Synthesis and antibacterial activity of O-hexanoyl quaternary ammonium chitosan

O-methyl free N,N,N-trimethyl chitosan(TMC) was synthesized through two steps,then TMC and hexanoyl chloride were used to prepare N,N,N-trimethyl-O-hexanoyl-chitosan(TMHC).The products were characterized by 1H NMR,FT-IR and EA.The results of antimicrobial test indicated that the antibacterial activity of TMHC was stronger than TMC by acylation modification,and increased with the degree of substitution increased.TMHC showed stronger antibacterial activity against S.aureus than against E.coli.In addition,the same concentration(50mmol/L) of divalent cations reduced the antibacterial activity of TMHC in the following order:Ba2+ Ca2+Mg2+.And the antibacterial activity inhibition of TMHC at the same metal ion(Mg2+) condition reduced with the increasing ion concentration.