MXPA96002959A - Highly active double metal cyanide complex catalysts - Google Patents

Abstract

Highly active double metal cyanide (DMC) complex catalysts and methods for making them are disclosed. The catalysts contain less than about 0.2 moles of metal salt per mole of DMC compound in the catalyst, and unlike other highly active DMC catalysts, are substantially crystalline. Polyether polyols made from the catalysts have low unsaturation and are useful for making many types of polyurethane products.

Description

COMPLEX CATALYSTS OF CYANIDE DIMETA ICO HIGHLY ACTIVE FIELD OF THE INVENTION The invention relates to complex dimethyl-cyanide (DMC) complex catalysts useful for epoxide polymerization. The catalysts, which contain an unusually low level of metal salt, are highly active. The invention includes methods for preparing the catalysts. The polyether polyol products made by the use of the catalysts have exceptionally low unsaturations. BACKGROUND OF THE INVENTION Dimethyl cyanide (DMC) compounds are well-known catalysts for the polymerization of epoxide. The catalysts are highly active, and give polyether polyols having low unsaturation in comparison to similar polyols made by the use of basic catalysis (KOH). Conventional DMC catalysts are prepared by reaction of aqueous solutions of metal salts and metal cyanide salts to form a precipitate of the DMC compound. The catalysts can be used to make a variety of polymer products, including polyether, polyester and polyether ester polyols. Many of the polyols are useful in various coatings, elastomers, seals, foams, and polyurethane adhesives. The DMC catalysts are usually prepared in the presence of a low molecular weight organic complexing agent, typically an ether such as glyme (dimethoxyethane) or diglyme. The complexing agent favorably impacts the activity of the catalysts for the epoxide polymerization. Other known complexing agents include alcohols, ketones, esters, amides, ureas and the like. Recently, we have described substantially the amorphous DMC catalysts prepared by the use of water-soluble aliphatic alcohol complexing agents such as tert-butyl alcohol (EP-A-0654302). In a conventional preparation, aqueous solutions of zinc chloride and potassium hexacyanocobaltate are combined. The resulting precipitate of zinc hexacyanocobaltate is combined with an organic complexing agent. The resulting catalyst has the general formula: Zn3 [Co (CN) 6] 2 -xZnCl2 - and H2O-z Complexing agent The DMC catalysts are made with an excess of the metal salt compared to the amount of metal cyanide salt used. See, for example, US Patents. Nos. 3,427,256, 3,278,457, and 3,941,849. More recently, we presented (U.S. Patent No. 5,158,922) an improved process for easily elaborating filtered DMC catalysts by controlling the order of reagent addition, the reaction temperature, and the stoichiometric rate of the reagents. The '922 patent teaches the use of at least about 100% stoichiometric excess of the metal salt relative to the metal cyanide salt. Thus, in the above example, at least about 3 moles of zinc chloride are used per mole of potassium hexacyanocobaltate. The examples in the reference use glyme as the organic complexing agent. The zinc hexacyanocobaltate catalysts prepared by this process generally have mole ratios of zinc chloride to zinc hexacyanocobaltate of about 0.6 or more. The '922 patent discloses (in a formula) compositions having as little as 0.2 moles of metal salt per mole of DMC compound in the catalyst. Although the process described in the '922 patent (large excess of zinc chloride) works well with glyme, it is less satisfactory for use with other complexing agents, including tert-butyl alcohol. When tert-butyl alcohol is used, the precipitate of the catalyst becomes gelatinous and difficult to separate. In addition, the activity of these catalysts for epoxide polymerizations, although they are fairly compared with KOH catalysts, it is still something less than desirable. Catalysts prepared by the glyme reference process as the organic complexing agent typically polymerize propylene oxide with activity less than about 2 g PO / min in 100 ppm catalyst, based on the weight of the finished polyol, 105 ° C. Recently, we described substantially the amorphous DMC catalysts (EP-A-0654302). These catalysts are preferably made using a water-soluble aliphatic alcohol complexing agent such as tert-butyl alcohol. An excessive amount of metal salt is used to make the catalyst. The zinc hexacyanocobaltate catalysts described herein have more than 0.2 moles of metal salt per mole of zinc hexacyanocobaltate present, typically more than 0.5 moles of metal salt per mole of zinc hexacyanocobaltate. X-ray diffraction patterns show that the catalysts are substantially amorphous; that is, the catalysts are characterized by the substantial absence of sharp lines in the powder X-ray diffraction pattern (see Figure 5). The catalysts described in the '534 application have a much higher activity for the polymerization of propylene oxide than previously known catalysts. For example, velocities of more than about 3 g PO / min were obtained in 100 ppm of catalyst. Improved dimetic cyanide catalysts are needed. The preferred catalysts would be easy to prepare and separate and would have excellent activity for the polymerization of epoxides. Preferred catalysts would give polyether polyols having narrow molecular weight distributions and low unsaturation. SUMMARY OF THE INVENTION The invention is an improved catalyst for the polymerization of epoxides. The catalyst is a highly active crystalline dimethalic cyanide (DMC) catalyst. Like other DMC catalysts, these complexes are made by reacting aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent. The metal salt is used in excess compared to the amount of metal cyanide salt, and the resulting DMC complex includes some of the metal salt. Unlike previously known catalysts, these catalysts contain less than about 0.2 moles of the metal salt per mole of DMC compound in the catalyst. In contrast to the substantially amorphous DMC catalysts that we previously discovered (EP-A-0654302), the catalysts of the invention exhibit an X-ray diffraction pattern of the powder of sharp lines (see Figures 2 and 3). Surprisingly, these crystalline catalysts have an excellent activity for the polymerization of epoxides (greater than 3 g PO / min in 100 ppm of catalyst). The catalyst activities are significantly greater than the available activities of conventional KOH catalysts, and are also greater than those of ordinary DMC catalysts (as reported, for example, in U.S. Patent No. 5,158,922). Previously, the only known catalysts having such high activities were the substantially amorphous catalysts described in EP-A-0654302. The polyols made by the use of the catalysts of the invention have exceptionally low unsaturation, typically less than 0.006 meq / g. The invention also includes methods for making the catalysts. In one method, the catalyst is made by using an excessive amount of the metal salt, but the excess is less than 100% stoichiometric excess relative to the amount of metal cyanide salt. The resulting catalyst contains less than about 0.2 moles of the metal salt per mole of the DMC compound in the catalyst. In a second method, a larger amount of the metal salt can be used, but the resulting catalyst is subsequently rinsed with a mixture of water and an organic complexing agent in an effective manner to produce a DMC catalyst containing less than about 0.2 moles. of the metal salt per mole of DMC compound in the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a plot of the propylene oxide consumption versus the time during a polymerization reaction with one of the catalyst compositions of the invention in 100 ppm of catalyst. The speed of the reaction is determined from the inclination of this graph. Figures 2-5 are powder X-ray diffraction patterns for various zinc hexacyanocobaltate catalysts. The figures are described more fully below. DETAILED DESCRIPTION OF THE INVENTION The dimethyl cyanide (DMC) catalysts of the invention generally resemble catalysts known in the art, but contain a relatively low level of the metal salt. The catalysts of 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), C (II), Sn (II), Pb (II), Fe (III), Mo (IV), Mo (VI), Al (III) ), V (V), V (IV), Sr (II), (IV), (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 valence state of M. Examples of suitable metal salts include, but are not limited to, zinc chloride, zinc bromide, zinc acetate, zinc acetonylacetate, benzoate zinc, zinc nitrate, iron (II) sulfate, iron (II) bromide, cobalt (II) chloride, cobalt (II) thiocyanate, nickel (II) format, nickel (II) nitrate and the like , and mixtures thereof. Zinc halides are preferred. The water-soluble metal cyanide salts used to make the dimethalic cyanide compounds useful in the invention, preferably have the general formula (Y) to M '(CN) b (A) c in which M' is selected from the group consists 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 C (II), C (III), Fe (II), Fe (III), Cr (III), Ir (III), and Ni (II). The water-soluble metal cyanide salt may 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 load 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), hexacyanidate (III) of lithium, and the like. Examples of dimethalic 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), hexacyanocobaltate (III) of cobalt (II), and the like. Additional examples of suitable dimethalic cyanide compounds are listed in the U.S. Patent. No. 5,158,922, the teachings of which are incorporated herein by reference. The catalysts of the invention are prepared in the presence of a complexing agent. Generally, the complexing agent must be relatively soluble in water. Suitable complexing agents are those commonly known in the art, as presented, for example, in U.S. Pat. No. 5,158,922. The complexing agent is added either during the preparation or immediately after the precipitation of the catalyst. As explained elsewhere in this application, the manner in which the complexing agent is introduced to the DMC complex can be extremely important. Normally, an excessive amount of the complexing agent is used. Preferred complexing agents are organic compounds containing water-soluble heteroatoms, which can be complexed with the dimethalic cyanide compound. Suitable complexing agents include, but are not limited to, alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides, and mixtures of the mimes. Preferred complexing agents are water-soluble aliphatic alcohols selected from the group consisting of ethanol, isopropyl alcohol, N-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Tert-butyl alcohol is the most preferred. The conventional method for preparing DMC compounds useful for epoxide polymerization is fully described in many references, including US Patents. Nos. 5,158,922, 4,843,054 4,477,589, 3,427,335, 3,427,334, 3,427,256, 3,278,457, and 3,941,849, and Japanese Patent Application No. 4-145123 to Kokai. The teachings of these references related to the preparation of conventional catalysts and suitable DMC compounds are hereby incorporated by reference in their entirety. The catalysts of the invention differ from the DMC catalysts known in the art in that those of the invention contain a relatively small proportion of the metal salt. The catalysts of the invention contain some metal salt, but in an amount of less than about 0.2 moles of metal salt per mole of DMC compound. Preferably, the catalyst contains less than about 0.15 moles of metal salt per mole of DMC compound; more preferred are catalysts containing less than about 0.1 moles of metal salt per mole of DMC compound. DMC complexes containing no metal salt are inactive as epoxide polymerization catalysts. In this way, it is necessary to leave some metallic salt in the catalyst during the preparation. Excessive rinsing of the catalyst with water can deactivate the DMC catalysts by removing the entire metal salt component, even if an excess of the metal salt is used to prepare the catalyst. DMC catalysts made by conventional methods with a large excess of metal salt contain more than 0.2, typically more than 0.5, moles of metal salt per mole of DMC compound. The catalysts of the invention are substantially crystalline. X-ray diffraction analysis of the powder shows that these catalysts have predominantly sharp lines, which indicates a relatively high degree of crystallinity (see Figures 2 and 3). Interestingly, zinc hexacyanocobaltate dodecahydrate, which is prepared in the absence of a complexing agent, is also highly crystalline by X-ray analysis (see Figure 4), but has no activity for the polymerization of epoxides. Previously, we prepared highly active DMC catalysts that were substantially amorphous by X-ray diffraction analysis (see Figure 5, see also EP-A-0654302). These catalysts had a much higher activity than the DMC catalysts previously known in the art. Catalysts were obtained which polymerize propylene oxide at speeds greater than about 3 g PO / min in 100 ppm catalyst at 105 ° C (based on the weight of the finished polyether). Catalysts having both a high degree of crystallinity and high activity were not known. Surprisingly, we found that catalysts prepared under conditions effective to leave a small proportion of metal halide in the catalysts are highly crystalline and can polymerize propylene oxide at a rate greater than about 3 g PO / min in 100 ppm catalyst at 105 ° C. C (based on the weight of the finished polyether). For example, the zinc hexacyanocobaltate catalysts prepared by using the methods of the invention contained, by elemental analysis (chloride content), from about 0.07 to 0.18 moles of zinc chloride per mole of zinc hexacyanocobaltate. The catalysts exhibited X-ray powder diffraction patterns, substantially crystalline, with signals present at approximately 6.1, 5.9, 5.1, 4.2, 3.8, 3.6, 2.5, and 2.3 (d space, angstroms). Figures 2 and 3 show X-ray diffraction patterns of the powder for the catalysts of the invention. In addition to their elevated activities, the catalysts of the invention give polyether polyol products which have an exceptionally low level of unsaturation. The value of low unsaturation polyols to make polyurethanes with excellent physical properties is well documented. Polyether polyols having unsaturations of less than about 0.004 meq / g can be made using the catalysts of the invention. The invention includes methods for making the highly active DMC complex catalysts. Generally, the methods used to make the catalysts of the invention resemble the known methods for making the highly active, substantially amorphous catalysts described in EP-A-0654302 and in co-pending Application No. 08 / 435,116, filed on 15 May 1995. In these methods, a substantially amorphous DMC catalyst is prepared either by: (1) combining and reacting intimately the aqueous solutions of metal salt and metal cyanide salt in the presence of an organic complexing agent, usually with homogenization, high shear, or mixed by collision of the reagents; or (2) reacting the aqueous solutions of the metal salt and the metal cyanide salt in the presence of the organic complexing agent, wherein one or more of the reactive solutions contains the complexing agent. When the second method (organic complexing agent present before the reaction of the metal salt and the metal cyanide salt) is used, the intimate combination of the reactants is not required to obtain a substantially amorphous catalyst. The methods of the invention, which vary somewhat from these approaches, surprisingly give substantially crystalline DMC catalysts. The methods of the invention give catalysts that contain a relatively small proportion of metal salt compared to the substantially amorphous catalysts described in the preceding paragraph. One way of making a catalyst of the invention is to follow the procedures used to make a substantially amorphous catalyst, but using a smaller excess of the metal salt in the catalyst preparation (see example 3 and figure 3). The previous methods used a large excess of metallic salt. In this method of the invention, the metal salt is used in excess but the amount of excess is less than 100% stoichiometric excess relative to the amount of metal cyanide salt. The resulting catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound in the catalyst.

(The previous catalysts contained at least about 0.5 moles of the metal salt per mole of DMC compound in the catalyst). Another way of making a catalyst of the invention is to follow the procedures used to make a substantially amorphous catalyst, but modifying the rinsing routine (see Examples 1-2 and Figure 2). In this method, the aqueous solutions of the metal salt and the metal cyanide salt are first reacted in the presence of a substantially amorphous catalyst of organic complexing agents. In the case of making the reagents, they are either intimately combined, or the organic complexing agent is initially present in one or both of the reactive solutions. The metal salt is used in an excessive amount compared to the amount of metal cyanide salt, and the excess can be large or small. Unlike the above methods, this method rinses the catalyst precipitate with a mixture of water and an organic complexing agent in an effective manner to produce a highly active DMC complex catalyst containing less than about 0.2 moles of the metal salt per mole. of DMC compound in the catalyst. The amount and kind of rinsing necessary to obtain less than about 0.2 moles of residual metal salt per mold composed of DMC in the catalyst, depends on many factors, including which complexing agent is used, the relative amounts of water and organic complexing agent. in the rinsing solutions, the number of rinses, the volume of rinsing solution per gram of catalyst, the separation method used (ie, filtration or centrifugation), and other factors. With routine experimentation, a skilled person can select the conditions to make a catalyst of the invention that best suits his needs. The effectiveness of the rinsing routine can be calibrated by measuring the chloride and metal contents of the catalyst, and by inspecting the X-ray diffraction pattern of the powder exhibited by the catalyst. The invention includes a process for making an epoxide polymer. This process comprises the polymerization of an epoxide in the presence of a dimetic cyanide catalyst composition of the invention. Preferred epoxides are ethylene oxide, propylene oxide, butene oxides, styrene oxide, and the like, and mixtures thereof. The process can be used to make block or random copolymers. The epoxide polymer is preferably a polyether polyol made by the epoxide polymerization in the presence of an initiator containing a hydroxyl group. Other monomers which will be copolymerized with an epoxide in the presence of a DMC compound to make other types of epoxide polymers may be included in the process of the invention. Any of the copolymers known in the art made by the use of conventional DMC catalysts can be made with the catalysts of the invention. For example, the epoxides are copolymerized with oxetanes (as disclosed in US Patent Nos. 3,278,457 and 3,404,109) to give polyethers, or with anhydrides (as disclosed in US Patent Nos. 5,145,883 and 3,538,043) to give polyester or polyether ester polyols . For example, in US Patents. Nos. 5,223,583, 5,145,883, 4,472,560, 3,941,849, 3,900,518, 3,538,043, 3,404,109, 3,278,458, 3,278,457, and in J. L. Schuchardt and S.D. Harper, SPI Proceedings. 32nd Annual Polyurethane Tech. / Market. Conf. (1989) 360, the preparation of polyether, polyester and polyester polyols using dimethalic cyanide catalysts is fully described. The teachings of these E.U. related to the synthesis of polyol using DMC catalysts are hereby incorporated by reference in their entirety. The DMC catalysts of the invention are highly active in comparison to conventional DMC catalysts. One consequence of the high polymerization rates is that the polyol producers can use less of the relatively expensive DMC catalyst and save money. Many of the active catalysts also allow the producer to reduce production times and increase their productivity. further, the catalysts of the invention are often active enough to allow their use at very low concentrations, such as 25 ppm or less. At such low concentrations, the catalysts can often be left in the polyether polyol without an adverse effect on the quality of the product. The ability to leave the catalysts in the polyol is an important advantage because commercial polyols currently require a catalyst removal stage. The polyether polyols prepared by the use of the catalysts of the invention have exceptionally low unsaturations, consistently less than about 0.007 meq / g. Preferred polyols of the invention have unsaturations less than about 0.006 meq / g, and more preferably less than about 0.005 meq / g. The reduced unsaturation compared to polyols made with conventional DMC catalysts offer advantages for the polyurethanes made with the polyols of the invention. The polyether polyols made with the catalysts of the invention, preferably have average hydroxyl functionalities from about 2 to 8, more preferably from about 2 to 6, and more preferably from about 2 to 3. Preferably, the polyols have a number of weight molecular averages within the range of approximately 500 to approximately 50,000. A more preferred range is from about 1,000 to about 12,000; the most preferred range is the range from about 2,000 to about 8,000. The following examples merely illustrate the invention. Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims. EXAMPLE 1 Preparation of a Zinc Hexacyanocobaltate / Tert-Butyl Alcohol Complex Containing Less Than 0.2 Mole of ZnCl2 by Zn3 Mol [Co (CN) 6] 2 In this example, a stoichiometric excess of zinc chloride of 306 is used. % to make the catalyst, but the rinsing routine reduced the amount of zinc chloride remaining to less than 0.2 moles per mole of zinc hexacyanocobaltate present in the catalyst. Potassium hexacyanocobaltate (4 g) is dissolved in water (75 mL) to make Solution 1. Zinc chloride (10 g) is dissolved in distilled water (15 mL) to make Solution 2. Solution 3 contains tertiary alcohol. butyl (50 mL) and distilled water (150 mL). Solution 1 is combined with Solution 3. The aqueous solution of zinc chloride (Solution 2) is then slowly added while the reaction mixture is homogenized. After the addition of the zinc chloride is complete, the mixture is homogenized for another 20 min. The resulting solid catalyst is separated by filtration (5 micron filter) at 40 psi. The wet solids are combined with tert-butyl alcohol (50 mL) and distilled water (50 mL), and the mixture is homogenized for 20 min. The catalyst is filtered as previously described. The wet solids are combined with tert-butyl alcohol (70 mL) and distilled water (30 mL), the mixture is homogenized for 20 min, and the solids are separated. Finally, the solids are combined with clean tert-butyl alcohol (100 mL), they are homogenized and separated. The solids are then dried in a vacuum oven at 50-60 ° C, in 30 inches (Hg) for 4-5 hours.

The catalyst polymerizes the propylene oxide at a rate of ll.l g / min (100 ppm of catalyst, 105 ° C, as described in Example 4). Elemental analysis of the catalyst indicates a chloride content of 1.4% by weight (0.14 mole of ZnCl2 per mole of Zn3 [Co (CN) 6] 2). The X-ray diffraction analysis of the catalyst powder shows a substantially crystalline material exhibiting signals at approximately: 6.1, 5.9, 5.1, 4.2, 3.8, 3.6, 2.5, and 2.3 (d-space, angstroms) (see Figure 2). A polyether triol made by using the catalyst (see Example 5 for the process) has an unsaturation of 0.0043 meq / g and a hydroxyl number of 30 mg KOH / g. EXAMPLE 2 Preparation of a Complex of Zinc Hexacyanocobaltate / Tert-Butyl Alcohol Containing Less than 0.2 Mole of ZnCl2 by Zn3 Mol [Co (CN) 6] 2 In this example, a stoichiometric excess of zinc chloride of 306 is used. % to make the catalyst, but the rinsing routine reduces the amount of zinc chloride remaining to less than 0.2 moles per mole of zinc hexacyanocobaltate present in the catalyst. Generally the procedure of Example 1 is followed, except that the homogenized reaction mixture is heated to 30 ° C during the addition of the aqueous zinc chloride. The resulting solid catalyst is separated by filtration as in Example 1, except that a 1.2 micron nylon filter is used. The rinse sequence uses a 50/50 (volume) mixture of tert-butyl alcohol / water for the first two rinses, and clean tert-butyl alcohol for final rinsing. The catalyst is separated and dried as described in Example 1. The catalyst polymerizes the propylene oxide at a rate of 10 g / min (100 ppm of catalyst, 105 ° C, as described in Example 4). Elemental analysis of the catalyst indicates a chloride content of 1.8% by weight (0.18 mole of ZnCl2 per mole of Zn3 [Co (CN) 6] 2). X-ray diffraction analysis of the catalyst powder shows a substantially crystalline material exhibiting signals at approximately: 6.1, 5.9, 5.1, 4.2, 3.8, 3.6, 2.5, and 2.3 (d space, angstroms). A polyether triol made by using the catalyst (see Example 5 for the process) has an unsaturation of 0.0039 meq / g and a hydroxyl number of 31.1 mg KOH / g. EXAMPLE 3 Preparation of a Complex of Zinc Hexacyanocobaltate / Tert-Butyl Alcohol Containing Less than 0.2 Mole of ZnCl2 by Zn3 Mol [Co (CN) 6] 2 This example illustrates the preparation of a DMC catalyst by the use of a stoichiometric excess of only 63% of the metal salt to prepare the catalyst. A one-liter round bottom flask, equipped with mechanical stirrer, addition funnel for pressure equalization, and thermometer, is charged with potassium hexacyanocobaltate (5.0 g), tert-butyl alcohol (95 g), and distilled water ( 445 g). The mixture is stirred until all the metal cyanide salt is dissolved. The solution is heated to 25 ° C. A solution of zinc chloride (5 g) in water (5 g) is added during one minute to the stirred reaction mixture. Agitation continues for another 30 min. at 25 ° C. The resulting white suspension is filtered through a pressure filter at 30 psig. The solids are resuspended with vigorous stirring in a solution of tert-butyl alcohol (68 g) and water (38 g), which is a solution of 70:30 (by volume). After all the solids are completely suspended in the rinsing mixture, stirring is continued for an additional 30 minutes. The solids are again separated by pressure filtration, and resuspended in tert-butyl alcohol (99.5%) (98 g, 125 mL). After all the solids are completely suspended in the rinsing mixture, stirring is continued for an additional 30 minutes. The solids are separated and dried in a vacuum oven at 45 ° C, 30 inches (Hg) for 18 hours. The catalyst polymerizes propylene oxide at a rate of 10.9 g / min (100 ppm catalyst, 105 ° C, as described in Example 4). Elemental analysis of the catalyst indicates a chloride content of 0.7% by weight (0.07 mole of ZnCl2 per mole of Zn3 [Co (CN) 6] 2). X-ray diffraction analysis of the catalyst powder (see figure 3) shows a substantially crystalline material exhibiting signals at approximately: 6.1, 5.9, 5.1, 4.2, 3.8, 3.6, 3.1, 2.5, 2.3, and 2.1 (space d) , angstroms). A polyether triol made by using the catalyst (see Example 5 for the process) has an unsaturation of 0.0026 meq / g and a hydroxyl number of 29.8 mg KOH / g. EXAMPLE 4 Epoxide Polymerizations: Speed Experiments - General Procedure A stirred one-liter reactor was charged with initiator (70 g) of polyoxypropylene triol (700 moles by weight) and zinc hexacyanocobaltate catalyst (0.057 g, 100 level). ppm in the finished polyol). The mixture is stirred and heated to 105 ° C and removed in vacuo to remove traces of water from the triol initiator. The reactor pressure is adjusted to a vacuum of about 30 inches (Hg), and propylene oxide (10-11 g) is added in one portion. The reactor pressure was then carefully monitored. The additional propylene oxide was not added until an accelerated drop in pressure occurred in the reactor; the drop in pressure is evidence that the catalyst has become active. When catalyst activation is verified, the remaining propylene oxide (490 g) is added gradually to maintain the reactor pressure at approximately 10 psig. After the addition of the propylene oxide is completed, the mixture is maintained at 105 ° C until a constant pressure is observed. Unreacted residual monomer was then removed under vacuum from the polyol product, and the polyol was cooled and recovered. To determine the reaction rate, a consumption chart of PO (g) versus reaction time (min) was prepared (see figure 1). The declination of the curve at its steepest point is measured to find the reaction rate in grams of PO converted per minute. The intersection of this line and a horizontal line extended from the baseline of the curve is taken as the induction time (in minutes) required for the catalyst to become active.

When this method is used to measure the polymerization rates of the propylene oxide, the catalysts of the invention typically polymerize the PO at speeds of more than about 10 g / min in 100 ppm of catalyst at 105 ° C (see Figure 1). In contrast, a catalyst made by the method of the U.S. Patent. No. 5,158,922 polymerizes the PO at a rate of about 2 g / min in 100 ppm catalyst at 105 ° C. EXAMPLE 5 Synthesis of a Polyether Polyol A stirred two-gallon reactor is charged with initiator (685 g) of polyoxypropylene triol (700 moles by weight) and zinc hexacyanocobaltate catalyst (1.63 g). The mixture is stirred and heated to 105 ° C, and removed in vacuo to remove traces of water from the triol initiator. The propylene oxide (102 g) is fed to the reactor, initially under a vacuum of about 30 inches (Hg), and the reactor pressure is carefully monitored. No additional propylene oxide is added until an accelerated drop in pressure occurs in the reactor; the drop in pressure is evidence that the catalyst has become active. When catalyst activation is verified, the remaining propylene oxide (5713 g) is added gradually for about 2 hours while maintaining a reactor pressure at less than 40 psi. After the addition of the propylene oxide is complete, the mixture is maintained at 105 ° C until a constant pressure is observed. The residual unreacted monomer is then removed under vacuum from the polyol product. The hot polyol product is filtered at 100 ° C through a filter cartridge (0.45 to 1.2 microns) attached to the bottom of the reactor to remove the catalyst. The preceding examples are considered only as illustrations; the following claims define the scope of the invention.

Claims (18)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property. A complex dimethalic cyanide (DMC) catalyst comprising a DMC compound, an organic complexing agent, and a metal salt, wherein the catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound.
2. 2. A catalyst according to claim 1, characterized in that the DMC compound is a zinc hexacyanocobaltate and the metal salt is a zinc halide.
3. 3. A catalyst according to claim 1 or 2, characterized in that the organic complexing agent is selected from alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides, and mixtures thereof.
4. 4. A catalyst according to claim 3, characterized in that the organic complexing agent is tert-butyl alcohol.
5. 5. A catalyst according to claim 1, characterized in that it comprises zinc hexacyanocobaltate, tert-butyl alcohol, and zinc chloride and wherein the catalyst contains less than about 0.2 moles of zinc chloride per mole of zinc hexacyanocobaltate.
6. 6. A catalyst according to any of the preceding claims, characterized in that it contains less than about 0.15 moles of the metal salt per mole of DMC compound.
7. 7. A catalyst according to claim 6, characterized in that it contains less than about 0.1 mole of the metal salt per mole of DMC compound. A catalyst according to any of the preceding claims, characterized in that it is substantially crystalline and has X-ray diffraction signals of the powder at about 6.1, 5.9, 5.1, 4.2, 3.
8. 8, 3.6, 2.5, and 2.3 (space d, angstroms) .
9. 9. A catalyst according to any of claims 1 to 7, and characterized in that it has a powder X-ray diffraction pattern, as substantially shown in Figure 2.
10. 10. A catalyst according to any of the preceding claims, characterized in that it is effective to polymerize propylene oxide at a rate of more than 3 g PO / min in 100 ppm catalyst, based on the weight of the finished polyether, at 105 ° C.
11. 11. A catalyst according to any of the preceding claims, characterized in that it is capable of producing a polyether polyol having an unsaturation of less than about 0.005 meq / g.
12. 12. A method for making a highly active DMC complex catalyst, said method comprises reacting aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent, wherein the metal salt is used in an amount excessive of less than 100% stoichiometric excess relative to the amount of metal cyanide salt, and the resulting catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound in the catalyst.
13. 13. A method for making a highly active DMC complex catalyst, said method comprising: (a) reacting aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent to produce a catalyst precipitate, said excess metal salt being used in comparison with the amount of metal cyanide salt used; and (b) rinsing the catalyst precipitate with a mixture of water and an organic complexing agent in an effective manner to produce a highly active DMC complex catalyst containing less than about 0.2 moles of the metal salt per mole of DMC compound. in the catalyst.
14. 14. A method according to claim 12 or 13, characterized in that the DMC catalyst is a zinc hexacyanocobaltate.
15. 15. A method according to claim 12, 13 or 14, characterized in that the organic complexing agent is tert-butyl alcohol.
16. 16. A method according to any of claims 12 to 15, characterized in that the DMC catalyst is substantially crystalline and has X-ray diffraction signals of the powder at about 6.1, 5.9, 5.1, 4.2, 3.8, 3.6, 2.5, and 2.3 (d space, angstroms).
17. 17. A method according to any of claims 12 to 16, characterized in that the DMC catalyst contains less than about 0.1 moles of the metal salt per mole of DMC compound in the catalyst.
18. 18. A method for preparing an epoxide polymer, said method comprising the polymerization of epoxide in the presence of a catalyst as claimed in any of claims 1 to 11 or obtained by a method as claimed in any of claims 12 to 17 COMPLEX CATALYSTS OF DIMETALLIC CYANIDE HIGHLY ACTIVE SUMMARY The highly active dimethyl-cyanide (DMC) complex catalysts which, unlike other highly active DMC catalysts, are substantially crystalline, comprise a DMC compound, an organic complexing agent, and a metal salt, wherein the catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound. The catalysts can be formed by the reaction of aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent, wherein the metal salt is used in an excessive amount of less than 100% stoichiometric excess in relation to the amount of metal cyanide salt. Alternatively, the aqueous solution can be reacted with the excess metal salt to form a catalyst precipitate and then the precipitate is rinsed with water and the complexing agent to produce the catalyst product. The polyether polyols made from the catalysts have low unsaturation and are useful for making many types of polyurethane products.