This paper describes the investigation of acids in crude oils from different geological sources. The major acidic compound types in ten high-boiling crude-oil distillates were identified as carboxylic acids, phenols, carbazoles, and amides. Three methods were used for the quantitative estimation of major compound types; the compound types were determined gravimetrically after chromatographic separation and by two qualitative infrared methods. The structures of the acidic compounds were also examined in detail using fluorescence, mass, infrared, and nuclear magnetic resonance spectrometry.
Fuel, V. 54, January 1975, PP. 50-61