4972-13-8Relevant academic research and scientific papers
Eclipsed ground-state conformations of the tert-butyl-X bond in N-tert-butoxy- and N-neopentyl-2,2,6,6-tetramethylpiperidine. X-ray crystal structure determinations and molecular mechanics calculations
Anderson, J. Edgar,Tocher, Derek A.,Corrie, John E. T.,Lunazzi, Lodovico
, p. 3494 - 3498 (1993)
X-ray crystallographic studies of derivatives of N-methoxy- and N-tert-butoxy-2,2,6,6-tetramethylpiperidine show that as expected the N-O bond is staggered with respect to the C-H bonds of the methoxy group in the former case, yet it eclipses a C-methyl b
POLYMERISATION INITIATOR
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Page/Page column 37, (2010/08/04)
The invention relates to novel O-dialkylamino-isoureas and polymerizable compositions comprising these O-dialkylamino-isoureas of compounds of the general formula (I). The invention further relates to the use of O-dialkylamino-isoureas as polymerization initiators, especially to prepare coatings or for controlled degradation of polyolefins.
The thermal reaction of sterically hindered nitroxyl radicals with allylic and benzylic substrates: Experimental and computational evidence for divergent mechanisms
Babiarz, Joseph E.,Cunkle, Glen T.,DeBellis, Anthony D.,Eveland, David,Pastor, Stephen D.,Shum, Sai P.
, p. 6831 - 6834 (2007/10/03)
The reaction of stable sterically hindered nitroxyl radicals with benzylic and allylic substrates was investigated. An allyloxyamine derivative was obtained by the reaction of 2 molar equiv of a nitroxyl radical with an unactivated alkene. Experimental an
Process for stabilizing ethylenically unsaturated compounds and stabilized monomer compositions
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, (2008/06/13)
A process for stabilizing an ethylenically unsaturated monomer or oligomer from premature polymerization is disclosed whereby a stabilizing amount of an N-hydroxy substituted hindered amine is added to said polymerizable monomer or oligomer. The ethylenically unsaturated monomer or oligomer encompass vinyl monomers or oligomers bearing at least one polymerizable moiety. The N-hydroxy substituted hindered amine inhibits premature polymerization in the liquid and/or vapor phase.
Prevention of oxidation in petrochemical extraction solvents
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, (2008/06/13)
A wide variety of hindered amine compounds are effective as antioxidant stabilizers to prevent the oxidation of liquid hydrocarbons and of oxygenated compounds, such as sulfolane or tetraethylene glycol, used as extraction solvents in the petroleum industry.
The influence of the polymer matrix on the reactions of the nitroxyl radical with aromatic amines
Griva, A. P.,Denisova, L. N.,Denisov, E. T.
, p. 1429 - 1432 (2007/10/02)
The kinetics of the reactions of 4-benzoyloxy-2,2,6,6-tetramethylpiperidin-1-yloxy radical () with six aromatic amines in benzene and polypropylene (PP) have been investigated.It has been established that the reactions proceed bimolecularly in the kinetic region.The rate constants and activation energies for the reactions, and the frequencies of the rotational and translational diffusion of the radical under the experimental conditions have been measured.It has been shown that, on passing from the solution to PP, the reaction rate constants diminish and the activation energies increase and that in PP the reactivities of the amines are levelled out.There is a correlation between the rate constants and the molecular mobilities in the PP - benzene system.The following rule has been established for the first time: the greater the volume of the reactant (the amine), the greater the difference between the rate constants and activation energies for the reaction in the liquid phase and in the polymer.These features of the reactions in the solid phase have been explained in terms of the concept of the "rigid cage".The energy barrier which must be overcome by the reactants in PP in order to assume orientations favourable for the reaction has been calculated from the experimental data ( Vor = 8.5 - 13.5 kJmol-1 ; 333 K ).It has been observed that Vor increases with increasing volume of the reactant.The Gibbs free energy necessary to rearrange the form of the PP cage when the reaction of the radical with an amine takes place in it has been determined ( 33 kJ mol-1).
Process for preparing nitroxyls of sterically hindered amines
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, (2008/06/13)
Nitroxyls of the formula STR1 where E1, E2, E3 and E4 are independently an organic radical so that the carbon atoms to which they are attached are each a quaternary carbon and T is a divalent radical are prepared by the oxidation of the corresponding amine in an inert organic solvent with a hydroperoxide in the presence of a metal carbonyl, metal oxide or metal alkoxide catalyst in high yield and purity. The nitroxyls may be directly reduced to the corresponding hydroxylamines by catalytic hydrogenation. The nitroxyls are useful as polymerization inhibitors and the hydroxylamines as polymer stabilizers.
Hydroxylamines derived from hindered amines
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, (2008/06/13)
Hydroxylamines derived from hindered amines are effective in stabilizing polyolefin compositions containing a stabilizer or mixture of stabilizers selected from the group consisting of the phenolic antioxidants, the hindered amine light stabilizers, the a
The Oxidative Properties of Nitroxy-radicals in Their Reactions with Sterically Hindered Hydroxylamines
Dikanov, S. A.,Grigor'ev, I. A.,Volodarskii, L. B.,Tsvetkov, Yu. D.
, p. 1696 - 1699 (2007/10/02)
A relative scale of the oxidative properties of cyclic nitroxy-radicals has been constructed and the influence of various structural factors on the oxidising capacity of the nitroxy-group in the radicals has been investigated.It is shown that the oxidative properties of the nitroxy-group in cyclic nitroxy-radicals become more pronounced with the increase in ring size.A relation has been established between the oxidative properties and the electron-accepting properties of functional groups separated from the nitroxy-group by two and more ?-bonds.
