Defence Ting Wang: "Chitin: Sustainable valorization into nitrogen-rich chemical products"

Promotors: 1^st promotor: Prof. Peter Deuss, 2^nd promotor: Prof Erik Heeres

Abstract: Chitin, an abundant biopolymer derived from crustacean waste, represents a valuable renewable source with both carbon and naturally fixed nitrogen. Its efficient valorization holds significant potential for advancing sustainable biorefineries to allow for direct synthesis of organic nitrogen-containing chemicals thereby reducing our reliance on fossil-based chemicals and the energy-intensive Haber-Bosch process. This thesis explores chitin valorization through chemocatalytic, thermochemical, and mechanochemical approaches, aiming to develop sustainable pathways for producing nitrogen-rich bio-based chemicals. Key strategies include the synthesis of chitin-derived amido furans and exploration of their reactivity in Diels–Alder transformations, offering pathways to functionalized nitrogenous platforms. Catalytic upgrading of those intermediates was achieved using CoOx@Co-NC catalysts for the selective hydrogenation to alcohols. The resulting BHMF-rich mixtures were further polymerized enzymatically, enabling the synthesis of bio-based polyesters. Finally, the pyrolytic behavior of chitin was examined, with a focus on the effects of pretreatment (e.g., ball milling, acid hydrolysis) and catalytic additives (CaO, Al₂O₃, H-ZSM-5) on thermal decomposition and product selectivity. The combined findings highlight the potential of chitin as a renewable resource for valuable chemicals, demonstrating how targeted catalytic and process innovations can unlock new routes to nitrogen-functionalized organic materials in a bio-based economy.

Dissertation