Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - ESR spin-trap study of the radicals present during the thermolysis of some novel dialkyl peroxides.
AU - Mekarbane, P. G.
AU - Tabner, B. J.
PY - 2001/1
Y1 - 2001/1
N2 - The thermolysis of two bifunctional dialkyl peroxides [2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (1) and 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne (2)] and two novel monofunctional dialkyl peroxides [2-methyl-(2-tert-amylperoxy)pentan-4-ol (3) and 2-methyl-(2-tert-butylperoxy)pentan-4-ol (4)] was undertaken, in various solvents, between 353 and 383 K and the radicals generated trapped employing DMPO, PBN-d14 and 2,4,6-tri-tert-butylnitrosobenzene (TTBNB). We established that both 1 and 2 release the tert-butoxyl radical (and the methyl radical via -scission) following cleavage of one of the O - O bonds. During the thermolysis of 1 a ·CH2R radical was trapped which we assign to the 3-methyl-3-(tert-butylperoxy)butyl radical (6). We found no evidence for the presence of an alkynyl radical during the thermolysis of 2. The tert-amyloxyl (and the ethyl radical via -scission) and the tert-butoxyl radical (and the methyl radical via -scission) were trapped during the thermolysis of 3 and 4, respectively. The 2-hydroxypropyl radical (10) was trapped employing TTBNB during the thermolysis of both 3 and 4 with its adduct exhibiting two magnetically non-equivalent -protons as a consequence of the adjacent chiral carbon atom. Reaction schemes for the thermolysis all four peroxides are proposed based on the nature of the trapped radicals.
AB - The thermolysis of two bifunctional dialkyl peroxides [2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (1) and 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne (2)] and two novel monofunctional dialkyl peroxides [2-methyl-(2-tert-amylperoxy)pentan-4-ol (3) and 2-methyl-(2-tert-butylperoxy)pentan-4-ol (4)] was undertaken, in various solvents, between 353 and 383 K and the radicals generated trapped employing DMPO, PBN-d14 and 2,4,6-tri-tert-butylnitrosobenzene (TTBNB). We established that both 1 and 2 release the tert-butoxyl radical (and the methyl radical via -scission) following cleavage of one of the O - O bonds. During the thermolysis of 1 a ·CH2R radical was trapped which we assign to the 3-methyl-3-(tert-butylperoxy)butyl radical (6). We found no evidence for the presence of an alkynyl radical during the thermolysis of 2. The tert-amyloxyl (and the ethyl radical via -scission) and the tert-butoxyl radical (and the methyl radical via -scission) were trapped during the thermolysis of 3 and 4, respectively. The 2-hydroxypropyl radical (10) was trapped employing TTBNB during the thermolysis of both 3 and 4 with its adduct exhibiting two magnetically non-equivalent -protons as a consequence of the adjacent chiral carbon atom. Reaction schemes for the thermolysis all four peroxides are proposed based on the nature of the trapped radicals.
KW - ESR
KW - radicals
KW - reaction mechanisms
KW - peroxides
KW - spin trap
KW - thermolysis
U2 - 10.1002/1097-458X(200101)39:1<9::AID-MRC776>3.0.CO;2-3
DO - 10.1002/1097-458X(200101)39:1<9::AID-MRC776>3.0.CO;2-3
M3 - Journal article
VL - 39
SP - 9
EP - 14
JO - Magnetic Resonance in Chemistry
JF - Magnetic Resonance in Chemistry
SN - 0749-1581
IS - 1
ER -