PYROLYSIS OF SEC-BUTYL ACETATE - IS THE STEREOSPECIFIC SYN ELIMINATION A HOMOGENEOUS OR HETEROGENEOUS REACTION

A kinetic isotope effect of ca. 2 was obtained for the pyrolysis of either 1,1,1-trideuterio-2-butyl acetate or erythro-2-butyl-3-di acetate over glass beads. Under the same reaction conditions, except for the use of a high surface area silica rather than glass beads, the isotope effect was lower. With the high area silica, 2-butanol dehydration produced no isotope effect, and, in contrast to acetate pyrolysis, the silica catalyzed H-D exchange during the formation of the butene products. Butene and D2O did not undergo exchange under the alcohol dehydration conditions. It is concluded that surface catalysis during acetate pyrolysis over low surface area glass beads does not make an important contribution but may with high surface area silica. © 1990, American Chemical Society. All rights reserved.