¹³C-Selective Infrared Multiple Photon Decomposition of β-Propiolactone, β-Butyrolactone, and Diketene with a CO₂ TEA Laser

Abstract

13C-Selective infrared multiple photon decomposition of lactone compounds has been studied using a CO2 TEA (transversely excited atmospheric) laser. The main decomposition products were ethylene and CO2 in β-propiolactone. We obtained CO2 with a 13C atomic fraction of 55% in the irradiation of 2 Torr (1 Torr = 1 mmHg = 133.322 Pa) β-propiolactone at 1035.47 cm-1. The addition of 100 Torr of N2 to 2 Torr of β-propiolactone resulted in a remarkable increase in selectivity, i.e., 75% 13C in CO2, while the yield was considerably decreased. Respective olefinic products were propylene and allene in the multiple photon decompositions of β-butyrolactone and diketene. The common product CO2 was also found to be significantly enriched with 13C in these lactone compounds.