Knowledge Bank

Infrared spectroscopy is a major tool in work on modern petroleum processes such as alkylation, polymerization and catalytic reforming. Because of current interest in petroleum-derived benzene, analytical procedures used for charge stocks and reformates will be given. A spectroscopic method for methylcyclopentane, cyclohexane, and individual paraffins which avoids most apparent deviations from Beer's Law is used. Significant experimental conditions are: compensated scanning of 2-10% solutions in $CS2,1-mm$ cells, good resolution and measurements in the 45-70% transmittance range. For the sharp $650-850cm-1$ bands of aromatic hydrocarbons, working curves of absorptivity vs. absorbance are used to compensate for slit-width effects. Applications of infrared spectroscopy to chemical research will be given. Examples include butylated phenol antioxidants, alkyl aryl detergents, $C4$ gas mixtures, and alkylation of thiophene.