Selective catalytic synthesis of 1,2- and 8,9-cyclic limonene carbonates as versatile building blocks for novel hydroxyurethanes

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2 Citations (Scopus)

Abstract

The selective catalytic synthesis of limonene-derived monofunctional cyclic carbonates and their subsequent functionalisation via thiol–ene addition and amine ring-opening is reported. A phosphotungstate polyoxometalate catalyst used for limonene epoxidation in the 1,2-position is shown to also be active in cyclic carbonate synthesis, allowing a two-step, one-pot synthesis without intermittent epoxide isolation. When used in conjunction with a classical halide catalyst, the polyoxometalate increased the rate of carbonation in a synergistic double-activation of both substrates. The cis isomer is shown to be responsible for incomplete conversion and by-product formation in commercial mixtures of 1,2-limomene oxide. Carbonation of 8,9-limonene epoxide furnished the 8,9-limonene carbonate for the first time. Both cyclic carbonates underwent thiol–ene addition reactions to yield linked di-monocarbonates, which can be used in linear non-isocyanate polyurethanes synthesis, as shown by their facile ring-opening with N-hexylamine. Thus, the selective catalytic route to monofunctional limonene carbonates gives straightforward access to monomers for novel bio-based polymers.

Original languageEnglish
Pages (from-to)7405-7415
Number of pages11
JournalChemistry - A European Journal
Volume26
Issue number33
Early online date20 Feb 2020
DOIs
Publication statusPublished - 10 Jun 2020

Keywords

  • biomass
  • epoxidation
  • polymers
  • polyoxometalates
  • renewable resources

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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