Electron transfer ability of polyaromatic hydrocarbons in the crudes

The suppression of coking is important during the hydrocracking reaction, to enhance catalyst activity and life. This paper mainly discusses the coking phenomena with reference to the electron (charge) transfer ability of hydrocarbons and asphaltene. Aromatic hydrocarbons and asphaltene generate charge transfer complexes (CTC) with electron accepters, This fact is related to the electron donor ability (basicity) of aromatic hydrocarbon molecules, The addition of iodine causes an enhancement of the ESR intensity of asphaltene, The method allows the application of ESR to a complex mixture system such as asphaltene. From the temperature dependence of ESR intensity for a CTC, the free radicals in the asphaltene of Khafji (Saudi Arabia) and Minas (Indonesia) crudes are divided into two types; singlet-triplet transitions (N), and doublet states (N,). Molecular associations derived from the free radical behavior are used to explore the mechanism of cake formation.