ALKYLENE OXIDE POLYMERIZATION USING ALUMINUM COMPOUNDS AND PHOSPHORUS-NITROGEN BASES

Abstract

Polyethers are prepared by polymerizing an alkylene oxide in the presence of a starter, an aluminum compound that has at least one hydrocarbyl substituent, and a phosphorus-nitrogen base. The phosphorus-nitrogen base is present in only a small molar ratio relative to the amount of starter. The presence of such small amounts of phosphorus-nitrogen base greatly increases the catalytic activity of the system, compared to the case in which the aluminum compound is used by itself. The product polyethers have low amounts of unsaturated polyether impurities and little or no unwanted high molecular weight fraction. Polymers of propylene oxide have very low proportions of primary hydroxyl groups.

Claims

1. A method for producing an alkylene oxide polymer or copolymer, comprising combining (i) at least one aluminum compound containing at least one trisubstituted aluminum atom, wherein at least one of the substituents of at least one trisubstituted aluminum atom is hydrocarbyl, (ii) at least one starter, (iii) at least one alkylene oxide, (iv) from 0.00005 to 0.1 mole, per equivalent of starter, of at least one phosphazene-nitrogen base and optionally (v) at least one comonomer that is not an oxirane, and polymerizing the alkylene oxide(s) or copolymerizing the alkylene oxide(s) and the comonomer to form the alkylene oxide polymer or copolymer.

2. The method of claim 1 wherein an aluminum atom of the aluminum compound is substituted with one or two hydrocarbyl groups, and is substituted with one or two halogen, oxo, ether, hydride or phosphonate groups.

3. The method of claim 1 wherein the aluminum compound includes one or more of trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, tri-n-propyl aluminum, triisobutyl aluminum, tri-n-butyl aluminum, tri-t-butylaluminum and trioctadecylaluminum.

4. The method of claim 1 wherein the aluminum compound includes one or more of dimethyl aluminum chloride, methyl aluminum dichloride, diethyl aluminum chloride, ethyl aluminum dichloride, diisobutyl aluminum chloride, isobutyl aluminum dichloride, methyl aluminum di [(2,6-di-t-butyl-4-methyl)phenoxide] (Al(BHT).sub.2Me), dimethyl 2,6-di-t-butyl-4-methylphenoxide (AlBHTMe.sub.2) methyl aluminum di(2,6-diisopropyl)phenoxide, di methyl aluminum (2,6-diisopropyl)phenoxide methyl aluminum di [(2,6-diphenyl)phenoxide], dimethyl aluminum (2,6-diphenyl) phenoxide, methyl aluminum di[(2,4,6-trimethyl)phenoxide], dimethyl aluminum (2,4,6-trimethyl)phenoxide, tetraethylaluminane, tetramethylaluminane, diisobutyl aluminum hydride, isobutyl aluminum dihydride, dimethyl alumimum hydride, methyl aluminum dihydride, diethyl aluminum hydride, ethyl aluminum dihydride, diisopropyl aluminum hydride, isopropyl aluminum dihydride, diethyl aluminum ethoxide, ethyl aluminum diethoxide, dimethyl aluminum ethoxide, methyl aluminum diethoxide, dimethyl aluminum fluoride, methyl aluminum difluoride, diethyl aluminum fluoride, ethyl aluminum difluoride, diisobutyl aluminum fluoride, isobutyl aluminum difluoride, dimethyl aluminum bromide, methyl aluminum dibromide, diethyl aluminum bromide, ethyl aluminum dibromide, diisobutyl aluminum bromide, isobutyl aluminum dibromide, dimethyl aluminum iodide, methyl aluminum diiodide, diethyl aluminum iodide, ethyl aluminum diiodide, diisobutyl aluminum iodide and isobutyl aluminum iodide.

5. The method of claim 1 wherein the aluminum compound includes one or more of bis(dimethylaluminum) methylphosphonate, bis(diethyl aluminum) methylphosphonate, bis(diethoxyaluminum) methylphosponate, bis(di-n-propylaluminum) methyl phosphonate, bis(diisopropyl aluminum) methylphosphonate, bis(di-n-propoxylaluminum) methyl phosphonate, bis(diisopropoxylaluminum) methylphosphonate, bis(di-t-butylaluminum) methyl phosphonate, bis(di-t-butoxyaluminum) methyl phosphonate, bis(diphenylaluminum) methyl phosphonate, bis(diphenoxyaluminum) methyl phosphonate, bis(diisobutylaluminum) methylphosphonate and a tetraalkylaluminoxane in which each alkyl group independently contains 1 to 6 carbon atoms.

6. The method of claim 1 wherein the phosphorus-nitrogen bases is represented by the structure I: ##STR00011## wherein each R is hydrocarbyl, NH.sub.2 or —N═P—R.sub.3, A is an anion, and n is the valence of the anion A, the phosphorus-nitrogen base having a molecular mass of up to 1000 g/mol.

7. The method of claim 6 wherein the phosphorus-nitrogen base is a fluoride, chloride, bromide, iodide, acetate, triflate, BF4.sup.− or PF6.sup.− salt of bis(triphenylphosphoranylidene)ammonium.

8. The method of claim 1 wherein the phosphorus-nitrogen base is represented by the structure II: ##STR00012## wherein R.sup.5 and each R.sup.4 are independently —P[N(R.sup.4).sub.2].sub.3 or hydrocarbyl, provided that any two hydrocarbyl R.sup.4 groups may form a divalent hydrocarbyl group that forms a ring that includes the nitrogen atom or atoms to which such R.sup.4 groups are bonded, x is zero or a positive number and the phosphorus-nitrogen base has a molecular weight of up to 1000 g/mol.

9. The method of claim 8 wherein the phosphorus-nitrogen base is one or more of methylimino-tris(dimethylamino)phosphorane, ethylimino-tris(dimethylamino)phosphorane, t-butylimino-tris(dimethylamino)phosphorane, tert-octylimino-tris(dimethylamino)phosphorane), phosphazene base P2, phosphazene base P2-Et, phosphazene base P2-t-Bu, phosphazene base P2-tert-octyl, ethylimino-tris(pyrrollidino)phosphorane, t-butylimino-tris(pyrrollidino)phosphorane, tert-octylimino-tris(pyrrollidino)phosphorane, 2-ethylimino-2-diethylamino-1,3-dimethylperhydro-1,3-2-diazaphosphorine, 2-t-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3-2-diazaphosphorine, 2-tert-octylimino-2-diethylamino-1,3-dimethylperhydro-1,3-2-diazaphosphorine, phosphazene base P4 (1-methyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylidenamino]-2λ.sup.5,4λ.sup.5-catenadi(phosphazene)), 1-ethyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylidenamino]-2λ.sup.5,4λ.sup.5-catenadi(phosphazene)) and 1-tert-Butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylidenamino]-2λ.sup.5,4λ.sup.5-catenadi(phosphazene).

10. The method of claim 1 wherein the phosphorus-nitrogen base is represented by structure III or IIIa: ##STR00013## wherein each R.sup.4 are independently —PN(R.sup.4).sub.3, hydrocarbyl (more preferably alkyl or alkylene), provided that any two R.sup.4 groups may form a divalent hydrocarbyl group that forms a ring that includes the nitrogen atom or atoms to which such R.sup.4 groups are bonded, R.sup.10 is hydrocarbyl, and the phosphorus-nitrogen base has a molecular weight of up to 1000 g/mol.

11. The method of claim 10 wherein the phosphorus-nitrogen base is one or more of hexamethylphosphoramide (tris(dimethylaminophosphine oxide), hexaethylphosphoramide, hexa-t-butylphosphoramide and tris (N,N-tetramethylene) phosphoramide.

12. The method of claim 1 wherein the phosphorus-nitrogen base is represented by the structure IV: ##STR00014## where A is an anion, and n is the valence of the anion A, and each R.sup.6 is independently hydrocarbyl or —N═P—(NR.sup.6.sub.2).sub.3, provided further that any two R.sup.6 groups may form a divalent hydrocarbyl group that forms a ring that includes the nitrogen atom or atoms to which such R.sup.6 groups are bonded, and the phosphorus-nitrogen base having a molecular mass of up to 1000 g/mol.

13. The method of any claim 12 wherein the phosphorus-nitrogen bases is one or more 1,1,1,3,3,3-hexakis(dimethylamino)diphosphazenium fluoride, 1,1,1,3,3,3-hexakis(dimethylamino)diphosphazenium chloride, 1,1,1,3,3,3-hexakis(dimethylamino)diphosphazenium bromide, tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium fluoride, tetrakis[tris(dimethylamino)phosphoranylidenamino]phosphonium chloride and tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium bromide.

14. The method of claim 1 wherein the phosphorus-nitrogen bases is a phosphine compound represented by structure V or structure VI: ##STR00015## wherein each R.sup.7 is independently hydrocarbyl, provided that any two R.sup.7 groups may form a divalent hydrocarbyl group that forms a ring that includes the nitrogen atom or atoms to which such R.sup.7 groups are bonded, Y is halogen, A is a monovalent anion and the phosphorus-nitrogen base has a molecular weight of up to 1000 g/mol.

15. The method of claim 14 wherein the phosphine compound is one or more of tris(dimethylamino)phosphine, tris(diethylamino)phosphine and tri(di-t-butylamino)phosphine.

16. The method of claim 1 wherein the phosphorus-nitrogen base is represented by the structure VI: ##STR00016## in which m is a number from 3 to 20, each Q is independently selected from hydrocarbyl; —N═P—R.sub.3 where each R is independently hydrocarbyl; aryloxy; alkoxy; and ##STR00017## wherein c is zero or a positive number which is preferably up to 4, each R.sup.9 is independently hydrocarbon, and each R.sup.8 is independently hydrocarbon.

17. (canceled)

18. The method of claim 1 wherein the aluminum compound and starter are combined at proportions that provide 0.00005 to 0.05 moles of aluminum per equivalent of starter.

19. The method of claim 1 wherein the mole ratio of the aluminum compound to the phosphorus-nitrogen base is at least 1:3, and up to 5:1.

20-21. (canceled)

22. The method of claim 1 wherein the alkylene oxide is propylene oxide, ethylene oxide or a mixture of propylene oxide and ethylene oxide.

23. The method of claim 1 wherein the starter is a homopolymer of propylene oxide and/or a random or block copolymer of propylene oxide that has a hydroxyl equivalent weight of at least 125 and up to 4000 g/equivalent and in which no more than 25% of the hydroxyl groups are primary.

Description

EXAMPLES 1-7 AND COMPARATIVE SAMPLE A

[0092] Propoxylations of a 700 molecular weight, trifunctional poly(propylene oxide) starter are performed in a semi-batch reactor using various aluminum compounds and bis(triphenylphosphoranylidene(ammonium) chloride salt (PPNCl) as the phosphorus-nitrogen base. Polymerization temperature is 160° C.

[0093] The aluminum compounds are triethyl aluminum (AlEt.sub.3), diethyl aluminum chloricde (Et.sub.2AlCl), diisobutyl aluminum hydride (DIBAL) and tetraethyldialuminoxane (TEDA), as indicated in Table 1.

[0094] The aluminum compound:PPNCl molar ratio in each of Examples 1, 2 and 5-7 is 1:0.5; this ratio is 1:1 for Examples 3 and 4. The mole ratios of PPNCl to aluminum provided by the aluminum compound are as indicated in Table 1. The PPNCl is omitted in Comp. Sample A.

[0095] The amount of 1,2-propylene oxide (PO) fed, the run time and yield are indicated in Table 1, together with the % primary hydroxyl groups, polydispersity and M.sub.n of the product.

TABLE-US-00001 TABLE 1 Semi-Batch Polymerizations using Aluminum Catalysts and PPNCl Mole ratio, PO P—N partial PO Run ppm base to pressure fed Time Yield %1 Sample Catalyst Catalyst Al (psi/kPa) (mL) (hr) (g) OH PDI M.sub.n 1 AlEt.sub.3 1900 0.5:1 30/207 164.1 1.0 160.2 ND 1.02 3972 2 AlEt.sub.3 955.6 0.5:1 30/207 163.9 2.5 163.9 ND ND ND 3 Et.sub.2AlCl 2000 .sup. 1:1 20/138 163.8 19.5 159.7 ND 1.11 3175 4 DIBAL 2000 .sup. 1:1 20/138 164 28.3 173.1 ND 103 3630 5 TEDA 3110 0.5:1 20/138 164.4 1.3 164.4 4.6 1.02 3900 6 TEDA 1555 0.5:1 30/207 164.5 1.2 163.0 4.5 1.02 3848 7 TEDA 778 0.5:1 40/276 147.5 2.2 140.2 2.6 1.03 3327 A* TEDA 1555 N/A 30/207 34.1 19.6 56.2 ND 1.04 1356 *Comparative. ND is not determined

[0096] Comparative Sample A is a control in which TEDA is the aluminum catalyst by itself; no phosphorus-nitrogen base is present. The polymerization proceeds sluggishly. Little PO is consumed after almost 20 hours and yield to product is correspondingly low, as is product molecular weight.

[0097] In each of Examples 1-7, an aluminum compound is paired with PPNCl. In each case, about 5 times as much PO is consumed, compared to Comparative Sample A, and yields and product molecular weights are higher as a result. The runs made using triethyl aluminum and TEDA are especially remarkable as the run times are an order of magnitude shorter than with the control. These combinations of aluminum compound and PPNCl are especially active polymerization catalysts.

[0098] In all cases, polydispersity is low and % primary hydroxyl is also very low in those cases in which it is measured.

EXAMPLES 8-26 AND COMPARATIVE SAMPLE B

[0099] Propylene oxide polymerizations are performed using the PPR procedure described above. The starter is the 700 molecular weight triol described in the previous examples. The aluminum compound and the amount of aluminum compound (in parts per million, ppm) by weight based on the amount of starter) in each case is as indicated in Table 2. The phosphorus-nitrogen base is PPNCl in all cases. The initial molar ratios of aluminum compound to phosphorus-nitrogen base are as indicated in Table 2. The polymerization temperature is 160° C. The amount of product produced, the % of hydroxyl groups that are primary, the number average molecular weight and the polydispersity (PDI, M.sub.w/M.sub.n) are as reported in Table 2.

TABLE-US-00002 TABLE 2 PO Polymerizations with Various Al Compound and PPNCl Aluminum ppm Al Mole ratio, Al % 1° Sample Compound Compound compound:PPNCl Yield, g OH PDI M.sub.n Ex. 8 EtAlCl.sub.2.sup.1 2100 1:2 0.86 ND ND ND Ex. 9 EtAlCl.sub.2 2100 1:1 1.01 6 1.03 1263 Ex. 10 EtAlCl.sub.2 2100 2:1 3.15 5 1.06 3856 Ex. 11 EtAlCl.sub.2 2100 4:1 3.11 4 1.06 3791 Ex. 12 DIBAL.sup.2 2350 1:2 0.86 ND ND ND Ex. 13 DIBAL 2350 1:1 3.14 4 1.03 4032 Ex. 14 DIBAL 2350 2:1 3.19 5 1.06 4118 Ex. 15 DIBAL 2350 4:1 3.12 5 1.06 3983 Ex. 16 AlEt.sub.3.sup.3 2000 1:2 0.81 ND 1.03 1015 Ex. 17 AlEt.sub.3 2000 1:1 1.24 5 1.03 1380 Ex. 18 AlEt.sub.3 2000 2:1 2.20 5 1.03 2584 Ex. 19 AlEt.sub.3 2000 4:1 0.78 4 1.03  974 Ex. 20 TEDA.sup.4 1550 1:8 0.88 4 1.03 1074 Ex. 21 TEDA 1500 1:4 0.88 4 1.03 1069 Ex. 22 TEDA 1500 1:2 0.90 4 1.03 1086 Ex. 23 TEDA 1500 1:1 2.82 5 1.02 3505 Ex. 24 TEDA 1500 2:1 3.26 5 1.02 4281 Comp. B* TDIPAP.sup.5 2950 N/A 1.02 23  1.05 1254 Ex. 25 TDIPAP 2950 1:3 0.81 ND 1.03 1010 Ex. 26 TDIPAP 2950 1:1 2.77 ND 1.02 3352 *Comparative. ND = not done. .sup.1Ethyl aluminum dichloride. .sup.2Diisobutyl aluminum chloride. .sup.3Triethyl aluminum. .sup.4Tetramethyl aluminane. .sup.5Tris(diisopropoxylaluminum) phosphate.

[0100] As the data for Examples 8, 12, 16, 20-22 and 25 show, a 2:1 or greater excess of PPNCl results in little polymerization under these conditions. When used in such an excess, PPNCl may actually repress polymerization, as suggested by comparing Comp. Sample B with Ex. 25. Much greater yields and much higher molecular weights are obtained when the molar ratio of Al compound to PPNCl is 1:1 to 2:1. The results for Examples 20-24 suggest that, for the TEDA/PPNCl combination at least, the molar ratio should be maintained below 4:1.

EXAMPLES 27-31

[0101] EO polymerizations are performed using the PPR procedure described above. The starter is the 700 molecular weight triol described in the previous examples. The aluminum catalyst is as indicated in Table 3 below. The amount of aluminum compound in each case is as indicated in Table 3; amounts are ppm by weight based on starter. The phosphorus-nitrogen base is PPNCl. The aluminum compound and phosphorus-nitrogen base are initially present at a 1:1 molar ratio in Examples 27-29; it is 1:0.5 in Example 30 and 1:0.25 in Example 31. The polymerization temperature is 160° C. The amount of product produced, the % of hydroxyl groups that are primary, the number average molecular weight and the polydispersity (PDI, M.sub.w/M.sub.n) are as reported in Table 3.

TABLE-US-00003 TABLE 3 EO Polymerizations with PPNCl ppm Al Aluminum Sample compound Compound Yield, g % 1° OH PDI M.sub.n Ex. 27 2000 Et.sub.2AlCl 1.96 86 1.08 2379 Ex. 28 2000 EtAlCl.sub.2 2.78 ND 1.06 3895 Ex. 29 1550 TEDA 2.91 ND 1.04 3680 Ex. 30 1550 TEDA* 2.50 ND 1.05 3189 Ex. 31 1550 TEDA** 2.54 ND 1.05 3162 *TEDA/PPNCl mole ratio 1:0.5, 0.25 moles of PPNCl per mole of Al atoms. **TEDA/PPNCL mole ratio is mole ratio 1:0.25, 0.125 moles of PPNCl per mole of Al atoms. ND is not determined.

[0102] Rapid polymerizations yielding high molecular weight, low polydispersity polymer are obtained in each case.

EXAMPLES 32-36

[0103] Various combinations of various aluminum compounds and PPNCl are evaluated in propoxylations of small molecule starters. The mole ratio of PPNCl to aluminum provided by the aluminum compound is 1:1 in all cases. The starters are ortho-toluene diamine (oTDA), bis(3-aminopropyl) methyl amine (BAPMA), glycerin and sorbitol, as indicated in Table 4. Polymerizations are performed using the PPR procedure in the same general manner as in the previous examples. The aluminum compound is as indicated in Table 4, as are the results of the polymerizations.

TABLE-US-00004 TABLE 4 PO Polymerizations from Small Molecules Using PPNCl Starter ppm Al molecular Sample Al compund compound Starter weight Yield, g PDI M.sub.n Ex. 32 Et.sub.2AlCl 2000 OTDA 122 2.58 1.01 378 Ex. 33 Et.sub.2AlCl 2000 BAPMA 142 2.09 1.07 341 Ex. 34 EtAlCl.sub.2 2000 BAPMA 142 2.23 1.07 338 Ex. 35 Al(BHT).sub.2Me 8000 glycerin 92 2.08 1.03 363 Ex. 36 DIBAL 2000 sorbitol 182 2.29 1.04 527

[0104] As demonstrated by the data in Table 4, the combination of various aluminum compounds with TBD results in the effective propoxylation of various low molecular weight hydroxyl-containing and amine-containing starters. As before, polydispersity remains low.

EXAMPLES 37-45 AND COMPARATIVE SAMPLES C-E

[0105] In these polymerizations, the starter is the same 700 molecular weight triol describe in earlier examples and the alkylene oxide is propylene oxide. The aluminum compound and phosphorus-nitrogen base are as indicated in Table 5.

[0106] In Table 5, “PAZ-P1” indicates t-butylimino-tris(dimethylamino)phosphorane and “HMPA” indicates hexamethylphosphoramide (i.e, tris(dimethylaminophosphine oxide). “DCI16302” and “DCI16303” have the respective structures:

##STR00010##

PPNF, PPNOAc and PPNPF.sub.6 are, respectively, the fluorine, acetate and PF.sub.6 bis(triphenylphosphoranylidene)ammonium salts.

[0107] The amount of catalyst in each case is 2000 parts per million based on the starter. The phosphorus-nitrogen base (when present) and the aluminum compound are initially present at a 1:1 molar ratio, which also produces a 1:1 molar ratio of PPNCl to aluminum. The polymerization temperature is 160° C. The amount of product produced, the % of hydroxyl groups that are primary, the number average molecular weight and the polydispersity (PDI, M.sub.w/M.sub.n) are as indicated in Table 5.

TABLE-US-00005 TABLE 5 Al ppm Al Phosphorus- Sample compound compound nitrogen base Yield, g %1° OH PDI M.sub.n Comp. C* Et.sub.2AlCl 2000 None 1.5 7 1.08 1636 Ex. 37 Et.sub.2AlCl 2000 PAZ-P1 2.89 5 1.03 3499 Ex. 38 Et.sub.2AlCl 2000 HMPA 0.97 ND 1.04 1213 Comp. D* EtAlCl.sub.2 2000 None 1.41 33 1.06 1669 Ex. 39 EtAlCl.sub.2 2000 PAZ-P1 2.20 6 1.04 2536 Ex. 40 EtAlCl.sub.2 2100 DCI16302 1.60 11 1.05 1897 Ex. 41 EtAlCl.sub.2 2100 DCI16303 1.41 19 1.05 1681 Comp. E* DIBAL 2000 None 1.19 31 1.06 1392 Ex. 42 DIBAL 2000 HMPA 1.43 ND 1.05 1630 Ex. 43 TEDA 1550 PPNF 2.90 5 1.02 3693 Ex. 44 TEDA 1550 PPNOAc 2.87 5 1.02 3487 Ex. 45 TEDA 1550 PPNPF.sub.6 2.04 4 1.03 2489

[0108] PAZ-P1 has a strong enhancing effect when used in combination with either the Et.sub.2AlCl or the EtAlCl.sub.2 catalyst. HMPA, DCI16302 and DCI16303 all exhibit a mild enhancing effect when used together with the DIBAL catalyst. The fluoride, acetate and hexafluorophosphate bis(triphenylphosphoranylidene(ammonium) salts all exhibit substantial enhancing effects.