REACTIONS OF C-13-LABELED 4-METHYLDIBENZOTHIOPHENE CARBONIZED WITH FCC DECANT OILS

Two decant oils were spiked with C-13-labeled 4-methyldibenzothiophene (4-(MDBT)-M-13) and carbonized at 500 degrees C to study the reactivi ty of the C-13-labeled compound. A quantitative analysis of the reacti on product maltenes was performed using GC/MS. The GC/MS was also used to estimate the isotopic enrichment in C-13 of the reaction products. Data shows that demethylation and methylation of 4-MDBT are the princ ipal reactions occurring during the early carbonization of the compoun d in the decant oils and that the molecular composition of the decant oils is an important factor in determining the extent of these reactio ns. Incorporation of 4-(MDBT)-M-13 into the solid phase (semicoke) is, therefore, attributed to an enhanced reactivity due to further alkyla tion of the molecule.