Synthesis and characterization of new chitosan-based Schiff base compounds

•New chitosan Schiff bases are synthesized.•4-(2-Chloroethyl) and 4-(2-bromoethyl)benzaldehydes are used in the synthesis.•The product composition slightly depends on the reaction temperature (room temperature vs 80 °C).•Vinyl derivatives of chitosan Schiff base are obtained in alkaline environment.

Chitin (Cn) was extracted from the armors of crustaceans Astacus leptodactylus (Lake Sevan, Armenia) and then converted to chitosan (Cs), its deacetylated derivative. Novel Schiff bases (CsSB) were synthesized by interaction of Cs with 4-(2-chloroethyl)benzaldehyde (aldehyde-1) and 4-(2-bromoethyl)benzaldehyde (aldehyde-2), and underwent dehydrohalogenation, under basic conditions (10 °C), to yield respective vinyl derivatives. All newly synthesized compounds were structurally characterized by solubility tests, elemental analysis, infrared spectroscopy (FTIR), thermogravimetry (TGA), proton nuclear magnetic resonance (1H NMR), and X-ray diffraction (XRD).