Polyether Polymerization Process

Abstract

Catalyst complexes include a zinc hexacyanocobaltate with M.sup.5 metal and M.sup.6 metal or semi-metal phases, wherein M.sup.5 metal is gallium, hafnium, manganese, titanium and/or indium and the M.sup.6 metal or semi-metal is one or more of aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc and is different from the M.sup.5 metal. The catalysts are highly efficient propylene oxide polymerization catalysts characterized by rapid activation, short times to the onset of rapid polymerization and high polymerization rates once rapid polymerization has begun.

Claims

1. A catalyst complex selected from the group consisting of catalyst complexes I and II, wherein: catalyst complex I is corresponds to 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.pM.sup.5.sub.wA.sup.2.sub.z.Math.qM.sup.6.sub.gA.sup.3.sub.h 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.++, V.sup.4+, V.sup.5+, Sr2+, W.sup.6+, Mn.sup.2+, Sn.sup.2+, Sn.sup.4+,Pv.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+, Rh3+, Ru.sub.2+, V.sup.4+, V.sup.5+, Ni.sup.2+, Pd.sup.2, and Pt.sup.2+; M.sup.5 represents one or more of gallium, hafnium, manganese, titanium and indium; M.sup.6 represents one or more of aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc and is different from M.sup.5; 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; A.sup.2 and A.sup.3 each represents least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate, phosphate, thiophosphate, amide, oxide, siloxide, hydride, carbamate, halide or hydrocarbon anion; 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; p is a number from 0.001 to 10; q is a number from 0.002 to 10; p q=0.025 to 1.5; w and z are numbers that balance the charges in the metal salt M.sup.5.sub.wA.sup.2.sub.z, provided that w is from 1 to 4; and g and h are numbers that balance the charges in the metal salt M.sup.6.sub.gA.sup.3.sub.h, provided that w is from 1 to 4; and catalyst complex II is a mixture of a zinc hexacyanocobaltate catalyst, a particulate M.sup.5 metal oxide wherein M.sup.5 is selected from one or more of gallium, hafnium, manganese, titanium or indium and a particulate M.sup.6 metal or semi-metal oxide wherein M.sup.6 is selected from one or more of aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc and is different from M.sup.5, wherein the M.sup.5 metal oxide is present in an amount that provides 0.001 to 10 moles of M.sup.5 metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst and the M.sup.6 metal or semi-metal oxide is present in an amount that provides 0.002 to 10 moles of M.sup.6 metal or semi-metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst, and the mole ratio of M.sup.5 metal to M.sup.6 metal or semi-metal is 0.025 to 1.5.

2. The catalyst complex of claim 1 wherein M.sup.1 is zinc, M.sup.2 is cobalt, and M.sup.4 is iron or zinc.

3. The catalyst complex of claim 2 wherein the M.sup.6 metal or semi-metal is Al, Si or Ti.

4. The catalyst complex of claim 2 which is catalyst complex I in which p is 0.0025 to 1.5 and q is 0.025 to 2.

5. The catalyst complex of claim 2 which is catalyst complex I in which p is 0.0025 to 0.25 and q is 0.05 to 0.5.

6. The catalyst complex of claim 2 which is catalyst complex I in which p q is 0.05 to 0.5.

7. The catalyst complex of claim 2 which is catalyst II in which the M.sup.5 metal oxide is present in an amount that provides 0.0025 to 1.5 moles of M.sup.5 metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst and the M.sup.6 metal or semi-metal oxide is present in an amount that provides 0.025 to 2 moles of M.sup.6 metal or semi-metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst.

8. The catalyst complex of claim 2 which is catalyst II in which the M.sup.5 metal oxide is present in an amount that provides 0.0025 to 0.25 moles of M.sup.5 metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst and the M.sup.6 metal or semi-metal oxide is present in an amount that provides 0.05 to 0.5 moles of M.sup.6 metal or semi-metal per mole of cobalt provided by the zinc hexacyanocobaltate catalyst.

9. The catalyst complex of claim 2 wherein the M.sup.6 metal or semi-metal is Al and the M.sup.5 metal is one or more of Ga and Hf.

10. The catalyst complex of claim 2 wherein the M.sup.6 metal or semi-metal is Si and the M.sup.5 metal is one or more of Ga, In, Ti or Hf.

11. The catalyst complex of claim 2 wherein the M.sup.6 metal or semi-metal is Ti and the M.sup.5 metal is one or more of In and Ga.

12. A method for producing a polyether, the method forming a reaction mixture comprising a hydroxyl-containing starter, at least one alkylene oxide and a catalyst complex of claim 1, and polymerizing the alkylene oxide onto the hydroxyl-containing starter to produce the polyether in the presence of no more than 0.01 moles of a carbonate precursor per mole of alkylene oxide.

13-14. (canceled)

Description

EXAMPLE 1 AND COMPARATIVE SAMPLES A AND B

[0099] To make Example 1: 2.07 g of gallium tri(isopropoxide) and 20 mL of anhydrous t-butanol are heated at 40° C. under nitrogen for an hour. 20mL of water are added. 2.07 g of aluminum tri(s-butoxide) are added. Zinc chloride (8.00 grams) is then added and the mixture stirred for 30 minutes at 40° C. Next, a solution of potassium hexacyanocobaltate (1.728 grams) premixed with water (40 mL) is added dropwise over a period of 2.5 hours. The mixture in the flask then is heated under reflux until a white gel forms after a period of approximately 20 hours. The resultant gel is dispersed in water (60 mL) and tert-butyl alcohol (60 mL) and centrifuged (5000 rpm) for a period of 15 minutes. The solvent is decanted and the resultant material is again dispersed in a mixture of water (60 mL) and tert-butyl alcohol (60 mL). The resultant dispersion is heated to 55° C. for 35 minutes and then centrifuged (5000 rpm) for a period of 15 minutes. The resultant material is then washed four times with 50/50 by volume mixture of distilled water and tert-butyl alcohol and once more using tert-butyl alcohol (120 mL). The washed material is dried under vacuum at 60° C. overnight to a constant pressure (<10 mbar). The resultant dried solid is milled, forming a catalyst sample in the form of a finely divided powder.

[0100] Comparative Sample A is made in the same manner, except the gallium tri(isopropoxide) is omitted and the amount of aluminum tri(s-butoxide) is doubled.

[0101] Comparative Sample B is made in the same manner, except the aluminum tri(s-butoxide) is omitted and the amount of gallium tri(isopropoxide) is doubled.

[0102] The metals and chlorine analysis of each of these catalysts is determined using XRF methods, with results as follows:

TABLE-US-00001 Moles per mole Cobalt Sample Co Zn Ga Al Cl Ex. 1 1 1.8 1.25 1.1 0.7 A 1 2.2 0 2.3 0.75 B 1 2.0 4.7 0 0.7

[0103] Catalyst Example 1 and Comparative Samples A and B are used to produce polyether polyols in a semi-batch process. Dipropylene glycol (475.4 g) and 142.0 milligrams of the catalyst sample (enough to provide 100 parts per million based on the expected mass of the product) are added a 7 L Juchheim reactor at 60° C. and stirred at 50 rpm under dry nitrogen. The reactor is closed and set to 100° C. and 400 rpm. Then, the atmosphere within the reactor is purged with dry nitrogen and vacuum is applied. This part of the procedure is repeated four additional times. The reactor is isolated and placed under vacuum for one hour at 160° C. to dry the starting materials. 140 g of propylene oxide are then added to the reactor at the same temperature. This raises the internal reactor pressure to about 3 bar gauge (304 kPa) (all pressures reported herein are gauge pressures unless noted otherwise). The pressure inside the reactor is continuously monitored for a pressure drop that indicates catalyst activation has taken place. The time required for the reactor pressure to drop to 1 bar (101 kPa) is noted as the activation time. 40 minutes after the start of the process (or upon catalyst activation in cases in which the catalyst has not yet activated after 40 minutes), 868.8 g of propylene oxide is fed to the reaction at 160° C. The feed rate is increased linearly from zero to 29 g/min over the course of one hour unless the internal pressure during the feed reaches 4 bar (405 kPa), in which case the feed rate is discontinued until the pressure drops to 3.5 bar (354 kPa), at which point the feed is resumed. Therefore, the shortest possible time for the propylene oxide addition is 60 minutes, which can be obtained only if the reactor pressure does not reach the pressure limit during the propylene oxide feed. After the propylene oxide is completed, the reaction mixture is digested for 15 minutes at 160° C. Vacuum is then is applied to remove any unreacted propylene oxide. The reactor is then cooled to 100° C. and 200 ppm of an antioxidant is added to the reaction mixture under dry nitrogen. Then, the product is cooled to ambient temperature and collected. Batch size is approximately 1421.8 grams in each case. The product molecular weight is 400 g/mol. During the polymerization, the hydroxyl content of the reaction mixture decreases from about 20% by weight to about 4.25% by weight.

[0104] The internal reactor pressure is monitored during the reaction as in indication of the activity of the catalyst. These polymerization conditions represent a difficult challenge for conventional double metal cyanide catalysts because of the low molecular weight of the starter (dipropylene glycol). Conventional DMC catalysts perform poorly in the presence of high concentrations of hydroxyl groups, which is the case during early stages of a semi-batch process such as this in which the starter molecular weight is low. It is for this reason that the propylene oxide feed rate is ramped up gradually after catalyst activation. The catalyst activity and therefore polymerization rate is expected to increase as the product builds molecular weight, which allows the propylene oxide to be consumed more rapidly and therefore be fed more rapidly.

[0105] FIG. 1 shows the corresponding pressure vs. time plots for Example 1 (line 1) and Comparative Samples A and B (lines A and B, respectively). Each of lines 1, A and B illustrates a similar general trend of pressure vs. time. Thus, each of lines 1, A and B include a Segment 2 which represents the increase in reactor pressure during the initial propylene oxide feed in each case. The pressure increases to about 3 bar (303 kPa). The following slow decrease in reactor pressure indicated in Segment 3 of lines 1, A and B indicates the consumption of propylene oxide as the catalyst activates. The time at which the pressure decreases to 1 bar (101 kPa) is taken as the catalyst activation time. This time is less than 20 minutes for each of Example 1 and Comparative Sample A and 25-30 minutes for Comparative Sample 1. Segment 4 of lines 1, A and B indicates the increase in pressure as the subsequent propylene oxide feed is commenced. As shown in the Figure, the reactor pressure in each case reaches a maximum (5, 5A and 5B) after which reactor pressure falls substantially despite the rapid feed rate, as indicated by segment 6 of lines 1, A and B. At this point of the reaction, propylene oxide is being consumed at rates greater than 30 g/minute. The entire amount of propylene oxide fed (868.6 grams) is consumed in each case 100-105 minutes after the start of the process. Segment 7 of lines 1, A and B indicates the reactor pressure during the final digestion step in each case, after all propylene oxide has been fed to the reactor.

[0106] The advantage of the invention is seen by comparing the activation time and the time to onset of rapid polymerization, as well as by comparing the maximum pressure achieved once the catalyst has activated. These values are summarized in the following table:

TABLE-US-00002 TABLE 2 Added Metal, Activation Onset of Rapid Moles per mole Time, Polymerization, Maximum Designation Co.sup.1 min min Presure.sup.2 A* Al, 2.3 25-30 71 3.87 psi B* Ga, 4.7 10-15 59 1.71 psi 1 Ga, 1.25, Al, 1.1 10-15 65 1.69 psi *Not an example of the invention. .sup.1The additional metal (aluminum and/or gallium) added into the catalyst precipitation step, and moles of that metal per mole of cobalt in the product as determined by XRF. .sup.2The maximum pressure obtained in the reactor after the catalyst has activated and the 29 g/minute propylene oxide feed is started.

[0107] Comparative Sample B is a gallium-containing hybrid catalyst. It performs very well compared even to the aluminum-containing catalyst (Comparative Sample A, which itself performs very well on this stringent test). However the proportion of gallium is high in that catalyst; gallium being expensive it is desirable to obtain equivalent performance while reducing the amount of gallium. Example 1 achieves this goal; the amount of gallium is reduced by about three-quarters relative to Comparative Sample A, yet the performance is quite similar. Although the aluminum-containing catalyst performs less well, it is seen that by using a combination of aluminum and gallium in the catalyst one can mimic the performance of the gallium-containing catalyst (Comp. Sample B) while vastly reducing the amount of expensive gallium.

EXAMPLES 2-14 AND COMPARATIVE SAMPLES B AND C

[0108] Hybrid catalysts containing silicon as the M.sup.6 semi-metal and gallium, hafnium, indium or titanium as the M.sup.5 metal are made in the following general manner: The M.sup.5 metal compound (as identified in Table 3 below) and tetrapropyl orthosilicate are weighed into a vial, to yield molar proportions of silicone to M.sup.5 metal as indicated in Table 3. t-butanol (10 moles per combined moles of silicon and M.sup.5 metal) and 0.01M HCl solution (0.05 moles per combined moles of silicon and M.sup.5 metal) and water (equal to the t-butanol volume minus the HCl solution volume) are added and the mixture is heated at 60° C. for 30 minutes with mixing. The mixture is cooled to 30° C. t-Butanol and water are added at a 1:6 volume ratio, followed by K.sub.3Co(CN).sub.6, which is allowed to dissolve. The amount of K.sub.3Co(CN).sub.6 is sufficient to provide silicon to cobalt mole ratio as indicated in Table 3. A 50% solution of zinc chloride in water is added, followed by a small amount of a 4000 molecular weight poly(propylene oxide) diol. The resulting reaction solution is mixed at room temperature for at least one hour.

[0109] The precipitate is recovered by centrifuging and decanting the liquid phase. It is then washed successively with mixtures of t-butanol, water and the 4000 molecular weight poly(propylene oxide) diol, in each case followed by centrifuging and decanting the liquid phase. The solids are then dried at 60° C. overnight under vacuum, followed by breaking up larger agglomerates, to form a powdered catalyst complex.

[0110] A sample of the catalyst complex is analyzed by X-ray fluorescense for Co, Si and the M.sup.5 metal. Molar ratios of these metals as measured are as indicated in Table 3.

[0111] Comparative Samples B and C are made without the silicone and M.sup.5 metal (Comp. B) or with silicone but without an M.sup.5 metal (Comp. C).

[0112] Alkylene oxide polymerizations and/or propylene oxide oxide/carbon dioxide copolymerizations are performed on using a 48-well Symyx Technologies Parallel Pressure Reactor (PPR). Each of the 48 wells is equipped with an individually weighed glass insert having an internal working liquid volume of approximately 5 mL. The wells each contain an overhead paddle stirrer.

[0113] 720.65 milligrams of a 700 molecular weight poly(propylene oxide) starter and 0.35 milligrams of the catalyst complex are charged to each insert. Each well is pressurized with 50 psig (344.7 kPa) of nitrogen and then heated to the polymerization temperature. Upon reaching the polymerization temperature 1 mL of the epoxide is injected into each well, where it reacts with the starter in the glass insert.

[0114] The internal pressure in the headspace of each well is monitored individually throughout the polymerization. Each hour after the first injection of epoxide, the internal pressure is observed, and if the pressure in any particular well has fallen below 190 psig (1.31 MPa), another 1 mL of the alkylene oxide is injected. This is repeated up to three times throughout the entire length of the run, which is 4 hours. 4 hours after the first epoxide injection, the wells are allowed to cool to room temperature and vented. The glass inserts are allowed to stand under nitrogen over night to allow residual epoxide to volatilize, after which the inserts are weighed to determine the amount of product as an indication of the relative activity of the catalyst complex. Results are as indicated in Table 3.

TABLE-US-00003 TABLE 3 Mole Ratios (Recipe) Mole Ratios (XRF) M.sup.5 Metal M.sup.5 M.sup.5 Product Sample Compound Si:Co metal:Si M.sup.5:Co Si:Co metal:Si m.sup.5:Co Yield, g B* None 0 0 0 0 0 0 1.33 C* None 0.2 0 0 0.18 0 0 1.19 2 Ga Isopropoxide 0.2 0.05 0.01 0.15 0.1 0.015 2.54 3 Ga Isopropoxide 0.2 0.275 0.055 0.15 0.37 0.056 2.57 4 Ga Isopropoxide 0.2 0.5 0.1 0.13 0.87 0.11 2.04 5 Hf Isopropoxide 0.2 0.05 0.01 0.12 0.06 0.007 2.46 6 Hf Isopropoxide 0.2 0.275 0.055 0.15 0.32 0.05 2.59 7 Hf Isopropoxide 0.2 0.5 0.01 0.11 0.66 0.075 1.87 8 In Isopropoxide 0.2 0.05 0.01 0.10 0.126 0.012 2.16 9 In Isopropoxide 0.2 0.275 0.055 0.10 0.74 0.074 2.02 10 In Isopropoxide 0.2 0.5 0.1 0.1 1.35 0.13 2.06 11 Ti Butoxide 0.2 0.05 0.01 0.2 0.065 0.013 1.28 12 Ti Butoxide 0.2 0.275 0.055 0.18 0.315 0.058 3.03 13 Ti Butoxide 0.2 0.5 0.1 0.15 0.46 0.07 3.07 14 Ti Butoxide 0.05 0.5 0.025 0.02 0.94 0.022 1.76 *Not an example of the invention.

EXAMPLES 15-18 AND COMPARATIVE SAMPLE D

[0115] Catalyst complexes are made and evaluated in the same general manner as Examples 2-14. Aluminum is the M.sup.6 metal (supplied in the form of aluminum tri-butoxide). The M.sup.5 metal compound is titanium tetra(butoxide) or indium isopropoxide. Amounts of the aluminum and M.sup.5 metal are as indicated in Table 4, as are the yields of product in each case. No titanium is present in the comparative samples.

TABLE-US-00004 TABLE 4 M.sup.5 Metal Mole Ratios (Recipe) Mole Ratios (XRF) Sample Compound Al:Co M.sup.5:Al M.sup.5:Co Al:Co M.sup.5:Al M.sup.5:Co Yield, g D* None 0.05 0 0 0.03 0 0 1.28 15 Ti butoxide 0.05 0.05 0.0025 0.01 0.22 0.0022 2.56 16 Ti butoxide 0.05 0.275 0.0413 0.02 0.36 0.0072 2.53 17 Ti butoxide 0.05 0.5 0.025 0.03 1.00 0.03 3.10 18 In isopropoxide 0.2 0.5 0.1 0.06 2.03 0.1218 2.91

EXAMPLES 19-25

[0116] Catalyst complexes are made and evaluated in the same general manner as Examples 2-14. Titanium is the M.sup.6 metal (supplied in the form of tetra(butoxide)). The M.sup.5 metal compound is as indicated in Table 5. Amounts of the titanium and M.sup.5 metal are as indicated in Table 5, as are the yields of product in each case.

TABLE-US-00005 TABLE 5 M.sup.5 Metal Mole Ratios (Recipe) Mole Ratios (XRF) Sample Compound Ti:Co M.sup.5:Ti M.sup.5:Co Ti:Co M.sup.5:Ti M.sup.5:Co Yield, g 19 In isopropoxide 0.2 0.05 0.01 0.18 0.23 0.043 2.87 20 In isopropoxide 0.2 0.275 0.055 0.17 0.5 0.08 3.06 21 In isopropoxide 0.2 0.5 0.1 0.19 0.48 0.09 2.63 22 Ga isopropoxide 0.2 0.05 0.01 0.18 0.10 0.018 3.14 23 Ga isopropoxide 0.2 0.5 0.1 0.18 0.55 0.096 3.06 24 Mn (III) oxide 0.2 0.275 0.055 0.18 0.63 0.11 3.10 25 Mn (III) oxide 0.2 0.5 0.1 0.20 0.66 0.13 2.87