Determination of aromatic hydrocarbons in petroleum fractions by infrared spectroscopy

Different petroleum fractions (of aromatic content between 0 and 22%) distilled from northern and Sharki-Baghdad Iraqi crude oils and reformates (of aromatic content between 22 and 55%), in addition to artificial hydrocarbon mixtures (of aromatic content between 5 and 60%), were prepared. The peak area of the 1650–1550 cm–1 band, representing the stretching vibration of the CC bond in the aromatic ring, is proportional to the aromatic content of the reference mixtures. The aromatic contents of naphtha, kerosene and gas oil fractions and reformates were calculated from the measured peak areas and the aromatic contents of the reference mixtures. The determined values of the aromatic contents were in satisfactory agreement with those obtained by sulphonation for naphtha and kerosene fractions, elution adsorption chromatography for gas oil fractions and gas-liquid chromatography for reformates.