thereof. This is conveniently done by reslurrying the catalyst in the liquid with agitation for several minutes and then filtering. Washing is preferably continued at least until essentially all unwanted ions, particularly alkali metal and halide ions, are removed from the complex. The final catalyst complex is conveniently dried, preferably under vacuum and moderately elevated temperatures (such as from 50-60°C) to remove excess water and volatile organics. Drying is preferably done until the catalyst complex reaches a constant weight. The catalyst complex of the invention is used to polymerize alkylene oxides to make polyethers. In general, the process includes mixing a catalytically effective amount of the catalyst with an alkylene oxide under polymerization conditions, and allowing the polymerization to proceed until the supply of alkylene oxide is essentially exhausted. The concentration of the catalyst is selected to polymerize the alkylene oxide at a desired rate or within a desired period of time. An amount of supported catalyst sufficient to provide from 5 to 10,000 parts by weight metal cyanide catalyst (calculated as M_b[M¹(CN)_r(X)_t]_c[M²(X) _d • nM³ A_y, exclusive of zeolite and any associated water or complexing agent compounds) per million parts combined weight of alkylene oxide, and initiator and comonomers, if present. More preferred catalyst levels are from 20, especially from 30, to 5000, more preferably 1000 ppm, even more preferably 100 pp , on the same basis.

For making high molecular weight monofunctional polyethers, it is not necessary to include an initiator compound. However, to control molecular weight, impart a desired functionality (number of hydroxyl groups/molecule) or a desired terminal functional group, an initiator compound as described before is preferably mixed with the catalyst complex at the beginning of the reaction. Suitable initiator compounds include monoalcohols such methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 1 -t-butoxy-2- propanol, octanol, octadecanol, 3-butyn-1 -ol, 3-butene-1 -ol, propargyl alcohol, 2-methyl-2- propanol, 2-methyl-3-butyn-2-ol, 2-methyl-3-butene-2-ol, and 3-butyn-1-ol, 3-butene-1-ol. The suitable monoalcohol initiator compounds include halogenated alcohols such as 2- chloroethanol, 2-bromoethanol, 2-chloro-1 -propanol, 3-chloro-1-propanol, 3-bromo-1 - propanol, 1 ,3-dichloro-2-propanol, 1 -chloro-2-methyl-2-propanol as well as nitroalcohols, keto-alcohols, ester-alcohols, cyanoalcohols, and other inertly substituted alcohols. Suitable polyalcohol initiators include ethylene glycol, propylene glycol, glycerine, 1 ,1 ,1 -trimethylol propane, 1 ,1 ,1-trimethylol ethane, 1 ,2,3-trihydroxybutane, pentaerythritol, xylitol, arabitol, mannitol, 2,5-dimethyl-3-hexyn-2,5-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, sucrose, sorbitol, alkyl glucosides such a methyl glucoside and ethyl glucoside. Low molecular weight polyether polyols, particular those having an equivalent weight of 350 or less, more preferably 125-250, are also useful initiator compounds. Among the alkylene oxides that can be polymerized with the catalyst complex of the invention are ethylene oxide, propylene oxide, 1 ,2-butylene oxide, styrene oxide, and mixtures thereof. Various alkylene oxides can be polymerized sequentially to make block copolymers. More preferably, the alkylene oxide is propylene oxide or a mixture of propylene oxide and ethylene oxide and/or butylene oxide. Especially preferred are propylene oxide along or a mixture of at least 75 weight percent propylene oxide and up to 25 weight percent ethylene oxide. In addition, monomers that will copolymerize with the alkylene oxide in the presence of the catalyst complex can be used to prepare modified polyether polyols. Such comonomers include oxetanes as described in U. S. Patent Nos. 3,278,457 and 3,404,109, and anhydrides as described in U. S. Patent Nos. 5,145,883 and 3,538,043, which yield polyethers and polyester or polyetherester polyols, respectively. Hydroxyalkanoates such as lactic acid, 3-hydroxybufyrate, 3-hydroxyvalerate (and their dimers), lactones and carbon dioxide are examples of other suitable monomers that can be polymerized with the catalyst of the invention.

The polymerization reaction typically proceeds well at temperatures from 25 to 150°C or more, preferably from 80-130°C. A convenient polymerization technique involves mixing the catalyst complex and initiator, and pressuring the reactor with the alkylene oxide. Polymerization proceeds after a short induction period, as indicated by a loss of pressure in the reactor. Once the polymerization has begun, additional alkylene oxide is conveniently fed to the reactor on demand, until enough alkylene oxide has been added to produce a polymer of the desired equivalent weight.

Another convenient polymerization technique is a continuous method. In such continuous processes, an initiator compound is continuously fed into a continuous reactor, such as a continuously stirred tank reactor (CSTR) or a tubular reactor, which contains the supported catalyst complex. A feed of alkylene oxide is introduced into the reactor and the product continuously removed.

The catalyst of this invention is easily separated from the product polyether by any convenient solid-liquid separation, including simple filtration and centrifuging. The recovered catalyst can be re-used in further polymerization reactions.

The recovered catalyst may be washed one or more times, preferably multiple times, with water or preferably an organic solvent such as methanol and then dried prior to being reused. If the surface of the catalyst becomes fouled or coated with polymer, the catalyst may be washed or treated to remove the fouling or polymer coating.

The catalyst of this invention is especially useful in making propylene oxide homopolymers and random copolymers of propylene oxide and up to 15 weight percent ethylene oxide (based on all monomers). The polymers of particular interest have a hydroxyl equivalent weight of from 800, preferably from 1000, to 5000, preferably 4000, more preferably to 2500, and unsaturation of no more than 0.02 meq/g, preferably no more than 0.01 meq/g.

The product polymer may have various uses, depending on its molecular weight, equivalent weight, functionality and the presence of any functional groups. Polyether polyols so made are useful as raw materials for making polyurethanes. Polyethers can also be used as surfactants, hydraulic fluids, as raw materials for making surfactants and as starting materials for making aminated polyethers, among other uses.

The following example is provided to illustrate the invention, but is not intended to limit its scope. All parts and percentages are by weight unless otherwise indicated.

Example 1

A. Preparation of Zeolite-Supported Catalyst

Y zeolite in the sodium form (5.0 g) is slurried in 250 mL of water. Solid K₃Co(CN)₆ (4.0 g, 0.012 mol) is added and the mixture stirred until it has dissolved. A solution of zinc chloride (19.35 g, 0.142 mol) in water (40 mL) is added over 2-3 minutes with continued stirring. When all of the zinc chloride solution has been added, 100 mL t-butanol is added all at once. The mixture is stirred for about 10 minutes, then filtered through Whatman® #41 filter paper. The filtration proceeds slowly and suction-drying is performed to help remove the supernatant fluid. The filter cake is pasty and difficult to remove from the filter paper. The filter cake is recovered and reslurried in a solution of zinc chloride (6.45 g, 0.047 mol) in 140 mL t-butanol and 60 mL water. The slurry is stirred for 10 minutes and again filtered and suction-dried to form a filter cake. The filter cake is again reslurried in 200 mL t- butanol and stirred for 10 minutes. A powdery filtrate is recovered and dried in a vacuum oven at 50°C overnight. The mass of the dried product is 8.48 g.

B. Propylene oxide polymerization

The supported catalyst from Part A is evaluated by mixing 0.12 g of a 700 MW polypropylene oxide) triol, 0.58 g propylene oxide and 0.03 g of the catalyst in a sealed vial and heating at 90°C for 18 hours. The conversion of the propylene oxide is then determined as an indication of the activity of the catalyst. Essentially quantitative conversion of the propylene oxide is seen. The same results are seen when the supported catalyst loading is dropped to 0.006 g.

Claims

WHAT IS CLAIMED IS:

1. A metal cyanide catalyst supported on a zeolite capable of engaging in cation exchange reactions.

2. The supported metal cyanide catalyst of claim 1 , wherein the metal cyanide catalyst is represented by the general structure

M_b[M¹ (CN)_r(X)_t]_c[M²(X)J_d . nM³ A_y wherein M is a metal ion that forms an insoluble precipitate with the M¹(CN)_r(X)_t group and which has at least one water soluble salt;

M¹ and M² are transition metal ions that may be the same or different; each X independently represents a group other than cyanide that coordinates with an M' or

M² ion;

M³ _xA_y represents a water-soluble salt of metal ion M³ and anion A, wherein M³ is the same as or different than M; b and c are positive numbers that, together with d, reflect an electrostatically neutral complex; d is zero or a positive number; x and y are numbers that reflect an electrostatically neutral salt; r is from 4 to 6; t is from 0 to 2; and n is a positive number indicating the relative quantity of M³ _xA .

3. The supported metal cyanide catalyst of claim 2 wherein the zeolite is Y zeolite.

4. The supported metal cyanide catalyst of claim 3 wherein the metal cyanide catalyst is complexed with a complexing agent.

5. The supported metal cyanide catalyst of claim 4 wherein the complexing agent is 1 -t- butoxy-2-propanol, t-butanol, a polyether polyol having an equivalent weight of 75-350, DMSO, sulfolane or a dialkyl ether of an alkylene or polyalkylene glycol.

6. The supported metal cyanide catalyst of claim 5 wherein the metal cyanide catalyst is: Zinc hexacyanocobaltate • nZnCI₂;

Zn[Co(CN)₅NO]^« nZnCI₂; Zn_s[Co(CN)₆]_o[Fe(CN)₅NO]_p» nZnCL, (o, p = positive numbers, s=1.5o + p);

Zn_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nZnCI₂ (o, p, q = positive numbers, s=1.5(o+p)+q); Zinc hexacyanocobaltate • nLaCI₃;

Zn[Co(CN)₅NO]^« nLaCI₃;

Zn[Co(CN)₆]_o[Fe(CN)₅NO]_p ^« nLaCI₃ (o, p = positive numbers, s=1.5o + p);

Zn_s[Co(CN)₆]_o[Co(N0₂) _p[Fe(CN)₅NO]_q • nLaCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q); Zinc hexacyanocobaltate • nCrCI₃;

Zn[Co(CN)₅NO] nCrCI₃;

Zn_s[Co(CN) _o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nCrCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nZnCI₂; Mg[Co(CN)₅NO] • nZnCI₂;

Mg_s[Co(CN) ₀[Fe(CN)₅NO]_p ^« nZnCL (o, p = positive numbers,s=1.5o + p);

Mg_s[Co(CN)₆]₀[Co(NO₂)J_p[Fe(CN)₅NO]_q • nZnC (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nLaCI₃;

Mg[Co(CN)₅NO]^» nLaCI₃; Mg_s[Co(CN)₆]_o[Fe(CN)₅NO]_p ^» nLaCI₃ (o, p = positive numbers, s=1.5o + p);

Mg_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nLaCI₃ (o, p, q = positive numbers, s=1.5(o+p)+q);

Magnesium hexacyanocobaltate • nCrCI₃;

Mg[Co(CN)₅NO] • nCrCI₃;

Mg_s[Co(CN)₆]_o[Fe(CN)₅NO]_p ^« nCrCI₃ (o, p = positive numbers, s=1.5o + p); or Mg_s[Co(CN)₆]_o[Co(N0₂)₆]_p[Fe(CN)₅NO]_q • nCrCI₃ where n in each instance is a positive number indicating the relative quantity of the indicated salt of general structure M³ _xA_y.

7. A method of polymerizing an alkylene oxide, comprising contacting said alkylene oxide with an initiator compound under polymerization conditions in the presence of a metal cyanide catalyst supported on a zeolite capable of engaging in cation exchange reactions.