Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2000-03-15
2002-10-22
Wood, Elizabeth D. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S163000, C502S164000, C502S175000, C502S200000
Reexamination Certificate
active
06468939
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to novel double metal cyanide (DMC) catalysts, to a process for the preparation of these novel DMC catalysts, and to a process for the preparation of polyether polyols by the polyaddition of alkylene oxides to starter compounds which comprise active hydrogen atoms in the presence of these novel DMC catalysts and to the polyether polyols produced by this process.
Double metal cyanide (DMC) catalysts for the polyaddition of alkylene oxides to starter compounds which comprise active hydrogen atoms are known and described in, for example, U.S. Pat. Nos. 3,404,109, 3,829,505, 3,941,849 and 5,158,922. Compared with the conventional preparation of polyether polyols by means of alkali catalysts such as, for example, alkali hydroxides, the use of these DMC catalysts for the preparation of polyether polyols has the particular effect of reducing the proportion of monofunctional polyethers with terminal double bonds, i.e., the so-called monools. Thus, the polyether polyols which are obtained from DMC catalysts can be processed to form high-grade polyurethanes (e.g., elastomers, foams, coatings). DMC catalysts are usually obtained by the reaction of an aqueous solution of a metal salt with an aqueous solution of a metal cyanide salt in the presence of an organic complexing ligand such as, for example, an ether. In a typical catalyst preparation, for example, aqueous solutions of zinc chloride (in excess) and potassium hexacyanocobaltate are mixed, and dimethoxyethane (glyme) is subsequently added to the formed suspension. After filtration and washing of the catalyst with aqueous glyme solution, an active catalyst of general formula:
Zn
3
[Co(CN)
6
]
2
·x ZnCl
2
·yH
2
O·z glyme
is obtained. This process is described in detail in, for example, EP-A 700 949.
Other DMC catalysts are disclosed in, for example, JP-A 4,145,123, U.S. Pat. No. 5,470,813, EP-A 700 949, EP-A 743 093, EP-A 761 708, and WO 97/40086. These DMC catalysts are described as further reducing the proportion of monofunctional polyethers comprising terminal double bonds during the preparation of polyether polyols by the use of tert.-butanol as the organic complexing ligand, either alone or in combination with a polyether as described in, for example, EP-A 700 949, EP-A 761 708, and WO 97/40086. Moreover, by the use of these DMC catalysts in the preparation of polyether polyols the induction time of the polyaddition reaction of alkylene oxide with corresponding starter compounds is reduced and the catalytic activity is increased.
The object of the present invention was to provide improved DMC catalysts for the polyaddition of alkylene oxides to corresponding starter compounds, which catalysts exhibit further increased catalytic activity in comparison with the various types of catalysts known previously. By reducing the requisite times of alkoxylation, this results in improved economics of the production process for polyether polyols. Ideally, due to its increased activity, the catalyst can then be used in such low concentrations (25 ppm or less) such that the very costly separation of catalyst from the product is no longer necessary and the product can be used directly for the production of polyurethane.
Surprisingly, it has now been found that DMC catalysts which contain esters of phosphoric acid, phosphorous acid, phosphonic acid, phosphonous acid, phosphinic acid or phosphinous acid as complexing ligands exhibit a considerably increased activity with regard to the production process of polyether polyols.
SUMMARY OF THE INVENTION
The present invention therefore relates to a double metal cyanide (DMC) catalyst comprising:
a) one or more, preferably one, double metal cyanide compounds,
b) one or more, preferably one, organic complexing ligands (which are different from c)), and
c) one or more, preferably one, compound selected from the group consisting of organic phosphates, organic phosphites, organic phosphonates, organic phosphonites, organic phosphinates and organic phosphinites.
The catalyst according to the invention may also optionally contain d) water, preferably in an amount of 1 to 10% by weight, based on the total weight of the catalyst, and/or e) one or more water-soluble metal salts, preferably in an amount of 5 to 25% by weight, based on the total weight of the catalyst from the preparation of the double metal cyanide compounds.
Suitable water-soluble metal salts include those corresponding to the general formula (I): M(X)
n
, for the preparation of double metal cyanide compounds a). In formula (I), M represents a metal which is selected from the group consisting of: 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). Zn (II), Fe (II), Co (II) and Ni (II) are particularly preferred metals. The anions X may be the same or different, are preferably the same, and are each independently (and preferably) selected from the group consisting of halides, hydroxides, sulfates, carbonates, cyanates, thiocyanates, isocyanates, isothiocyanates, carboxylates, oxalates or nitrates. The value of n is 1, 2 or 3.
The double metal cyanide compounds a) which are contained in the catalysts according to the invention comprise the reaction products of (i) one or more water-soluble metal salts and (ii) one or more water-soluble metal cyanide salts.
Water-soluble metal salts which are suitable for the production of double metal cyanide compounds a) include, preferably, metal salts corresponding to general formula (I): M(X)
n
, wherein: M represents a metal and is selected from the group consisting of: 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). The metals Zn (II), Fe (II), Co (II) and Ni (II) are particularly preferred. The anions X may be either the same or different, but are preferably the same, and are each independently (and preferably) selected from the group consisting of halides, hydroxides, sulfates, carbonates, cyanates, thiocyanates, isocyanates, isothiocyanates, carboxylates, oxalates or nitrates. The value of n is 1, 2 or 3.
Examples of suitable water-soluble metal salts include zinc chloride, zinc bromide, zinc acetate, zinc acetylacetonate, zinc benzoate, zinc nitrate, iron(II) sulfate, iron(II) bromide, iron(II) chloride, cobalt(II) chloride, cobalt(II) thiocyanate, nickel(II) chloride and nickel(II) nitrate. Mixtures of different water-soluble metal salts can also be used.
Water-soluble metal cyanide salts which are suitable for the production of double metal cyanide compounds a) include, for example, those which preferably correspond to general formula (II):
(Y)
a
M′(CN)
b
(A)
c
(II)
wherein:
M′ represents a metal and is selected from the group consisting of 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); and preferably represents a metal selected from the group consisting of Co(II), Co(III), Fe(II), Fe(III), Cr(III), Ir(III) and Ni(II);
each Y represents a cation and may be the same or different (preferably the same), and each is independently selected from the group consisting of alkali metal ions and alkaline earth metal ions;
each A represents an anion and may be the same or different (preferably the same), and each is selected from the group consisting of halides, hydroxides, sulfates, carbonates, cyanates, thiocyanates, isocyanates, isothiocyanates, carboxylates, oxalates and nitrates;
a, b and c each represents an integer value, with the values of a, b and c being selected such that the electroneutrality of the metal cyanide salt is achieved; a preferably represents 1, 2, 3 or 4; b preferably represents 4, 5 or 6; and c preferably has the value 0.
The water-soluble metal cyanide salt may contain one or more of these metals M′ as described above. Since the cations Y are independently selected, the water-soluble metal cyanide salt may
Gupta Pramod
Hofmann Jörg
Ooms Pieter
Bayer Aktiengesellschaft
Brown N. Denise
Gil Joseph C.
Sloane Carolyn M.
Wood Elizabeth D.
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