HK1051660A - Double-metal cyanide catalysts for preparing polyether polyols - Google Patents

Description

Double metal cyanide catalysts for preparing polyether polyols

Technical Field

The present invention relates to double metal cyanide ("DMC") catalysts for preparing polyether polyols by the polyaddition of alkylene oxides to starter compounds containing active hydrogen atoms.

Background

DMC catalysts for the polyaddition of alkylene oxides to starter compounds containing active hydrogen atoms are known. See, for example, U.S. Pat. nos. 3,404,109, 3,829,505, 3,941,849, and 5,158,922. The use of these DMC catalysts in the preparation of polyether polyols reduces the content of monofunctional polyethers having terminal double bonds, the so-called "monools", compared with the preparation of polyether polyols with basic catalysts, such as alkali metal hydroxides.

Polyether polyols produced by DMC catalysisTo be used for processing high quality polyurethanes such as elastomers, foams and coatings. DMC catalysts are usually obtained by reacting an aqueous solution of a metal salt with an aqueous solution of a metal cyanide salt in the presence of an organic complex ligand, such as an ether. In a typical DMC catalyst preparation, zinc chloride (in excess) is mixed with an aqueous solution of potassium hexacyanocobaltate to form a suspension. Dimethoxyethane (glyme) was then added to the suspension. After filtration and washing of the suspension with an aqueous glyme solution, a solution having the general formula Zn is obtained₃[Co(CN)₆]₂·xZnCl₂·yH₂An active catalyst for O.z glyme. See for example EP 700949.

The following references disclose DMC catalysts that use tertiary butanol (by itself or in combination with polyether) as an organic complexing ligand in the preparation of polyether polyols to further reduce the content of monofunctional polyethers having terminal double bonds: JP4145123, U.S. Pat. No. 5,470,813, EP700949, EP743093, EP761708 and WO 97/40086. Furthermore, the use of these DMC catalysts shortens the induction time in the polyaddition reaction of alkylene oxides with the corresponding starter compounds. The catalyst activity is also improved. By shortening the alkoxylation time, the process for preparing polyether polyols becomes more cost effective. Moreover, because of their increased activity, DMC catalysts can be used at low concentrations (25ppm or less), eliminating the need for expensive catalyst removal steps from polyether polyols.

Disclosure of Invention

It is an object of the present invention to provide DMC catalysts for the preparation of polyether polyols by polyaddition of alkylene oxides onto starter compounds. The DMC catalysts of the present invention have increased catalyst activity compared to known DMC catalysts. The object of the invention is achieved by providing a DMC catalyst comprising: a) at least one DMC compound; b) at least one organic complexing ligand which is not a polyether, a bile acid salt, a bile acid ester or a bile acid amide; c) at least one polyether; and d) at least one bile acid, bile acid salt, bile acid ester or bile acid amide.

Hereinafter, the polyether c) and the bile acid, bile acid salt, bile acid ester or bile acid amide d) may be collectively referred to as "complexing component".

The DMC catalysts of the present invention may optionally contain water, preferably in an amount of from 1 to 10% by weight. The DMC catalysts of the present invention may also optionally contain one or more water-soluble metal salts, preferably in an amount of from 5 to 25% by weight.

The DMC compound a) is the reaction product of a water-soluble metal salt and a water-soluble metal cyanide salt. Suitable water-soluble metal salts for preparing the DMC compound a) are represented by the formula (I):

m (X) n (I) wherein

M is selected from Zn (II), Fe (II), Ni (II), Mn (II), Co (II), Sn (II), Pb (II),

Fe(III)、Mo(IV)、Mo(VI)、Al(III)、V(V)、V(IV)、Sr(II)、W(IV)、

W (VI), Cu (II) and Cr (III) (preferably Zn (II), Fe (II), Co (II) and Ni (II));

each X, which may be the same or different, preferably the same, is an anion selected from the group consisting of halides, hydroxides

Sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanates

Cyanates, carboxylates, oxalates, and nitrates; and is

n is 1, 2 or 3.

Examples of suitable water-soluble metal salts useful in the present invention are zinc chloride, zinc bromide, zinc acetate, zinc acetylacetonate, zinc benzoate, zinc nitrate, iron (II) sulfate, iron (II) bromide, iron (II) chloride, cobalt (II) thiocyanate, nickel (II) chloride, nickel (II) nitrate, and mixtures thereof.

Suitable water-soluble metal cyanide salts for preparing the DMC compounds a) are represented by the formula (II):

(Y)_aM′(CN)_b(A)_c(II) wherein

M' is selected from 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) (preferably Co (II)),

Co (III), Fe (II), Fe (III), Cr (III), Ir (III) and Ni (II)), water-soluble metal cyanide

The salt may contain one or more of these metals;

each Y, which is identical or different, preferably identical, is selected from alkali metal ions and alkaline earth metal ions;

a, which are identical or different, preferably identical, are selected from the group consisting of halides, hydroxides, sulfates,

Carbonates, cyanates, thiocyanates, isocyanates, isothiocyanates, carboxyls

Acid salts, oxalate salts and nitrate salts; and is

a. b and c are integers, and the values of a, b and c are selected to achieve the electrification of a metal cyanide salt

Neutral (a is preferably 1, 2, 3 or 4; b is preferably 4, 5 or 6; c is preferably 0).

Examples of water-soluble metal cyanide salts useful in the present invention are potassium hexacyanocobaltate (III), potassium hexacyanocobaltate (II), potassium hexacyanocobaltate (III), calcium hexacyanocobaltate (III) and lithium hexacyanocobaltate (III).

The DMC compounds a) preferred according to the invention are those represented by the formula (III):

M_x[M′_x′(CN)_y]_z(III) wherein

M is as defined for formula (I);

m' is as defined for formula (II);

x, x', y and z are integers selected such that the DMC compound is

Is electrically neutral.

Preference is given to

x is 3, x 'is 1, y is 6 and z is 2';

m ═ Zn (II), Fe (II), Co (II), or Ni (II); and is

M ═ Co (III), Fe (III), Cr (III), or Ir (III).

Examples of suitable DMC compounds a) useful in the present invention are zinc hexacyanocobaltate (III), zinc hexacyanocobaltate (III) and cobalt (II) hexacyanocobaltate (III). Examples of other suitable DMC compounds a) can be found in U.S. Pat. No. 5,158,922. Zinc hexacyanocobaltate (III) is a preferred DMC compound useful in the present invention.

Organic complexing ligands b) useful in the present invention are known and disclosed in the following references: U.S.5,158,922, U.S.3,404,109, 3,829,505, U.S.3,941,849, EP700949, EP761708, JP4145123, U.S.5,470,813, EP743093 and WO 97/40086. Organic complexing ligands useful in the present invention are water-soluble organic compounds which carry heteroatoms, such as oxygen, nitrogen, phosphorus or sulfur, and which can form complexes with the DMC compound a).

Suitable organic complexing ligands useful in the present invention are alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides and mixtures thereof. Preferred organic complexing ligands are water-soluble aliphatic alcohols, such as ethanol, isopropanol, n-butanol, isobutanol, sec-butanol or tert-butanol. Tert-butanol is particularly preferred.

The organic complexing ligand b) can be added during the preparation of the DMC catalyst or immediately after the DMC compound a) has precipitated out. The organic complexing ligand b) is usually used in excess.

The DMC compound a) is present in an amount of from about 20 to about 90% by weight, preferably from 25 to 80% by weight, based on the total amount of DMC catalyst. The organic complexing ligand b) is present in an amount of from about 0.5 to about 30% by weight, preferably from 1 to 25% by weight, based on the total amount of DMC catalyst. Preferably, the DMC catalysts of the present invention contain from about 1 to about 80% by weight, preferably from 1 to 40% by weight, based on the total amount of DMC catalyst, of a mixture of polyether c) and a bile acid, bile acid salt, bile acid ester or bile acid amide d).

Polyethers c) suitable for use in the present invention are known and are disclosed in the following references: EP700949, EP761708 and WO 97/40086. Preferably, the hydroxyl functionality is from 1 to 8, preferably from 1 to 3, and the number average molecular weight is from 150 to 10⁷Preferably 200 to 5.10⁴The polyether polyol of (1) is used in the present invention. The polyether polyols can be obtained by ring-opening polymerization of epoxides in the presence of starter compounds containing active hydrogen atoms under base, acid or coordination catalysis (e.g., DMC catalysis).

Examples of suitable polyether polyols useful in the present invention are poly (oxypropylene) polyols, poly (oxyethylene) polyols, EO-capped poly (oxypropylene) polyols, EO/PO-polyols, butylene oxide polymers, butylene oxide copolymers with ethylene oxide and/or propylene oxide and poly (oxybutylene) glycol.

Suitable bile acids d) useful in the present invention are C₂₄Steroid carboxylic acids, which are decomposition products of cholesterol, can be derived from 5 β -cholan-24-oic acid by introducing hydroxyl groups in the α -position of C-3, C-6, C-7 and C-12. Preferred bile acids are represented by the following general formula:wherein

R₁、R₂、R₃And R₄Each independently represents H or OH;

R₅represents OH, NH-CH₂-COOH、NH-CH₂-CH₂-SO₃H、NH-(CH₂)₃-N⁺(CH₃)₂-CH₂-CHOH-CH₂-SO₃ ^-Or NH- (CH)₂)₃-N⁺(CH₃)₂-(CH₂)₃-SO₃ ^-。

Suitable for use in the present invention are the free acids; salts of bile acids, preferably alkali metal or alkaline earth metal salts; or esters of bile acids, preferably alkyl with 1 to 30 carbon atoms; or amides of bile acids, preferably with alkyl, sulfoalkyl, sulfoalkylaminoalkyl, sulfohydroxyalkylaminoalkyl or carboxyalkyl groups in acid or salt form.

Examples of suitable bile acids or salts, esters or amides thereof useful in the present invention are cholic acid (3 α, 7 α, 12 α -trihydroxy-5 β -cholan-24-oic acid; R₁＝R₃＝R₄＝R₅＝OH，R₂H), sodium cholate (sodium cholate), lithium cholate, potassium cholate, ethylene glycol-cholic acid (3 α, 7 α, 12 α -trihydroxy-5 β -cholane-24-oic acid N- [ carboxymethyl group]An amide; r₁＝R₃＝R₄＝OH，R₂＝H，R₅＝NH-CH₂-COOH), sodium glycocholate, taurocholic acid (3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholane-24-oic acid N- [ 2-sulfoethyl group]An amide; r₁＝R₃＝R₄＝OH，R₂＝H，R₅＝NH-CH₂-CH₂-SO₃H) Sodium taurocholate, deoxycholic acid (3 α, 12 α -dihydroxy-5 β -cholan-24-oic acid; r₁＝R₄＝R₅＝OH，R₂＝R₃H), sodium deoxycholate, potassium deoxycholate, lithium deoxycholate, glycodeoxycholic acid (3 α, 12 α -dihydroxy-5 β -cholane-24-oic acid N- [ carboxymethyl group)]An amide; r₁＝R₄＝OH，R₂＝R₃＝H，R₅＝NH-CH₂-COOH), sodium glycodeoxycholate, taurodeoxycholic acid (3 alpha, 12 alpha-dihydroxy-5 beta-cholane-24-oic acid N- [ 2-sulfoethyl)]An amide; r₁＝R₄＝OH，R₂＝R₃＝H，R₅＝NH-CH₂-CH₂-SO₃H) Sodium taurodeoxycholate, chenodeoxycholic acid (3 α, 7 α -dihydroxy-5 β -cholane-24-oic acid; r₁＝R₃＝R₅＝OH，R₂＝R₄H), sodium chenodeoxycholate, glycochenodeoxycholic acid (3 α, 7 α -dihydroxy-5 β -cholane-24-oic acid N- [ carboxymethyl group)]An amide; r₁＝R₃＝OH，R₂＝R₄＝H，R₅＝NH-CH₂-COOH), sodium glycochenodeoxycholate, taurochenodeoxycholic acid (3 alpha, 7 alpha-dihydroxy-5 beta-cholane-24-oic acid N- [ 2-sulfoethyl group)]An amide; r₁＝R₃＝OH，R₂＝R₄＝H，R₅＝NH-CH₂-CH₂-SO₃H) Sodium taurochenodeoxycholate, lithocholic acid (3 alpha-hydroxy-5 beta-cholane-24-oic acid, R)₁＝R₅＝OH，R₂＝R₃＝R₄H), sodium lithocholate, potassium lithocholate, hyocholic acid (3 α, 6 α, 7 α -trihydroxy-5 β -cholane-24-oic acid, R₁＝R₂＝R₃＝R₅＝OH，R₄H), sodium hyocholate, lithium hyocholate, potassium hyocholate, hyodeoxycholic acid (3 α, 6 α -dihydroxy-5 β -cholane-24-oic acid, R1 ═ R2 ═ R₅＝OH，R₃＝R₄H), sodium hyodeoxycholate, lithium hyodeoxycholate, potassium hyodeoxycholate, cholic acid methyl ester, cholic acid ethyl ester, deoxycholic acid ethyl ester and hyocholic acid methyl ester.

In the present invention, preferably used are sodium, lithium or potassium salts or methyl or ethyl esters of cholic acid, glycocholic acid, taurocholic acid, deoxycholic acid, glycodeoxycholic acid, taurodeoxycholic acid, chenodeoxycholic acid, glycochenodeoxycholic acid, taurochenodeoxycholic acid, lithocholic acid, hyocholic acid, hyodeoxycholic acid or mixtures thereof.

Bile acids useful in the present invention are ursocholic acid (3 α, 7 α, 12 α -trihydroxy-5 α -cholan-24-oic acid), ursodeoxycholic acid (3 α, 7 α -dihydroxy-5 β -cholan-24-oic acid), 7-oxolithocholic acid (3 α -hydroxy-7-oxo-5 β -cholan-24-oic acid), lithocholic acid 3-sulfate (3 α -hydroxy-5 β -cholan-24-oic acid 3-sulfate), norcholic acid and bisnorcholic acid or their salts, esters or amides.

Bile Acids, salts, esters or amides thereof are known and are disclosed in detail in Nachr. Chen. Tech. Lab.43(1995)1047, and Setchell et al, The Bile Acids, Vol.4, Plenum, New York 1998 andR*mpp，Lexikon Naturstoffestuttgart, New York 1997, pages 248 and subsequent pages, and so on.

The DMC catalysts of the present invention may be crystalline, partially crystalline or amorphous. Crystallinity is typically analyzed by powder X-ray diffraction.

The DMC catalyst compositions are typically analyzed by elemental analysis, thermogravimetric analysis, or extractive removal of the complexing component followed by gravimetric determination.

Preferred DMC catalysts of the present invention comprise a) zinc hexacyanocobaltate (III); b) tert-butyl alcohol; c) at least one polyether; and d) at least one bile acid, bile acid salt, bile acid ester or bile acid amide.

The DMC catalysts of the invention are generally prepared by reacting a metal salt, preferably represented by formula (I), with a metal cyanide salt, preferably represented by formula (II), in an aqueous solution in the presence of an organic complexing ligand b), wherein the organic complexing ligand b) is neither a polyether nor a bile acid, bile acid salt, bile acid ester or bile acid amide. In this preparation, a metal salt, such as zinc chloride, used in stoichiometric excess (at least 50 mole percent based on moles of metal cyanide salt), is reacted with a metal cyanide salt, such as potassium hexacyanocobaltate, in an aqueous solution in the presence of an organic complexing ligand b), such as t-butanol. A suspension is formed comprising the DMC compound a) (e.g., zinc hexacyanocobaltate), water, excess metal salt, and organic complexing ligand b).

The organic complexing ligands b) are present in aqueous solutions of metal salts and/or metal cyanide salts or are added directly to the suspension after the DMC compound a) has precipitated out. The mixture of aqueous solution and organic complexing ligand b) is preferably stirred vigorously. The suspension formed is then treated with a mixture of complexing components c) and d). Preferably, a mixture of complexing components c) and d) is used in a mixture of water and organic complexing ligand b).

The DMC catalyst is then separated from the suspension by known techniques, such as centrifugation or filtration. In a preferred embodiment of the present invention, the separated DMC catalyst is washed with an aqueous solution of the organic complexing ligand b) (for example by resuspension and subsequent re-separation by filtration or centrifugation). Water soluble by-products, such as potassium chloride, are removed from the DMC catalyst by washing the DMC catalyst with an aqueous solution of an organic complexing ligand b).

Preferably, the amount of organic complexing ligand b) is from 40 to 80% by weight, based on the total weight of the aqueous wash. It is preferred to add small amounts of complexing components c) and d) to the aqueous wash, preferably from 0.5 to 5% by weight, based on the total weight of the aqueous wash.

The DMC catalyst is preferably washed more than once. This can be accomplished by repeating the aqueous wash step described above. However, it is preferred to use a non-aqueous wash liquor in the further washing operation. The non-aqueous wash solution comprises a mixture of an organic complexing ligand b) and complexing components c) and d).

The washed DMC catalyst is then dried, optionally after comminution, at a temperature of from 20 to 100 ℃ and a pressure of from 0.1 mbar to 1,013 mbar.

The invention also relates to the use of the DMC catalysts of the invention in a process for preparing polyether polyols by polyaddition of alkylene oxides to starter compounds containing active hydrogen atoms.

Alkylene oxides which are preferably used in the present invention are ethylene oxide, propylene oxide, butylene oxide and mixtures thereof. The establishment of polyether chains by alkoxylation can be achieved by random or blockwise application using only one monomeric epoxide, or 2 or 3 different monomeric epoxides. A detailed description of this can be found in Ullmanns encyclopedia der industrillen Chemie, volume A21, 1992, page 670 and subsequent pages.

Preferred starting compounds containing active hydrogen atoms for use in the present invention are compounds having a number average molecular weight of 18 to 2,000 and 1 to 8 hydroxyl groups. Examples of such starter compounds are ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propanediol, 1, 4-butanediol, 1, 6-hexanediol, bisphenol A, trimethylolpropane, glycerol, pentaerythritol, sorbitol, sucrose, degraded starch or water.

It is preferred in the present invention to use an active hydrogen atom-containing starting compound prepared by conventional base catalysis from the above-mentioned low molecular weight starting compound, which is an oligomeric alkoxylation product having a number average molecular weight of 200 to 2,000.

The polyaddition of alkylene oxides onto starter compounds containing active hydrogen atoms, catalyzed by the DMC catalysts of the present invention, is carried out at temperatures of from 20 to 200 deg.C, preferably from 40 to 180 deg.C, more preferably from 50 to 150 deg.C. The reaction can be carried out at a total pressure of from 0.0001 to 20 bar. The polyaddition can be carried out in bulk or in an inert organic solution such as toluene and/or tetrahydrofuran ("THF"). The amount of the solvent is usually from 10 to 30% by weight, based on the total weight of the polyether polyol to be produced.

The concentration of the DMC catalyst is chosen such that the polyaddition reaction is adequately controlled under the given reaction conditions. The catalyst concentration is usually from 0.0005% by weight to 1% by weight, preferably from 0.001% by weight to 0.1% by weight, more preferably from 0.001 to 0.0025% by weight, based on the total weight of the polyether polyol to be produced.

The number average molecular weight of the polyether polyol prepared by the process of the present invention is in the range of 500 to 100,000g/mol, preferably 1,000 to 50,000g/mol, more preferably 2,000 to 20,000 g/mol.

The polyaddition can be carried out continuously or discontinuously (e.g., in a batch or semi-batch process).

Due to the significantly increased activity, the DMC catalysts of the invention can be used in low concentrations (25ppm and less based on the amount of polyether polyol to be produced). In the production of polyurethanes, if a polyether polyol is produced in the presence of the DMC catalyst of the present invention, the step of removing the DMC catalyst from the polyether polyol can be omitted without adversely affecting the product quality of the resulting polyurethane (Kunststoffhandbuch, Vol.7, polyurethane, third edition, 1993, pages 25-32 and 57-67).

Detailed Description

Catalyst preparation

Example A

Preparation of the DMC catalyst with polyether and bile acid salt (catalyst A):

to a solution of 4g (12mmol) of potassium hexacyanocobaltate in 70ml of distilled water was added a solution of 12.5g (91.5mmol) of zinc chloride in 20ml of distilled water and stirred vigorously (24,000rpm) until a suspension was formed. Immediately thereafter, a mixture of 50g of tert-butanol and 50g of distilled water was added to the suspension, and the resulting mixture was stirred vigorously (24,000rpm) for 10 minutes. Then, a mixture of 0.5g of polypropylene glycol having a number average molecular weight of 2,000 ("polypropylene glycol 2000") and 0.5g of sodium cholate, 1g of t-butanol and 100g of distilled water was added, and the resulting mixture was stirred (1,000rpm) for 3 minutes. The resulting solid was isolated by filtration, followed by stirring (10,000rpm) with a mixture of 70g of t-butanol, 30g of distilled water, 0.5g of polypropylene glycol 2000 and 0.5g of sodium cholate salt for 10 minutes, and filtration was performed again. Finally, the solid is stirred (10,000rpm) for a further 10 minutes with a mixture of 100g of tert-butanol, 0.25g of polypropylene glycol 2000 and 0.25g of the sodium salt of cholic acid. After filtration, the catalyst was dried to constant weight at 50 ℃ under normal pressure.

Yield of dried crushed catalyst: 4.8g

Elemental analysis, thermogravimetric analysis and extraction:

cobalt 11.9 wt%, zinc 25.3 wt%, tert-butanol 7.8 wt%, polypropylene glycol 2000 22.7 wt%, and sodium cholate 3.2 wt%.

Example B (comparative)

Preparation of the DMC catalyst with a polyether (catalyst B), without the use of bile acid salts:

to a solution of 4g (12mmol) of potassium hexacyanocobaltate in 70ml of distilled water was added a solution of 12.5g (91.5mmol) of zinc chloride in 20ml of distilled water and stirred vigorously (24,000rpm) until a suspension was formed. Immediately thereafter, a mixture of 50g of tert-butanol and 50g of distilled water was added to the suspension, and the resulting mixture was stirred vigorously (24,000rpm) for 10 minutes. Then, a mixture of 1g of polypropylene glycol 2000, 1g of t-butanol and 100g of distilled water was added, and the resulting mixture was stirred (1,000rpm) for 3 minutes. The resulting solid was separated by filtration, followed by stirring (10,000rpm) with a mixture of 70g of t-butanol, 30g of distilled water and 1g of polypropylene glycol 2000 for 10 minutes, and filtration was performed again. Finally, the solid was stirred (10,000rpm) with a mixture of 100g of tert-butanol and 0.5g of polypropylene glycol 2000 for a further 10 minutes. After filtration, the catalyst was dried to constant weight at 50 ℃ under normal pressure.

Yield of dried crushed catalyst: 6.2g

Elemental analysis, thermogravimetric analysis and extraction:

cobalt 11.6 wt%, zinc 24.6 wt%, tert-butanol 3.0 wt%, and polypropylene glycol 2000 25.8 wt%.

Example C (comparative)

Preparation of the DMC catalyst with a bile acid salt (catalyst C), without polyether:

procedure as described in example B, but using the sodium salt of cholic acid instead of the polyether.

Yield of dried crushed catalyst: 4.2g

Elemental analysis, thermogravimetric analysis and extraction:

12.6% by weight of cobalt, 27.3% by weight of zinc, 10.9% by weight of tert-butanol and 4.3% by weight of sodium cholate.

Preparation of polyether polyols

General procedure

50g of a polypropylene glycol raw material (number average molecular weight of 1,000g/mol) and 5mg of a catalyst (25ppm based on the amount of polyether polyol to be produced) were introduced into a 500ml pressure reactor under an inert gas (argon) and heated to 105 ℃ while stirring. Propylene oxide (about 5g) was then metered in immediately until the total pressure had risen to 2.5 bar. When an accelerated drop in pressure in the reactor was observed, propylene oxide was metered in again. An accelerated drop in pressure indicates that the catalyst is activated. The remainder of the propylene oxide (145g) was metered in continuously at a constant total pressure of 2.5 bar. When the metering of propylene oxide was complete and 2 hours after the reaction at 105 ℃, volatile constituents were distilled off at 90 ℃ (1 mbar) and the mixture was then cooled to room temperature.

The polyether polyol produced is characterized by determining the OH number, double bond content and viscosity.

The course of the reaction is monitored by means of a time/conversion curve (propylene oxide consumption [ g ] -reaction time [ min ]). The induction time is determined from the intersection of the extended baseline of the time/conversion curve with the tangent at the steepest point of the curve. The propoxylation time, which is decisive for the catalyst activity, corresponds to the time between the activation of the catalyst (end of the induction period) and the end of the metering of propylene oxide. The total reaction time is the sum of the induction and propoxylation times.

Example 1

Preparation of polyether polyol with catalyst A (25 ppm):

induction time: 135 minutes

Time of propoxylation: 19 minutes

Total reaction time: 154 minutes

Polyether polyol: OH number (mg KOH/g): 29.8

Double bond content (mmol/kg): 7

Viscosity at 25 ℃ (mPas): 843

Example 2 (comparative):

preparation of polyether polyol with catalyst B (25 ppm):

induction time: 100 minutes

Time of propoxylation: 110 minutes

Total reaction time: 210 minutes

Polyether polyol: OH number (mg KOH/g): 28.1

Double bond content (mmol/kg): 7

Viscosity at 25 ℃ (mPas): 849

Example 3 (comparative)

Preparation of polyether polyol with catalyst C (25 ppm):

induction time: 217 minute

Time of propoxylation: 33 minutes

Total reaction time: 250 minutes

Polyether polyol: OH number (mg KOH/g): 29.6

Double bond content (mmol/kg): 6

Viscosity at 25 ℃ (mPas): 855

Catalyst a having polypropylene glycol 2000 and a sodium cholate salt as complexing components had substantially higher activity than catalyst B and catalyst C having only polypropylene glycol 2000 or a sodium cholate salt as complexing components.

Claims (11)

1. A double metal cyanide catalyst comprising:

a) at least one double metal cyanide compound;

b) at least one organic complexing ligand which is not a polyether, a bile acid salt, a bile acid ester or a bile acid amide;

c) at least one polyether;

d) at least one bile acid, bile acid salt, bile acid ester or bile acid amide.

2. The double metal cyanide catalyst of claim 1, further comprising water and/or a water soluble metal salt.

3. The double metal cyanide catalyst of claim 1, wherein the double metal cyanide compound is zinc hexacyanocobaltate (III).

4. The double metal cyanide catalyst of claim 1 wherein the organic complexing ligand is an alcohol, aldehyde, ketone, ether, ester, amide, urea, nitrile, sulfide and/or mixtures thereof.

5. The double metal cyanide catalyst of claim 1 wherein the organic complexing ligand is t-butanol.

6. The double metal cyanide catalyst of claim 1, wherein the double metal cyanide catalyst contains up to about 80% by weight, based on the total weight of the double metal cyanide catalyst, of a mixture of polyether c) and a bile acid, bile acid salt, bile acid ester or bile acid amide d).

7. The double metal cyanide catalyst of claim 1, wherein the component d) is a sodium, lithium or potassium salt or a methyl or ethyl ester of cholic acid, glycocholic acid, taurocholic acid, deoxycholic acid, glycodeoxycholic acid, taurodeoxycholic acid, chenodeoxycholic acid, glycochenodeoxycholic acid, taurochenodeoxycholic acid, lithocholic acid, hyocholic acid, hyodeoxycholic acid or mixtures thereof.

8. A process for preparing the double metal cyanide catalyst of claim 1, comprising the steps of: (a) reacting (i) at least one metal salt with (ii) at least one metal cyanide salt in an aqueous solution in the presence of (iii) an organic complexing ligand to form a suspension, wherein the organic complexing ligand is not a polyether, a bile acid salt, a bile acid ester, or a bile acid amide; and (b) treating the suspension with at least one polyether and at least one bile acid, bile acid salt, bile acid ester or bile acid amide.

9. The method of claim 8, further comprising the steps of: (c) separating the catalyst from the suspension after (b); (d) washing the separated catalyst; and (e) drying the separated catalyst.

10. A process for producing polyether polyols by polyaddition of alkylene oxides to starter compounds containing active hydrogen atoms, wherein the polyaddition of the alkylene oxides is carried out in the presence of the double metal cyanide catalysts of claim 1.

11. A polyether polyol prepared by the process of claim 10.