19978-15-5Relevant articles and documents
Flash-vacuum pyrolysis (FVP) on zeolites. II: Pyrolysis of 5β-(acetoxyethyl)-5H-dibenzo[a,d]cycloheptene; 11-acetoxy-9,10-dihydro-9,10-propanoanthracene and 11-hydroxy-9,10-dihydro-9,10-propanoanthracene
Banciu, Mircea D.,Cira, Ovidiu,Petride, Aurica,Banciu, Anca
, p. 1093 - 1098 (2007/10/03)
Flash-vacuum pyrolyses (FVP) of the title compounds 8, 7 and 6, performed at 0.65 mbar in argon atmosphere at 350°C in the presence of different acidic zeolites, afforded product distributions similar to FVP of 5β-(hydroxyethyl)-5H-dibenzo[a,d]cycloheptene (1) indicating 7H-benzo[c]fluorene (2); 6,11b-dihydro-7H-benzo[c]fluorene (3) and benzo[a]fluorene (13) as main reaction products. The reaction seems to involve only the outer surface of catalysts. The cationic reaction mechanism is supported by identification of two hydrocarbon intermediates which afford the same FVP products as 6-8 as well as by comparison with the results of the FVP of 6-8 over acidic alumina at different temperatures.
FLOW-VACUUM PYROLYSIS OF POLYCYCLIC COMPOUNDS. PYROLYSIS OF EXO-10,11-DIHYDRO-5,10-ETHANO-5H-DIBENZOCYCLOHEPTEN-11-YL ACETATE AND EXO-10,11-DIHYDRO-5,10-ETHANO-5H-DIBENZOCYCLOHEPTEN-11-OL
Stanescu, Michaela Dina,Florea, Cristina,Banciu, Mircea D.
, p. 815 - 820 (2007/10/02)
The flow-vacuum pyrolyses of the title compounds 2, respectively 1, were performed between 300 deg C and 675 deg C (650 deg C), at 1 Torr.The results are discussed in comparison with those obtained in the previously described pyrolyses of the corresponding endo-isomers 5, respectively 4.
Benzoannelated valence isomers of homoannulenes. I. Thermal behaviour of some dibenzo(C9H10)hydrocarbons
Banciu, M. D.,Stanescu, M. D.,Florea, C.,Petride, A.,Draghici, C.,Cioranescu, E.
, p. 919 - 925 (2007/10/02)
The flow-vacuum pyrolyses of 9,10-dihydro-9,10-propenoanthracene 1 and 1,1a,6,10b-tetrahydro-1,6-methanodibenzocyclopropacycloheptene 2 (two isomeric dibenzo(C9H10)hydrocarbons occuring in the acetolysis of 5-(β-tosyloxyethyl)-5H-dibenzocycloheptene 4a) were examined at 1.33 mbar and various temperatures between 300 deg C and 700 deg C.The thermal interconversion of 1 and 2 was proved as well as the formation of a new unstable dibenzo(C9H10) valence isomer, 3, which is converted further at higher temperatures into stable benzofluorene derivatives 6 and 7.Radical mechanisms are proposed and the possibility of formation of another transient dibenzo(C9H10)hydrocarbon 30 is supposed.The essential role of the CH2 moiety in pyrolyses of the investigated hydrocarbons is underlined and a comparsion of pyrolysis mechanisms in C9H10-, benzo(C9H10)- and dibenzo(C9H10)-series is made. Key words: valence isomers of homoannulenes / dibenzo(C9H10)hydrocarbons / flow-vacuum pyrolysis