Organic Peroxides—diisopropyl Peroxydicarbonate

An EPR spin-trap study of the radicals present during the thermolysis of some novel monoperoxycarbonates and peroxydicarbonates

“…A thermolysis scheme for diisopropyl peroxydicarbonate was outlined in 1950 2, 6 which, based on the nature of the decomposition products, suggested that the primary step was dissociation into alkoxycarbonyloxyl radicals followed either by decarboxylation or hydrogen atom abstraction from the parent peroxide. This conclusion has been supported by Strong 4 and Duynstee et al 11 Similar conclusions have been drawn from product analysis following the decomposition of dicyclohexyl peroxydicarbonate 8 and of bis(4-tert-butylcyclohexyl) peroxydicarbonate 12 where Scheme 1 the presence of the corresponding alkoxycarbonyloxyl radical and hydrogen atom abstraction of the α-hydrogen atom from the cyclohexane ring of the parent peroxide has been invoked.…”

“…Peroxydicarbonates are now widely used commercially as initiators for radical polymerisations, especially of vinyl monomers and esters. 3,4 They have proven to be useful initiators at relatively low temperatures, releasing two alkoxycarbonyloxyl radicals upon thermolysis, the nature of the alkyl group having little effect on their 10 hour half-life decomposition temperature. 5 Although the rate of decarboxylation of alkoxycarbonyloxyl radicals is relatively slow 6-9 these radicals are more reactive towards hydrogen atom abstraction from substrates and addition to monomers than tert-butoxyl and other alkoxyl radicals due to the inductive electron-withdrawing effect of the RO group.…”

“…Consequently induced decomposition can occur and has been widely reported. [3][4][5]8,10,11 Detailed studies of the species present during the thermolysis of peroxydicarbonates seem rather limited. A thermolysis scheme for diisopropyl peroxydicarbonate was outlined in 1950 2, 6 which, based on the nature of the decomposition products, suggested that the primary step was dissociation into alkoxycarbonyloxyl radicals followed either by decarboxylation or hydrogen atom abstraction from the parent peroxide.…”

On the incompatibility of lithium–O2 battery technology with CO2

“…15 The observed isotope scrambling was likely due to a sequence of H-atom abstraction/radical recombination reactions. By analogy to the behavior of organic peroxydicarbonates, 26 symmetrical peroxydicarbonate would be expected to undergo O–O bond homolysis generating two equivalents of the reactive carbonate radical CO 3 ˙ – ( Fig. 6 , hydrogen atom transfer (HAT) pathway).…”

Determination of isopropyl peroxydicarbonate decomposition rate constant using EPR

“…At a concentration of 0.0425 m/l. b At a concentration of 45% which produces a more rapid reaction owing to deviation 0 At a concentration of 0.144 m/l.from first order r X n 18. …”