- Flow-vacuum pyrolysis of dibenzocycloheptane annelated derivative on zeolites catalysts
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The pyrolysis of 5H-6,7-dihydrodibenzo[a,c]cyclohepten-6-ol (5) in FVP conditions, a method of thermal decomposition in advanced vacuum, inert atmosphere on zeolites/acid Al2O3 at variable temperature between 300- 350° C is presented. The reaction products were identified by GC/MS using authentic samples and a reaction mechanism involving cationic species as intermediates was proposed. A comparison with the pyrolysis of the same compound performed in FVP conditions on quartz is presented.
- Istrati, Daniela,Parvulescu, Luminitza,Popescu, Angela,Mihaiescu, Dan,Andrei, Elena,Badea, Florin
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p. 847 - 850
(2011/06/21)
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- Thermal Reorganizations of 1,2:3,4-Dibenzotropilidene (5H-Dibenzocycloheptene), 7,7'-Bi(1,2:3,4-dibenzotropyl) cycloheptenyl)>, and the 1,2:3,4-Dibenzotropyl (Dibenzocycloheptenyl) Free Radical
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1,2:3,4-Dibenzotropilidene (5H-dibenzocycloheptene, 8) has been shown to thermally produce phenanthrene (12), 9-methylphenanthrene (13), 9,10-dihydrophenanthrene (14), and 1,2:3,4-dibenzocycloheptadiene (6,7-dihydro-5H-dibenzocycloheptene, 15).With added naphthalene, to trap the extruded one-carbon species, 1,2-benzotropilidene (16), α-methyl- and β-methylnaphthalene (17 and 18), 1,2-benzo-1,3-cycloheptadiene (19), and benzocycloheptene (20) were also produced.Reaction of 1,2-benzotropilidene with phenanthrene produced 1,2:3,4-dibenzotropilidene (8) and naphthalene, showing the reversibility of this thermal carbon extrusion reaction. 7,7'-Bi(1,2:3,4-dibenzotropyl) cycloheptenyl), 10> was prepared by VCl2 reduction of the 1,2:3,4-dibenzotropylium cation.Thermally it underwent the same reactions as 8, demonstrating that it is the 1,2:3,4-dibenzotropyl (dibenzocycloheptenyl) free radical (9) which lost a carbon atom (CH group) to the aromatic acceptor.At 200 deg C the dimer 10 produced significant quantities of 9-methylphenanthrene (13), shown not to arise from 8, in addition to phenanthrene, 12.Mechanisms for the thermal transfer of a CH group from 9 to an aromatic acceptor and for the production of 13 from 9 are presented.
- Pomerantz, Martin,Dassanayake, Nissanke L.,McManus, Timothy R.,Reynolds, Charles H.
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p. 4029 - 4032
(2007/10/02)
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