POLYETHER POLYMERIZATION PROCESS

Abstract

Polyethers are prepared by polymerizing an alkylene oxide in the presence of a double metal cyanide catalyst complex and certain M.sup.5 metal or semi-metal compounds. The double metal cyanide catalyst complex contains 0 5 to 2 weight percent potassium. The ability of this catalyst system to tolerate such high amounts of potassium permits the catalyst preparation procedure to be simplified and less expensive.

Claims

1. A method for producing a polyether, the method comprising: I. forming a reaction mixture comprising a) a hydroxyl-containing starter, b) at least one alkylene oxide, c) a water insoluble polymerization catalyst complex that includes at least one double metal cyanide compound and d), as part of the water insoluble polymerization catalyst complex or as a separate component, at least one M.sup.5 metal or semi-metal compound, in which the M.sup.5 metal or semi-metal is selected from aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc, and is bonded to at least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate, phosphate, thiophosphate, dithiophosphate, phosphate ester, thiophosphate ester, amide, oxide, siloxide, hydride, carbamate, halide or hydrocarbon anion, and II. polymerizing the alkylene oxide onto the hydroxyl-containing starter in the presence of the water insoluble polymerization catalyst complex and the M.sup.5 metal or semi-metal compound to produce the polyether, wherein the water insoluble polymerization catalyst complex contains 0.5 to 2 weight percent potassium, based on the weight of the water insoluble polymerization catalyst complex.

2. The method of claim 1 wherein component d) is a separate component from the water insoluble polymerization catalyst complex and the double metal cyanide compound has the formula:
M.sup.1.sub.b[M.sup.2(CN).sub.r(X.sup.1).sub.t].sub.c[M.sup.3(X.sup.2).sub.6].sub.d.Math.nM.sup.4.sub.xA.sup.1.sub.y  (I) wherein: M.sup.1 and M.sup.4 each represent a metal ion independently selected from Zn.sup.2+, Fe.sup.2+, Co.sup.+2+, Ni.sup.2+, Mo.sup.4+, Mo.sup.6+, Al.sup.+3+, V.sup.4+, V.sup.5+, Sr.sup.2+, W.sup.4+, W.sup.6+, Mn.sup.2+, Sn.sup.2+, Sn.sup.4+, Pb.sup.2+, Cu.sup.2+, La.sup.3+, and Cr.sup.3+; M.sup.2 and M.sup.3 each represent a metal ion independently selected from Fe.sup.3+, Fe.sup.2+, Co.sup.3+, Co.sup.2+, Cr.sup.2+, Cr.sup.3+, Mn.sup.2+, Mn.sup.3+, Ir.sup.3+, Ni.sup.2+, Rh.sup.3+, Ru.sup.2+, V.sup.4+, V.sup.5+, Ni.sup.2+, Pd.sup.2+, and Pt.sup.2+; X.sup.1 represents a group other than cyanide that coordinates with the M.sup.2 ion; X.sup.2 represents a group other than cyanide that coordinates with the M.sup.3 ion; A.sup.1 represents a halide, nitrate, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, perchlorate, isothiocyanate, an alkanesulfonate, an arylenesulfonate, trifluoromethanesulfonate, or a C.sub.1-4 carboxylate; b, c and d are each numbers that reflect an electrostatically neutral complex, provided that b and c each are greater than zero; x and y are integers that balance the charges in the metal salt M.sup.4.sub.xA.sup.1.sub.y; r is an integer from 4 to 6; t is an integer from 0 to 2; and n is a number from 0 and 20.

3. The method of claim 1 wherein component d) forms part of the water insoluble polymerization catalyst complex and the catalyst complex has the formula:
M.sup.1.sub.b[M.sup.2(CN).sub.r(X.sup.1).sub.t].sub.c[M.sup.3(X.sup.2).sub.6].sub.d.Math.nM.sup.4.sub.xA.sup.1.sub.y.Math.qM.sup.5.sub.gA.sup.2.sub.h  (II) wherein: M.sup.1 and M.sup.4 each represent a metal ion independently selected from Zn.sup.2+, Fe.sup.2+, Co.sup.+2+, Ni.sup.2+, Mo.sup.4+, Mo.sup.6+, Al.sup.+3+, V.sup.4+, V.sup.5+, Sr.sup.2+, W.sup.4+, W.sup.6+, Mn.sup.2+, Sn.sup.2+, Sn.sup.4+, Pb.sup.2+, Cu.sup.2+, La.sup.3+, and Cr.sup.3+; M.sup.2 and M.sup.3 each represent a metal ion independently selected from Fe.sup.3+, Fe.sup.2+, Co.sup.3+, Co.sup.2+, Cr.sup.2+, Cr.sup.3+, Mn.sup.2+, Mn.sup.3+, Ir.sup.3+, Ni.sup.2+, Rh.sup.3+, Ru.sup.2+, V.sup.4+, V.sup.5+, Ni.sup.2+, Pd.sup.2+, and Pt.sup.2+; X.sup.1 represents a group other than cyanide that coordinates with the M.sup.2 ion; X.sup.2 represents a group other than cyanide that coordinates with the M.sup.3 ion; A.sup.1 represents a halide, nitrate, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, perchlorate, isothiocyanate, an alkanesulfonate, an arylenesulfonate, trifluoromethanesulfonate, or a C.sub.1-4 carboxylate; b, c and d are each numbers that reflect an electrostatically neutral complex, provided that b and c each are greater than zero; x and y are integers that balance the charges in the metal salt M.sup.4.sub.xA.sup.1.sub.y; r is an integer from 4 to 6; t is an integer from 0 to 2; n is a number from 0 and 20; M.sup.5 represents one or more of gallium, hafnium, indium, aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc; A.sup.2 represents least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate, phosphate, thiophosphate, amide, oxide, siloxide, hydride, carbamate, halide or hydrocarbon anion; p and q each are independently from 0.002 to 10; and g and h are numbers that balance the charges in the metal salt M.sup.5.sub.gA.sup.2.sub.h, provided that w is from 1 to 4.

4. The method of claim 1 wherein the M.sup.5 metal or semi-metal is selected from the group consisting of gallium, aluminum, hafnium, indium, manganese and magnesium.

5. The method of claim 1 which is a semi-batch process in which the catalyst complex and starter are charged to a reaction vessel, the catalyst complex is activated and at least a portion of the alkylene oxide is thereafter added to the reaction vessel containing the activated catalyst complex and starter under polymerization conditions without removal of product until all of the alkylene oxide has been added.

6. The method of claim 1 which is a continuous process in which the catalyst complex, starter and alkylene oxide are fed continuous to a reaction vessel under polymerization conditions and product is continuously removed from the reaction vessel.

7. The method of claim 1 wherein the starter has a hydroxyl equivalent weight of 30 to 200.

8. The method of any preceding claim claim 1 wherein the hydroxyl concentration during at least a portion of the polymerization is in the range of 4.25 to 20% by weight of the reaction mixture.

Description

Example 1

A. Preparation of Zinc Hexacyanocobaltate Catalysts Having Varying Potassium Concentrations

[0077] Step 1: An aqueous zinc chloride solution (228 g, 50 wt. % ZnCl.sub.2) is added at 5 mL/min with stirring to 523.5 g of an aqueous solution containing 2.1% potassium hexacyanocobaltate and 11.2% t-butanol. A 4000 number average molecular weight polypropylene oxide diol (2.8 g) is then added. The process temperature is controlled at 30° C.

[0078] Step 2: A solid precipitate forms that is recovered using a centrifuge. A portion of the resulting cake is dried in an oven at 50° C. to constant weight, crushed and sieved to produce a polymerization catalyst complex designated DMC-1. DMC-1 contains 1.9% potassium.

[0079] Step 3: A second portion of the cake from the centrifuging step is re-slurried in an aqueous solution containing 49.7% t-butanol and 0.65 of the polypropylene oxide diol. The solids are again separated using a centrifuge. A portion of the resulting wet cake is dried in an oven at 50° C. to constant weight, crushed and sieved to produce catalyst complex DMC-2. DMC-2 contains 0.63% potassium.

[0080] Step 4: The remaining portion of the wet cake from step 3 is re-slurried in an aqueous solution containing 64.4% t-butanol and 1.0% of the polypropylene oxide. The solids are again separated by centrifuging. A portion of the resulting cake is dried in an oven at 50° C. to constant weight, crushed and sieved to produce a polymerization catalyst complex designated DMC-3. DMC-3 contains 0.23% potassium.

[0081] Step 5: The remaining wet cake from Step 4 is re-slurried in a solution of 90.9% t-butanol, 0.6 wt. % of the polypropylene oxide diol and 8.5% water. The solids are once again recovered by centrifuging. The resulting cake is dried, crushed and sieved as before to produce polymerization catalyst DMC-4. DMC-4 contains 0.3% potassium.

[0082] DMC-5 is a zinc hexacyanocobaltate catalyst complex available commercially as Arcol®-3 catalyst. It contains 0.16% potassium.

B. General Procedure for Evaluation of the Polymerization Catalyst Complexes

[0083] Catalyst activity is evaluated using a high throughput Symyx Technologies Parallel Pressure Reactor (PPR) reactor.

[0084] Starter formulations are prepared by combining 30 g of 700 molecular weight polypropylene oxide triol, 15 milligrams of the catalyst complex and additives as indicated below. The starter formulations are pretreated by heating at 130° C. for 30 minutes while stirring and sparging with nitrogen. The pretreated formulations are cooled to room temperature.

[0085] 0.7 milliliter of starter formulation is transferred into a pre-weighed glass reactor vial. The filled vials are heated to 125° C. for at least 12 hours, and then are loaded into a well of the PPR reactor. The wells are sealed, pressurized to about 50 psig (345 kPa) with nitrogen and heated to 160° C. with stirring. 1 mL of propylene oxide is added to each reactor well. Pressure is monitored as an indication of catalyst activity. If active polymerization is taking place, the reactor pressure will decrease over time because propylene oxide is consumed. If pressure drops below 190 psi (1310 kPa) within one hour, a second 1 mL aliquot of propylene oxide is added, followed by a third 1 mL aliquot an hour later, if the pressure has again dropped below 190 psig (1310 kPa). The reaction is then maintained at the reaction temperature for a total run time of 4 hours.

C. Comparative Samples A-E

[0086] The activity of each of catalyst complexes DMC-1 through DMC-5 are evaluated according to the foregoing general procedure. Each run is replicated three times. Results are indicated in Table 1.

TABLE-US-00001 TABLE 1 Activity of DMC catalysts without additives Sample Designation Comp. A Comp. B Comp. C Comp. D Comp. E Catalyst DMC-1 DMC-2 DMC-3 DMC-4 DMC-5 Potassium 1.9 0.63 0.23 0.30 0.16 content, wt.-% Result No activity No activity Moderate Moderate Moderate, activity activity inconsistent activity

[0087] These results demonstrate the effect of potassium on catalyst activity. When the potassium content is low, as in Samples C, D and E, the catalyst is moderately active even in the absence of any performance-improving additive. Samples C and D each exhibit a decrease in reactor pressure after all three propylene oxide additions, although the rate of decrease (which indicates rate of polymerization and therefore catalyst activity) is in some cases gradual. Sample E performs inconsistently under these conditions, failing to activate at all on at least one of the replicate runs. When the potassium level increases as in Samples A and B, even this moderate activity is lost.

D. Comparative Samples F-J

[0088] In this series of experiments, phosphoric acid (0.154 mg/mL) is added to the starting formulation prior to performing the general procedure described in B above. Results are as indicated in Table 2.

TABLE-US-00002 TABLE 2 Activity of DMC catalysts in the presence of H.sub.3PO.sub.4 Sample Designation Comp. F Comp. G Comp. H Comp. I Comp. J Catalyst DMC-1 DMC-2 DMC-3 DMC-4 DMC-5 Potassium 1.9 0.63 0.23 0.30 0.16 content, wt.-% Result Poor activity Good Good initial Excellent Excellent followed by activity activity activity activity deactivation followed by falling to poor deactivation

[0089] Phosphoric acid is known to improve the performance of DMC catalysts. These results show that phosphoric acid is effecting in improving DMC catalyst performance (compared to that of the catalyst by itself) when the potassium concentration is low. Thus Comp. H performs better than Comp. C, Comp. I, performs better than Comp D, and Comp. J performs better than Comp. E. In each of Comp. H, I and J, adequate to good performance is attained through adding phosphoric acid.

[0090] Different results are obtained when the potassium concentration is higher, as in Comp. F and Comp. G. There, the performance of the catalyst is improved (Comp. F vs. Comp A. and Comp. G vs. Comp. B) but remains unsatisfactory.

E. Examples 1-2 and Comparative Samples K-M

[0091] In this series of experiments, aluminum isopropoxide (4.556 mg/mL) is added to the starting formulation prior to performing the general procedure described in B above. Results are as indicated in Table 3.

TABLE-US-00003 TABLE 3 Activity of DMC catalysts in the presence of aluminum isopropoxide Sample Designation Ex. 1 Ex. 2 Comp. K Comp. L Comp. M Catalyst DMC-1 DMC-2 DMC-3 DMC-4 DMC-5 Potassium 1.9 0.63 0.23 0.30 0.16 content, wt.-% Result Very good Excellent Excellent Excellent Excellent initial activity Activity Activity activity activity falling to moderate

[0092] These results show that the performance of all the catalysts is improved by adding the aluminum isopropoxide. Notably, even the performances of DMC-1 and DMC-2 are quite good, contrary to the case in which no additive or phosphoric acid was present. Example 1 indicates that the benefit of the invention is seen at potassium concentrations of up to about 2% in the catalyst complex; at this level of potassium, the addition of aluminum isopropoxide is not quite as effective when the potassium content is up to about 0.63%. 0.63% potassium is not only tolerated; the adverse effects of the higher potassium content are entirely overcome by the presence of the aluminum isopropoxide.

[0093] As these results show, this invention permits a simplification of the catalyst preparation. Less washing (fewer steps and/or less stringent conditions) is necessary because it is not necessary to scrupulously remove potassium to very low levels. DMC-1, which is washed only a single time with only partial potassium removal, performs well in accordance with this invention.

F. Examples 3-4 and Comparative Samples N-P

[0094] In this series of experiments, aluminum sec-butoxide (4.556 mg/mL) is added to the starting formulation prior to performing the general procedure described in B above. Results are as indicated in Table 4.

TABLE-US-00004 TABLE 4 Activity of DMC catalysts in the presence of aluminum sec-butoxide Sample Designation Ex. 3 Ex. 4 Comp. N Comp. O Comp. P Catalyst DMC-1 DMC-2 DMC-3 DMC-4 DMC-5 Potassium 1.9 0.63 0.23 0.30 0.16 content, wt.-% Result Very good Excellent Excellent Excellent Excellent initial activity Activity Activity activity activity falling to moderate

[0095] The results shown in Table 4 show that similar results are obtained using aluminum sec-butoxide instead of aluminum isopropoxide.