利用红外光谱鉴别饱和脂肪酸及其盐

有人认为饱和脂肪酸及其盐是碳酸盐岩中的生烃母质，但将它们从天然沉积物中鉴别出来的方法尚不成熟，对分析评价它们在沉积物中的分布造成困难。文章对几种合成饱和脂肪酸及其盐进行红外光谱测试，获得它们的红外吸收光谱。对特征峰进行指认，分析了饱和脂肪酸及其盐红外光谱的区别。从基团推电子能力、分子折合质量、离子核外电子构型及碳链长度的角度，解释不同饱和脂肪酸以及不同阳离子形成的饱和脂肪酸盐的特征官能团吸收峰波数的变化规律。为地质体中此类物质的鉴别提供参考。

The Identification of Several Saturated Fatty Acids and Their Salts by Means of Infrared Spectrometry

It is considered that saturated fatty acids and their salts may be potential hydrocarbon-generation matters in carbonate rocks. However, there is no effective method to distinguish them from natural sediments, making recognizing their distribution in sediments a challenge. Formic acid, acetic acid, stearic acid, calcium formate, calcium acetate, magnesium acetate, calcium stearate, and magnesium stearate from some chemical plants were investigated by means of Fourier transform infrared spectroscopy. Their infrared spectra were obtained and the distinctions of the infrared spectra between saturated fatty acids and their salts were studied in detail. The differences in the group's electron-releasing ability, molecular reduced mass, ion configuration and the length of carbon chain can cause wavelength shifts of infrared absorption peaks of the saturated fatty acids and their salts. The research provides a method for the identification of saturated fatty acids and their salts in samples from nature.