Efficient Hydrolysis of Chitin in a Deep Eutectic Solvent Synergism for Production of Chitin Nanocrystals

Abstract

A deep eutectic solvent (DES) derived from ferric chloride hexahydrate and betaine chloride (molar ratio of 1:1) was used as hydrolytic media for production of chitin nanocrystals (ChNCs) with a high yield (up to 88.5%). The synergistic effect of Lewis acid and released Brønsted acid from betaine hydrochloride enabled the efficient hydrolysis of chitin for production of ChNCs coupled with ultrasonication with low energy consumption. The obtained ChNCs were with an average diameter of 10 nm and length of 268 nm, and a crystallinity of 89.2% with optimal synthesis conditions (at 100 °C for 1 h with chitin-to-DES mass ratio of 1:20). The ChNCs were further investigated as efficient emulsion stabilizers, and they resulted in stable o/w emulsions even at a high oil content of 50% with a low ChNC dosage of 1 mg/g. Therefore, a potential approach based on a DES on the production of chitin-based nanoparticles as emulsifiers is introduced.

Chitin nanowhiskers with improved properties obtained using natural deep eutectic solvent and mild mechanical processing

“…The crystallinity index (CrI) for NADES-ChNW is comparable to that of from another recent study on producing ChNW using betaine hydrochloride and ferric chloride hexahydrate. 28 The value of CrI for Ac-ChNW is 97.2%. Indeed, the earlier analysis also found increases in crystallinity upon ChNW isolation.…”

“…27 In another study from the same group, Hong et al proposed that a different eutectic solvent derived from ferric chloride hexahydrate and betaine chloride can also be used as sufficient media to produce ChNW. 28 Generally speaking, while previous studies have mainly focused on optimizing (NA)DES-based extraction of ChNW from raw materials without explicitly considering mechanical processing as a key variable in any detail. 27,28 Here, we not only systematically combine NADES pre-treatments with controlled and mild mechanical processing (defibrillation) for ChNW extraction, we also investigate in detail how the physical properties of the NADES-ChNW that we obtain differ from those obtained by traditional acid hydrolysis (Ac-ChNW).…”

Valorization of Starch to Biobased Materials: A Review

“…Majorly sourced from skeletal components of insects and broadly crustaceans, chitin and chitosan are naturally abundant green materials, and their application with starch-based sources have been documented in several articles [ 13 , 153 ]. The literatures available suggests various processing techniques such as acid hydrolysis [ 154 , 155 ] and ultrasonication [ 138 , 156 ]. Other methods such as mechanical treatment [ 155 ], ammonium persulfate (APS) oxidation [ 157 ], and 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO)-mediated oxidation [ 158 ] have also been proposed for the extraction of chitin.…”

Isolation of Chitin Nano-whiskers Directly from Crustacean Biomass Waste in a Single Step with Acidic Ionic Liquids

“…17 Methods of ChNWs' preparation from purified chitin in addition to acid hydrolysis 21,50−53 include 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation, 17,54,55 periodate-mediated oxidation, 56,57 ammonium persulfate-mediated oxidation, 58 and extraction with deep eutectic solvents (DESs). 59 There is also a report of the formation of ChNW-based films (without isolation of individual ChNWs) from purified chitin using 1-allyl-3-methylimidazolium bromide ([Amim]Br]). 60 It is important to note that this collection of referenced works is by no means exhaustive and/or complete but provides the list of main routes to ChNWs' production.…”

“…Hydrolysis with sulfuric acid is also used . Methods of ChNWs' preparation from purified chitin in addition to acid hydrolysis ,− include 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation, ,, periodate-mediated oxidation, , ammonium persulfate-mediated oxidation, and extraction with deep eutectic solvents (DESs) . There is also a report of the formation of ChNW-based films (without isolation of individual ChNWs) from purified chitin using 1-allyl-3-methylimidazolium bromide ([Amim]­Br]) .…”