Composition and Distribution of Naphthenic Acids in Penglai Crude Oil with High Acid Number

Naphthenic Acids(NAs) were separated from the Penglai acidic crude oil by ethanolamine,and their compositions and structures were analyzed by element analysis and characterized by different spectroscopic methods such as IR,MS,and NMR.The NAs in Penglai crude oil were mainly unitary acids containing one or two rings.The carbon number ranges from 9 to 28,the average molecular weight was 278 and the empirical formula averaged to C_(18)H_(30)O_2.