Synthesis and Enzymatic Degradation of Sustainable Levoglucosenone-Derived Copolyesters with Renewable Citronellol Side Chains

Abstract

Recently, a renewable five-membered lactone containing citronellol (HBO-citro) was synthesized from levoglucosenone (LGO). A one-pot two-step pathway was then developed to produce a mixture of 5- and 6-membered Lactol-citro molecules (5ML and 6ML, respectively) from HBO-citro. Proton nuclear magnetic resonance (1H NMR) of a mixture of 5ML and 6ML at varying temperatures showed that the chemical shifts of the hydroxyls, as well as the 5ML:6ML ratio, are temperature-dependent. Indeed, a high temperature, such as 65 °C, led to an up-field shielding of the hydroxyl protons as well as a drop in the 5ML:6ML ratio. The monomers 5ML and 6ML were then engaged in polycondensation reactions involving diacyl chlorides. Renewable copolyesters with low glass transition temperatures (as low as −67 °C) and cross-linked citronellol chains were prepared. The polymers were then hydrolyzed using a commercial lipase from Thermomyces lanuginosus (Lipopan® 50 BG). A higher degradation rate was found for the polymers prepared using Lactol-citro molecules, compared to those obtained by the polycondensation reactions of diacyl chlorides with Triol-citro—a monomer recently obtained by the selective reduction of HBO-citro.

Levoglucosenone to 3D-printed green materials: synthesizing sustainable and tunable monomers for eco-friendly photo-curing

“…8 Various oxa-Michael additions to the β-position of the α,β-unsaturated ketone have been reported with water, 42 benzyl alcohol, 43 ethanol 44 or citronellol. 13,45 However, in all cases, a large excess of alcohol was necessary to not only achieve a maximum conversion of LGO into the desired product, but also limit its dimerization into LGO-Cyrene. With the aim of introducing a terminal alkene function, allyl alcohol was added to LGO (Scheme 1).…”

“…8 Recently, we have been concentrating on developing new types of functional monomers using LGO, taking advantage of its highly reactive functionalities and commercial availability (currently at 50 T per year and soon increasing to 1000 T per year). These new LGO polymer derivatives include polyacrylates, 9 polycyclic olefins, 10 polyesters, 11,12 and polycarbonates. 13 However, until now, the controlled formation of polymer networks derived from LGO-based monomers has not been reported.…”

Levoglucosan and levoglucosenone as bio-based platforms for polymer synthesis

“…The same research group reported 49 the use of LGO as a starting material to provide access to 5- and 6-membered lactol-citro molecules. The monomers were polymerised with diacyl chlorides under solvent free, catalyst free conditions.…”

“…The investigation involved the polycondensation reaction between 2H-HBO-HBO and dimethyl carbonate (DMC) yielded polymers that have higher T g 's of 90.3 and 92.2 °C. 48 The same research group reported 49 the use of LGO as a starting material to provide access to 5-and 6-membered lactol-citro molecules. The monomers were polymerised with diacyl chlorides under solvent free, catalyst free conditions.…”

Synthesis of Citronellol-Derived Antibacterial Polymers and Effect of Thioether, Sulfoxide, Sulfone, and Ether Functional Groups on Their Bactericidal Activity

“…In this study, citronellol-derived methacrylate polymers with different interconnecting functional groups were synthesized to prepare bio-based bactericidal polymers and investigate the relationship between their side chain structure and bactericidal properties. Since citronellol, a monoterpenoid widely used in perfumes and insect repellents, , displays bactericidal properties by interacting with bacterial surface constituents to form a monolayer that alters the cell-surface properties (electrostatic potential and hydrophobicity), it was incorporated to impart bactericidal properties to polymers. , While various citronellol-containing polymers have been prepared for applications in fully bio-based degradable polymers , and photocrosslinkable polymers, , to the best of our knowledge, this is the first study to elucidate the bactericidal properties of citronellol-derived polymers with different interconnecting functional groups. Furthermore, although a variety of monoterpenes such as geraniol, eugenol, and borneol have been exploited to prepare antibacterial polymers, the effect of side chain interconnecting functional groups between the polymer backbone and the monoterpenes on the bactericidal properties has not been systematically investigated possibly because the preparation of a series of antibacterial polymers encompassing diverse interconnecting groups is laborious. − …”