Study On Synthesis, Properties And Applications Of Esterquat Gemini Surfactant

The preparation, properties, mixed systems with other commonly used surfactants andapplications of esterquat Gemini surfactants,[H2m-1Cm-1COOCH2CH2(CH3)2N+(CH2)n+N(CH3)2CH2CH2OOCCm-1H2m-1]2Br?(symbolizedII-m-n, m=10,12,14,18;n=3,4,6), were investigated in this dissertation.The preparation of esterquat Gemini surfactants was completed through two steps.The fatty acid was reacted with thionyl chloride to produce alkylnoyl chloride, thenalkylnoyl chloride was reacted with dimethylaminoethanol to produce the desiredintermediate compound. The intermediate compound was qualitatively detected and verifiedby IR and MS, and was also quantitatively determined by acid-base titration. The resultsshowed that the purity of the four synthesized intermediate compounds are greater than98.55% in weight.The esterquat Gemini surfactants were synthesized from the intermediate compoundsmentioned above and α,ω-alkyl dibromide by using 2-propanol as solvent. The reactants wererecrystallized in acetone and gave the purified products. The chemical structure of the purifiedproducts were confirmed using IR and 1HNMR. The content in weight of the products wasdetermined by two-phase chemical titration and the results showed that the purity of thetwelve prepared esterquat Gemini surfactants are greater than 98.60% in weight.The Krafft point, critical micelle concentration, foaming property, emulsificationproperty and wetting property of the synthesized esterquat Gemini surfactants weredetermined, the corresponding "monomer" surfactants C10TABr, C12TABr and C14TABr wereused for comparison.The surface activity of the mixed systems II-10-n/SDS and II-12-n/SDS were studied.The micellization parameter (βm) was calculated;the effects of the molecular structure ofesterquat Gemini surfactants on the synergistic effect of the mixed systems were investigatedand the effects of inorganic salt on the surface activity of the mixed systems were investigatedas well.The surface activity of the mixed systems II-10-n/AEO9 and II-12-3/AEO9 were studied.The components of the mixed micelle were calculated;the effects of the molecular structureof esterquat Gemini surfactants on the surface activity of the mixed systems were investigated;the aggregation number of the mixed micelle formed by II-10-6 and AEO9 was determined.The bactericidal activities against Escherchia, Candida alibicans and Staphylococcus ofthe synthesized esterquat Gemini surfactants were examined and the bactericidal activitieswere also compared with that of C12TABr. The effects of the molecular structure of esterquatGemini surfactants on their bactericidal activities were investigated.The softening property of II-18-n and II-14-6 was evaluateded and the commerciallyavailable product D1821 was used for comparison.