Abstract:The yield of geraniol-modified chitosan oligosaccharide (COS-M-Ger) derivatives was increased based on the improvement of experimental scheme described in previous research. COS-M-Ger1，COS-M-Ger2 and COS-M-Ger3 were synthesized through a two-step reaction of geraniol bromination and substitution, and the yield was 4~7 times higher than that of the previous study. The products were characterized by UV-Vis, FT-IR, 1H-NMR and elemental analysis to confirm the successful synthesis, and the substitution degrees of products were in the range from 0.260 to 0.283. Solubility, X-ray diffraction analysis and TGA showed that the products had better solubility than Ger under acidic and neutral conditions. Compared to COS, the crystallinity of product was stronger, however, the thermal stability was worse. The antibacterial results showed that the antibacterial effects of COS-M-Ger1，COS-M-Ger2 and COS-M-Ger3 were better than those of COS and two commercially available antibacterial agents. This paper provides a theoretical basis for the mass production of COS derivatives with good solubility and high antibacterial effect.
