Polycarbonates made using highly selective catalysts

• US 20060089252A1
• Filed: 10/06/2005
• Published: 04/27/2006
• Est. Priority Date: 10/08/2004
• Status: Active Grant

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Coates, Geoffrey W., Qin, Zengquan, Cohen, Claire Tova
• Granted Patent: US 7,304,172 B2
• Time in Patent Office: Days
• US Class Current: 502/150
• CPC Class Codes: B01J 2231/14 Other (co) polymerisation, e.g. of lactides, epoxides "ROMP", i.e. ring-opening metathesis polymerisation B01J2231/54
• CPC Class Codes: B01J 2531/0252 Salen ligands or analogues, e.g. derived from ethylenediamine and salicylaldehyde
• CPC Class Codes: B01J 2531/845 Cobalt
• CPC Class Codes: B01J 31/1805 the ligands containing nitrogen
• CPC Class Codes: C07F 15/065 without a metal-carbon linkage

Abstract

Poly(propylene carbonates) are prepared from propylene oxide and CO₂ with less than 10% cyclic propylene carbonate by product using cobalt based catalysts of structure
preferably in combination with salt cocatalyst, very preferably cocatalyst where the cation is PPN⁺ and the anion is Cl⁻ or OBzF₅⁻. Novel products include poly(propylene carbonates) having a stereoregularity greater than 90% and/or a regioregularity of greater than 90%.

Claims

1. Compound having the structure

2. Compound having the structure

3. Compound which is

4. Compound having the structure

5. A catalyst system for epoxide/CO₂ copolymerization comprising as a catalyst

6. The catalyst system of claim 5 where the cocatalyst is a salt where the cation is:

7. The catalyst system of claim 6 where the catalyst has the structural formula (VIII) where X is OBzF₅ and the cocatalyst is PPNCl.

8. The catalyst system of claim 6 where the catalyst has the structural formula (VIII) where X is Cl and the cocatalyst is [PPN] [BzF₅].

9. The catalyst system of claim 6 where the catalyst has the structural formula (VIII) where X is Cl and the cocatalyst is [PPN]Cl.

10. The catalyst system of claim 6 where the cocatalyst is NBu₄Cl and the catalyst has the structural formula (VIII) where X is OBzF₅.

11. The catalyst system of claim 6, the catalyst has the structural formula (XI) where R¹⁰ and R¹¹ are CPh(CH₃)₂ and the cocatalyst is [PPN]Cl.

16. A method for preparing poly(C₂-C₁₀ alkylene carbonate, e.g., poly(propylene carbonate), with less than 10% cyclic alkylene carbonate by-product, comprising the step of reacting C₂-C₁₀ alkylene oxide, e.g., propylene oxide, and CO₂ at a CO₂ pressure ranging from 10 psi to 300 psi, a reaction temperature of 20 to 25°

C., a reaction time of 0.5 to 10 hours in the presence of the catalyst system of claim 5 where the ratio of alkylene oxide to cocatalyst to catalyst ranges from 500-100,000;

0.5-1.5;

0.5-1.5.

17. The method of claim 16 where the cocatalyst of the catalyst system is selected from the group consisting of [PPN]Cl and [PPN][OBzF₅].

18. The method of claim 17 where the catalyst has the structural formula (VIII) where X is Cl and the cocatalyst is [PPN][OBzF₅].

12. A method for preparing copolymers of C₂-C₁₀ alkylene oxide and CO₂, e.g., (poly(propylene carbonates)), with less than 10% cyclic alkylene carbonate by-product, comprising the step of reacting C₂-C₁₀ alkylene oxide and CO₂ at a CO₂ pressure ranging from 1 to 1,000 psi and reaction temperature of 0 to 150°

C. and a time of 0.1 to 50 hours in the presence of a catalyst at an alkylene oxide to catalyst ratio on a cobalt basis ranging from 200;

1 to 100,000;

1, said catalyst having the structure

13. The method of claim 12 where the CO₂ pressure ranges from 750 to 850 psi, the reaction temperature ranges from 20 to 25°

C., the reaction time ranges from 0.5 to 4 hours, the catalyst has the structure (VIII) where X is Br, Cl or OBzF₅ and the alkylene oxide to catalyst ratio, on a cobalt basis, ranges from 400;

1 to 600;

1.

14. The method of claim 13 where the alkylene oxide is rac-propylene oxide.

15. The method of claim 13 where the alkylene oxide is enantiomerically-enriched propylene oxide.

19. Poly(propylene carbonate) of M_n ranging from 1,000 to 1,000,000 g/mol and PDI ranging from 1.05 to 5.0 with greater than 90% head-to-tail linkages.

20. The poly(propylene carbonate) of claim 19 which has random stereochemistry.

21. The poly(propylene carbonate) of claim 19 where more than 90% of adjacent stereocenters have the same relative stereochemistry.

22. The poly(propylene carbonate) of claim 19 where more than 60% of adjacent stereocenters have the opposite relative stereochemistry

23. Poly(propylene carbonate) of M_n ranging from 1,000 to 1,000,000 g/mol and PDI ranging from 1.05 to 5.0 where greater than 90% of the stereocenters are of the same stereochemistry.

24. [PPN][OBzF₅].