POLYMERIZATION OF MICHAEL-TYPE MONOMERS

Abstract

A process for precision polymerization is described using a system of a Lewis acid, a Lewis base and a Michael-type monomer that can form a frustrated triple, wherein a Michael-type monomer, optionally dissolved in an organic solvent, is reached with a Lewis acid to form at least one zwitterionic type complex, a Lewis base is added to form a frustrated triple with the zwitterionic type complex which initiates the polymerization reaction, and the reaction is continued to form a polymer.

Claims

1. A process for precision polymerization using a catalyst system of a Lewis acid and a Lewis base, with a Michael-type monomer that can form a frustrated triple, wherein a) the Michael-type monomer, optionally dissolved in an organic solvent, is reacted with the Lewis acid to form at least one zwitterionic type complex, b) the Lewis base is added to form a frustrated triple with the at least one zwitterionic type complex which initiates a polymerization reaction, and c) the polymerization reaction is continued to form a polymer; wherein the Lewis acid is X.sub.aMR.sub.3-a, wherein M is Al, B, Ga, or In, each X independently is Cl, F, I, or Br; each R independently is linear, branched, or cyclic alkyl, heterocycloalkyl, linear, branched, or cyclic alkenyl, heterocyclo-alkenyl, linear, branched, or cyclic alkinyl, heterocycloalkinyl, linear, branched, or cyclic alkoxy, aryl, heteroaryl, aryloxy, silyl, metallocenyl, nitro, nitroso, hydroxy, or carboxyl, wherein each alkyl, alkenyl or alkinyl group independently has up to 12 carbon atoms, wherein each aryl independently has 6 to 10 carbon atoms, wherein any hetero group has at least one hetero atom selected from the group consisting of O, S and N; wherein each alkyl, alkenyl, alkinyl, or alkoxy, heterocycloalkyl, heterocycloalkenyl, heterocycloalkinyl, aryl, heteroaryl, aryloxy group can be substituted by 1 up to the highest possible number of halogen atoms or by at least one unsubstituted or halogensubstituted linear, branched or cyclic alkyl group having up to 6 carbon atoms, and wherein a is an integer from 0 to 3, and wherein if a is 1, X can also be selected to be hydrogen; and wherein the Lewis base is PZ.sub.3, wherein each Z independently is a linear, branched, or cyclic alkyl, alkenyl, or alkinyl group, or heteroalkyl, heteroal-kenyl, or heteroalkinyl group, having up to 12 carbon atoms; or a donor substituted aryl or hetero aryl group having 6 to 10 carbon atoms, with the proviso that the tolman angle is 180 or less; wherein any hetero group comprises at least one hetero atom selected from the group consisting of O, S and N.

2. Process according to claim 1, wherein the at least one Michael-type monomer is polymerized in the presence of a frustrated Lewis pair of a Lewis acid and a Lewis base, wherein the monomer has the formula C(R.sup.1R.sup.2)C(R.sup.3)C(O)OR.sup.4, wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently selected from the group consisting of hydrogen, methyl, aryl, heteroaryl and a bulky group, and wherein at least one of R.sup.1 to R.sup.4 is the bulky group, or wherein the monomers are aerylonitrile, vinylsulfonates, vinylpyridines or vinylphosphonates wherein the process comprises that the monomer is contacted with the catalyst.

3. Process according to claim 1, wherein the Lewis acid is triphenyl aluminum, trimethyl aluminum, tri-isobutyl aluminum, or aluminum isopropoxide.

4. Process according to claim 1, wherein the Lewis base is trime-thylphosphine, triethylphosphine or tricyclohexylphosphine.

5. Process according to claim 1, wherein the molar ratio of Lewis base/Lewis acid is in a range between 0.1-0.5:1.

6. Process according to claim 1, wherein the molar ratio of monomer/catalyst system is 1,000 to 15,000.

7. Process according to claim 1, wherein the process is carried out at a temperature between 115 C. and +150 C.

8. Process according to claim 1, wherein the monomer is acrylonitrile or tert.-butylmethacrylate.

9. Process according to claim 1, wherein the monomer is acrylonitrile and wherein the catalyst system comprises triphenylaluminum and trimethylphosphine.

10. Process according to claim 1, wherein the monomer is tert.-butylmethacrylate and wherein the catalyst system comprises trimethylphosphine and trimethylaluminum.

11. Polymer produced by the process of claim 1.

12. System for precision polymerization comprising a) a Michael-type monomer, b) a Lewis acid X.sub.aMR.sub.3-a, as catalyst, and c) a Lewis base PZ.sub.3 as initiator, d) and optionally a solvent wherein components a), b), and c) can form a frustrated triple, wherein X, M, R, Z, and a are defined as in claim 1.

13. Catalyst system for precision polymerization of acrylonitrile comprising tri-phenylaluminum and trimethylphosphine in a ratio of 4:1 to 1:1.

14. (canceled)

15. A method for identifying a frustrating triple system comprising the steps of a) determining the electronic state of a Michael-type monomer, b) choosing a Lewis acid based on its acidity, wherein the acidity is the higher the lower the electron richness of the monomer is, c) combining the Michael-type monomer and the Lewis acid and adding a Lewis base and d) determining if a polymer with predetermined properties has formed as indication for the formation of the frustrated triple.

Description

[0066] The drawings show analytical data of polymers obtained with the method of the present invention, wherein

[0067] FIG. 1 shows the GPC spectrum and the NMR spectra of the polymer obtained in example 1.

[0068] FIG. 2 shows the GPC spectrum and the NMR spectra of the polymer obtained in example 3.

[0069] FIG. 3 shows the GPC spectrum and the NMR spectra of the polymer obtained in example 4.

[0070] FIG. 4 shows the GPC spectrum and the NMR spectra of the polymer obtained in example 5.

[0071] FIG. 5 shows linear growth of the mean molecular mass of poly(furfurylmethacrylate) with increasing turnover.

[0072] Gel permeation chromatography detection was made using a WTC Dawn Heleos II MALS detector. GPC was carried out on a Varian LC-920 system with two PL polar gel columns and N,N-dimethyl formamide (0.025 M LiBr) (polyacrylonitrile) or tetrahydrofurane (poly(tert.-butylmethacrylate)) were used as liquid medium. The retention times were recorded via a MALLS detector and via an integrated RI detector (356-LC). The GPC spectrum is shown in FIG. 2.

[0073] The NMR spectra were recorded with an AV III 500C of Bruker and were evaluated with Top Spin 3 software.

[0074] In the following examples specific embodiments of the present invention are shown without thereby limiting the scope of the invention.

EXAMPLES

[0075] Acrylonitrile was polymerized using a frustrated triple system. The conditions and results are shown in Table 1. The method is described in detail below.

TABLE-US-00001 TABLE 1 Selected results of the polymerization of acrylonitrile with Al(R).sub.3 Tol/Lewis base Reaction M.sub.n 10.sup.4 [Base]/ [Monomer]/ volume Temp t Yield.sup.[a] [B] PDI Run Acid Base [Acid] [Cat] [mL] [ C.] [min] [%] [g/mol] [B] TOF 1 Al(Me).sub.3 PEt.sub.3 1 2000 7.5 0 15 42 1.9 1.97 3360 2 AlCl.sub.3 PCy.sub.3 1 500 7.5 0 15 3 Al(Et).sub.3 PCy.sub.3 1 2000 7.5 0 10 47 2.2 2.04 5640 4 Al(Ph).sub.3 PCy.sub.3 1 2000 7.5 0 10 37 5.2 1.75 4440 5 Al(OiPr).sub.3 PCy.sub.3 0.1 100 7.5 0 10 87 25.3 1.53 5220 6 Al(Ph).sub.3 PMe.sub.3 1 2000 7.5 0 10 45 4.6 1.62 5400 .sup.[a]Yields determined by .sup.1H-NMR spectroscopy of sample aliquots and of the isolated polymers determined by using gravimetric methods. [B] M.sub.n and PDI determined using multi angle laser light scattering (MALLS) detection methods.

Example 1

[0076] Polyacrylonitrile was produced using a catalyst system of the present invention. The reaction was performed in oven-dried glass reactor Al(Me).sub.3 (302 L, 12.5 mmol/L solution in toluene) was added and cooled to 0 C. Acrylonitrile (500 L, 3.77 mmol, 400 mg, 2,000 equivalents) and thereafter triethylphosphine (PEt.sub.3) (151 L, 25.0 mmol/L solution in toluene, 1 equivalents) were added and the mixture was stirred for 15 min at 0 C. The reaction was stopped by adding a mixture of DMF-MeOHHCl (100:10:1). A sample was taken and an .sup.1H-NMR was recorded. Thereafter, the polymer was precipitated in 40 mL MeOH. Centrifugation, washing a few times with each 10 mL MeOH, centrifugation and drying at 40 C. (12 h) in high vacuum yielded 169 mg (42%) polyacrylonitrile. The analytical data are shown in FIG. 1.

Example 2 (for Comparison)

[0077] Polyacrylonitrile was produced using a catalystAlCl.sub.3as known in the prior art. The reaction was performed in oven-dried glass reactor AlCl.sub.3 (302 L, 12.5 mmol/L suspension in toluene) was added and cooled to 0 C. Acrylonitrile (500 L, 3.77 mmol, 400 mg, 2,000 equivalents) and thereafter tricyclohexylphosphine (PEt.sub.3) (151 L, 25.0 mmol/L solution in toluene, 1 equivalents) were added and the mixture was stirred for 15 min at 0 C. The reaction was stopped by adding a mixture of DMF-MeOHHCl (100:10:1). A sample was taken and an .sup.1H-NMR was recorded. The reaction yielded no polymer.

Example 3

[0078] Polyacrylonitrile was produced using a catalyst system of the present invention. The reaction was performed in oven-dried glass reactor Al(Et).sub.3 (302 L, 12.5 mmol/L solution in toluene) was added and cooled to 0 C. Acrylonitrile (500 L, 3.77 mmol, 400 mg, 2,000 equivalents) and thereafter triethylphosphine (PEt.sub.3) (151 L, 25.0 mmol/L solution in toluene, 1 equivalents) were added and the mixture was stirred for 15 min at 0 C. The reaction was stopped by adding a mixture of DMF-MeOHHCl (100:10:1). A sample was taken and an .sup.1H-NMR was recorded. Thereafter, the polymer was precipitated in 40 mL MeOH. Centrifugation, washing a few times with each 10 mL MeOH, centrifugation and drying at 40 C. (12 h) in high vacuum yielded 189 mg (47%) polyacrylonitrile. The analytical data are shown in FIG. 2.

Example 4

[0079] Polyacrylonitrile was produced using a catalyst system of the present invention. The reaction was performed in oven-dried glass reactor Al(Ph).sub.3 (302 L, 12.5 mmol/L solution in toluene) was added and cooled to 0 C. Acrylonitrile (500 L, 3.77 mmol, 400 mg, 2,000 equivalents) and thereafter tricyclohexylphosphine (PCy.sub.3) (151 L, 25.0 mmol/L solution in toluene, 1 equivalents) were added and the mixture was stirred for 15 min at 0 C. The reaction was stopped by adding a mixture of DMF-MeOHHCl (100:10:1). A sample was taken and an .sup.1H-NMR was recorded. Thereafter, the polymer was precipitated in 40 mL MeOH. Centrifugation, washing a few times with each 10 mL MeOH, centrifugation and drying at 40 C. (12 h) in high vacuum yielded 149 mg (37%) polyacrylonitrile. The analytical data are shown in FIG. 3.

Example 5

[0080] Tert.-butylmethacrylate was polymerized using a catalyst system of the present invention. The reaction was performed in a glovebox. Toluene (1.85 mL) and Al-Me.sub.3 (620.0 L, 25 mmol/L solution in toluene) were added to an oven-dried glass reactor. Tert.-butylmethacrylate (500 L, 3.07 mmol, 437 mg, 200 equivalents) and PEt.sub.3 (310.0 L, 25 mmol/L solution in toluene, 0.5 equivalents) were added and immediately stirred for 90 min at room temperature. The reaction was stopped by adding a mixture of MeOHHCl (100:10) and a .sup.1H-NMR was recorded and the obtained polymer was lyophilized. 406 mg (93%) poly(tert.-butylmethacrylate) were obtained. The analytical data are shown in FIG. 4.

Example 6

[0081] Further polymerization reactions were performed analoguously as described in example 5 using furfuryl methacrylate as another demanding monomer. The results are shown in the table 2. As can be seen in table 2, the catalyst system of the present invention provides for a living-type polymerization, i.e. poly(furfuryl methacrylate) can be produced with a linear growth of the mean molecular mass of the polymer with increasing turnover, as is also shown in FIG. 5. This is in contrast to the teaching of Zhang in Dalton transactions 2012, 41, 9119-9134, where polymerization of the sterically encumbering monomer furfuryl methacrylate was deemed to be impossible.

TABLE-US-00002 TABLE 2 Polymerization of furfuryl methacrylate M.sub.n [Base]/ [Monomer]/ Temp t Yield.sup.[a] [B] PDI Run Acid Base [Acid] [Cat] [ C.] [min] [%] [g/mol] [B] 7 Al(Ph).sub.3 PCy.sub.3 0.5 100 RT 60 84 61000 1.38 8 Al(Me).sub.3 P(Et).sub.3 0.5 100 RT 60 88 120000 1.16 .sup.[a]Yields determined by .sup.1H-NMR spectroscopy of sample aliquots and of the isolated polymers determined by using gravimetric methods. [B] M.sub.n and PDI determined using multi angle laser light scattering (MALLS) detection methods.

Example 7

[0082] Further polymerization reactions were performed analoguously as described in example 5 using tert.-butylmethacrylate as monomer and using different bases. The results are shown in the table 3. As can be seen in table 3, polymerization results depend on the type of Lewis base used. The more sterically demanding the base is the higher the molecular mass of the obtained polymer will be. These results reveal the crucial importance of the implied Lewis Base (Run 9-11). The molecular mass of the produced polymers can be controlled by the sterical encumbrance of the used phosphine. This shows that the system of acid/base/monomer can be adjusted to get a polymer with desirable properties regarding molecular mass and/or PDI, with at the same time high TOF.

TABLE-US-00003 TABLE 3 Polymerization of tert.-butylmethacrylate M.sub.n [Base]/ [Monomer]/ Temp t Yield.sup.[a] [B] PDI Run Acid Base [Acid] [Cat] [ C.] [min] [%] [g/mol] [B] 9 Al(Me).sub.3 PMe.sub.3 0.5 200 RT 90 100 61370 1.00 10 Al(Me).sub.3 P(nBu).sub.3 0.5 200 RT 90 100 120000 1.08 11 Al(Me).sub.3 PCy.sub.3 0.5 200 RT 90 100 475000 1.07 .sup.[a]Yields determined by .sup.1H-NMR spectroscopy of sample aliquots and of the isolated polymers determined by using gravimetric methods. [B] M.sub.n and PDI determined using multi angle laser light scattering (MALLS) detection methods.