Synthesis of N,N-Diethyl, N-Methyl Chitosan Chloride with Certain Quaternization Degree and Molecular Spectroscopic and Thermo-Morphological Study of the Alkylation

Abstract

The quartenizeid chloride derivative of natural polyaminosaccharide chitosan was synthesized in two stages with acetate aldehyde and methyl iodide chemical reaction and ion replacement, which could be soluble in the water and wide pH ranges. The synthesis of the homopolymer was initially carried out with acetate aldehyde in Schiff reaction, and reduction was held on with the presence of NaBH4. The quaternization was accomplished in the acetonitrile medium with methyl iodine by continuous exposure of N2.7-8% quartenized N,N-diethyl, N-methyl chitosan iodine were synthesized with 89-91% yield, obtained by deprotonation of amine groups, with reaction of CH3J and N,N-diethyl chitosan. The ion exchange was carried out at 10% NaCl solution during 24 hours and N,N-diethyl, N-methyl chitosan chloride was obtained. Synthesis was performed with simpler and chemically effective methods compared to previous studies. The structure of product was characterized by FT-IR, UV-Vis, NMR, SEM, TGA, DTA and elemental analysis was determined. Functional changes in the structure of macromolecules were monitored with NMR and UV-Vis, and it was proved that, the main intermediate product was composed to be N,N-diethyl carbocation carrying >C=N-chromophore group. The increasing percent of carbon in content while alkylation is depeering and the presence of halogenated ions (Cl- or J-) after quaternization were observed. It has been determined that, the solubility of N,N-diethyl,N-methyl chitosan chloride or iodide in water and in pH =1-10 increased frequently. Key words. Chitosan; alkylation; diethylmethyl chitosan iodine; quartenization; UV-Vis; NMR