82894-88-0Relevant academic research and scientific papers
Initiation Processes in Copolymerization Studied by the Nitroxide Radical-Trapping Technique: Ethyl Vinyl Ether and Acrylonitrile
Busfield, W. Ken,Jenkins, Ian D.,Monteiro, Michael J.
, p. 1 - 8 (2007/10/03)
The nitroxide free-radical trapping technique has been applied to an investigation of the initiation mechanism of the copolymerization of ethyl vinyl ether and acrylonitrile initiated by t-butoxyl radicals.In addition to a range of products normally produced from reactions with individual monomers, four new trapped products each involving both monomers have been observed.These arise because the strongly electron-accepting acrylonitrile reacts so fast with the strongly nucleophilic ethyl vinyl ether radical end groups that the reaction competes successfully with radical trapping. t-Butoxyl radicals react 3-6 times faster with ethyl vinyl ether than with acrylonitrile depending on solvent, illustrating the strong electrophilic nature of the t-butoxyl radicals.Reactions carried out in non-olefinic solvents show that polarity is not a major factor in the solvent effect.It is more likely to be due to selective interaction of one monomer with the radical end enhancing its electrophilic nature.A similar effect is caused by a hydrogen-bonding solvent.
The Reaction of Organophosphorus Radicals with Vinyl Acetate and Acrylonitrile in the Presence of an Aminoxyl Radical Scavenger
Busfield, W. Ken,Grice, I. Darren,Jenkins, Ian D.
, p. 625 - 634 (2007/10/02)
The radical-trapping technique employing 1,1,3,3-tetramethyl-1,3-dihydro-2H-isoindol-2-yloxyl (1) as a radical scavenger has been used to study the reaction of diphenylphosphinoyl (2) and dimethoxyphosphinoyl (3) radicals with vinyl acetate and acrylonitrile.The phosphorus-centred radicals were generated by hydrogen abstraction from diphenylphosphine oxide and dimethyl phosphite respectively.Diphenylphosphine oxide was approximately three times as reactive as dimethyl phosphite towards hydrogen abstraction by t-butoxyl radicals and four times as reactive as tetrahydrofuran (towards abstraction of an α-hydrogen).Diphenylphosphinoyl radicals were found to be relatively nucleophilic and, in competition experiments, reacted about an order of magnitude faster with acrylonitrile than with vinyl acetate.Dimethoxyphosphinoyl radicals were rather less nucleophilic and reacted only twice as fast with acrylonitrile as they did with vinyl acetate.In the presence of excess aminoxyl (1), both diphenylphosphinoyl and dimethoxyphosphinoyl radicals were efficiently scavenged to produce stable phosphinic and phosphate esters respectively.The rate of scavenging was close to diffusion-controlled (c. 1.8E9 l.mol-1s-1).
QUANTITATIVE STUDIES ON FREE RADICAL REACTIONS WITH THE SCAVENGER 1,1,3,3-TETRAMETHYLISOINDOLINYL-2-OXY
Griffiths, Peter G.,Rizzardo, Ezio,Solomon, David H.
, p. 1309 - 1312 (2007/10/02)
Previously unobserved reaction pathways for the attack of tert-butoxy radicals on vinyl monomers have been found by a technique which employs the title nitroxide as radical scavenging agent.
