Chitosan is the fully or partially deacetylated form of chitin, the second most abundant natural polysaccharide derived from exoskeletons of crustaceans and also cell walls of fungi and insects. This low-cost biopolymer possesses very interesting properties, for instance it is known to be biocompatible, biodegradable in the human body, nontoxic and antibacterial. Interest in chitosan materials is quite recent compared to cellulose, which has an age-long exploitation history. Therefore, chitosan is one of the most promising materials derived from renewable resources and is currently explored very intensively. In our group, we have designed a chemical platform to functionalize oligomers of chitosan through 3 different reactions: epoxy-amine, thiol-ene and phosphonation via Kabachnick-Fields. This chemical platform allowed performing a wide range of functionalized chitosans (e.g. carrying alkyl chains, cationic groups, phosphonic acids,…) with specific properties, which were evaluated. For instance, chitosan was modified and used as a catalytic support in presence of potassium iodide. We reported herein the high efficiency of this system toward the incorporation of carbon dioxide (CO2) into epoxides. It demonstrates a very good thermal stability and is recyclable more than five times without loss of activity. The optimal reaction conditions were determined using allylglycidyl ether (AGE) as a model and extended to a wide range of other epoxides. Cyclic carbonates were obtained with very high yield in a couple of hours under mild conditions (2-7 bars, 80 °C) and no solvent.

Functionalization of chitosan oligomers: Towards bio-based products with new functionalities

2019 Fall National Meeting

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