Selective Hydrogenation of Polynuclear Aromatic Hydrocarbons

8.17 Homogeneous Catalytic Hydrogenation of CåC and CåC

“…[120][121][122][123][124] Partial hydrogenation of polyaromatics can also be achieved with [Co 2 (CO) 8 ] under carbon monoxide and hydrogen but an isolated benzene nucleus will not reduce. [125][126][127] H 2 (197 atm) [Co 2 (CO) 8 ] 135 °C…”

Free radical mechanisms in coordination chemistry

“…t.Ho (kcal/mole) regeneration by reaction of H2 with the corresponding dehydrogenated complexes (i.e., Coz(C0)8 and Co(CN)53-, respectively) occurs under milder conditions so that catalytic cycles corresponding to the overall hydrogenation reaction (38) and encompassing the reaction sequence (34)-(37), followed by reaction (39), can be achieved (23,8). …”

Use of Transition Metal Complexes as Selective Hydrogenation Catalysts

“…(Bird, 1967c;Frankel et al, 1965b;Ogata and Misono, 1965). Unlike most homogeneous hydrogenation catalysts, including others containing cobalt such as C O ( C N )~~-, Cos(CO)~ is able to reduce various aromatic systems (Bird, 1967c;Friedman et al, 1959), including naphthalene, anthracene, phenanthrene, thiophene, pyridine, and pyrrole. A complete list is given in Table 111.…”

“…) are hydrogenated to dihydro species, leaving two benzene rings intact (Friedman et al, 1959). However, the heteroaromatic systems, thiophene and pyridine, are completely reduced, thiophene yielding thiolane and pyridine yielding piperidine (Bird, 1967c;Greenfield et al, 1958).…”

“…Thus chrysene, a benzphenanthrene, is reduced only very slowly to the 5,6-dihydrido compound (Equation 25), while perylene and pyrene are reduced to phenanthrene derivatives (Equations 26 and 27) (Friedman et al, 1959).…”