Microwave Spectrum, Barrier to Internal Rotation, and Quadrupole Coupling Constants of trans-1-Chloropropylene

Abstract

The microwave spectra of two isotopic species of trans‐chloropropylene, CH₃CH=CHCl³⁵ and CH₃CH=CHCl³⁷, have been measured and assigned. The quadrupole coupling constants of the chlorine³⁵ nucleus were determined from the hyperfine structure. A few transitions were further split by the linear effect of the barrier to internal rotation of the methyl group. From these separations the barrier height was measured to be 2170±100 cal/mole.