Characterization and chemistry of vinylketene prepared by flash vacuum pyrolysis. Study of the flash vacuum pyrolysis of hydroaromatic compounds: 5,8-diphenyltetralin and the parent and substituted 5,6,11,12-tetrahydrodibenzo(a,e)cyclooctenes. Revision 1

Technical Report · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6950260

Surber, B W

In Part I, benzocyclobutene (9) and its (4+4) dimer, 1,5-dibenzocyclooctadiene (14) were found to give anthracene (7) as a major product. The similarity of the product mixtures is taken as evidence that essentially the same mechanism is operating in both cases. By labeling studies, the (4+2) spirodimer (14') appears to be an intermediate. The fragmentation by which 14' is thought to give 7 is new and analogous to the retroene reaction. In Part II, vinylketene (66), prepared by FVP, was characterized by low-temperature /sup 1/H- and /sup 13/C-NMR spectroscopy. It was found to dimerize by a novel (4+2) cyclo-addition reaction. The resulting delta-lactone (90) was isomerized to a mixture of sibirinone (91) and 6-allyl-..cap alpha..-pyrone (92). Acid-catalyzed isomerization gave primarily 91 (9:1 mole ratio). When vinylketene was mixed with cyclopentadiene, the (2 + 2) cycloadduct (72) was formed with high regio- and stereospecificity. Compound 72 was isomerized to bicyclo(4.2.1)nona-3,7-dien-2-one (97). Part III described an attempt to determine the effect of surface catalysis in FVP. The synthesis of 5,8-diphenyltetralin (9) was described. Comparison of the pyrolysis of 9 to that of the parent compound, tetralin (1) was not possible since the thermal chemistry of 9 was found to be too different from that of 1. The major product of the pyrolysis of 9 at 1000/sup 0/C and 10/sup -5/ torr was due to the loss of C/sub 2/H/sub 6/ while 1 gave styrene as the major product by the loss of C/sub 2/H/sub 4/ under similar conditions.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA). Dept. of Chemistry
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6950260
• Report Number(s): IS-T-1111(Rev.1); ON: DE84011487
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
AROMATICS
CHEMICAL REACTIONS
CYCLOALKENES
CYCLOPENTADIENE
DECOMPOSITION
DIENES
HYDROCARBONS
ISOMERIZATION
KETENES
MAGNETIC RESONANCE
MONOMERS
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
POLYENES
PYROLYSIS
RESONANCE
THERMOCHEMICAL PROCESSES
VINYL MONOMERS