Isomerization of Linear to Hyperbranched Polymers: Two Isomeric Lactones Converge via Metastable Isostructural Polyesters to a Highly Branched Analogue
| Autor: | Grant W. Fahnhorst, William B. Tolman, Daniel E. Stasiw, Thomas R. Hoye |
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| Rok vydání: | 2022 |
| Předmět: |
chemistry.chemical_classification
Polymers and Plastics 010405 organic chemistry Organic Chemistry Transesterification Polymer 010402 general chemistry 01 natural sciences 0104 chemical sciences Inorganic Chemistry Polyester chemistry.chemical_compound Monomer chemistry Polymerization Functional group Polymer chemistry Materials Chemistry Isostructural Isomerization |
| Zdroj: | ACS macro letters. 7(10) |
| ISSN: | 2161-1653 |
| Popis: | We report here the Zn(II)-catalyzed convergence of two metastable and isostructural polyesters to an isomeric polymer having a hyperbranched architecture. Ring-opening transesterification polymerization (ROTEP) of 4-carbomethoxyvalerolactone (CMVL) under Bronsted catalysis is known to give the linear polyester PCMVL. We show here that this can be isomerized to the equilibrated (and highly branched) polyester EQ-PCMVL. Analysis of the fragments obtained from eliminative degradation of EQ-PCMVL were critical in the formulation of its structure. The isomerization of PCMVL to EQ-PCMVL is a direct consequence of the presence of the second ester functional group in the CMVL ester-lactone, a rarely studied class of monomer. Zn(II)-catalysis of the ROTEP of the isomeric β-lactone, 2-(2-carbomethoxyethyl)propiolactone (isoCMVL), as well as isomerization of the isostructural linear homopolymer derived from that isomeric monomer, led to the same EQ-PCMVL. These results suggest a new strategy for the introduction of ... |
| Databáze: | OpenAIRE |
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