Process for preparing polyether alcohols

Process for preparing polyether alcohols

Technical field

The present invention relates to polyetherols, their preparation and their use in the preparation of polyurethanes.

BACKGROUND OF THE INVENTION

Polyether alcohols are used in large quantities for the preparation of polyurethanes. They are usually prepared by catalytic addition of lower alkylene oxides, in particular ethylene oxide and propylene oxide, to the H-functional initiator compounds. Base metal hydroxides or salts are usually used as catalysts, with potassium hydroxide being of greatest industrial importance.

Many industrial applications use polyether alcohols whose polyether chains are built from more than one alkylene oxide. Lower alkylene oxides, such as ethylene oxide, propylene oxide and butylene oxide, are commonly used in industry, with ethylene oxide and propylene oxide being of greatest industrial importance. The molecular addition may be performed in a block fashion, ie. only one alkylene oxide is attached at a time. The polyether alcohols prepared in this way have polyether chains in which the segments of one alkylene oxide are arranged in sequences. Another possible method for preparing polyether alcohols from at least two alkylene oxides is the disordered process, also known as heterogeneous, molecular addition of alkylene oxides. Here, the alkylene oxides are fed to the reaction mixture in the form of a mixture. These mixtures usually contain alkylene oxides in a constant ratio to each other. This method of introducing alkylene oxides is hereinafter referred to as "classical disordered". The ratio referred to herein is the ratio of the amount of the alkylene oxides, provided that it is irrelevant whether it is an "amount by weight or molar amount, for example, expressed in units of" moles of alkylene oxides.

The known processes for the preparation of polyether alcohols have disadvantages, which become particularly obvious when using catalysts having high catalytic activity, and their use results in the molecular addition of alkylene oxides occurring at high speeds. Thus, when multimetallic cyanide catalysts, also known as DMC catalysts, are used to prepare polyether alcohols by molecular addition of a plurality of alkylene oxides, qualitative problems often occur with respect to polyether alcohols. The block molecular addition of alkylene oxides often results in very high molecular weight distribution and haze in polyether alcohols, while a disordered process often results in an end-chain ethylene oxide segment content that is too high for many applications. The addition of terminal ethylene oxide blocks to propoxylates or blocks of disordered alkylene oxide mixtures results in the formation of very high molecular weight ethoxylates that weigh large proportions of ethylene oxide introduced. These polyols have viscosities that are undesirably high for processing. This has the additional consequence that the ethylene oxide content of the polyether alcohols must be very high in order to achieve the high end ethylene oxide contents desired for the reactive polyols, as a result of which the hydrophilicity of the polyethers is greatly increased. Even in cases where it is possible to treat these polyethers to obtain a polyurethane foam, this results in foams that are very susceptible to hydrolysis. Other problems often stem from the fact that various organic or inorganic substances, such as water, glycerol and catalysts, which are the usual formulation ingredients in the production of polyurethanes, must be dissolved in the polyol during processing to give a polyol component which is then used in the urethane reaction. . Block types, block lengths and block splits are therefore often subject to severe restrictions.

WO 97/27236 (EP 876 416) discloses a polyether alcohol for use in highly elastic flexible foams, wherein the polyether alcohol comprises propylene oxide inner blocks containing no more than 35% by weight of the total amount of alkylene oxide and one or more ethylene oxide and propylene oxide outer blocks having ethylene oxide content at least 2% by weight, wherein the inner block is at least partially catalyzed and the outer blocks are catalyzed completely by multimetallic cyanide catalysts. However, such polyether alcohols are usually substantially more reactive than industrial, base catalyzed polyether alcohols and thus cannot easily be incorporated into known polyurethane systems. In addition, the polyether alcohols prepared in this way are usually cloudy.

The problems indicated are particularly evident in the case of polyurethane foams, in particular resilient foams, and are most obvious in the case of resilient sheet foams. In particular, cracks in the foam occur and the mechanical properties of the foams deteriorate.

When multimetallic cyanide catalysts are used, high contents of terminal primary hydroxyl groups can be achieved with ethylene oxide terminal blocks only at the cost of high hydrophilicity and extremely high viscosities.

DD-A-275 695 describes a process for preparing polyether alcohols in which ethylene oxide and propylene oxide are added as a disordered mixture in which the ratio of alkylene oxides increases or decreases uniformly. However, because of the low catalytic activity of the potassium hydroxide used as a catalyst, the incorporation of alkylene oxides into the polyether chain is not in the ratio in which they are introduced, but instead is altered by back mixing with a previously introduced alkylene oxide which has not yet been incorporated. As a result, the desired block structures can be realized only to a limited extent and the properties of the polyether alcohols prepared in this way sometimes differ slightly from the properties of the polyether alcohols prepared in the conventional disordered manner. Although this deficiency can be alleviated by slower dosing, it can lead to uneconomically long batch retention times. Use of catalysts that are not highly active, e.g. potassium hydroxide leads to undesired secondary reactions during the synthesis and these reactions cause losses of alkylene oxides as well as deterioration of product quality. Thus, iodine numbers of less than 0.4 cannot be achieved, which still indicates a considerable level of secondary reactions. In particular, the formation of unsaturated components results in a loss of hydroxyl functionality as a result of which the amount of polyetherol required in the polyurethane reaction is increased. In addition, the formation of colored or odor-causing by-products adversely affects the quality of the polyether polyols prepared by this process.

In addition, the starting and end points of the feed of the alkylene oxides described in DD-A-275 695 must in any case be pure alkylene oxide. As a consequence, the disordered blocks described in DD-A-275 695 cannot always be advantageously combined with classical disordered blocks. Thus, polyols having moderate primary hydroxyl contents cannot be obtained. In addition, the polyether alcohols which must be prepared by this process and initiated with ethylene oxide always contain a chain section consisting of pure ethylene oxide. This leads to undesirable high susceptibility to hydrolysis, high viscosities, and susceptibility to turbidity of the polyether. If these disordered polyethers terminate in ethylene oxide, the effects of back-mixing become undesirable in such a way that some propylene oxide can always be found at the end of the chain.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide polyether alcohols which can be prepared by the catalytic addition of at least two alkylene oxides to H-functional initiator compounds having no haze, having processing-friendly viscosities and which can be processed without problems to obtain polyurethanes, particularly flexible polyurethane foams. In addition, the content of alkylene oxides at the end of the polyether chain should be capable of being treated as intended. High molecular weight ends, such as occur in the molecular addition of alkylene oxides by a conventional block process using DMC catalysts to prepare polyether alcohols, should be avoided. In addition, the long transition and pressure stabilizing phases that are usually needed between blocks should be avoided.

We have found that this object is achieved by a process for preparing polyether alcohols by catalytic addition of at least two alkylene oxides to an H-functional initiator compound, wherein at least one co-introduction of two alkylene oxides is performed during addition of alkylene oxides to the initiator compound. .

• · ···· · · · · · ·· • ·· · · · · · · ··

This type of metered introduction of alkylene oxides is hereinafter referred to as the dynamic process.

For the purposes of the present invention, the term "ratio as described above" is the ratio of the amount of alkylene oxides dosed during the dynamic process.

The present invention therefore provides a process for preparing polyether alcohols by catalytic addition of at least two alkylene oxides to an H-functional initiator compound, wherein at least one multimetallic cyanide compound is used as a catalyst and the addition of alkylene oxides to the initiator compound comprises incorporating at least one oxyalkylene block. during which at least two alkylene oxides are fed together and the ratio of alkylene oxides fed in the mixture is varied during co-introduction.

The present invention also provides polyether alcohols prepared by said process for their use in the preparation of polyurethanes, in particular flexible polyurethane foams, and for polyurethanes produced using polyether alcohols.

The change in the ratio of alkylene oxides can be linear or non-linear. A linear change in the ratio of alkylene oxides means that the ratio of alkylene oxides varies in equal amounts over any of the same time intervals. In this case, plotting the ratio of alkylene oxides versus time gives a straight line. A non-linear change in the ratio of alkylene oxides means that the amounts after which the ratio changes at the same time intervals vary. In this case, plotting the ratio of alkylene oxides versus time gives a curve that is not a straight line. This curve can also be exponential.

The dynamic process may also be arranged such that the total amount of ethylene oxide dosed over a given period of time is constant throughout the dynamic process, but it is also possible to vary the total amount of alkylene oxide dosed over a given period of time. This can be achieved on the one hand by maintaining a constant amount of one alkylene oxide and varying the amount of the other alkylene oxide or, on the other hand, by varying the amount of both alkylene oxides. In the latter case, the ratio of alkylene oxides to each other must be varied as described above.

The dynamic process can be carried out in such a way that the content of one of the alkylene oxides is continuously reduced during the process until the desired content of the alkylene oxide in the mixture is reached or only the other alkylene oxide is still fed. It is also possible to carry out the dynamic process in such a way that the content of one of the alkylene oxides in the mixture is first continuously increased and then, immediately or after the phase with a constant ratio of alkylene oxides, is continuously reduced. At the beginning and end of the dynamic process, one or both of the alkylene oxides may in each case be present in the feed mixture.

In the simplest embodiment of the method of the present invention, the total polyether chain is formed from individual blocks introduced by addition by a dynamic method.

However, it is preferred to add to a single portion of the polyether chain by a dynamic method and to add to the remaining alkylene oxide in a known block or disordered manner. Here, one or more alkylene oxide blocks

A · · ·

AA · · AA · «··········

AA · AAAAA ·

AA AA AAA · A

AA ··· ♦ ·

AAAAAA AAA AA AA AAA added by the dynamic method can be incorporated into the polyether chain.

The alkylene oxide blocks which have been added in a dynamic manner can be located at the beginning, at the end or in the middle of the polyether chain.

When an alkylene oxide block is added by a dynamic method, it is possible to directly add at least one block made up of only one alkylene oxide to the block. This is preferably done by continuously reducing the content of alkylene oxide, which is not used to form the next block, in the feed mixture during the dynamic process until its content in the mixture is finally zero and then continuing to feed the second alkylene oxide itself. However, it is also possible for both alkylene oxides to still be present in the mixture at the end of the dynamic process and then the introduction of one of the alkylene oxides is stopped while the other alkylene oxide is metered in.

It is also possible for at least one block containing two alkylene oxides that it can be added in a conventional disordered manner directly to an alkylene oxide block which has been attached by addition by a dynamic method. Here, it is possible to carry out a dynamic process as long as the alkylene oxide ratio is one in which the subsequent disordered block is to be added by addition and then the alkylene oxide introduction is to continue at that ratio or the dynamic dosing is stopped and then the alkylene oxide dosing is continued at the ratio connected in the subsequent block.

Similarly, it is possible to add at least one block of only one alkylene oxide or two alkylene oxides in a classical disordered manner to an alkylene oxide block that is 9 99

9 9 9 9

9 9 9 9

09 / 99 9999 connected by addition using a dynamic method. Also here, the ratio of alkylene oxides at the end of this classical block may be the same or different from the ratio of alkylene oxides at the beginning of the block according to the dynamic method.

As indicated above, it is possible to add the block in a dynamic manner directly to the initiator compound. This block may, as described above, contain one or both alkylene oxides at the beginning of the metered introduction and may be dosed in any of the above-described dynamic process variants. This may be followed, as described, by at least one pure alkylene oxide block or at least one alkylene oxide block added by a classical disordered method. The polyether chain may also comprise at least one additional alkylene oxide block, which may be added by a dynamic process.

In addition, the alkylene oxide block added by the dynamic process may also be incorporated at the end of the chain. Also in the case of this block, all the embodiments of the dynamic method described above are possible. Thus, the block may comprise one or both alkylene oxides at the beginning and one or both alkylene oxides may then be dosed at the end of the metered introduction.

In the case of alkylene oxide blocks that are added using a disordered polyether chain method, the described embodiments containing a block containing and located in the center similarly can be used. at the beginning of the dynamic process and at the beginning of the metered feed contains only the alkylene oxide previously metered

1 alone or in a mixture of alkylene oxides used to introduce dynamic blocks. Similarly, only one or both alkylene oxides may be present at the end of the dynamic block. Later, a pure alkylene oxide block or a classical disordered alkylene oxide block may similarly be added, which block may initially have the same or different ratio of alkylene oxides to the block.

Conventional molded elastomers other than the ratio present at the end of the dynamic polyether alcohol for use in flexible urethane foams or polyurethane foams typically have an inner block consisting of propylene oxide or a classic disordered mixture of ethylene oxide and propylene oxide. This is surrounded by pure ethylene oxide block, which is needed to provide a high content of primary hydroxy groups. When multimetallic cyanide catalysts are used, this process yields highly viscous, turbid polyethers having a low primary hydroxyl content. Although the content of primary hydroxy groups may be increased by the molecular addition of relatively long chains of ethylene oxide, it also results in an undesirably high increase in the hydrophilicity of the polyether alcohols. However, when a block having an increased ethylene oxide content at the end of the feed is added by a dynamic method to the end of a polyether chain starting from a classical disordered block or a block of only one alkylene oxide, the desired primary hydroxyl groups without long ethylene oxide blocks can be obtained. they had to be added to the end of this chain.

On the other hand, when polyols are used in flexible sheet foams, it is preferred to use polyether alcohols having a primary hydroxy content of & lt; 10%. On polyether with closed to unwanted hydroxy groups.

on the other hand, some ethylene oxide content should be present in the chain, since ethylene oxide in the polyether chain improves the solubility of water and various other additives needed to prepare polyurethanes in the polyol and is moreover cheaper than propylene oxide. In addition, some ethylene oxide content in the outer chain is useful for the excretion of foams by cells. However, in the classic disordered process, the ethylene oxide content cannot exceed certain limits, as too much ethylene oxide at the chain end results in an increased primary content. However, if the addition is introduced with an alkylene oxide mixture by a dynamic process in which the ethylene oxide content is reduced downstream content in the alkylene oxide mixture, high ethylene oxide contents can be introduced into the chain without causing an adverse effect on the reactivity, which is raised by primary hydroxy groups. An additional short block of pure propylene oxide at the chain end is also possible.

The process of the present invention is particularly advantageously carried out using multimetallic cyanide catalysts since these catalysts have a very high activity and therefore ensure that the introduced alkylene oxide is immediately incorporated into the chain.

These catalysts generally have the general formula (I)

M¹and [M² (CN) b (A) c-d. fM^XgXn. h (H₂O). eL (I) where

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• ·

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2+ groups consisting of Zn,

Τ-.Ί 2 + * 4+ _Kjr 6+ 71 η 3+ τ4 + τ5 +

Pb, Mo, Mo, Al, V, V,

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and consisting of Fe²⁺Cr³⁺, Rh³⁺, Ru²⁺ and Ir³⁺

M¹ and M² they are the same or different

A is an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, and nitrate,

X is an anion selected from the group consisting of halides, hydroxide, sulfate, carbonate, cyanide, thiocyanates, isocyanate, cyanate, carboxylates, oxalate and nitrate,

L is a water miscible ligand selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides, nitriles, and sulfides, and a, b, c, d, g, and n are selected such that the compound is electrically neutral, ae is a ligand coordination number, a fraction or an integer greater than or equal to zero, f is a fraction or an integer greater than or equal to zero, and h is a fraction or an integer greater than or equal to zero.

«» · I - 9 ·

9 91

These compounds are prepared by known methods by combining an aqueous solution of a water-soluble metal salt with an aqueous solution of hexacyanmetalate, in particular a salt or acid, and adding a water-soluble ligand, the solutions to be combined immediately or thereafter.

The catalyst is usually used in an amount of less than 1% by weight, preferably in an amount of less than 0.5% by weight, particularly preferably in an amount of less than 1000 ppm and particularly in an amount of less than 500 ppm, in each case based on the weight of the polyether alcohols.

Alkylene oxides which can be used for the process of the present invention are ethylene oxide, 1,2-epoxypropane (propylene oxide), 1,2-methyl-2-ethoxypropane, 1,2-epoxybutane,

2,3-epoxybutane (butylene oxide), 1,2-methyl-3-ethoxybutane, 1,2-epoxypentane, 1,2-methyl-3-ethoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2 -epoxyoctane, 1,2-epoxynonane, 1,2-epoxydecane,

1,2-epoxyundecane, 1,2-epoxydodecane, styrene oxide, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, (2,3-epoxypropyl) benzene, vinyloxirane, 3-phenoxy-1,2-epoxypropane, 2,3- epoxy (methyl ether),

2,3-epoxy (ethyl ether), 2,3-epoxy (isopropyl ether), 2,3-epoxy-1-

-propanol, (3,4-epoxybutyl stearate), 4,5-epoxypentyl acetate,

2,3-epoxypropyl methacrylate,

2,3-epoxypropyl acrylate, glycidyl butyrate, methyl glycidate, ethyl 2,3-epoxybutanoate, 4- (trimethylsilyl) butane-1,2-epoxide, 4- (triethylsilyl) butane-1,2-epoxide 3- (perfluoromethyl) propenoxide, 3- (perfluoroethyl) propenoxide, 3- (perfluorobutyl) propenoxide, 4- (2,3-epoxypropyl) morpholine or 1- (oxiran-2-ylmethyl) pyrrolidin-2-one.

Preference is given to using ethylene oxide, propylene oxide and butylene oxide, particularly preferably ethylene oxide and propylene oxide.

• · · ·

<img file="CZ20022018A3_D0004.tif" />

The H-functional initiator compounds used are, in particular, 2- to 8-polyhydric alcohols. For preparing polyether alcohols for use in flexible polyurethane foams, which may be prepared particularly advantageously by the process of the present invention, divalent and trivalent alcohols are particularly useful initiator compounds, for example ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, ethylene glycol. The alcohols may be used singly or in any mixture with one another.

To carry out the process of the present invention, at the beginning of the reaction, the initiator compound is placed in a reaction vessel and, if necessary, water or water is removed. other volatile compounds. This is usually done by distillation, preferably under reduced pressure or using vacuum gas stripping. The catalyst may already be present in the initiator compound, but it is also possible to add the catalyst itself after the pretreatment of the initiator compound. In the latter variant, the catalyst is exposed to less heat stress. Before alkylene oxides are introduced, it is customary to make the reactor inert to avoid undesired reactions of alkylene oxides with oxygen. The alkylene oxides are then metered together with performing the molecular addition according to the method described above. The molecular addition of alkylene oxides is usually carried out at a pressure in the range of from 1 kPa to 1 MPa and temperatures in the range of from 50 to 200 ° C, preferably from 90 to 150 ° C.

The reaction may be carried out continuously or batchwise. Upon completion of the reaction, unreacted monomers and volatile compounds are removed from the reaction mixture, usually by distillation. When DMC catalysts are used, the catalysts can essentially remain in the polyether alcohols, but can also be removed, for example by treating the polyether alcohol with oxidizing agents and separating the insoluble compounds formed.

As noted, the polyether alcohols prepared by the process of the present invention can be advantageously used for the preparation of polyurethanes, especially for the preparation of flexible polyurethane foams. Polyurethanes are prepared according to methods known per se by reacting the polyether alcohol of the present invention with polyisocyanates, if desired in admixture with other compounds containing at least two hydrogen atoms that are reactive with isocyanate groups. This reaction is preferably carried out in the presence of conventional catalysts, blowing agents and excipients and additives. The polyether alcohols prepared by the process of the present invention can be used alone or in admixture with other H-functional compounds.

The polyisocyanates used herein are all isocyanates having two or more isocyanate groups per molecule. It is also possible to use either aliphatic isocyanates such as hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), or preferably aromatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) or mixtures of diphenylmethane diisocyanate and polymethylene polyphenylene polyisocyanates (crude MDI). It is also possible to use isocyanates which can be modified by incorporating urethane, uretdione, isocyanurate, allophanate, uretoimine and other groups known as modified isocyanates.

Amines, mercaptans and preferably polyols can also be used as compounds containing at least two isocyanate-reactive groups and which can be used in admixture with the polyether alcohols of the present invention. Among the polyols, polyether polyols and polyester polyols are of greatest industrial importance. The polyether polyols used to prepare the polyurethanes are usually prepared by the base-catalysed addition of alkylene oxides, in particular ethylene oxide and / or propylene oxide, to the H-functional initiator compounds. Polyester polyols are usually prepared by esterifying polyhydric carboxylic acids with polyhydric alcohols.

Compounds containing at least two groups which are reactive with isocyanate groups also contain chain extending agents and / or crosslinking agents which may be used if desired. They are at least divalent amines and / or alcohols having molecular weights ranging from 60 to 400.

Water and / or compounds which are inert to the starting materials for polyurethanes and are gaseous at the reaction temperature of the urethane reaction known as physically acting blowing agents, as well as mixtures thereof, are commonly used as blowing agents. The physical blowing agents used are hydrocarbons having from 2 to 6 carbon atoms, halogenated hydrocarbons having from 2 to 6 carbon atoms, ketones, acetals, ethers and inert gases such as carbon dioxide and / or noble gases.

The catalysts used are in particular amine compounds and / or metallic compounds, in particular heavy metal salts and / or organometallic compounds. In particular, tertiary amines and / or organometallic compounds are used as catalysts.

Examples of excipients and / or additives that may be used are compression release agents, flame retardants, dyes, fillers and / or reinforcing materials.

• · · ·

It is customary in industry to mix all starting materials, with the exception of polyisocyanates, to form polyol components and to react these components with polyisocyanates to form polyurethane.

Polyurethanes can be produced by a one-step process or by a prepolymerization process. The resilient polyurethane foams may be either base foams for the boards or press foams.

An overview of starting materials for preparing polyurethanes and the methods used for this purpose can be found, for example, in Kunststoffhandbuch, Volume 7 "Polyurethane, Carl-Hanser Publishing House, Munich, Vienna, 1st edition, 1966, 2nd edition, 1983 and 3rd edition, 1993 .

The polyether alcohols of the present invention have a very narrow molecular weight distribution and surprisingly show no turbidity. Due to the very high reaction rate of the molecular addition of alkylene oxides using DMC catalysts, controlled addition of alkylene oxides to the initiator compound is possible. The dynamic process can reduce the total number of blocks requiring a change in the alkylene oxide or the ratio of alkylene oxides at the end of the block in a subsequent classical disordered process. This results in a time advantage in the preparation, since the interruption in the dosing and the stabilization phase usually required between the blocks due to the change in the alkylene oxide dosing becomes unnecessary.

The invention is illustrated by the following examples.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 • ·

1000 ml of strong acid ion exchange resin (K2431, Bayer) is regenerated twice using 450 g of HCl (37% HCl content) and then washed with water until the eluate is neutral. Solution 80.8 g K₃[Co (CN)₆1 in 25 ml of water is then introduced into an ion exchange column. The column is then eluted until the eluate is neutral again. The Co: K ratio obtained in the eluate is greater than 10: 1.

1269 g of the eluate is heated to 40 ° C and then mixed with a solution of 80.0 g of zinc acetate dihydrate in 240 g of water with stirring. Subsequently, 276.4 g of tert-butanol are added to the suspension and the suspension is stirred for a further 30 minutes at 40 ° C. The solid is then filtered off with suction and washed with 300 ml of tert-butanol on the filter. The solids treated in this way are dried at room temperature.

Example 2

Solution 400 g K₃[Co (CN) 6] in 1300 ml of water is loaded onto a column containing 5000 ml of freshly regenerated, strong acid ion exchange resin (K2431, Bayer). The column is then eluted until the eluate is neutral again. The Co: K ratio obtained in the eluate is greater than 10: 1. 5000 g of the eluate are heated to 40 ° C and then mixed with a solution of 396 g of zinc acetate dihydrate in 1400 g of water with stirring (screw stirrer, speed of 500 rpm). . Subsequently, 1400 g of tert-butanol is added to the suspension and the suspension is stirred for a further 30 minutes at 40 ° C. The solid is then filtered off with suction, then suspended with 4000 ml of tert-butanol and filtered again. The solid which is treated in this way is dried at 50 ° C and 2.5 kPa.

Example 3 liters of strong acidic ion exchanger in sodium form (Amberlite 252 Na, Rohm &amp; Haas) are loaded into an ion exchange column (length 1 m).

<img file="CZ20022018A3_D0005.tif" />

volume 7.7 liters). The ion exchanger is then converted to the H-form by passing 10% hydrochloric acid through an ion exchange column at a rate of 2 bed volumes per hour for 9 hours until the Na content of the effluent acid is less than 1 ppm. The ion exchanger is then washed with water until neutral.

The regenerated ion exchange resin is then used to prepare the alkali-free hexacyanocobaltic acid base. To this end, a 0.24 molar solution of hexacyanocobaltic potassium salt in water is passed through the ion exchange resin at a rate of 1 bed volume per hour. After 2.5 bed volumes, replace the hexacyanocobaltic potassium salt solution with water. The 2.5 bed volumes obtained have an average hexacyanocobaltic acid content of 4.5% by weight and an alkali metal content of less than 1 ppm.

The hexacyanocobaltic acid solution used below is appropriately diluted with water.

2432.9 g of an aqueous solution of hexacyanocobaltic acid (cobalt content of 6 g / l) is heated to 40 ° C and 120 ml of Pluronic® PE 6100 surfactant (BASF) are added and dissolved under stirring (paddle, 500 rpm). Aktiengesellschaft, a block copolymer of propylene oxide and ethylene oxide). Subsequently, a solution of 108.8 g of zinc acetate dihydrate in 400 g of water is added with stirring (paddle stirrer, speed of 500 rpm). 400 g of tert-butanol are then added to the suspension. The suspension was stirred at 40 ° C for an additional 30 minutes, after which the solid was filtered off with suction. The wet filter cake (330 g) was dispersed in 2000 ml of water for 5 minutes using an Ultraturrax.

Example 4 (comparative example)

The synthesis is carried out in a cleaned and dried 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The reactor contents are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 ° C. 820 g of a mixture of 68% by weight of propylene oxide and 32% by weight of ethylene oxide are metered in at 1 hour at 115 ° C. The reaction mixture is stirred for an additional 15 minutes and degassed at 105 ° C and 0.8 kPa. The product is then worked up by filtration. The polyol is cloudy. Hydroxyl number: 33.9 mg KOH / g;

viscosity at 25 ° C: 4966 mPa · s;

primary hydroxy content: 23%;

M_w: 15,990 g / mol; and

D: 2.98 (polydispersity, quotient M_w and M_n) .

Example 5 (comparative example)

The synthesis was carried out in a clean and dry 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The reactor contents are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 ° C. At 115 ° C 560 g of propylene oxide are metered in over a period of 45 minutes and 260 g of ethylene oxide are metered in over a period of 45 minutes. The reaction mixture is stirred for an additional 15 minutes and degassed at 105 ° C and 1 kPa. The product is worked up by filtration. The polyol is white and viscous. Hydroxyl number: 37.4 mg KOH / g;

viscosity at 25 ° C: 1482 mPa.s primary hydroxyl content: 27%; and

M_w: cannot be determined because the sample is insoluble.

Example 6

The synthesis was carried out in a clean and dry 10 liter stirred autoclave. 424.8 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 1.505 g of the catalyst of Example 3 (250 ppm based on solids). The reactor contents were rendered inert using nitrogen and vacuum treated for a total of 1.5 hours at 110 ° C. Nitrogen is injected at 125 ° C and 0.35 kPa and 3853.5 g propylene oxide and 571.1 g ethylene oxide are metered in over a period of 3 hours. The ethylene oxide content of the mixture is maintained at 12.8% until 87.5% of the total amount of alkylene oxides is metered in and then linearly reduced to 0%. The product is filtered. The polyol is clear.

Hydroxyl number: 35.0 mg KOH / g;

viscosity at 25 ° C: 845 mPa · s;

primary hydroxy content: 5.3%;

M_w4107 g / mol; and

D: 1.13.

Example 7

The synthesis was carried out in a clean and dry 10 liter stirred autoclave. 423.4 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 1.50 g of the catalyst of Example 2 (312 ppm based on solids). The reactor contents were rendered inert using nitrogen and vacuum treated for a total of 1.5 hours at 110 ° C. Nitrogen is injected at 125 ° C and 0.35 kPa and subsequently 3819.2 g propylene oxide is metered in over a period of 3 hours and 566.0 g ethylene oxide are then metered in over a period of 2 hours 43 minutes and 52 seconds. The propylene oxide dosing rate is increased continuously and linearly over a period of 60 minutes from 0 g / h to 1465.1 g / h, kept constant for 1 hour 7 minutes and 52 seconds, and increased continuously and linearly to 1759 g / h for 36 minutes. minutes and then kept constant for 16 minutes and 8 seconds. Simultaneously with the initiation of propylene oxide feed, the ethylene oxide feed rate is increased from 0 to 293.2 g / h in 60 minutes, kept constant for 1 hour 7 minutes and 52 seconds, and then continuously and linearly reduced to 0 g / h over a 36 minute period . The initial pressure is 357.6 kPa and the final pressure is 706.7 kPpa. The mixture is stirred for an additional 25 minutes and subsequently degassed for 20 minutes at 105 ° C and 0.6 kPa. The product is filtered. The polyol is clear.

Hydroxyl number: 35.1 mg KOH / g;

viscosity at 25 ° C: 817 mPa · s;

primary hydroxy content: 4.3%;

M_w4111 g / mol; and

D: 1.1.

Example 8 (comparative example)

The synthesis was carried out in a clean and dry 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The reactor contents are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 ° C. At 115 ° C, 650 g of propylene oxide is initially introduced, followed by 118 g of ethylene oxide and then 98 g of propylene oxide. The reaction mixture is stirred for a further 15 minutes and degassed at 105 ° C and 0.6 kPa. The product is worked up by filtration. The polyol is cloudy and so highly viscous that viscosity measurements at 25 ° C are not possible.

Hydroxyl number: 35.4 mg KOH / g;

viscosity at 75 ° C: 95.8 mPa · s;

primary hydroxy content: 7%; a ····· · · ··· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

D: 1.24.

Example 9 (comparative example)

The synthesis was carried out in a clean and dry 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The reactor contents are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 ° C. At 115 ° C, a mixture of 651 g propylene oxide and 118 g ethylene oxide was metered in first, followed by 98 g propylene oxide. The reaction mixture is stirred for a further 15 minutes and degassed at 105 ° C and 0.6 kPa. The product is filtered. The polyol is cloudy.

Hydroxyl number: 36.2 mg KOH / g;

viscosity at 25 ° C: 719 mPas;

primary hydroxy content: 6%; and

D: 1.23.

Example 10

The synthesis was carried out in a clean and dry 10 liter stirred autoclave. 424.8 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 1.505 g of the catalyst of Example 2 (312 ppm, based on solids). The contents of the reactor were rendered inert using nitrogen and vacuum treated for a total of 1 hour at 110 ° C.

Nitrogen is injected at 125 ° C and 0.35 kPa and 3853.5 g of propylene oxide are metered in within 3 hours and dosing is started 1 hour after the start of propylene oxide introduction.

571.1 g of ethylene oxide for a period of 2 hours. The propylene oxide dosing rate increases continuously and linearly over a period of 60 minutes from 0 g / h to 1759, 9 g / h, then decreases to propylene oxide.

352.0 g / h for 2 hours, 1 hour after the start of propylene oxide introduction, the ethylene oxide feed rate is increased from 0 to 352.0 g / h for 2 hours. The initial pressure is 352.5 kPa and the final pressure is 728.0 kPa. The mixture is stirred for an additional 30 minutes and subsequently degassed for 35 minutes at 105 ° C and 1 kPa. The product is filtered. The polyol is clear.

Hydroxyl number: 35.8 mg KOH / g;

viscosity at 25 ° C: 767 mPa · s;

primary hydroxy content: 46%;

M_w3890 g / mol; and

D: 1.1.

Example 11 (comparative example)

The synthesis was carried out in a clean and dry 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The contents of the reactor are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 ° C. At 115 ° C, 749 g of propylene oxide is metered in first, followed by 118 g of ethylene oxide. The reaction mixture is stirred for a further 15 minutes and degassed at 105 ° C and 0.9 kPa. The product is worked up by filtration. The polyol is cloudy.

Hydroxyl number: 34.8 mg KOH / g;

viscosity at 75 ° C: 95.9 mPa · s;

primary hydroxy content: 11%; and

D: 1.27.

Example 12 (comparative example)

The synthesis was carried out in a clean and dry 1 liter stirred autoclave. 80 g of propoxylated glycerol having a molecular weight of 400 g / mol are introduced into the autoclave and mixed with 250 ppm of the catalyst of Example 3. The contents of the reactor are rendered inert using nitrogen and vacuum treated for a total of 1 hour at 125 DEG C. Deň: 32 ° C. A mixture of 74 9 g propylene oxide and 118 g ethylene oxide is metered in at 115 ° C. The reaction mixture is stirred for a further 15 minutes and degassed at 105 ° C and 0.6 kPa. The product is worked up by filtration. The polyol is cloudy.

Hydroxyl number: 35.5 mg KOH / g;

viscosity at 25 ° C: 919 mPas;

primary hydroxy content: 106%; and

D: 1.24.

The primary hydroxy content is determined by achieving the hydroxy groups with trichloroacetyl isocyanate and recording the 1 H-NMR spectrum of the polyether alcohols treated in this way. The primary and secondary hydroxyl groups obtained in the spectrum show different peaks.