Thermolysis of Bibenzyl: Roles of Sulfur and Hydrogen Sulfide

Article abstract of DOI:10.1021/jo00211a004

The presence of sulfur in the thermolysis of bibenzyl considerably reduces the severity of the conditions required to cleave the aliphatic carbon-carbon bond.Bibenzyl rapidly reacts with sulfur at 425 deg C to give nine fully characterized products: benzene, toluene, ethylbenzene, diphenylmethane, 1,1-diphenylethane, trans-stilbene, phenanthrene, 2-phenylbenzothiophene, and 2,3,4,5-tetraphenylthiophene.Toluene is the principal product, and its yields are dependent on reaction time,temperature, and sulfur loading.With the addition of H2S to the sulfur-bibenzyl reaction mixture, the required elemental sulfur loading for maximum toluene yields is greatly decreased, and the mass recovery decreases with amounts of sulfur loaded.The two minor products, 2-phenylbenzothiophene and 2,3,4,5-tetraphenylthiophene, give evidence of sulfur incorporation under these sulfur concentration conditions.The addition of hydrogen to the reaction mixtures improves mass recovery and decreases conversion.