Double metal cyanide catalyst having a controlled reactivity for preparing a polyol and preparation thereof
A double metal cyanide catalyst of the present invention having a controlled reactivity for preparing a polyol, which contains an ether ligand having a molecular weight of less than 200 and a glycol ligand having a molecular weight of less than 200 can be used in the preparation of a polyol having a unsaturation degree suitable for direct use for producing a polyurethane having suitable properties.
1. A double metal cyanide catalyst, represented by formula (I):
M a [M′(CN) 6 ] b L c L′ d (I)
wherein,
M is a metal element 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);
M′ is a metal element 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(V), and V(IV);
L is a first complexing agent, said first complexing agent being an ether having a molecular weight of less than 200;
L′ is a second complexing agent, said second complexing agent being a mixture of an ether having a molecular weight of less than 200 and a glycol having a molecular weight of less than 200; and
a, b, c and d are each independently an integer, the sum of which is equal to the sum of the charges of M and M′,
wherein the glycol is selected from the group consisting of propylene glycol, dipropylene glycol, tripropylene glycol, ethylene glycol, diethylene glycol, and a mixture thereof.
2. The double metal cyanide catalyst of claim 1 , wherein the ether is selected from the group consisting of diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, propylene glycol propyl ether, propylene glycol methyl ether, and a mixture thereof.
3. The double metal cyanide catalyst of claim 1 , wherein the second complexing agent L′ comprises the ether and the glycol in a weight ratio of 1:9 to 9:1.
4. A method for preparing the double metal cyanide catalyst of claim 1 , which comprises:
(1) mixing an aqueous metal (M) salt solution, an aqueous metal (M′) cyanide solution, and a first complexing agent (L), said first complexing agent being an ether having a molecular weight of less than 200 to obtain a slurry;
(2) adding to the slurry obtained in step (1) a second cocomplexing agent (L′) composed of an ether having a molecular weight of less than 200 and a glycol having a molecular weight of less than 200, wherein the glycol is selected from the group consisting of propylene glycol, dipropylene glycol, tripropylene glycol, ethylene glycol, diethylene glycol, and a mixture thereof; and
(3) subjecting the resulting slurry mixture obtained in step (2) to filtration or centrifugation to separate a solid form of the double metal cyanide catalyst.
5. The method of claim 4 , wherein, in step (1), the first complexing agent L is used in an amount ranging from 10 to 90 wt % based on the total weight of the used materials.
6. The method of claim 4 , wherein, in step (2), the second complexing agent L′ is used in an amount ranging from 0.1 to 20 wt % based on the total weight of the used materials.
7. The method of claim 4 , wherein the isolated solid double metal cyanide catalyst in step (3) is further subjected to washing with an aqueous alcohol.
8. A method for preparing a polyol comprising subjecting a propylene oxide to homo polymerization in the presence of a double metal cyanide catalyst or subjecting a propylene oxide and an ethylene oxide to a random copolymerization in the presence of a double metal cyanide catalyst, wherein the double metal cyanide catalyst is the of the double metal cyanide catalyst of claim 1 .
9. The method of claim 8 , wherein the random copolymerization of the propylene oxide and the ethylene oxide employs the propylene oxide and the ethylene oxide in a weight ratio of 9.5:0.5-8:2.