Frequency‐dependent branching ratio in the infrared multiphoton photochemistry of diethyl carbonates

Abstract

Unimolecular decomposition of 0·1 Torr of diethyl carbonate, diethyl‐d5 carbonate and diethyl‐d10 carbonate induced by irradiation with a CO2 TEA laser was investigated. In all cases only ethylene, ethanol and CO2 were obtained. In the case of diethyl‐d5 carbonate, both ethylene‐d4 and ethylene‐d0 were observed together with the corresponding isotopic variants of ethanol. The chemical branching ratio was determined as a function of irradiation frequency and laser fluence by analysis of the ethylene‐d0/ethylene‐d4 ratio. RRKM theory applied to the branching ratio data requires very different average energies for two sets of fluence and frequency conditions that give identical total yields.

The Stereochemistry of the Thermal Cheletropic Decarbonylation of 3-Cyclopentenone As Determined by Multiphoton Infrared Photolysis/Thermolysis

“…MP-IR decompositions of a number of systems have been reported. [28][29][30][31][32][33][34][35][36][37][38] Of the most relevance to the current work, MP-IR thermolysis of cyclobutyl acetate yields cyclobutene, while pyrolysis gives only butadiene as the product of secondary thermolysis of cyclobutene. 39 Thus, we anticipated that the reaction scheme for the MP-IR photolysis/thermolysis of 4 would be as in eq 2.…”