I. Mechanism of the formation of methylenecyclobutenone by the flash vacuum pyrolysis of furfuryl benzoate, II. Chemistry of 2-methylenebenzocyclobutenone and indenone prepared by the flash vacuum pyrolysis of 3-benzoyloxymethylbenzofuran
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The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).
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The Department of Chemistry was founded in 1880.
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1880-present
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- College of Liberal Arts and Sciences (parent college)
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Abstract
The flash vacuum pyrolysis chemistry of a series of deuterated furfuryl benzoates, furfuryl-(alpha), (alpha)-d(,2) benzoate, furfuryl-5-d(,1) benzoate, and furfuryl-3-d(,1) benzoate have been investigated. Mechanisms were proposed for the formation of the pyrolysis products, methylenecyclobutenone, vinylacetylene, and the dimer of cyclopentadienone, from each of the compounds studied which involved initial alpha elimination of benzoic acid, a single 3,3 migration followed by alpha elimination of benzoic acid, and two 3,3 migrations followed by alpha elimination of benzoic acid. GLC/MS analyses of the deuterium content of these products showed that the major contributing route for the formation of these products involves two 3,3 migrations followed by alpha elimination of benzoic acid which provides 70-90% range of contribution. The other two routes are minor contributors. It was also shown that the difference between the pyrolysis chemistry of furfuryl benzoate and furfuryl acetate was minor;Synthesis of 2-methylenebenzocyclobutenone for the first time, and indenone by the flash vacuum pyrolysis of 3-benzoyloxymethylbenzofuran is described. A procedure was developed for the decarboxylation of 2,3-benzofurandicarboxylic acid in > 80% yield to the key intermediate 3-benzofurancarboxylic acid which involved FVP at 700(DEGREES)C and ca. 10('-4) Torr. For the preparation of pure samples of 2-methylenebenzocyclobutenone, two procedures were developed which involved: (a) adding a known amount of pyrrolidine to the product mixture obtained by the FVP of 3-benzoyloxymethylbenzofuran at 500-580(DEGREES)C followed by flash chromatography which gave a 13% yield, and (b) adding a large excess of cyclopentadiene to the product mixture obtained by the FVP of 3-benzoyloxymethylbenzofuran at 500-580(DEGREES)C followed by flash chromatography of the resulting mixture which gave 25% yield. Mechanisms were proposed for the formation of the pyrolysis products 2-methylenebenzocyclobutenone, indenone, phenylacetylene, and o-ethynylbenzaldehyde.