Process for extracting and purifying chitin by using green solvents

Process for the treatment of biomass comprising chitin with a process solvent selected from a eutectic solvent consisting of a hydrogen bond acceptor and a hydrogen bond donor, an ionic liquid and/or a mixture of said eutectic solvent and said ionic liquid, said process comprising the following steps: A. mixing the biomass with the process solvent; B. separating the chitin precipitated in step A. from the remainder of the mixture; wherein: i. the hydrogen bond acceptor is a choline salt with a C2-C6 organic acid, and containing at least one carboxyl group and optionally substituted in the alkyl chain with at least one hydroxyl group, ii. the hydrogen bond donor is an organic acid selected from: glycolic acid, diglycolic acid, levulinic acid, or is imidazole; provided that when choline glycolate is used as a hydrogen bond acceptor, the hydrogen bond donor must be different from glycolic acid; iii. in step A. a polar protic solvent soluble in both said process solvent and water is added to the process solvent; selected from a linear or branched C1-C6 aliphatic alcohol; iv. the ionic liquid is the salt resulting from the exchange reaction between one of the organic acids used as a hydrogen bond donor listed above in point ii. and a choline salt specified in i. used as a hydrogen bond acceptor.