Polycyclic Aromatic Sulfur Heterocycles. I. Use of Hydrogen Peroxide Oxidation for the Group Separation of Polycyclic Aromatic Hydrocarbons and Their Sulfur Analogs

Abstract

Some of the reasons for the difficulty of devising a generally valid analytical procedure for polycyclic aromatic sulfur heterocycles (PASHs) are discussed. A procedure for the separation of polycyclic aromatic hydrocarbons and PASHs which has been used for many years is investigated. It is shown that the oxidation with hydrogen peroxide in acetic acid/benzene produces not only the desired sulfones of the PASHs but that also the aromatic rings of polycyclic compounds of all types are oxidized. Low or zero recovery of the analytes is therefore often found. A large number of reagents was tested for the reduction of aromatic sulfones to PASHs in order to find a substitute for lithium aluminum hydride. None was discovered that cleanly affects this conversion. It is strongly recommended that oxidation with hydrogen peroxide not be used for any samples in which aromatic compounds are to be analyzed.

Key Words:

• Polycyclic aromatic heterocycles
• polycyclic aromatic sulfur heterocycles
• sulfur-selective detection
• crude oil