KINETICS OF THERMAL NITRIC OXIDE-CATALYZED GEOMETRICAL ISOMERIZATION OF CIS- AND TRANS-PROPYLENE-1-D1

The thermal cis-trans isomerization of propylene-1-d1 has been studied from 460°-541°C over a pressure range of 3-250 mm Hg in a Pyrex reaction vessel. The reaction below 20 mm Hg is homogeneous and unimolecular but just in the pressure-dependent region, k∞,cis-trans(sec -1) = 1013-16 exp( -61 300/RT). Above 20 mm a second-order reaction begins to contribute to the isomerization rate. The nitric oxide-catalyzed isomerization of cis-propylene-1-d1 was studied between 398° and 452°C at propylene pressures of between 8 and 22 mm, Hg and NO pressures of 5-35 mm Hg. The reaction is first order in propylene and nitric oxide. The second-order rate constant is given by k(liters mole -1-second-1) =108.27 exp(-27900/AD.