Synthesis And Properties Of Alkylated Tannin Derivatives With Surface Activity

Tannins,as one of the most abundant renewable resources,are a class of green polyphenol compounds widely found in plants with good biocompatibility and biodegradability.The molecular structure of tannins contains a large number of phenolic hydroxyl groups,which makes it have unique chemical properties and special physiological and pharmacological functions.It has been widely used in daily chemical industries,biomedicine,food,leather and other fields.However,tannins are severely limited in some industrial applications to a certain extent due to the defects of high water solubility and low fat solubility.In order to overcome this disadvantage,the hydrophobic modification of tannins are carried out,which can not only endow tannins with good surface activity,but also benefit to develop their biological activity.In this paper,alkynylated tannins were prepared by the reaction of tannin and propargyl bromide,tannin derivatives with surface activity were synthesized by the click chemical reaction of alkyl azide and alkynylated tannins,the structure of tannin derivatives were characterized by FT-IR and elemental analysis,and the surface activity,antioxidant activity and antibacterial activity of tannin derivatives were investigated.The main contents are as follows:1.The 1,2,3-triazole-linked dodecyl tannin derivatives were synthesized by click reaction of alkynylated tannins and dodecyl azide.The prepared dodecyl tannin derivatives could significantly reduce the surface tension of aqueous solution due to the introduction of the long chain alkyl groups and the increased of the fat-solubility of tannin.The lowest surface tension of dodecyl tannin derivatives was 38.87 m N/m at 0.8mg/m L.The dodecyl tannin derivatives had good ability to scavenge1,1-diphenyl-2-picrylhydrazyl radical,the scavenging rate of dodecyl tannin derivatives to 1,1-diphenyl-2-picrylhydrazyl radica could reach 89.08 % at 0.25 mg/m L.The dodecyl tannin derivatives exhibited strong antibacterial activity against E.coli and S.aureus due to the increased fat-solubility of tannin and the introduction of antibacterial triazol groups in the molecular structure of tannin.The bacteriostatic ratios of dodecyl tannin derivatives against E.coli and S.aureus were 92.16 % and 89.21 % at 0.8mg/m L,and the minimum inhibitory concentration were 0.625 mg/m L and 1.25 mg/m L,respectively.2.The 1,2,3-triazole-linked dodecyl-benzenesulfonyl tannin derivatives were synthesized by click reaction of alkynylated tannins and p-dodecyl-benzenesulfonyl azide,the benzenesulfonyl groups were introduced into the molecules structure of tannin.The decodecyl-benzenesulfonyl tannin derivatives had stong surface activity due to the hydrophobicity of benzene ring of benzenesulfonyl group,the decodecyl-benzenesulfonyl tannin derivatives could reduce the surface tension of aqueous solution to 28.94 m N/m at 0.8 mg/m L.The dodecyl-benzenesulfonyl tannin derivatives had strong ability to scavenge 1,1-diphenyl-2-picrylhydrazyl radical,the maximum scavenging rate to 1,1-diphenyl-2-picrylhydrazyl radical could reach 97.08 %at 0.25 mg/m L.The dodecyl-benzenesulfonyl tannin derivatives had significant bacteriostatic activity against E.coli and S.aureus due to the increased fat-solubility of tannin derivatives and the introducted of benzenesulfonyl and triazole.The bacteriostatic ratios of dodecyl-benzenesulfonyl tannin derivatives against E.coli and S.aureus could be up to 94.21 % and 91.16 %,and the minimum inhibitory concentration were 0.313 mg/m L and 0.625 mg/m L,respectively.