TRANSFORMATION OF CIS-2,3-DIMETHYLOXIRANE AND TRANS-2,3-DIMETHYLOXIRANE ON A CU SIO2 CATALYST/

Transformation of cis- and trans-2,3-dimethyloxiranes on a copper cata lyst was studied at 363 K at various hydrogen pressures as well as in the presence of deuterium, in a recirculating reactor. The main reacti ons are hydrogenolysis, isomerization, and deoxygenation (2-butanol, 2 -butanone, and 2-butenes are formed). In the course of transformation. the surface of the catalyst is oxidized via deoxygenation, leading to the generation of Lewis acid-base ion pairs. 2-Butanol and 2-butenes are formed on Cu(0) atoms while the formation of 2-butanone occurs mai nly on copper ions. Differences between the reactivities of the oxiran e isomers and the characteristic features of the mechanism of the thre e reactions observed are discussed in detail. Finally, experimental ob servations are compared with the transformation of cis- and trans-1,2- dimethylcyclopropanes under similar conditions. (C) 1997 Academic Pres s.