WO2000014143A1

WO2000014143A1 - Catalysts for producing polyetherols by ring-opening polymerisation of alkylene oxides

Info

Publication number: WO2000014143A1
Application number: PCT/EP1999/006225
Authority: WO
Inventors: Georg Heinrich Grosch; Harald Larbig; Reinhard Lorenz; Dieter Junge; Kathrin Harre
Original assignee: Basf Aktiengesellschaft
Priority date: 1998-09-05
Filing date: 1999-08-25
Publication date: 2000-03-16
Also published as: DE19840587A1

Abstract

The invention relates to a catalyst for producing polyetherols by ring-opening polymerisation of alkylene oxides and is characterised in that one or more compounds of type (I) M'aM''b (OH)c Od * Ae * Lf are applied to or introduced into solid inert supports or moulded into shapes, M' being at least one metal ion selected from the groups IA, IIA, Ni or Zn and mixtures thereof, M'' being at least one metal ion selected from the groups IIIA,IVA, IB to VIIIB, As, Sb and Bi, and mixtures thereof, A being at least one monovalent or multivalent inorganic or organic anion and L being an inorganic or organic ligand, a being a rational number, b, c, d, e and f being rational numbers greater than or equal to zero, although c and d may not both be zero at the same time, and a, b, c, d, e and f being selected with the aim of guaranteeing the electroneutrality of the compound.

Description

Catalysts for the production of polyetherols by ring-opening polymerization of al ylene oxides

description

The invention relates to catalysts, their preparation and their use for the preparation of polyether alcohols.

Polyether alcohols, also known as polyetherols, are important feedstocks in the production of polyurethanes. They are usually produced by catalytic addition of lower alkylene oxides, in particular ethylene oxide and / or propylene oxide, to H-functional starter substances. Mostly soluble basic metal hydroxides or salts are used as catalysts, with potassium hydroxide having the greatest practical importance.

For reducing the level of unsaturated by-products ir _¬ the polyether will propose in EP-A-268 922 to use cesium hydroxide as catalyst. Basic metal hydroxides, which dissolve in the polyether polyols, have the major disadvantage that they have to be extracted from the polyetherol with great effort after the synthesis and the resulting waste has to be disposed of.

It is also proposed to use multimetal cyanide compounds, in particular zinc hexacyanometalates, as catalysts. There are a large number of publications in which such compounds have been described. DD-A-203 734 and DD-A-203 735 describe a process for the preparation of polyether alcohols using zinc hexacyanocobaltate.

The production of zinc hexacyanometalates is also known. It is usually carried out by reacting solutions of metal salts, mostly zinc chloride, with solutions of alkali metal or alkaline earth metal cyanometallates, such as potassium hexacyanocobaltate. A water-miscible component containing one or more heteroatoms is normally added to the precipitation suspension formed immediately after the precipitation process. This component can already be present in one or in both educt solutions. The water-miscible component containing heteroatoms can preferably be an ether, polyether, alcohol, ketone or a mixture of at least two of the compounds mentioned. Such methods are described, for example, in US Pat. No. 3,278,457, US Pat. No. 3,278,458, US Pat. No. 3,278,459, US Pat. No. 3,427,256. Another class of substances that are also suitable as catalysts for the production of polyether polyols are poorly soluble basic oxides or hydroxides. Such basic oxides or hydroxides can include alkaline earth oxides or hydroxides. For example, US Pat. No. 5,679,764 describes the use of coarser magnesium oxide powders as a catalyst for the oxyalkylation.

It is also known to use doped basic alkaline earth metal oxides or hydroxides, such as, for example, hydrocetal, as catalysts for the ring-opening polymerization of alkylene oxides. A whole series of patents describes the production of fatty alcohol ethoxylates, with a narrow molecular weight distribution, using calcined or hydrophobic hydrotalcite as a catalyst. The following documents are representative of this: 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, WO-A 92/11 224, US-A 4 962 237.

The alkoxylation of low molecular weight starters is carried out according to the cited patents in the suspension mode. More or less coarse powders are used, which in most cases can only be removed from the product with great technical effort.

It would therefore be desirable to provide catalysts for ring-opening polymerization of alkylene oxides on H-functional starters, which can be immobilized in such a way that they do not pass into the polyetherol and their subsequent separation from the polyetherol is therefore not necessary.

The object of the invention was therefore to provide catalysts for the ring-opening polymerization of alkylene oxides on H-functional starters which can be easily separated from the polyetherol and which, if appropriate, permit a continuous procedure in the synthesis of polyether alcohol.

The object could be achieved by applying sparingly soluble, catalytically active compounds on solid supports, in solid supports or shaping the sparingly soluble, catalytically active compounds into shaped bodies.

The term "sparingly soluble" means that the concentration of the metal ions which are present in the compounds used as catalysts in the starting, intermediate and end products of polyether alcohol synthesis is less than 50 ppm per type of metal ion. The term "catalytically active" means that the compounds catalyze the ring-opening polymerization of alkylene oxides.

The invention accordingly relates to catalysts for the preparation of polyether alcohols by ring-opening polymerization of alkylene oxides, characterized in that one or more λ / compounds of the general formula (I)

M ' _a M " _b (OH) _c O _d * A _e - L _f (I),

in which

M 'is at least one metal ion selected from the group lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, nickel or zinc, and mixtures thereof,

M '' is at least one metal ion selected from Groups IIIA, IVA, IB to VIIIB and As, Sb and Bi, and mixtures thereof,

A is at least one monovalent or polyvalent, inorganic or organic anion,

L is an inorganic or organic ligand,

in which

a is a rational number greater than zero,

b, c, d, e, f rational numbers greater than or equal to zero,

c and d must not be zero at the same time,

a, b, c, d, e and f are selected so that the electroneutrality of the compound is ensured,

and which are applied to solid, inert carriers, introduced into them or shaped into shaped bodies.

The term "inert" means that the materials used as carriers are inert in the reaction medium of the polyether alcohol synthesis. The inert supports used according to the invention are macroscopic shaped bodies as are customary and known as catalyst supports, for example strands, grit, tablets, nets, packs, fabrics, fibers, spheres and the inner walls of reactors. The macroscopic shaped bodies can consist of inorganic and / or organic materials.

Inorganic materials are, for example, oxides, carbides, nitrides or inert metals. Examples of carbides are transition metal carbides, such as tungsten carbide, and silicon carbide or boron carbide. Suitable nitrides are, for example, boron nitride, silicon nitride or aluminum nitride. Examples of inert metals are steels, aluminum, precious metals, nickel, stainless steel, titanium, tantalum, kanthai. Metal oxides which are inert under the reaction conditions mentioned can be used, in particular those of metals from groups IIA to IVA and IB to Vlllb, and also oxidic compounds which contain elements from groups IA to VIIA and / or the metals from groups Ib to Vlllb.

The catalysts according to the invention can be prepared by applying the compounds of the general formula (I) to the surface of the shaped support or by mixing compounds of the general formula (I) with an unformed support material and subsequent shaping. It is also possible to deform powdered compounds of the general formula (I) into unsupported catalysts.

There are a large number of processes and possibilities for the preparation of compounds of the general formula (I).

So these compounds can be made by coprecipitation. For this purpose, the desired metal ions are placed in a common solution and precipitated by adding further reagents, for example by shifting the pH by adding a base. The precipitated solids can also be subjected to a hydrothermal treatment for further crystallization. An intimate mixing of the components by rotating the common solution in is also possible. The materials thus produced can then be dried and calcined.

Furthermore, such compounds can be produced by impregnation or impregnation. For this purpose, a solid which already contains at least one of the desired components is mixed with at least one solution which can contain the other metal ions. After the solvent has been stripped off, a drying and / or calcining step can also be carried out.

The solids obtained in this way can then be subjected to further treatments by treating them with organic or inorganic ligands.

Preferred compounds of the general formula (I) are those which, as M ', preferably contain alkaline earth or zinc ions, optionally together with the other aforementioned metal ions. The pure oxides and hydroxides such as magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide or zinc hydroxide are to be mentioned here as special compounds. In addition to the pure oxides and hydroxides, there is a wide range of possible doping, both on the cation and on the anion side.

By doping with other cations, such as the main group elements boron, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic, antimony and bismuth, as well as the subgroup elements from groups IB to VIIIB, in particular chromium, iron, lanthanum, manganese , Scandium, yttrium, titanium, vanadium, a large number of compounds can be produced. Inorganic anions can be used as anions, for example halides, anions containing sulfur, phosphorus, nitrogen or carbon, and also organic anions such as alkoxides, carboxylates, amides, sulfides.

Doping the pure oxides or hydroxides results in a large number of compounds. Here are just a few examples:

Hydrotalcite [Mg ₆ Al ₂ (OH) ₁₆ ] CO ₃ • 4 H ₂ 0

Takovit [Ni ₆ Al ₂ (OH) ₁₆ ] C0 ₃ • 4 H ₂ 0

Stichtite [Mg ₆ Cr ₂ (OH) ι ₆ ] C0 ₃ • 4 H ₂ 0

Hydrocalumite [Ca ₂ Al (OH) ₆ ] OH • 6 K ₂ 0

Magaldrat [Mgι ₀ Al ₅ (OH) ₃₁ ] (S0 ₄ ) ₂ • m H ₂ 0

Pyroaurite [Mg ₅ Al ₂ (OH) ₁₆ ] CO ₃ 4.5 H ₂ 0

Ettringite [Ca ₆ Al ₂ (OH) ₁₂ ] (S0 ₄ ) ₃ • 26 H ₂ 0 The solids so produced can be crystalline or amorphous. Crystalline compounds can be layered compounds, such as the hydrotalcite.

There are a number of methods for shaping the compounds of the general formula (I).

One method of applying the compounds of the general formula (I) to an inert shaped body is to spray on a suspension of these compounds in an inert liquid. The spray suspension can either be the precipitation mash of the compounds or the already synthesized and possibly dried compound can be suspended in a suitable suspension liquid.

In order to increase the adhesion of the sprayed-on multimetal cyanide compound to the shaped body, inorganic or organic substances which have a binding effect can also be added to the spray suspension.

The moldings produced in this way can then be subjected to a calcining step. This can have a positive effect on the adhesion to the molded body and can also promote the formation of the active phase.

Furthermore, reactive, inorganic or organic substances in pure form, in the form of their solutions, dispersions or emulsions, which can react either thermally or photochemically, i.e. are crosslinked and thus enable the compound of the general formula (I) to be held firmly on the support.

Reactive organic polymers whose crosslinking products form porous structures are preferred.

These application methods described above are also suitable if the compounds of the general formula (I) are to be applied to the inner walls of reactors.

In addition to spraying on a suspension containing compounds of the general formula (I), the powder of these compounds can be applied directly to the shaped body analogously to a high-solids coating process - one of which is described in DE 4,44,23,46, among others . As a rule, in this process, the moldings are sprayed with an adhesion-promoting liquid parallel to the feed of the powder. As with spraying, it is possible to add substances to the adhesion-promoting liquid which, through their binding action, increase the adhesion of Ensure connection of the general formula (I) on the shaped body.

Here too reactive, i.e. crosslinking inorganic or organic components are added.

Another method, the compounds of general

Applying formula (I) to the shaped body is direct

Synthesis of the compound or its precursor on the shaped body. For this purpose, the various solutions containing the educts are brought into contact with the shaped body either at the same time or in a short time offset. The shaped body can be brought into contact with the solutions by spraying, dipping, soaking, impregnating or similar procedures. Mixing the liquids on the shaped body can lead to precipitation of the compound of the general formula (I) or its precursor on the shaped body. It is also possible to apply the desired metal ions by successive soaking or impregnation. The shaped bodies obtained in this way can, if necessary, also be subjected to hydrothermal crystallization. Furthermore, the shaped bodies obtained in this way can be subjected to a temperature step, if this should be necessary in order to first produce the compounds of the general formula (I).

Here too, substances that promote adhesion can be added before or after the temperature step.

In the previously described production processes for the catalysts according to the invention, the compounds of the general formula (I) are applied to inert moldings. However, deformed compounds of the general formula (I) can also be prepared by making full contacts from the powders. This can be done by tableting, extruding or extruding. Depending on the level of the production costs for the compounds of the general formula (I), one will either choose to support them on inert shaped bodies or to deform them into full contacts. When tableting the compounds of the general formula (I), it is generally necessary to add additional lubricants. These can be graphite, boron nitride or organic molecules such as stearates or alginates. A temperature step can follow the tabletting in order to burn out the organic tabletting aids again.

When extruding or extruding, the powdery compounds of the general formula (I) are first mixed with a pasting liquid in a kneader, pan or similar device processed plastic mass. In this kneading step, further ingredients can be added to the resulting mass, which either improve the properties of the plastic mass during the actual shaping step or give the shaped body produced from this mass better cohesion. For the experts, there are a large number of options for using a wide variety of additives. The contents of the additives are not critical, they should be so high that they have their full effect, but not so high that the catalytic activity of the catalysts is reduced.

Another possibility is to include a compound of general formula (I) in a solid matrix. The solid matrix can be inorganic or organic in nature.

To include the compounds of the general formula (I) in an inorganic matrix, the compounds of the general formula (I) can be suspended in metal acid esters or alkoxymetalates. By adding bases or acids, the metal acid esters can be polymerized to solid substances. The esters of silicon, aluminum, titanium and / or zirconic acid are preferred.

All substances or mixtures of substances in which the compounds of the general formula (I) are suspended and which can be polymerized in any way to give solids can be used as organic components.

The polymerization should be carried out so that the resulting solid particles can be used in a fixed bed arrangement. Furthermore, the solid particles obtained should have sufficient porosity to enable the starting materials and products to be transported to and from the catalytically active centers. To improve the porosity, it is possible to add auxiliaries during the polymerization which are removed again after the polymerization by physical or chemical treatments. The polymerization can also be carried out in such a way that an open-pore foam is formed in which the compound of the general formula (I) is fixed.

The catalysts described above are outstandingly suitable for the continuously operated polymerization of alkylene oxides to polyether polyols. In such a continuous process, the catalyst can be in a fixed bed, floating bed or fluid bed. The fixed bed or floating bed is preferred. The polyether polyols are produced under the conditions customary for this purpose, namely at temperatures between 20 and 250 ° C and pressures between 0.10 to 100 bar, in particular 1 and 60 bar.

The removal of the supported or 5 shaped catalysts according to the invention from the finished polyether is very simple. In the fixed bed mode of operation, the previously required filtration step can be completely dispensed with. The catalytic activity of the catalysts is not impaired by the application to the supports or the shaping.

10

The invention is illustrated by the examples below.

example 1

15

600 g of hydrotalcite (C300, Giulini) are compacted with 400 g of boehmite (Pural® SB, from Condea) and 610 ml of an aqueous formic acid solution (2% by weight of formic acid) in a kneader and shaped into round strands with a diameter of 2 mm .

20 The strands are dried at 120 ° C and calcined at 500 ° C for 5 hours.

Example 2

25 A solution of 175 g of sodium carbonate and 398 g of sodium hydroxide in 2 l of water is placed in a beaker and heated to 40.degree. With constant stirring, a solution of 109 g of lithium nitrate and 1238 g of aluminum nitrate in 1.5 l of water is added over the course of 30 minutes. The resulting suspension is then a further 2 h at 40 ° C.

30 stirred. The resulting solid is then filtered off with suction, washed with water and dried at 110 ° C. for 16 hours.

Example 3

35 120g powder from Example 2 are mixed with 80g boehmite (Pural® SB,

Condea) and 59 ml of an aqueous formic acid solution (2% by weight of formic acid) for one hour in a kneader and shaped into round strands with a diameter of 2 mm. The strands are dried at 120 ° C and calcined at 500 ° C for 5 hours.

40

Example 4

200 g of powder from Example 2 are compacted with 52 ml of an aqueous formic acid solution (2% by weight of formic acid) for 45 hours in a kneader and shaped into round strands with a diameter of 2 mm. The strands are dried at 120 ° C. Example 5

50 g of magnesium hydroxide carbonate (4 MgC03 • Mg (OH) 2) are compacted with 33.3 g of boehmite (Pural® S3, from Condea) and 78 ml of an aqueous formic acid solution (2% by weight of formic acid) in a kneader and added Round strands with a 2 mm diameter deformed. The strands are dried at 120 ° C and calcined at 500 ° C for 5 hours.

Example 6

The synthesis was carried out in a cleaned and dried 5-1 stirred reactor. 779.5 g of glycerol and 35.3 g of split catalyst according to Example 1 were added to the reactor at room temperature. The contents of the vessel were then rendered inert by evacuating and filling the reactor three times with nitrogen. At 95 ° C, vacuum was less than 1 mbar abs for 5 hours. created. A total of 1648 g of propylene oxide were then added in portions at 125 ° C. in such a way that an internal reactor pressure of 7.2 bar abs. was not exceeded. After the end of the feed and reaction, a water jet vacuum was applied (at 125 ° C.) for 30 min. To remove the catalyst, it was filtered through a double layer of a Seitz depth filter. Analyzes: OH number = 588 mg KOH / g, viscosity = 788 mPa * s (at 25 ° C), unsaturated components = 0.0226 meq / g, GPC: M _n = 198.3 g / mol, M _w = 208.9 g / mol, D = 1.053.

Claims

claims

1. Catalysts for the preparation of polyetherols by ring-opening polymerization of alkylene oxides, characterized in that one or more compounds of the general formula (I)

M ' _a M " _b (OH) _c O _d * Ae * L _f (I),

in which

M 'denotes at least one metal ion selected from Groups IA, IIA and Ni or Zn, as well as mixtures thereof,

M '' means at least one metal ion selected from Groups IIIA, IVA, IB to VIIIB and As, Sb and Bi, and mixtures thereof,

A denotes at least one monovalent or polyvalent, inorganic or organic anion,

L represents an inorganic or organic ligand,

in which

a is a rational number greater than zero,

b, c, d, e, f rational numbers greater than or equal to zero,

c and d must not be zero at the same time,

and that the compounds of the general formula (I) are applied to solid carriers which are inert towards the starting materials, intermediate products and end products used in the production of polyetherols, or are introduced into these or shaped into shaped bodies.

2. Catalysts according to claim 1, characterized in that the solid, inert, carriers consist of inorganic or organic material.

3. Catalysts according to claim 1 or 2, characterized in that the supports are metals.

4. Catalysts according to claim 1 or 2, characterized in 5 that the supports are oxides.

5. Catalysts according to claim 1 or 2, characterized in that the supports are organic polymers.

6. Catalysts according to claim 1 or 2, characterized in that the supports are carbides.

7. Catalysts according to claim 1, characterized in that the compounds of general formula (I) on the inner wall

15 are applied by reactors.

8. Catalysts according to claim 1, characterized in that they are present as molded articles made from mechanically deformed compounds of the general formula (I).

20th

9. A catalyst according to claim 1, characterized in that it is designed as a fixed bed.

10. Use of catalysts according to claim 1 for the preparation 25 of polyether alcohols by ring-opening polymerization of

Alkylene oxides.

11. Process for the preparation of polyether alcohols by catalytic ring-opening polymerization of alkylene oxides,

30 characterized in that catalysts according to claim 1 are used as catalysts.

12. A process for the preparation of polyether alcohols according to claim 11, characterized in that it is continuous

35 is operated.

13. Polyetherols with a functionality of 1 to 8 and a molecular weight of 100 to 100,000, characterized in that they are produced 40 by a process according to claims 11 and 12.

14. Use of polyetherols according to claim 13 for the production of polyurethanes.

45 15. Polyurethanes, characterized in that they are under

Use of polyetherols according to claim 13 were produced. Catalysts for the production of polyetherols by ring-opening polymerization of alkylene oxides

Summary

Catalyst for the preparation of polyetherols by ring-opening polymerization of alkylene oxides, characterized in that one or more compounds of the type

M ' _a M'' _b (OH) _c O _d * Ae * L _f (I),

in which

M 'is at least one metal ion selected from Groups IA, IIA and Ni or Zn, and mixtures thereof,

A is at least one monovalent or polyvalent, inorganic or organic anion,

L is an inorganic or organic ligand,

in which

a is a rational number,

b, c, d, e, f rational numbers greater than or equal to zero,

c and d must not be zero at the same time,

characterized in that the compounds (I) -. applied to solid inert carriers or introduced into them or shaped into shaped bodies.