Polycarbonates made using highly selective catalysts

• US 7,304,172 B2
• Filed: 10/06/2005
• Issued: 12/04/2007
• 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
• Primary Examiner(s): Eyler; Yvonne
• Assistant Examiner(s): LAO, MARIALOUISA
• Application Number:
  US11/244,231
• Publication Number:
  US 20060089252A1
• Time in Patent Office: 789 Days
• Field of Search: 556/1
• US Class Current: 556/1
• 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. A method for preparing a copolymer of C₂-C₁₀ alkylene oxide and CO₂, with less than 10% cyclic alkylene carbonate by-product, comprising the step of reacting a C₂-C₁₀ alkylene oxide and CO₂ at a CO₂ pressure ranging from 1 to 1,000 psi and a 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

2. The method of claim 1 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)

3. The method of claim 2 where the alkylene oxide is rac-propylene oxide.

4. The method of claim 2 where the alkylene oxide is enantiomerically-enriched propylene oxide.

5. A method for preparing poly(C₂-C₁₀ alkylene 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 for epoxide/CO₂ copolymerization comprising as a catalyst

6. The method of claim 5 where the cocatalyst of the catalyst system is selected from the group consisting of [PPN]Cl and [PPN][OBzF₅].

7. The method of claim 6 where the catalyst has the structural formula (VIII)