DE19840587A1 - Catalysts for the production of polyetherols by ring-opening polymerization of alkylene oxides - Google Patents

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

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

Polyether alcohols, also called polyetherols, are important ingredients in the production of polyurethanes. They are usually produced by catalytic addition of lower alkylene oxides, especially ethylene oxide and / or Propylene oxide, on H-functional starter substances. As a kata Analyzers are mostly soluble basic metal hydroxides or Salts are used, with potassium hydroxide being the greatest practical Has meaning.

To reduce the content of unsaturated by-products in the polyether alcohols is proposed in EP A 268 922 as Use catalyst cesium hydroxide. Basic metal hydroxides, that dissolve in the polyether polyols have a big aftermath part that after the synthesis with great effort from the Polyetherol must be extracted and the resulting waste must be disposed of.

It is also proposed to use multimetal as catalysts cyanide compounds, especially zinc hexacyanometalates clog. There are a large number of publications in to whom such compounds have been described. So in DD-A-203 734 and DD-A-203 735 a manufacturing process of polyether alcohols using zinc hexacyanocobaltate described.

The production of zinc hexacyanometalates is also known. she usually takes place by solutions of metal salts, mostly Zinc chloride, with solutions of alkali or alkaline earth metal cyano metallates, such as potassium hexacyanocobaltate, are implemented. For Precipitation suspension is usually immediately after the precipitation process one water-miscible, one or more Component containing heteroatoms added. This component can already exist in one or in both educt solutions his. 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 his. Such methods are described for example in US-A 3,278,457, US-A-3,278,458, US-A-3,278,459, US-A-3,427,256.  

Another class of substances that can also be used as catalysts for suitable for the production of polyether polyols are poorly soluble basic oxides or hydroxides. Such basic oxides or hydro Among other things, xides can be alkaline earth metal oxides or hydroxides. So US-A 5 679 764 describes the use of coarser magnesium oxide powders as a catalyst for oxyalkylation.

The use of doped basic earth is also known alkali metal oxides or hydroxides, such as hydro Talcite as catalysts for ring-opening polymerization of alkylene oxides. A number of patents are described Production of fatty alcohol ethoxylates with a narrow molecular weight distribution, using calcined or hydro phobicized hydrotalcite as a catalyst. Representing this the following documents are listed: DE-A 42 42 017, DE-A 41 37 317, DE-A 41 22 200, DE-A 41 15 149, DE-A 40 34 305, 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 in accordance with the cited patents in suspension mode. It's getting more or less coarse powder used in most cases only with great technical effort from the product can be removed.

It would therefore be desirable to have catalysts for ring opening Polymerization of alkylene oxides to H-functional starters ready deliver that can be immobilized in such a way that they the polyetherol pass their subsequent separation from the poly etherol is therefore not necessary.

The object of the invention was therefore to ring catalysts opening polymerization of alkylene oxides to H-functional Provide starters that are easy to separate from the polyetherol are and possibly a continuous driving style at Allow polyether alcohol synthesis.

The task could be solved by applying heavy soluble, catalytically active compounds on solid supports, in solid supports or deforming the sparingly soluble, catalytically effective connections to moldings.

The term "poorly soluble" means that the concentration of the Metal ions, which are used as catalysts Connections are in the output, intermediate and end products of polyether alcohol synthesis less than 50 ppm each Is a metal ion type.  

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 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 used as a carrier Materials inert in the reaction medium of polyether alcohol synthesis behavior.  

The inert carriers used according to the invention are macro scopic moldings, as is customary as a catalyst carrier and are known, e.g. B. strands, grit, tablets, nets, packs, Fabrics, fibers, spheres and the inner walls of reactors. The Macroscopic moldings can be made of inorganic and / or organic materials.

Inorganic materials are, for example, oxides, carbides, Nitrides or inert metals. Examples of carbides are over gear metal carbides, such as tungsten carbide, and silicon carbide or boron carbide. Boron, for example, are suitable as nitrides nitride, silicon nitride or aluminum nitride. Examples of inert Metals are steels, aluminum, precious metals, nickel, stainless steels, Titan, tantalum, Kanthal. As oxides can be one of the above Use inert metal oxides, especially reaction conditions those of metals from groups IIA to IVA and IB to VIIIb, as well as oxidic compounds, the elements of groups IA to VIIA and / or the metals of groups Ib to VIIIb contain.

The catalysts according to the invention can be prepared by Application of the compounds of general formula (I) the surface of the shaped carrier or by mixing Unformed carrier compounds of general formula (I) material and subsequent shaping. Still is it is possible to use powdery compounds of the general formula (I) to form full catalysts.

For the preparation of compounds of the general formula (I) there are a large number of procedures and possibilities.

So these compounds can be made by coprecipitation become. To do this, the desired metal ions are combined in one presented the seed solution and by adding further reagents, for example, by shifting the pH by adding a base. The precipitated solids can also be used for further crystallization undergo a hydrothermal treatment.

Also intimate mixing of the components by spinning in the common solution is possible.

The materials thus produced can then be dried and be calcined.

Furthermore, such compounds can be impregnated or soaked getting produced. This is a solid that is at least contains one of the desired components, with at least one Solution, which may contain the other metal ions, added.  

After removing the solvent, a drying and / or calcining step.

The solids obtained in this way can then undergo further treatments undergo by using organic or inorganic Ligands are treated.

Preferred compounds of the general formula (I) are those those preferred as M 'are alkaline earth or zinc ions, if appropriate together with the other aforementioned metal ions. The pure oxides are special compounds 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.

In addition to the pure oxides and hydroxides, there is a broad one Range of possible dopings, both on cation and on the anion side.

By doping with other cations, such as the main groups elements boron, aluminum, gallium, indium, thallium, silicon, Germanium, tin, lead, arsenic, antimony and bismuth, as well as the Sub-group elements of groups IB to VIIIB, in particular Chrome, iron, lanthanum, manganese, scandium, yttrium, titanium, Vanadium, a variety of compounds can be made.

Inorganic anions can be used as anions, for example halides, sulfur, phosphorus, nitrogen or Anions containing carbon, as well as 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 O
Takovit [Ni ₆ Al ₂ (OH) ₁₆ ] CO ₃ .4 H ₂ O
Stichtite [Mg ₆ Cr ₂ (OH) ₁₆ ] CO ₃ .4 H ₂ O
Hydrocalumite [Ca ₂ Al (OH) ₆ ] OH.6 H ₂ O
Magaldrate [Mg ₁₀ Al ₅ (OH) ₃₁ ) (SO ₄ ) 2.m H ₂ O
Pyroaurite [Mg ₆ Al ₂ (OH) ₁₆ ] CO ₃ .4.5 H ₂ O
Ettringite [Ca ₆ Al ₂ (OH) _12] (SO _{4) 3} .26 H ₂ O.

The solids so produced can be crystalline or amorphous. Crystalline compounds can be layered connections, such as that Hydrotalcite.

For the shaping of the compounds of the general formula (I) there are a number of procedures.

A method based on the compounds of general formula (I) Bringing an inert molded body consists in spraying a suspension of these compounds in an inert liquid speed. As a spray suspension you can either use the precipitation mash use the connections or you already suspend them synthesized and possibly dried compound in a suitable suspension liquid.

To the adhesion of the sprayed multimetal cyanide compound to increase the shaped body, you can add the spray suspension Lich add inorganic or organic substances that a Develop binding effect.

The moldings thus produced can then be calcined be subjected to step. This can affect both liability have a positive effect on the molded body, as well as the formation of the active phase.

Furthermore, reactive, inorganic can be used to increase the adhesion or organic substances in their pure form, in the form of their solutions, Use dispersions or emulsions that are either thermal or can react photochemically, d. H. be networked and such a strong hold of the compound of general formula (I) enable the wearer.

Reactive organic polymers whose ver network products form porous structures.

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

In addition to spraying on a compound of the general formula (I) containing suspension can be analogous to a high-solids Coating process - one such is in DE 44 42 346 described - directly the powder of these compounds apply to the molding. Usually this one Process parallel to the feed of the powder with the moldings sprayed an adhesion-promoting liquid. As with the You can spray on the adhesion-promoting liquid substances add that due to their binding effect an increased liability of the  Grant compound of general formula (I) on the shaped body Afford.

Reactive, i.e. H. 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 that the educts ent hold, either at the same time or with a short time offset brought into contact with the molded body. Bring that in contact the shaped body with the solutions can be sprayed, dipped, Soaking, impregnation or similar procedures happen. By Mixing the liquids on the molded body can be used Precipitation of the compound of general formula (I) or its Precursors come on the molded body.

It is also possible to use successive watering or Impregnate to apply the desired metal ions. The moldings obtained in this way can, if necessary be subjected to hydrothermal crystallization. Furthermore, the moldings thus obtained can be at a temperature step if necessary, around the compounds of general formula (I) produce.

Here too, substances that promote adhesion can be used before or after Temperature step are added.

In the manufacturing processes described so far for the Invention modern catalysts are the compounds of the general Formula (I) applied to inert moldings. But you can also produce deformed compounds of the general formula (I), by making full contacts from the powders. This is through Tableting, extrusion or extrusion possible. Depending on the Amount of manufacturing costs for the connections of the general Formula (I) will either be inerted for the carrier Decide molded bodies or the deformation to full contacts. When tableting the compounds of general formula (I) must you usually add additional lubricants. You can Graphite, boron nitride or organic molecules such as stearates or Be alginates. There can be a temperature on the tablet Connect step to the organic tableting aid burn out again.

When extruding or extruding in a kneader, Koller or similar device the powdery compounds of the general my formula (I) first with a pasting liquid to one  processed plastic mass. In this kneading step, the resulting mass further ingredients are added, the either the properties of the plastic mass in the actual Chen deformation step improve or that from this mass Shaped body produced better cohesion. For the Experts have a large number of options here, ver various additives to use. The contents of the additives are not critical, they should be high enough to have their effect unfold fully, but not so high that the catalytic effect the catalysts is reduced.

Another option is to connect the to enclose general formula (I) in a solid matrix. The solid matrix can be inorganic or organic in nature.

To include the compounds of general formula (I) in a inorganic matrix one can use the compounds of general Formula (I) in metal acid ester or alkoxymetalates suspendie The metal can be removed by adding bases or acids Polymerize acid esters to solid materials. Are preferred the esters of silicon, aluminum, titanium and / or zirconic acid.

All substances or substance can be organic components use mixtures in which the compounds of general Formula (I) are suspended and which in any way and Can be polymerized to solids.

The polymerization should be carried out so that the ent standing solid particles used in a fixed bed arrangement can be. Furthermore, the solid particles obtained should have sufficient porosity to transport them to and from the site the educts or products to the catalytically active centers enable. To improve the porosity it is possible to to add auxiliaries to the polymerization, which by physi chemical or chemical treatments after the polymerization be removed. The polymerization can also be carried out in such a way that an open pore foam is created in which the connection of the general formula (I) is fixed.

The catalysts described above are excellent for the continuous polymerization of alkylene oxides to polyether polyols. The catalytic converter may become continuous process in a fixed bed, floating bed or Fluid bed. The fixed bed or is preferred Floating bed. The polyether polyols are produced here under the usual conditions for this, namely at temperatures  between 20 and 250 ° C and pressures between 0.10 and 100 bar, especially 1 and 60 bar.

The separation of the supported or molded catalysts from the finished polyether is very simple. In the case of a fixed bed mode of operation, Ver filtration step can be completely dispensed with. By the application to the carrier or the shape becomes the kata lytic activity of the catalysts is not impaired.

The invention is illustrated by the examples below become.

example 1

600g hydrotalcite (C300, Giulini) are mixed with 400g boehmite (Pural® SB, from Condea) and 610 ml of an aqueous formic acid solution (2% by weight formic acid) in the kneader for one hour compressed and formed into round strands with a diameter of 2 mm. The strands are dried at 120 ° C and at 500 ° C for 5 hours calcined.

Example 2

A solution of 175g sodium carbonate and 398 g of sodium hydroxide in 2 l of water and heated to 40 ° C. A solution is added within 30 minutes with constant stirring 109 g lithium nitrate and 1238 g aluminum nitrate in 1.5 l water to. The resulting suspension is then a further 2 h at 40 ° C. touched. Then the resulting solid is suctioned off with Washed water and dried at 110 ° C for 16 h.

Example 3

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 Formic acid) compacted in a kneader for one hour and rounded strands with 2 mm diameter deformed. The strands are at Dried 120 ° C and calcined at 500 ° C for 5 h.

Example 4

200 g of powder from Example 2 are mixed with 52 ml of an aqueous Formic acid solution (2% by weight formic acid) for one hour Compressed in the kneader and into round strands with a 2mm diameter deformed. The strands are dried at 120 ° C.  

Example 5

50g magnesium hydroxide carbonate (4 MgCO3.Mg (OH) 2) are with 33.3 g of boehmite (Pural® SB, Condea) and 78 ml of an aqueous Formic acid solution (2% by weight formic acid) for one hour in Kneader compacted and turned into round strands with a diameter of 2 mm forms. The strands are dried at 120 ° C and 5 h at 500 ° C long calcined.

Example 6

The synthesis was carried out in a cleaned and dried 5 liter 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), uns. Constituents = 0.0226 mg KOH / g, GPC: M _n = 198.3 g / mol, M _w = 208.9 g / mol, D = 1.053.

Claims (15)

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 .A _e .L _f (1),
in which
M 'denotes at least one metal ion selected from groups IA, IIA and Ni or Zn, and also 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,
a, b, c, d, e and f are selected so that the electroneutrality of the compound is ensured,
and in that the compounds of the general formula (I) are applied to solid carriers which are inert to the starting materials, intermediate products and end products used in the production of polyetherols, or are introduced into them or shaped to give shaped articles. 2. Catalysts according to claim 1, characterized in that that the solid, inert, inorganic or organic material.   3. Catalysts according to claim 1 or 2, characterized in that the carriers are metals. 4. Catalysts according to claim 1 or 2, characterized in that that the carriers are oxides. 5. Catalysts according to claim 1 or 2, characterized in that that the carriers are organic polymers. 6. Catalysts according to claim 1 or 2, characterized in that that the carriers are carbides. 7. Catalysts according to claim 1, characterized in that the compounds of general formula (I) on the inner wall are applied by reactors. 8. Catalysts according to claim 1, characterized in that it as a molded body from mechanically deformed connections of the general formula (I) are present. 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 of polyether alcohols by ring-opening polymerization of Alkylene oxides. 11. Process for the preparation of polyether alcohols catalytic ring-opening polymerization of alkylene oxides, characterized in that as catalysts, catalysts be used according to claim 1. 12. Process for the preparation of polyether alcohols Claim 11, characterized in that it is continuous is operated. 13. Polyetherols with a functionality of 1 to 8 and one Molar mass from 100 to 100,000, characterized in that it is produced by a method according to claims 11 and 12 become. 14. Use of polyetherols according to claim 13 for the preparation of polyurethanes. 15. Polyurethanes, characterized in that they are under Use of polyetherols prepared according to claim 13 were.