Catalytic depolymerization of polymers containing electrophilic linkages using nucleophilic reagents
View Patent ↗The disclosure relates to methods and materials useful for depolymerizing a polymer. In one embodiment, for example, the disclosure provides a method for depolymerizing a polymer containing electrophilic linkages, wherein the method comprises contacting the polymer with a nucleophilic reagent in the presence of a guanidine-containing compound. The methods and materials of the disclosure find utility, for example, in the field of waste reclamation and recycling.
1. A method for depolymerizing a polymer, the method comprising:
contacting a polymer having a backbone comprising electrophilic linkages with a nucleophilic reagent in the presence of a guanidine-containing compound, wherein the electrophilic linkages comprise ester linkages, such that the polymer is a polyester.
2. The method of claim 1 , wherein the contacting provides depolymerization products substantially free of metal contaminants.
3. The method of claim 1 , wherein the polymer contains a metal contaminant in a first concentration, and wherein the contacting provides a depolymerization product containing a metal contaminant in a second concentration, and wherein the second concentration is equal to or less than the first concentration.
4. The method of claim 1 , wherein the nucleophilic reagent comprises one or more nucleophilic groups selected from hydroxyl, ether, carboxylato, amine, azide, and sulfhydryl.
5. The method of claim 4 , wherein the nucleophilic reagent comprises two hydroxyl groups, two amine groups, or one hydroxyl group and one amine group.
6. The method of claim 1 , wherein the guanidine-containing compound has the structure of formula (I)
wherein R 2 , R 3 , R 4 and R 5 are independently selected from hydrogen and C 1 -C 30 hydrocarbyl, provided that any two of R 2 , R 3 , R 4 and R 5 may be linked to form a cycle.
7. The method of claim 6 , wherein at least two of R 2 , R 3 , R 4 and R 5 are linked to form a cycle.
8. The method of claim 7 , wherein the guanidine-containing compound has the structure of formula (Ia)
wherein
n1 and n2 are independently selected from 0 and 1; and
R 6a , R 6b , R 6c , R 6d , R 7a , R 7b , R 7c , and R 7d are independently selected from H, C 1 -C 30 alkyl, C 2 -C 30 alkenyl, C 2 -C 30 alkynyl, C 5 -C 30 aryl, C 6 -C 30 aralkyl, and C 6 -C 30 alkaryl, provided that any two of R 6a , R 6b , R 6c , R 6d , R 7a , R 7b , R 7c , and R 7d may be taken together to form a ring.
9. The method of claim 7 , wherein the guanidine-containing compound has the structure of formula (Ib)
wherein
n3 is selected from 0 and 1;
X 1 and X 2 are independently selected from —NR 10 — and —C(R 11 )(R 12 )—, wherein R 10 , R 11 , and R 12 are independently selected from H and alkyl; and
R 8a , R 8b , R 9a , and R 9b are independently selected from substituted or unsubstituted alkyl, aryl, aralkyl, and alkaryl, any of which may be heteroatom-containing, provided that any two of R 8a , R 8b , R 9a , R 9b , R 10 , R 11 , and R 12 may be taken together to form a cycle.
10. The method of claim 9 , wherein the guanidine-containing compound has the structure
11. The method of claim 1 , wherein the guanidine-containing compound is selected from
12. The method of claim 1 , wherein the polymer comprises monomer units, and wherein the guanidine-containing compound is present in an amount less than about 20 mol % relative to the amount of monomer units present.
13. The method of claim 1 , wherein the contacting is carried out at room temperature.
14. In a method for depolymerizing a polymer having a backbone comprising electrophilic linkages, the improvement comprising contacting the polymer with a nucleophile in the presence of a guanidine-containing compound, wherein the electrophilic linkages comprise ester linkages, such that the polymer is a polyester.