Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From heterocyclic reactant containing as ring atoms oxygen,...
Reexamination Certificate
2000-05-19
2002-02-19
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From heterocyclic reactant containing as ring atoms oxygen,...
C528S410000, C528S412000, C528S414000, C528S415000, C502S102000, C502S158000, C502S152000, C502S175000, C502S240000, C502S241000, C502S250000, C502S254000, C502S258000, C502S260000, C502S439000, C502S506000
Reexamination Certificate
active
06348565
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to metal cyanide complexes. More particularly, it relates to metal cyanide catalysts having specific complexing agents, to heterogeneous metal cyanide catalysts, and to methods for polymerizing alkylene oxides in the presence of a metal cyanide catalyst.
Polyethers are prepared in large commercial quantities through the polymerization of alkylene oxides such as propylene oxide and ethylene oxide. The polymerization is usually conducted in the presence of an initiator compound and a catalyst. The initiator compound usually determines the functionality (number of hydroxyl groups per molecule) of the polymer and in some instances incorporates some desired functional groups into the product. The catalyst is used to provide an economical rate of polymerization.
Metal cyanide complexes are becoming increasingly important alkylene oxide polymerization catalysts. These complexes are often referred to as “double metal cyanide” or “DMC” catalysts, and are the subject of a number of patents. Those patents include, for example, U. S. Pat. Nos. 3,278,457, 3,278,458, 3,278,459, 3,404,109, 3,427,256, 3,427,334, 3,427,335 and 5,470,813, among many others. In some instances, these metal cyanide complexes provide the benefit of fast polymerization rates and narrow polydispersities. Additionally, these catalysts sometimes are associated with the production of polyethers having very low levels of monofunctional unsaturated compounds.
The most common of these metal cyanide complexes, zinc hexacyano-cobaltate (together with the proper complexing agent and an amount of a poly(propylene oxide)), has the advantages of being active and of forming poly(propylene oxide) having very low unsaturation. However, the catalyst is quite difficult to remove from the product polyether. Because of this difficulty, and because the catalyst can be used in small amounts, the usual practice is to simply leave the catalyst in the product. However, this means that the catalyst must be replaced. In addition, the presence of the residual catalyst in the polyether product has been reported to cause certain performance problems. These include poor storage stability and, in some instances, interference with downstream processes. In order to reduce catalyst expense and to avoid these problems, it would be desirable to provide a catalyst that can be recovered easily from the product polyether.
SUMMARY OF THE INVENTION
In one aspect, this invention is a water insoluble metal cyanide catalyst that is complexed with a silane-functional complexing agent.
In a second aspect, this invention is an organosilicone polymer having pendant heteroatom-containing groups that are complexed with a water insoluble metal cyanide catalyst.
In a third aspect, this invention is a supported catalyst complex comprising a water-insoluble metal cyanide coupled to a support through a silane coupling agent containing a heteroatom-containing functional group that is complexed with said metal cyanide.
In a fourth aspect, this invention is a supported catalyst comprising a support having coated thereon a polymer containing repeating units derived from a complex of a water insoluble metal cyanide and a silane-functional complexing agent.
In a fifth aspect, this invention is a method of polymerizing an alkylene oxide, comprising contacting said alkylene oxide with an initiator compound under polymerization conditions with a polymer containing repeating units derived from a complex of a water insoluble metal cyanide and a silane-functional complexing agent.
DETAILED DESCRIPTION OF THE INVENTION
The complex of the invention includes a water insoluble metal cyanide catalyst. These metal cyanide catalysts are well known, and are often referred to as “double metal cyanide” or “MC” catalysts because in most instances these complexes include two different metal ions. The metal cyanide catalysts can be represented by the general formula
M
b
[M
1
(CN)
r
(X)
t
]
c
[M
2
(X)
6
]
d
.n
M
3
x
A
y
,
wherein M is a metal ion that forms an insoluble precipitate with the M
1
(CN)
r
(X)
t
group and which has at least one salt which is soluble in water or an organic compound as described below;
M
1
and M
2
are transition metal ions that may be the same or different;
each X independently represents a group other than cyanide that coordinates with an M
1
or M
2
ion;
M
3
x
A
y
represents a salt of metal ion M
3
and anion A which is soluble in water or an organic compound as described below, wherein M
3
is the same as or different than M;
b and c are positive numbers that, together with d, reflect an electrostatically neutral complex;
d is zero or a positive number;
x and y are numbers that reflect an electrostatically neutral salt;
r is from 4 to 6; t is from 0 to 2; and
n is a positive number (which may be a fraction) indicating the relative quantity of M
3
x
A
y
.
The X groups in any M
2
(X)
6
do not have to be all the same. The molar ratio of c:d is advantageously from about 100:0 to about 20:80, more preferably from about 100:0 to about 50:50, and even more preferably from about 100:0 to about 80:20.
The term “metal salt” is used herein to refer to a salt of the formula M
x
A
y
or M
3
x
A
y
, where M, M
3
, x, A and y are as defined above.
M and M
3
are preferably metal ions selected from the group consisting of Zn
+2
, Fe
+2
, Co
+2
, Ni
+2
, Mo
+4
, Mo
+6
, Al
+3
, V
+4
, V
+5
, Sr
+2
, W
+4
, W
+6
, Mn
+2
, Sn
+2
, Sn
+4
, Pb
+2
, Cu
+2
, La
+2
and Cr
+3
. M and M
3
are more preferably Zn
+2
, Fe
+2
, Co
+2
, Ni
+2
, La
+3
and Cr
+3
. M is most preferably Zn
+2
.
M
1
and M
2
are preferably Fe
+3
, Fe
+2
, Co
+3
, Co
+2
, Cr
+2
, Cr
+3
, Mn
+2
, Mn
+3
, Ir
+3
, Ni
+2
, Rh
+3
, Ru
+2
, V
+4
and V
+5
. Among the foregoing, those in the plus-three oxidation state are more preferred. Co
+3
and Fe
+3
are even more preferred and Co
+3
is most preferred. M
1
and M
2
may be the same or different.
Preferred groups X include anions such as halide (especially chloride), hydroxide, sulfate, carbonate, oxalate, thiocyanate, isocyanate, isothiocyanate, C
1-4
carboxylate and nitrite (NO
2
—), and uncharged species such as CO, H
2
O and NO. Particularly preferred groups X are NO, NO
2
— and CO.
r is preferably 5 or 6, most preferably 6 and t is preferably 0 or 1, most preferably 0. In many cases, r+t will equal six.
Suitable anions A include halides such as chloride and bromide, nitrate, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, perchlorate, an alkanesulfonate such as methanesulfonate, an arylenesulfonate such as p-toluenesulfonate, trifluoromethanesulfonate (triflate) and C
1-4
carboxylate. Chloride ion is especially preferred.
The metal cyanide catalyst is completed with a complexing agent that contains a hydrolyzable silane coupling group. By “complexed”, it is meant that the complexing agent becomes associated with the metal cyanide catalyst. The nature of the complexing is not fully understood, and may be due to a combination of factors. The completing may be due to the formation of a coordinate bond between a heteroatom on a functional group of the complexing agent and one or more of the metal ions (M, M
1
, M
2
, M
3
) of the metal cyanide catalyst. Another explanation of the complexing is that it is due to the complexing agent occupying vacancies within the crystalline structure of the metal cyanide, or that it otherwise is occluded within or bound into the crystalline lattice. However, it is not intended to limit this invention to any particular complexing mechanism.
The complexing agent has at least one hydrolyzable silane group that is linked to a group having at least one functional moiety through which the complexing agent can be complexed with the metal catalyst. The functional moiety advantageously contains at least one heteroatom
Dawson Robert
Robertson Jeffrey B.
The Dow Chemical Company
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