Methyl Ethyl Ketone in the Photolysis of Acetone Vapor

Abstract

By niass speclrorr~etric analyses, niethyl ethyl ketone was determined as a product of the photolysis of acetone between 100 and 284°C. According to the post~~lated mechanisni, ~iiethyl ethyl ketor~e together with methane and e t h a~~e accounted for approsirnately 05y0 of the methyl radicals procluced. INTRODUCTIONI t is no\v accepted that the mechanism for the photolj-sis oi acetone vapor between 100°C. and 250°C. is (6,7)Reaction [I] was shown to proceed with a quantum yielcl oi ~i n i t y in this temperature range (4). 'The kinetics of reactions [2] ancl [3] have been investigated (3,G,'i) in some detail. Methyl ethyl ketone was identifecl as a product but was not st~tdied quantitatively (1). Icetene was also found a t temperatures above 200°C., presumably resulting from the decomposition of acetonyl radicals (2) Considering reaction [I] T h e purpose of this work was t o study the material balances in the acetone photolysis when methyl ethyl ketone is included. I t serves a s the basis of an investigation of the kinetics of addition of methyl radicals to unsaiuratecl hydrocarbons, the loss of methyl radicals I)? acldition being related t o a clecrease in the material balance.

Predictability of Chain Reactions

“…Thus, from the observation that the second order rate constant for the addition reaction (32): For termination reactions we also find that their rate constants seem to fall in the range 1010-5 liter/mole-sec. for recombination of radicals while recombination of atoms are third order and have rate constants of about 1010 liter2/mole2-sec.…”

The Photolysis of Acetone Above 300 °c

“…The apparatus and procedure were the same as in a previous investigation (2), with the reaction cell isolated by a mercury cutoff (reaction volume = 195 cc.). T o get sufficient amounts of ethane the full intensity of a Hanovia S-100 lamp was used.…”