Date of Award
Master of Science in Chemical Engineering - (M.S.)
William H. Snyder
Howard David Perlmutter
Werner J. Wenisch
1-bromo-2,2-dimethoxyethane (I) was prepared in 68% yield from the addition of bromine to a solution of vinyl acetate and methanol. A Williamson ether synthesis, using sodium methoxide in methanol and I, gave 1,1,2-trimethoxyethane (II) in 48% yield. The compound (II) was the desired substrate for elimination reactions because it contains poor leaving alkoxide groups.
Many different reactions were investigated to convert II into 1,2-dimethoxyethylene. Among these were pyrolysis, acid catalyzed eliminations, and base initiated elimination reactions.
Best results were obtained using a bomb reactor, compound II as substrate, and potassium t-butoxide as the base. From this reaction, tertiary-butyl methyl ether, tertiary-butanol, cis-1,2-dimethoxyethylene and trans-1,2-dimethoxyethylene were isolated by preparative gas chromatography and identified as end products.
A combination of elemental analysis, chemical tests, infrared spectroscopy, analytical gas chromatography, and nuclear magnetic resonance spectroscopy, prove conclusively and unambiguously the structures of the final products.
An interesting analogy of the NMR spectra of cis-and-trans-1,2-dimethoxyethylene is made with the NMR spectra of cis-and-trans-1,2-difluoroethylene.
Waldron, James, "Potassium t-butoxide-initiated elimination on substrate 1,1,2-trimethoxyethane" (1967). Theses. 1483.