双烷链阳离子表面活性剂的合成与定量分析

Synthesis and Quantitative Determination of Alkanediyl-α,ω-bis (dimethyl alkylammonium bromide)

以N ,N 二甲基烷基叔胺和α,ω 二溴烷烃为原料 ,无水乙醇为溶剂合成阳离子型Gemini表面活性剂。反应产物以混合溶剂乙酸乙酯 乙醇重结晶纯化后 ,用红外光谱和核磁共振进行结构分析 ;以溴酚蓝为指示剂、二氯乙烷为分散相的两相化学滴定法测定其含量。结果表明 :7种已合成的阳离子型Gemini的活性物含量均在 97.5

Cationic Gemini surfactants, alkanediyl-α,ω-bis (dimethyl alkylammonium bromide) were synthesized from N,N-dimethyl alkyl tertiary amine and α,ω-alkyl dibromide by using ethanol as solvent. The reactants were recystallized in the ethyl acetate-ethanol solvent mixture and gave the purified products. The Gemini products were qualitatively detected and verified by infrared and 1H nuclear magnetic resonance analysis, and were also quantitatively determined by the two-phase chemical titration by using bromophenol blue as the indicator and dichloroethane as phase spiltting agent. The results showed that the purity of the seven synthesized Geminis are greater than 97.5% in weight.