One-Step Conversion of Crab Shells to Levulinic Acid Catalyzed by Ionic Liquids: Self-Healing of Chitin Fraction

Abstract

A highly selective route to produce levulinic acid (LA) from raw crab shells in one step has been provided by the catalysis of the ionic liquid (IL) 1-methyl-3-(3-sulfopropyl)imidazolium hydrogen sulfate ([C 3 SO 3 Hmim]HSO 4 ), resulting in the LA yield up to 77.9%. The relationship between the structure of ILs and the yield of LA was investigated, demonstrating both the acidity and hydrogen-bonding ability of ILs dictate their catalytic activity. Furthermore, by means of IR, scanning electron microscopy, elemental analysis, solid-state 13 C NMR, X-ray diffraction, and determination of the degree of acetylation, the self-healing of chitin fraction driven by hydrogenbond interactions was discovered upon the removal of CaCO 3 and protein for the first time. In the presence of a strong and interlocked hydrogen-bond network, direct depolymerization and consecutive deacetylation/depolymerization take place alternatively on the outer surface, whereas the interior crystalline structure of chitin remains intact.

Current Self-Healing Binders for Energetic Composite Material Applications

“…Ionic liquids and poly-ionic liquids have attracted extensive attention due to their high conductivity, electrochemical stability, flame retardancy and negligible volatility [ 120 , 121 ]. In particular, the supramolecular ion interaction has high stability and easy accessibility, which promotes the development of self-healing materials [ 122 , 123 ]. At the same time, the strong affinity of ion pairs is conducive to the rearrangement and association of physical crosslinking points [ 124 , 125 ].…”

Review of shell waste reutilization to promote sustainable shellfish aquaculture

“…Chitin and chitosan contain biologically fixed nitrogen in the side chain, and have been catalytically converted into numerous organonitrogen chemicals, including furan amides, amino sugars, amino alcohols, amino acids and heterocyclic compounds. [82][83][84] For instance, Zhao and Liu 85 prepared levulinic acid (LA) from raw crab shells in one step by the catalysis of the ionic liquid, resulting in the LA yield up to 77.9%. Both the acidity and hydrogen bonding of ionic liquid possess the catalytic activity.…”

Creating Pores in Chitosan-Derived Humins via in Situ CO2 Formation

“…Over the past decade, during our research on biomass conversion into LA platform chemical, ,− we have investigated the structure and formation mechanism of different feedstock-derived humins. Shen et al studied the formation mechanism of HMF-derived humins, revealing multiple elementary reactions such as etherification, esterification, aldol condensation, and acetalization .…”