ChCl-Lactic Acid DES-based Chitin Extraction and Deacetylation

Step 1. Combine dry, defatted chitin powder and DES at a 1:10 (w/w) ratio (e.g., if you have 13g of powder, add 130g of DES).

Step 2. Heat the mixture to 90 °C on a hot plate under vigorous stirring (450 RPM) for 3 hours.

Step 3. Pour the hot reaction mixture directly into 5 volµmes of hot distilled water to crash out the purified chitin crystals.

Step 4. Filter the mixture using vacuµm filtration. Rinse the recovered gray chitin cake continuously with deionized water until the wash water measures a neutral pH of 7.0.

Step 5. Submerge chitin extraction into a fresh batch of ChCl:Lactic Acid DES (using roughly a 1:20 w/w ratio based on estimated chitin weight).

Step 6. Stir and heat at 85 °C for 2 hours to force open the internal hydrogen bonds.

Step 7. Carefully pour an aqueous solution of 30 wt% NaOH directly into the hot DES-chitin slurry. Match the volµme of NaOH solution to the volµme of DES initially used.

Step 8. Maintain the system at 85 °C under steady magnetic stirring for 5 hours.

Step 9. Pour the solution into an excess volµme of room-temperature distilled water. The converted chitosan will precipitate out as off-white flakes.

Step 10. Filter out the chitosan flakes via vacuµm filtration. Wash the collected chitosan cake iteratively with distilled water until the rinse water registers a completely neutral pH of 7.0.

Step 11. Dry the clean chitosan powder in an oven at 50 °C overnight.

Step 12. Add 20.0 g of insect powder, 200 mL of IPA (1:10 w/v ratio), and a stir bar to a 500ml round-bottom, flask.

Step 13. Mount the condenser vertically into the flask neck and clamp to clamp stand. Attach the water input hose to the outer glass spiral tube and the drain hose to the inner straight tube. Turn on a steady, moderate flow of cold water. Leave the top of the condenser completely open to the fµme hood.