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Ring-Opening Polymerization of ε-Caprolactone and Styrene Oxide-CO₂ Coupling Reactions Catalyzed by Chelated Dehydroacetic Acid-Imine Aluminum Complexes.

ABSTRACT: A series of chelated dehydroacetic acid-imine-based ligands L¹H~L⁴H was synthesized by reacting dehydroacetic acid with 2-t-butylaniline, (S)-1-phenyl-ethylamine, 4-methoxylbenzylamine, and 2-(aminoethyl)pyridine, respectively, in moderate yields. Ligands L¹H~L⁴H reacted with AlMe₃ in toluene to afford corresponding compounds AlMe₂L¹ (1), AlMe₂L² (2), AlMe₂L³ (3), and AlMe₂L⁴ (4). All the ligands and aluminum compounds were characterized by IR spectra, ¹H and ¹³C NMR spectroscopy. Additionally, the ligands L¹H~L⁴H and corresponding aluminum derivatives 1, 3, and 4 were characterized by single-crystal X-ray diffractometry. The catalytic activities using these aluminum compounds as catalysts for the ε-caprolactone ring-opening polymerization (ROP) and styrene oxide-CO₂ coupling reactions were studied. The results show that increases in the reaction temperature and selective solvent intensify the conversions of ε-caprolactone to polycaprolactone. Regarding the coupling reactions of styrene oxide and CO₂, the conversion rate is over 90% for a period of 12 h at 90 °C. This strategy dispenses the origination of cyclic styrene carbonates, which is an appealing concern because of the transformation of CO₂ into an inexpensive, renewable and easy excess carbon feedstock.

SUBMITTER: Wang TY

PROVIDER: S-EPMC8746973 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Bimetallic aluminum complexes bearing novel spiro-phenanthrene-monoketone/OH derivatives: synthesis, characterization and the ring-opening polymerization of ε-caprolactone.

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