Synthesis of polymers from cyclic diolides

Patent metadata

Field	Value
Publication number	US-11629223-B2
Application number	US-202117206400-A
Country	US
Kind code	B2
Filing date	Mar 19, 2021
Priority date	Jan 11, 2018
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

Biodegradable polymers with advantageous physical and chemical properties are described, as well as methods for making such polymers. In one embodiment, a new chemical synthesis route to technologically important biodegradable poly(3-hydroxybutyrate) (P3HB) with high isotacticity and molecular weight required for a practical use is described. The new route can utilize racemic eight-membered cyclic diolide (rac-DL), meso-DL, or a rac-DL and meso-DL mixture, derived from bio-sourced dimethyl succinate, and enantiomeric (R,R)-DL and (S,S)-DL, optically resolved by metal-based catalysts. With a stereoselective racemic molecular catalyst, the ROP of rac-DL under ambient conditions produces rapidly P3HB with essentially perfect isotacticity ([mm]>99%), high crystallinity and melting temperature (Tm=171° C.), as well as high molecular weight and low dispersity (Mn=1.54×105 g/mol, Ð=1.01).

First claim

What is claimed is:

1. A copolymer comprising Formula II:

wherein:
x is 10 to about 100;
y is about 1 to about 100;
n is 10 to about 5,000;
each R 1 is (C 1 -C 18 )alkyl, (C 1 -C 8 )alkenyl, (C 1 -C 8 )alkynyl, benzyl, or aryl;
each R 2 is (C 1 -C 18 )alkyl, (C 1 -C 8 )alkenyl, (C 1 -C 8 )alkynyl, benzyl, or aryl;
the x block of Formula II comprises at least 95% isotactic triads with respect to the stereocenters of substituents R 1 on the polymer chain, wherein the at least 95% isotactic triads (mm) have consecutive (R) stereochemical configurations or consecutive (S) stereochemical configurations; and
the y block of Formula II comprises at least 95% isotactic triads with respect to the stereocenters of substituents R 2 on the polymer chain, wherein the at least 95% isotactic triads (mm) have consecutive (R) stereochemical configurations or consecutive (S) stereochemical configurations;
wherein the polymer of Formula II is an isotactic random copolymer.

2. A copolymer comprising Formula III:

wherein:
x is 10 to about 5,000;
y is about 10 to about 5,000;
n is 10-50;
each R is (C 1 -C 18 )alkyl, (C 1 -C 8 )alkenyl, (C 1 -C 8 )alkynyl, benzyl, or aryl;
the x block of Formula III comprises at least 95% isotactic triads with respect to the stereocenters of substituents R on the polymer chain, wherein the at least 95% isotactic triads (mm) have consecutive (R) stereochemical configurations or consecutive (S) stereochemical configurations; and
the y block of Formula III comprises consecutive R groups having (R) and (S) configurations, consecutive R groups having (S) and (R) configurations, or consecutive R groups having stereochemical configurations the opposite of the main stereochemical configuration of the x block;
wherein the polymer of Formula III is an isotactic-b-syndiotactic stereodiblock or stereotapered copolymer.

3. A copolymer comprising Formula IV:

wherein:
x is 10 to about 100;
y is about 1 to about 100;
k is about 1 to 16;
n is 10 to about 5,000;
R is (C 1 -C 18 )alkyl, (C 1 -C 8 )alkenyl, (C 1 -C 8 )alkynyl, benzyl, or aryl; and
the x block of Formula IV comprises at least 9500 isotactic triads with respect to the stereocenters of substituents R on the polymer chain, wherein the at least 9500 isotactic triads (mm) have consecutive (R) stereochemical configurations or consecutive (S) stereochemical configurations.

4. A method for preparing the copolymer according to claim 1 comprising:
contacting two or more monomers, an effective amount of a metal complex, and an alcohol initiator to initiate a ring opening polymerization reaction;
wherein:
the two or more monomers are monomers of Formula V-A and V-B:

wherein R 1 and R 2 are as defined for Formula II; and
the metal complex is a metal complex of Formula X:

wherein:
M is Sc, Y, or a lanthanide(III) metal;
Ligand is —OR x , —NR x 2 , or —N(SiR y 3 ) 2 , wherein R x is alkyl, and each R y is H or alkyl, wherein at least two R y groups are alkyl;
R a is H, alkyl, or phenyl; and
R b and R c are H, alkyl, or phenyl; or
R b and R c together with the carbon atoms to which they are attached form a 5, 6, 7, or 8 membered cycloalkyl group;
to thereby form an isotactic, syndiotactic, or isotactic-b-syndiotactic stereodiblock or stereotapered polymer of Formula II.

5. The method of claim 4 wherein the monomers of Formulas V-A and V-B comprise a mixture of meso and racemic diastereomers and the polymers formed are isotactic-b-syndiotactic stereodiblock or stereotapered polymers.

6. The method of claim 4 wherein the monomers of Formulas V-A and V-B comprise a mixture of racemic monomers wherein R 1 of Formula V-A is different than R 2 of Formula V-B, and the polymers formed are isotactic random copolymers.

7. The method of claim 4 wherein the monomers of Formulas V-A and V-B comprise a mixture of meso and racemic diastereomers and racemic monomers, and wherein R 1 of Formula V-A is different than R 2 of Formula V-B, and the polymers formed are isotactic-b-syndiotactic diblock copolymers or stereotapered copolymers.

8. A method for preparing an isotactic polymer of Formula I:

wherein:
n is about 10 to about 10,000;
R is (C 1 -C 18 )alkyl, (C 1 -C 8 )alkenyl, (C 1 -C 8 )alkynyl, benzyl, or aryl; and
Formula I comprises at least 95% isotactic triads with respect to the stereocenters of substituents R on the polymer chain, wherein the at least 95% isotactic triads (mm) have consecutive (R) stereochemical configurations or consecutive (S) stereochemical configurations;
the method comprising contacting one or more monomers, an effective amount of a metal complex, and an alcohol initiator to initiate a ring opening polymerization reaction;
wherein:
the monomer is a monomer of Formula V:

wherein R is as defined for Formula I; and
the metal complex is a metal complex of Formula X:

wherein:
M is Sc, Y, or a lanthanide metal;
Ligand is alkoxy, amide, or —N(SiR x 3 ) 2 wherein each R x is H or alkyl, and at least two R x groups are alkyl;
R a is H, alkyl, or phenyl;
R b is alkyl or phenyl; and
R c is alkyl or phenyl; or
R b and R c together with the carbon atoms to which they are attached form a 5, 6, 7, or 8 membered cycloalkyl group;
to thereby form the isotactic polymer of Formula I.

9. The method of claim 8 wherein the monomer of Formula V is a racemic mixture, the metal complex of Formula X is a racemic mixture, and the polymers of Formula I formed are a mixture of highly isotactic (R) polymers and highly isotactic (S) polymers.

10. The method of claim 8 wherein the polymer of Formula I has a molecular weight M n of at least 40 kDa, a dispersity index of less than 1.2, and a melting temperature, T m , of at least 171° C.

Assignees

• Univ Colorado State Res Found

Inventors

• Chen Eugene Y
• Tang Xiaoyan

Classifications

• C08G63/08 Primary

  Lactones or lactides · CPC title

• C08G63/664

  derived from hydroxy carboxylic acids · CPC title

• B01J2531/0213

  Complexes without C-metal linkages · CPC title

• B01J2531/35

  Scandium · CPC title

• C08G63/823

  for the preparation of polylactones or polylactides · CPC title