MXPA01002259A - Method for producing polyetherols by ring-opening polymerisation of alkylene oxides - Google Patents

Abstract

The invention relates to a method for producing polyetherols by ring-opening polymerisation of alkylene oxides on H-functional starters. The method is characterised in that it has at least one step a) in which at least one metal hydroxide, a metal oxide and/or a metallic salt is used as a catalyst, said catalyst being applied to solid inert supports or introduced into the same or shaped into forms, and at least one step b) in which a multimetal cyanide compound is used as a catalyst, said multimetal cyanide compound being applied to solid inert supports or introduced into the same or shaped into forms or being in powder or paste form.

Description

POLYETER PREPARATION, ^ THROUGH POLYMERIZATION WITH RING OPENING OF ALKYLENE OXIDES The present invention relates to a process for preparing polyether alcohols by ring opening polymerization of alkylene oxides and to the use of polyetherols. Polyether alcohols are important raw materials in the production of polyurethanes. These are normally prepared by catalytic addition of lower alkylene oxides, in particular ethylene oxide and / or propylene oxide, into functional H starter molecules. At present, the preparation of the polyether alcohols is carried out in batch processes in which the catalyst is suspended in the initiator substance. The catalysts normally used are basic metal hydroxides or soluble salts, the potassium hydroxide being of greater industrial importance. The main disadvantage of the use of potassium hydroxide as a catalyst is that, in the preparation of high molecular weight polyether alcohols, this gives rise to the formation of unsaturated by-products which reduce the functionality of the polyether alcohols and have a very adverse effect on the the production of polyurethanes. To decrease the amount of unsaturated constituents in the product, EP-A 268 922 has proposed the use of cesium hydroxide as a catalyst. However, the use of expensive cesium hydroxide as a catalyst makes the process less economical. The basic metal hydroxides that dissolve the polyether polyols, for example potassium hydroxide and cesium hydroxide, have another disadvantage that these have to be extracted from the polyetherol at a higher cost after the synthesis and the resulting residues have to be discarded. Another class of substances that are probably Suitable catalysts for the preparation of polyether polyols are the sparingly soluble basic oxides or hydroxides. These basic oxides or hydroxides can be, for example, oxides or hydroxides of alkaline earth metals. Thus, US-A 5 679 764 describes the use of relatively thick magnesium oxide powders as catalysts for the alkoxylation. The use of oxides or hydroxides of alkaline earth metals, basic, doped, for example, hydrotalcite, has also been described. A complete series of patents describes the Preparation of fatty alcohol alkoxylates having narrow molecular weight distribution using hydrophobicized or calcined hydrotalcite as a catalyst. Representative examples of a large number of these patents are: DE-A 4 242 017, DE-A 4 137 317, DE-A 4 122 200, DE-A 4 115 149, DE-A 4 034 305, WO-A 94/11 331, O-A 92/11 224, US- 's ^ ss ^^^^^^^ -., ^^ M ^ ^^^ & ^^^^., ^^ d ^^ faith .. ^^ ¿^^^^^^^^ ^^^ A 4 962 237. According to the aforementioned patents, the alkoxylation of low molecular weight starter substances is carried out using a suspension process. It makes use of more or less thick powders that in most cases can be removed from the product only with a large technical effort. The catalysts consisting of alkaline earth metal oxide / hydroxide can easily alkoxylate low molecular weight starter substances and also easily ethoxylate starter substances of high molecular weight, but the reaction rate in the propoxylation of starter substances having an intermediate molecular weight is very low. . In order to reduce the amount of unsaturated components in the polyether alcohols and increase the reaction rate in the molecular addition of propylene oxide, the use of multimetal cyanide compounds, in particular zinc hexacyanomethalates, has been proposed as catalysts. There are a large number of publications in which these compounds have been described. Thus, DD-A-203 734 and DD-A-203 735 describe a process for preparing polyether alcohols using zinc hexacyanocobaltate. The preparation of zinc hexacyanomethalates is also known. This is usually done by reacting solutions of metal salts, usually zinc chloride, ^^^^ J ^^^^^^^ = ^^^^ with solutions of alkali metal or alkaline earth metal cyanometalates, for example, potassium hexacyanocobaltate. A water-miscible component containing one or more heteroatoms is normally added to the suspension of the resulting precipitation immediately after the precipitation process. This heteroatom-containing component may already be present in one or both of the initial solutions. The water-miscible heteroatom-containing component is preferably an ether, polyether, alcohol, ketone or a mixture of at least two of the mentioned compounds. These processes are described, for example, in US-A 3 278 457, US-A 3 278 458, US-A 3 279 459, US-A 3 427 256. DD-A-148 957 describes the preparation of zinc hexacyanoizidate. and its use as a catalyst in the preparation of polyether alcohols. In this case, hexacyanoic acid is used in place of the corresponding salt as one of the starting materials. The multimetal cyanide compounds prepared by means of an acid normally have a higher activity than those prepared from hexacyanomethalate salts. Although the cyanomultimetal catalysts show high activities in the propoxylation of the initiator molecules having molar masses greater than 400 daltons and can propoxylate them to have products of molecular weight ^^ - «» ^ «^^ c-raaaaaaa ^ -M high, the reaction of the initiating molecules of low molecular weight is associated with considerable difficulties. A particular disadvantage in the industrial use of • Multimetal cyanide catalysts is that the Alkoxylation of the low molecular weight starter molecules is very difficult. Often there is a delayed start of the reaction giving rise to the addition of too much alkylene oxide at the start. This can, in addition to reducing space-time performance, drive to serious safety problems in the production plants. Another problem associated with the use of cyano multimetal catalysts is that the addition of ethylene oxide on both high molecular weight and low molecular weight starter molecules, for example, to prepare polyetherols having ethylene oxide end blocks as used, among others, to produce polyurethane HR foams, it is not possible and the use of multimetal cyanide catalysts is, therefore, restricted to particular polyetherols. A simple combination of both catalysts in the process by first reacting the initiator substance with alkylene oxide in the presence of a basic catalyst provided that a molecular weight in which a double metal cyanide catalyst can be used and ^^^^^^^ ^ ^ ^ ^ ^ ^ ^ ^ W ^^^^^^ M ^^^^^^^^ ^ ^^^^^^^^^^^^^^^ ¡^^^^^^^^ _-______-__ then continue the reaction using double metal cyanide catalyst founders due to, among others, that the basic catalyst has to be removed almost quantitatively since it acts as a catalyst poison for the Multimetal cyanide catalysts. Even, the alkali metal hydroxide contents that remain in the polyether alcohol after the customary treatment are too high for this purpose. When insoluble catalysts suspended in the polyetherol are used, their removal is very difficult to carry out industrially if these catalysts have not been adequately conditioned. In addition, the purification step during the preparation of the polyetherols is an additional process step that leads to product losses, a reduction in space-time yield and the formation of waste materials that have to be discarded. An object of the present invention is to develop a process for preparing polyether polyols that give rise to polyetherols having a low content of unsaturated components, in which process the molecular addition of propylene oxide proceeds at a high reaction rate from the beginning of the reaction to high molar masses and, in which the incorporation of ethylene oxide end blocks can be carried out.

We have found that this objective is achieved by a process for the preparation of polyetherols by ring opening polymerization of alkylene oxides on functional H starter molecules, which consists at least in a process step (a) in which a compound of the formula (I): M'aM "b (0H) C 0d * Ae * Lf (I), Where M 'is a metal ion selected from groups IA, IIA, from the Periodic Table and Ni or Zn, and mixtures thereof, M "is a metal ion selected from groups IIIA, IVA, IB to VIIIB of the Periodic Table and As, Sb, and Bi, and 15 mixtures of these, A is at least one inorganic or organic anion, with single charge or multiple charge, L is at least one inorganic or organic ligand, where 20 a is a rational number greater than zero, b, c, d, e, f are rational numbers greater than or equal to zero, c and d must not be simultaneously zero, 25 a, b, c, d, e and f ______ £ _-____!% * ^ "_____- l___ ^^^^^^^ gg ^^^^^ are selected so that the compound is electrically applied to an inert solid support or incorporated in the latter or molded to form a molded body is used as a catalyst, and at least one process step (b) in which a multimetal cyanide compound of the formula (II): M1a [M2 (CN) b (A) c] d • fM ^ Xn • h (H20) • eL (II) where M1 is at least one metal ion selected from the group consisting of: Zn2 +, Fe2 +, Co3 +, Ni2 +, Mn2 +, Co2 +, Sn2 +, Pb2 +, Mo4 +, M06 +, A13 +, V4 +, V5 +, Sr2 +, 4+, 6+, Cr2 + , Cr3 +, Cd2 +, M2 is at least one metal ion selected from the group consisting of: Fe2 +, Fe3 +, Co2 +, Co3 +, Mn2 +, Mn3 +, V4 +, V5 +, Cr2 +, Cr3 +, Rh3 +, Ru2 +, Ir3 + and M1 and M2 are identical or different, A is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, X is at least one anion selected from the group consisting of : halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, -oxalate and nitrate, L is at least one miscible ligand in water selected from the group consisting of alcohols, aldehydes, ketones, 5 ethers, polyethers, esters, ureas, amides, nitriles and sulfides, ya, b, c, d, gyn are selected so that the compound is electrically neutral, and e is the coordination number of the ligand, e and f are fractional or integer numbers greater than or equal to zero h is a fractional or integer number greater than or equal to zero, applied to a solid, inert support or incorporated in the latter or molded to form a molded body or in the form of powder or paste is used as a catalyst. A process step a) is preferably carried out at the beginning of the reaction since the reaction rate in the polymerization of the alkylene oxide at the start of the reaction is higher when the catalysts of the formula (I) are used. After reaching a molecular weight of preference when less than 40 daltons, follow a step of ^^^^^^^^^^^^ gaga ^^^^^ Mj reaction b). This may be extended until the end of the alkylene oxide addition reaction. However, it is also possible to add another reaction step a). This can be useful, for example, if a block of ethylene oxide is to be added, preferably at the end of the chain. The introduction of a reaction step b) may also be useful if an ethylene oxide block is to be introduced into the chain and another propylene oxide is to be added later. The molecular addition of the propylene oxide can be carried out by means of process step b). The process of the present invention for preparing polyether polyols can be carried out as a suspension process or a fixed bed process. If the process is carried out in the suspension mode, the removal of the catalyst has to be very simple in each individual step. It is preferred that the catalyst can be separated from the polyether polyol in each individual step by simple filtration or centrifugation operations. This can be carried out, for example, by the size of the catalyst particles being sufficiently large or by suitable additions of filtration aids. However, particular preference is given to the fixed-bed method. For this purpose, the catalysts used have to be immobilized so that they remain in the im'rrJüfftflia'1, '- < yyyy «a» ^ ato «^ a_Sa reactor and, if possible, only simple filtration operations are necessary to eliminate the suspended material. The catalysts used in step a) are, as indicated, compounds of the formula (I) M'aM "b (0H) C 0d * Ae * Lf (I), where the symbols are as defined. The compounds of the formula (I) can be used as powder or coarser granules in a suspension process. However, the active compositions for step a) and b) are preferably applied to solid supports, incorporated in the latter or molded to form moldings. The supports for the catalysts of the formula (I) used according to the present invention are macroscopic shaped bodies, as is customary and are known as catalyst supports, for example, extruded, granulated, pellets, meshes, packaged elements, woven fabrics, fibers, spheres and also the internal walls of the reactors. The macroscopic moldings may consist of inorganic and / or organic materials. The inorganic materials are, for example, oxides, carbides, nitrides or inert materials. The examples of carbides They are transition metal carbides such as tungsten carbide, and also silicon carbide and boron carbide. Suitable nitrides are, for example, boron nitride, silicon nitride and aluminum nitride. For the purposes of the present invention, the inert metals are metals or metal alloys which are inert to the reaction medium in the synthesis of the polyether alcohol. Examples of inert metals are steels, aluminum, noble metals, nickel, stainless steels, titanium, Tantalum and Kanthal. As oxides, it is possible to use metal oxides which are inert under the reaction conditions, particularly those of the metals of groups IIA to IVA and IB to VIIIB, and also the oxidic compounds containing the elements of groups IA to VIIA and / or the metals of groups IB to VIIIB. The catalysts of the present invention can be produced by applying the compounds of type (I) to the surface of the molded supports or by mixing the compounds of type (I) with non-molded support material and subsequently molded. It is also possible to mold pulverulent compounds of type (I) to produce unsupported catalysts. These unsupported catalysts can then also be processed to obtain coarser granules to be used, if desired, in a process in which suspension. __¿fe _-_ te __- £ - im ^ g ^ l To prepare compounds of type (I), there are a large number of methods and possibilities. Thus, these compounds can be prepared by co-precipitation. For this purpose, a solution containing all the desired metal ions is formed and the ions are precipitated by the addition of other reagents, for example by altering the pH by the addition of a base. The precipitated solids may also be subjected to a hydrothermal treatment to induce greater crystallization. The intimate mixing of the components by evaporation of the joint solution on a rotary evaporator is also possible. The materials prepared in this way can subsequently be dried and calcined. Such compounds can also be prepared by impregnation or by maceration. For this purpose, a solid that already contains at least one of the desired components is treated with at least one solution that may contain the other metal ions. After removing the solvent, a drying step 20 and / or calcination can be carried out in the same way. The solids obtained in this way can then be subjected to further treatments with organic or inorganic ligands. Preferred compounds of type (I) are those in which M 'consists of alkaline earth metal ions or «^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The specific compounds that can be mentioned here are the pure oxides and hydroxides, for example, magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide or zinc hydroxide. However, in addition to the pure oxides and hydroxides, there is a wide range of possible dopants, on the sides of the cation and the anion. The impurification with other cations such as the elements of the main group boron, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic, antimony and bismuth and also the transition elements of groups IB to VIIIB, in particular chromium , iron, lanthanum, manganese, scandium, yttrium, titanium and vanadium, allow the preparation of a large number of compounds. The anions that can be used are the inorganic anions, for example, halides and anions containing sulfur, phosphorus, nitrogen or carbon, and also organic anions such as alkoxides, carboxylates, amides and sulfides and many more. The impurification of the pure oxides or hydroxides gives a large amount of compounds. Only a few examples will be given below: Hydrotalcite [Mg6Al2 (OH) 16] Co3 • 4 H20 Ta ovite [Ni6Al2 (OH)? 6] Co3 • 4 H20 Stichtite [Mg6CR2 (OH)? 6] Co3 • 4 H20 Hydrocalumite [Ca2Al (OH6)? H * «6 H20 Magaldrate [Mg? 0Al5 (OH) 31] (S04) 2 • m H20 Piroaurite [Mg6Al2 (OH) 16] Co3 • 4.5 H20 Ettringite [Ca6Al2 (OH) 12] (S04) 3 • 26 H20 The solids prepared as already described may be crystalline or amorphous The crystalline compounds may be crosslinked layer compounds such as hydrotalcite There are a number of methods that can be employed to mold the compounds of the formula (I). Application of the compounds of the formula (I) to an inert molded body consists of spraying a suspension of these compounds in an inert liquid.As a suspension for the spray, it is possible to use the precipitation slurry of the compounds or the compound previously. synthesized and possibly dried, suspended in a suitable suspension medium To increase the adhesion of the type I sprayed compound to the molded body, additional inorganic materials that act as binders can be added to the spray suspension. The moldings produced in this way can then be subjected to a calcination step. This can have a positive effect on the adhesion to the molded body and can also favor the formation of the phase a¿ - ^^ - ^ -_ a? _____-? «-____ ¿- - * p active. In addition, the inorganic or organic materials that can react in thermal or photochemical form, that is to say, become crosslinked and thus allow the active composition to adhere strongly to the support, can be added in pure form, in the form of their solutions, dispersions. or emulsions to increase the adhesion of the compounds of the formula (I) that has been sprayed. Preference is given in this case to the use of reactive organic polymers whose crosslinking products form porous structures or reactive inorganic materials such as metal metalates. These already described application methods of the compounds of the formula (I) to the support material can also be used if the compounds of the formula (I) are to be applied to the inner walls of the reactors. In addition to spraying a suspension containing the compounds of the formula (I), the powder of these compounds can be applied directly to the molded body using a method similar to a coating process with a high solids content, as described in DE 4 442 346. In this process, the molded bodies are usually sprayed with a liquid that favors adhesion in parallel with the supply of dust. As in the case of spraying, the materials that act as binders and ensure greater adhesion of the active components to the molded body They can be added to the liquid that favors adhesion. In this case it is also possible to add reactive components, i.e., crosslinkers, inorganic or organic. Another method of applying the compounds of the formula (I) to the molded body is to synthesize the compound or its precursor directly on the molded body. For this purpose, the different solutions containing the raw materials are contacted with the formed body at the same time or in short intervals. The molded body can be contacted with the solutions by spraying, immersion, maceration, impregnation or similar procedures. The mixing of the liquids on the molded body can give rise to precipitation of the active component or its precursor on the formed body. In the same way it is possible to apply the desired metal ions by maceration or successive impregnation. The molded bodies obtained in this way can, if necessary, be subjected to a hydrothermal crystallization. The molded bodies obtained in this way can also be subjected to a thermal treatment step if it is necessary to generate the compounds of the formula (I). In this case also, the materials that favor the addition can be added before or after the thermal treatment step. In the processes already described for producing the catalysts of the present invention, the compounds of the formula (I) are applied to the inert shaped bodies. However, it is also possible to produce molded compounds of the formula (I) by producing unsupported catalysts from the powders. This can be achieved by rattle or extrusion. A choice will be made between application to the inert molded bodies as supports or molded parts to produce unsupported catalysts based on the production costs for the compounds of the formula (I). When the oxidic compounds of the formula (I) are tabletted, it is generally necessary to add lubricants. These may be graphite, boron nitride or organic molecules such as stearates or alginates. The rattle can also be followed by a heat treatment step to burn the organic rattling aids. In the case of extrusion, the powders of the active composition can first be processed with a liquid constituent in a kneader, container mill or similar apparatus to produce a plastic composition. In this step of composition, the composition to be produced can be mixed with other ingredients that improve the properties of the plastic composition in the actual shaping step or give the molded body produced from this composition better cohesion. For the expert, there are a lot of possibilities to make use of the different additives. The amounts of additives present is not crucial: these must be very high to be fully effective but not so high that the catalytic activity of the compounds of the formula (I) is reduced. The molded bodies obtained in this way subsequently can be converted into granules which can then also be used in a suspension process. The granules used then have particle sizes from 100 μ to 2 mm, preferably from 250 μ to 1 mm. Another possibility for producing the catalysts is to embed the compounds of the formula (I) in a solid matrix. The solid matrix may be of inorganic or organic nature. To embed the compounds of the formula (I) in an inorganic matrix, the compounds of the formula (I) can be suspended in metalates, esters or alkoxymethalates. The addition of bases or acids gives rise to the polymerization of the metalato esters to obtain solid materials. In this case preference is given to the esters of silicic, aluminum, titanic and / or zirconic acids. As organic components, it is possible to use all materials or mixtures of materials in which the compounds of the formula (I) can be suspended and which can be polymerized in some way to form *. * _. ^ _ $ £ &. * f > - ^ *. ^^^^^^^ te ^ M ^ solids. The polymerization must be carried out in such a way that the solid particles formed can be used in a fixed-bed arrangement. In addition, the solid particles obtained must have sufficient porosity so that the raw materials and products can be transported to and from the active composition. To improve the porosity, it is possible to add, during the polymerization, auxiliaries that can be eliminated again by physical or chemical treatments after the polymerization. The polymerization can also be carried out in such a way as to produce open-pored foam in which the active composition is fixed. The catalysts for step b) are, in particular, multimetal cyanide catalysts of the formula: M1a [M2 (CN) ".A) c] d • fM ^ Xn • h (H20) • eL (II) where M1 is at least one metal ion selected from the group consisting of Zn2 +, Fe2 +, Co3 +, Ni2 +, Mn2 +, Co2 +, Sn2 +, Pb2 +, Fe3 +, Mo4 +, Mo6 +, A13 +, V4 +, V5 +, Sr2 +, W4 +, 6+, Cr2 +, Cr3 +, Cd2 +, preferably consisting of Zn2 +, Fe2 +, Ni2 +, Mn2 +, Co2 + and Cr2 +, particularly preferably Zn2 +, M is at least one metal ion selected from the group consisting of: Fe2 +, Fe3 +, Co3 +, Cr3 +, Mn2 + , Mn3 +, Rh3 +, Ru2 +, Ru3 +, V4 +, V5 +, Co2 +, Ir3 + and Cr2 +, preferably consisting of Co3 +, Fe3 +, Fe2 +, Rh3 +, Ir3 +, particularly preferably Co3 +, Rh3 +, Ir3 + and Fe3 +, identical or different from M1, A is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, X is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, L is at least one organic ligand miscible anic water selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides, nitriles and sulfides, a, b, c, d, g and n are selected such that the compound is electrically neutral, e is the coordination number of the ligand, e and f are fractional or integer numbers greater than or equal to zero, h is a fractional or integer number greater than or equal to zero. These can again be used in the form of powder, in the form of paste or in the form of relatively thick granules for a suspension process. For the fixed bed method, the double metal cyanides can, according to the present invention, be applied to solid supports, incorporated in the latter or molded to form moldings. Suitable methods for this have already been described in detail in the foregoing. The double metal cyanide complex can be prepared by customary methods. These methods are described, for example, in US 5,741,428, US 5,693,584, US 5,637,673, US 5,627,122, US 5,627,120, US 5,589,431, US ,536,883, US 5,482,908 US 5,470,813. The preparation of the polyethers is normally divided into the following process steps: In process step a), the lower alkylene oxides, in particular ethylene oxide and / or propylene oxide, are added to the functional starting substances H . The functional H initiating substances used in the process of the present invention are preferably alcohols, in particular those having from 1 to 8, but preferably from 2 to 3 hydroxyl groups and from 2 to 6 carbon atoms in the molecule.

^^^^^^^^^ Mgl ^^ I ^ g ^^^^^ g ^^^^^^^^^^ Examples are glycols, particularly ethylene glycol and propylene glycol, and glycerol, trimethylolpropane or pentaerythritol It is also possible to use mixtures of alcohols with each other or with water. The addition of alkylene oxides on the initiator substances is carried out under the customary conditions for this purpose, that is, at temperatures in the range from 80 to 150 ° C and pressures in the range from 0.1 to 8 bar. Before the alkylene oxides are dosed, the reaction mixture must be made inert by dragging with an inert gas, preferably nitrogen. The catalyst of the formula (I) can in this case be present as a fixed bed or a moving bed or suspended in the initiator substance. The start of the reaction can be recognized by a decrease in the pressure in the reactor. After the alkylene oxide has reacted and, if appropriate a further time after the reaction, the reaction product of the alkylene oxide is separated from the catalyst and treated. In order to remove fine constituents of the catalyst and the abraded material, the reaction product of alkylene oxide can be filtered. To remove volatile constituents, the product, as is customary, is subjected to a distillation, preferably at reduced pressure.

The product of process step a) preferably has a molecular weight of from 100 to 1000 g / mol. To carry out process step b), the end product of process step a) is mixed with a multimetal catalyst of the formula (II) and reacted with an alkylene oxide, in particular propylene oxide. The multimetal catalyst can likewise be applied to inert supports or be incorporated in the latter or molded to form moldings. But you can also be present as a suspension in the reaction mixture. The reaction proceeds under the same reaction conditions as in process step a). The final product of process step b) has a molar mass from 100 to 100,000, in particular from 1000 to 50,000. Process step b) can be followed by another process step a), in particular using ethylene oxide as alkylene oxide. However, the molecular addition of a final block of ethylene oxide can also be carried out using customary alkaline catalysts such as potassium hydroxide. The polyetherols prepared by the process of the present invention have a low content of unsaturated compounds, even at high molar masses. The reaction proceeds in a very high space-time yield. The polyetherols 5 prepared by the process of the present invention are they use, in particular, to produce polyurethanes. The invention is illustrated by the following examples.

Production of catalysts for process step a) Example 1 600 g of hydrotalcite (C300, Giulini) were composed with 400 g of boehmite (Pural® SB, Condea) and 610 ml of an aqueous solution of formic acid (2% by weight of formic acid) for one hour in a kneader and extruded to produce round extrusions with a diameter of 2 mm. The extrudates were dried at 120 ° C and calcined at 500 ° C for 5 hours. Part of the obtained extrudates were converted into 1.6 mm granules for Example 6.

Example 2 A solution of 175 g of sodium carbonate and 398 g of sodium hydroxide in 2 1 of water was placed in a glass flask and heated to 40 ° C. With continuous agitation, a solution of 109 g of lithium nitrate and 1238 g of aluminum nitrate in 1.5 1 of water was added over a period of 30 minutes. The resulting suspension was then stirred . ^^^? ^^ .- ytiM. ^? ^ e ?, for another two hours A.40 ° C. The solid formed was then filtered with suction, washed with water and dried at 110 ° C for 16 hours. > Example 3 120 g of powder of Example 2 were compounded with 80 g of boehmite (Pural® SB, Condea) and 59 ml of an aqueous solution of formic acid (2% by weight of formic acid) for one hour in a kneader and extruded to produce round extrusions having a diameter of 2 mm. The extrudates were dried at 120 ° C and calcined at 500 ° C for 5 hours.

Example 4 200 g of powder of Example 2 were compounded with 52 ml of an aqueous solution of formic acid (2% by weight of formic acid) for one hour in a kneader and extruded to produce round extrudates with a diameter of 2 mm. The extrudates were dried at 120 ° C.

Example 5 < . = s 50 g of magnesium carbonate hydroxide (4 MgCo3 • MG (OH) 2) were composed of 33.3 g of boehmite (Pural® SB, Condea) and 78 ml of an aqueous solution of formic acid (2% by weight of formic acid) for one hour in a kneader and extruded to produce round extrusions with a diameter of 2 mm. The extrudates were dried at 120 ° C and calcined at 500 ° C for 5 hours.

Example 6 The synthesis was carried out in a 5 liter, cleaned and dried reactor, with stirring. At room temperature 779.5 g of glycerol and 35.3 g of granulated catalyst as described in Example 1 were placed in the reactor. The contents of the reactor were then made inert by evacuating the reactor three times and filling it with nitrogen after each evacuation. At 95 ° C, a vacuum better than [sic] 1 mbar absolute was applied for 5 hours. Subsequently, a total of 1648 g of propylene oxide were added little by little at 125 ° C at such a rate that an internal reactor pressure of 7.2 bar absolute was not exceeded. After the addition and reaction were complete, a vacuum was applied with a water pump for 30 minutes at 125 ° C. For i &ttáias? & In order to separate the catalyst, the reaction product was filtered through a double layer of a Seitz deep bed filter. Analysis: OH value = 588 mg KOH / g, viscosity = 788 mPa * s (at 25 ° C), unsaturated constituents = 0.0226 meq / g, GPC: Mn = 198.3 g / mol, Mw = 208.9 g / mol, D = 1.053.

Example 7 The synthesis was carried out in a 5 liter, cleaned and dried reactor, with stirring. At 50 ° C, 303.2 g of the product of Example 6 were introduced. The contents of the reactor were made inert by evacuating three times and then filling with nitrogen each time. The degassing was performed by evacuation to less than 1 mbar to absolute for 1.5 hours at 105 ° C. 1589 g of a multimetal catalyst of the reaction of zinc acetate with hexacyanocobatic acid were then added. The reactor was again evacuated three times and filled with nitrogen each time. This was followed by evacuation to less than 1 mbar abs. for 25 minutes at 125 ° C. At the same temperature, a nitrogen pre-pressure of 3.5 bar was applied and 195 g of propylene oxide and 29 g of ethylene oxide were added. The beginning of the reaction was recognized by the pressure drop. Subsequently, a mixture of 3996 g of propylene oxide and 570.5 g of ethylene oxide were ; = ^ ÍAS¿ £ ^ ^ fesá £ a ¡¡¡¡a ^^ introduced during a period of 3.3 hours. After another 30 minutes at 125 ° C, the crude polyol was released from the volatile constituents under reduced pressure. The catalyst was separated by means of a double layer of Seitz deep bed filter. Analysis: ce index OH = 35.8 mg KOH / g, viscosity = 1024 mPa * s (at 25 ° C), unsaturated constituents = 0.0028 meq / g, GPC: Mn = 3525 g / mol, Mw = 3673 g / mol, D = 1.042. fifteen twenty _-._- S_K__Bft_n_i_.

Claims (1)

1. CLAIMS A process for preparing polyetherols by ring opening polymerization of alkylene oxides on functional H starter molecules, which comprises at least one process step a) in which a compound of the formula (I): M'aM "b (0H) C Od Ae *: D where M 'is a metal ion selected from groups IA, IIA, of the Periodic Table and Ni or Zn, and mixtures thereof, M "is a metal ion selected from groups IIIA, VAT, IB to VIIIB of the Periodic Table and As, Sb, and Bi, and mixtures thereof, A is at least one inorganic or organic anion, with single charge or multiple charge, L is at least one inorganic or organic ligand, where a is a rational number greater than zero, b, c, d, e, f are rational numbers greater than or equal to zero, c and d ^ ^ A ^ _ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ A ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorporated in the latter or molded to form a molded body is used as a catalyst, and at least one process step (b) in which a multimetal cyanide compound of the formula (II): M1a [M2 (CN) b (A) c] d • fMA-n • h (H20) • eL (II) where M1 is at least one metal ion selected from the group consisting of: Zn2 +, Fe2 +, Co3 +, Ni2 +, Mn2 +, Co2 +, Sn2 +, Pb2 +, Mo4 +, Mo6 +, A13 +, V4 +, V5 +, Sr2 +, 4+, W6 +, Cr2 +, Cr3 +, Cd2 +, M2 is at least one metal ion selected from the group consisting of: Fe2 +, Fe3 +, Co2 +, Co3 +, Mn2 +, Mn3 +, V4 +, V5 +, Cr2 +, Cr3 +, Rh3 +, Ru2 +, Ir3 + and M1 and M2 are identical or different, A is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, X is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, L is at least one miscible ligand in water selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides, nitriles and sulfides, a, b, c, d, g and n are selected so that the compound is electrically neutral, and e is the coordination number of the ligand, e and f are fractional or integer numbers greater than or equal to zero is a fractional or integer number greater than or equal to zero, applied to a solid support, inert or incorporated in the latter or molded to form a molded body or powder or paste form It is used as a catalyst. The process as claimed in claim 1, wherein the alkylene oxide is first added onto the > j'w > you---. ugly-6a * á *? ****? mim ± »u? l *** '< ~ * ~ * initiator molecule in a process step a) and a process step b) then performed. The process as claimed in claim 1, wherein the alkylene oxide is first added onto the initiator molecule in a process step a) then a process step b) is performed and another process step a) is carried out subsequently. The process as claimed in claim 1, wherein the alkylene oxide used in process step a) is ethylene oxide and / or propylene oxide and the alkylene oxide used in process step b) is propylene. The process as claimed in claim 1, wherein the alkylene oxide used to carry out process step a) at the end of the process is ethylene oxide. SUMMARY A process for preparing polyetherols by ring opening polymerization of alkylene oxides on functional H starter molecules, which comprises at least one process step a) in which a compound of the formula (I): M'aM 'OH) c Od * Ae * Lf (I) where M 'is a metal ion selected from groups IA, IIA, from the Periodic Table and Ni or Zn, and mixtures thereof, M "is a metal ion selected from groups IIIA, IVA, IB to VIIIB of the Periodic Table and As, Sb, and Bi, and mixtures thereof, A is at least one inorganic or organic anion, with single charge or multiple charge, L is at least one inorganic or organic ligand, where a is a rational number greater than zero, b, c, d, e, f are rational numbers greater than or equal to zero, c and d must not be simultaneously zero, a, b, c, d, e and f are selected so that the The compound is electrically applied to an inert solid support or incorporated in the latter or molded to form a molded body is used as a catalyst, and at least one process step (b) in which a multimetal cyanide compound of the formula (II): M'atM ^ CN) fMAr h (H20) eL (II) where M1 is at least one metal ion selected from the group consisting of: Zn2 +, Fe2 +, Co3 +, Ni2 +, Mn2 +, Co2 +, Sn2 +, Pb2 +, Mo4 +, Mo6 +, A13 +, V4 +, V5 +, Sr2 +, 4+, 6+, Cr2 + , Cr3 +, Cd2 +, M2 is at least one metal ion selected from the group consisting of: Fe2 +, Fe3 +, Co2 +, Co3 +, Mn2 +, Mn3 +, V4 +, V5 +, Cr2 +, Cr3 +, Rh3 +, Ru2 +, Ir3 + and M1 and M2 are identical or different, A is at least one anion selected from the group consisting of: halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, X is at least one anion selected from the group consisting of : halide, hydrotroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate and nitrate, L is at least one miscible ligand in water selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides, nitriles and sulfides, ya, b, c, d, g and n are selected so that the compu this is electrically neutral, and e is the coordination number of the ligand, e and f are fractional or integer numbers greater than or equal to zero. h is a fractional or integer number greater than or equal to zero, applied to a solid support, inert or incorporated in the latter or molded to form a molded body or powder or paste form is used as a catalyst.