분광학적 방법에 의한 계면활성제의 확인

Qualitative Identification of Surfactants by Spectroscopic Method

Our study is aimed at proposal of systematic verification method of molecular structure using measuring method of selective ionic determination and spectrometry on 34 kinds of surfactants such as sodium dodecyl sulfate(SDS) which are most widely used today. In the IR spectrum, unsaturated fatty acids reveal themselves by HC= at $3000{\sim}3020cm^{-1}$, and intensity of $720cm^{-1}$ depends on carbon length of alkyl group. Also ethylene oxide(EO) adducts exhibit weak characteristic bands by $-CH_{2}-CH_{2}-O$ at 1350, 1100 and $950cm^{-1}$. Isethionate can be distinguished from diester succinate by intensity ratio of 1740 and $1200cm^{-1}$ spectrums, the ratio of latter is close to 1 due to 2 carboxylate radical in diester succinate. Quaternary ammonium salts exhibit characteristic band of $C_{4}N^{+}$ at $1000-900㎝^{-1}$. In the case of dialkyl dimethyl ammonium salts in quaternary ammonium surfactants, the spectrum of $3000cm^{-1}$ by $N-CH_{3}$ collapses to a very weak band at $3020cm^{-1}$. In ammonium heterocyclic derivatives, pyridinium salts show characteristic bands at 1640 and $1460cm^{-1}$, while imidazolinium salts exhibit characteristic band at $1620-1610cm^{-1}$. In the characteristic spectrum at $1080-1050cm^{-1}$ on OH radicals of the alkyl esters, primary alcohol appears as weak band and the 2 bands show in almost same intensity when primary and secondary alcohols exist together in one molecule. Also, alkyl ester of polyhydric alcohols appears as various broad band.