Chitin and chitosan production from shrimp shells using ammonium-based ionic liquids

Ammonium-based ionic liquids (ILs): diisopropylethylammonium acetate ([DIPEA][Ac]), diisopropylethylammonium propanoate ([DIPEA][P]) and dimethylbutylammonium acetate ([DMBA][Ac]) are used for the extraction of chitin from shrimp shells. The extracted chitins were characterized by FT-IR, TGA, XRD, SEM and ¹H NMR. The yield of chitin, with moderate molecular weights, can be as high as 13.4% (mass of extracted chitin/mass of shrimp shells) when the extraction was operated at 110 °C for 24 h. The extracted chitin can be further converted into chitosan and the product has 93% degree of deacetylation. The experimental results reveal that the ILs play a remarkable role in the extraction of chitin from shrimp shells with high selectivity. These ammonium-based ILs can be a promising green solvent to extract chitin from wasted shrimp shells and then converted into chitosan.