Degree Type

Dissertation

Date of Award

1984

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

Flash vacuum pyrolysis (FVP) has been used successfully to discover some novel thermal reactions. These provide new insights into some fundamental chemistry;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. The proposed mechanism lends new insight into the mechanism of the pyrolytic formation of benzene and higher aromatics;In part II, vinylketene (66), prepared by FVP, was characterized by low-temperature ('1)H- and ('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-(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 bicyclo4.2.1nona-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(DEGREES)C and 10('-5) torr was due to the loss of;C(,2)H(,6) while 1 gave styrene as the major product by the loss of C(,2)H(,4) under similar conditions; *DOE Report IS-T-1111. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-5386

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Bruce Warren Surber

Language

en

Proquest ID

AAI8423677

File Format

application/pdf

File Size

178 pages

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