Use of zinc derivatives as cyclic ester polymerization catalysts
View Patent ↗The invention concerns the use of zinc derivatives of general formula (I) wherein: L 1 represents a group of formula: —E 14 (R 14 )(R′ 14 )(R″ 14 ), —E 15 (R 15 ) (R′ 15 ) or —E 16 (R 16 ); E is an atom of group 15; L 2 and L 3 independently represent a group of formula: —E 14 (R 14 )(R′ 14 )(R″ 14 ), —E 15 (R 15 )(R′ 15 ) or —E 16 (R 16 ), or together form a chain of formula —L′ 2 —A—L′ 3 —; A represents a saturated or unsaturated chain comprising one, two or three elements of group 14; L′ 2 and L′ 3 independently represent a group of formula —E 14 (R 14 )(R′ 14 ) —E 15 (R 15 ) or —E 16 —; E 14 is an element of group 14; E 15 is an element of group 15; E 16 is an element of group 16; R 14 , R′ 14 , R″ 14 , R 15 , R′ 15 and R 16 represent various groups, as (co) polymerisation catalysts of cyclic esters
1. In the (co)polymerization of cyclic esters, the improvement comprising using as catalyst zinc derivatives of the formula
wherein
L 1 is selected from the group consisting of —E 14 (R 14 )(R′ 14 )(R″ 14 ),
—E 15 (R 15 )(R′ 15 ) and —E 16 (R 16 );
E is nitrogen or phosphorous;
L 2 and L 3 are, independently, selected from the group consisting of
—E 14 (R 14 )(R′ 14 )(R″ 14 ), —E 15 (R 15 )(R′ 15 ) and —E 16 (R 16 ),
E 14 is carbon or silicon;
E 15 is nitrogen or phosphorous;
E 16 is oxygen or sulfur;
R 14 , R′ 14 , R″ 14 , R 15 , R′ 15 and R 16 are, independently selected from the group consisting of hydrogen, alkyl, aryl and E′ —14 RR′R″;
E′ 14 is carbon or silicon;
R, R′ and R″ are, independently, hydrogen or alkyl.
2. The polymerization process of claim 1 wherein
E is nitrogen;
E 14 is carbon;
E 15 is nitrogen;
E 16 is oxygen or sulfur;
R 14 , R′ 14 , R″ 14 , R 15 and R′ 15 are independently alkyl or —E′ —14 RR′R″;
R 16 is alkyl or aryl optionally substituted by at least one alkyl and halogen;
E′ 14 is silicon;
R, R′ and R″ are, independently selected from the group consisting of hydrogen methyl, ethyl, propyl and isopropyl.
3. The polymerization process of claim 1
wherein
L 1 is —E 15 (R 15 )(R′ 15 );
L 2 and L 3 are, independently, —E 14 (R 14 )(R′ 14 )(R″ 14 ).
4. The polymerization process of claim 1 wherein
E is a nitrogen atom;
E 15 is a nitrogen;
R 14 , R′ 14 , R″ 14 , R 15 and R′ 15 are, independently, alkyl or —E′ —14 RR′R″;
R,R′ and R″ are, independently, optionally substituted alkyl.
5. In the polymerization of cyclic esters, the improvement of comprising using as the catalyst, [(Me 3 Si) 2 N] 2 Zn.
6. The polymerization process of claim 1 wherein cyclic ester polymers are lactic and/or glycolic acid polymers.
7. In a process for the preparing block or random copolymers, or polymers, which consists of bringing together one or more monomers, a polymerization catalyst and, optionally, an additive, optionally a polymerization solvent, at a temperature between ambient temperature and 250° C. for a period of a few minutes and 300 hours, the improvement comprising using as the chain initiator and the polymerization catalyst a compound of (I) as defined in claim 1 .
8. The process of claim 7 wherein the monomer is a cyclic ester polymer of lactic and/or glycolic acid.