CYCLOPENT[bc]ACENAPHTHYLENE: A PUTATIVE INTERMEDIATE ON THE PATHWAY FOR THERMAL CYCLODEHYDROGENATION OF PHENANTHRENE

Abstract

Phenanthrene, the archetypal “bay region” polycyclic aromatic hydrocarbon (PAH), loses two hydrogen atoms when subjected to flash vacuum pyrolysis (FVP) at 1100 °C and suffers a major skeletal rearrangement to form pyracylene (1), along with 1-, 3-, and 4-ethynylacenaphthylene (2, 3, and 4, respectively). Evidence is presented that implicates cyclopenta[bc]acenaphthylene (7) as a key intermediate on the reaction pathway from phenanthrene to these four C₁₄H₈ products.

Keywords:

• aryl radicals
• carbene
• Flash Vacuum Pyrolysis (FVP)
• PAH
• reaction mechanism

We thank the Department of Energy for financial support of this research.