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2 edition of Aliphatic nitroxyl radicals as antifatigue agents for rubbers. found in the catalog.

Aliphatic nitroxyl radicals as antifatigue agents for rubbers.

Lakshman Premal Nethsinghe

Aliphatic nitroxyl radicals as antifatigue agents for rubbers.

by Lakshman Premal Nethsinghe

  • 380 Want to read
  • 34 Currently reading

Published by University of Aston. Department of Chemistry in Birmingham .
Written in English


Edition Notes

Thesis (PhD) - University of Aston in Birmingham, 1982.

ID Numbers
Open LibraryOL13776131M

Design Concept of α-Hydrogen Nitroxyl Radicals 38 1: pushing out the substituent • R 6 push R 5 away from the plane.-> H abstraction by another molecule is inhibited. 2: 1,3-allylic strain • Nitrone formation is disfavored due to A(1,3) strain. New α-hydrogen nitroxyl radicals Design concept Amar, M. et al. Nat. Commun. , 6, 1. Compare Nitroxyl to other products. Nitroxyl is formulated with L-citrulline instead of L-arginine. L-citrulline is a far safer and more effective precursor to nitric oxide. Nitroxyl contains plant-derived compounds found in hawthorn, cocoa and pomegranate, which have all been shown to boost nitric oxide.

Aliphatic nitroxyl radicals and derived hydroxylamines are almost ineffective as antifatigue agents when compounded into rubbers by a conventional procedure. are effective antifatigue agents. Nitroxyl radicals containing the diphenylmethyl group as one of the substituents at the nitroxyl group are stable compounds that can be isolated in an individual state.N-(2-Hydroxymethylphenylcyclohexyl)-N-diphenylmethylnitroxyl was characterized by X .

Nitroxyl Radicals. Hydroxylamines, Oximes and Hydroxamic Acids () Carlo Galli. E-mail address: @ Fax: + 06 Università ‘La Sapienza’ and IMC‐CNR Sezione Meccanismi di Reazione, Dipartimento di Chimica, Roma, Italy, organic radical contrast agents [2]. 2,2,5,5-tetraethyl and -dispirocyclohexyl substituted 3-pyrroline nitroxyl radicals have been effectively incorporated into amino acids for use as spin labels to study protein synthesis [4]. The kinetics of reduction of variously substituted pyrrolidine nitroxyl radicals has been studied using electron.


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Aliphatic nitroxyl radicals as antifatigue agents for rubbers by Lakshman Premal Nethsinghe Download PDF EPUB FB2

Both processes have the effect of increasing the rate of autoxidation by introducing CH3 CH3 L I --~CHCH2CH2~CH-- ~1 lamine (!)) as antifatigue agents, the mechanistic sequence involved in its action has been compared in the present study with an aliphatic hindered amine known to give a stable nitroxyl radical [bispiperidine (lla)] which has Cited by: Aliphatic nitroxyl radicals as antifatigue agents for rubbers By Lakshman P.

Nethsinghe OAI identifier: oai:or: Lakshman P. Nethsinghe. Aliphatic nitroxyl radicals as antifatigue agents for rubbers Author: Nethsinghe, Lakshman P. ISNI: Awarding Body: University of Aston in Birmingham Current Institution: Aston University Date of Award: Availability of Full Text: Author: Lakshman P.

Nethsinghe. INTRODUCTION It has been previously suggested [1, 2] that there is a mechanistic relationship between the role of nitroxyl radicals as antifatigue agents and as melt stabilisers in polymers. The broad outline of the catalytic anti- oxidant mechanism involved is now understood and is summarised in Scheme 1 for by: 7.

Aliphatic amines: a study of their spectrochemical series and of some of their reactions with anhydrous metal halides Aliphatic nitroxyl radicals as antifatigue agents for rubbers Author: Nethsinghe, L. P., Student thesis: Doctoral Thesis › Doctor of Philosophy.

A mechanistic study of esters of thiodipropionic acid as antioxidants. Dweik and G. Scott () Mechanisms of Antioxidant Action: Aromatic Nitroxyl Radicals and Their Derived Hydroxylamines as Antifatigue Agents for Natural Chemistry and Technology: SeptemberVol.

57, No. 4, pp. There is an interesting and important difference between the behaviour of the nitrosamines as anti-fatigue agents in rubbers and as uv stabilisers in polypropylene. Under the former conditions, the initial concentration of nitroxyl in the polymer is approximately ~o of the nitrosamine added, whereas, during the processing of PP, almost 5 ~o.

In the short time since the first nitroxyl radical was obtained ina new branch of chemical science has arisen and taken shape-the chemistry of stable nitroxyl radicals. The present book was written by E. Rozantsev, one of the pioneers. The chemical structure of the nitroxyl ether determines the stability of the N–O–C bond and consequently the thermal stability and the thermally induced split between the N–O or the O–C bond.

However, the generation of radicals from nitroxyl derivatives is the key step in all these processes. Nitroxylethers as flame retardants. Nitroxyl radicals synthesis using 3-bromocarboxy-2,2,5,5-tetramethyl-2,5-dihydropyrroleoxyl, Izv AN SSSR Ser Khim 2: Google Scholar Kosman DJ, Piette LH () Nitroxide spin labels: new synthetic sequences, Chem Communs Google Scholar.

When there is a proton on the carbon α to the nitrogen, hydroxylamines are oxidized to nitrones. However, when the α carbons are quaternary or the double bond of nitrones would be anti-Bredt (bridgehead), the partially oxidized nitroxyl radicals can exist as stable compounds. These nitroxyl radicals are known to catalyze oxidation reactions.

The number of nitroxyl radicals formed at the initial stage of the reaction is proportional to the exposure dose.

The rapidly reached limit for the 4,4'dimethoxydiphenylamine kinetic curve is probably associated with further conversions of the corresponding nitroxyl radical. so 60 40 Reeaf ue un:t~ /s z 4 5 3 6 it t 0 0 4 8 12 16 20 t,min zo. A series of nitroxyl radicals -products of the addition of shortlived radicals [(NO2)3Ċ, CH3Ċ(NO2)2, (CH3)2ĊNO2, (CH3)3C., (CH3)3CO, ho.

and N3.] to phenyl-tert-butylnitrone, used as radical trap — was produced. The identification of the nitroxyl radicals obtained was performed on the basis of an analysis of the ESR spectra, using the method of countersynthesis. A series of nitroxyl.

For the reaction of the nitroxyl radicals with other radicals, rate constants are found to be quite similar (about 5 × 10 8 M-1 s-1) for several alkyl radicals and for the tert-butyloxyl radical and less than 10 5 M-1 s-1 for alkylperoxyl radicals. Because of the minor importance of radical reactions with the sterically hindered amines (HALS.

Nitroxyl (common name) or azanone (IUPAC name) is the chemical compound HNO. It is well known in the gas phase. Nitroxyl can be formed as a short-lived intermediate in the solution phase. The conjugate base, NO −, nitroxide anion, is the reduced form of nitric oxide (NO) and is isoelectronic with dioxygen.

The bond dissociation energy of H–NO is kcal/mol, which is. The explosive nitramine RDX (1,3,5-trinitrohexahydro-s-triazine) is thought to decompose largely by homolytic N–N bond cleavage, among other possible initiation reactions. Density-functional theory (DFT) calculations indicate that the resulting secondary aminyl (R2N) radical can abstract an oxygen atom from NO2 or from a neighboring nitramine molecule, producing an aminoxyl.

In the short time since the first nitroxyl radical was obtained ina new branch of chemical science has arisen and taken shape-the chemistry of stable nitroxyl radicals. The present book was written by E. Rozantsev, one of the pioneers in this field and a prominent specialist on stable radicals at the Division of Chemical and.

The present study describes a novel non-radioactive methodology for in vivo non-invasive, real-time imaging of blood–brain barrier (BBB) permeability for conventional drugs, using nitroxyl radicals as spin-labels and magnetic resonance imaging (MRI).

Thereby, the free amine precursors of the nitroxyl radicals (1) would be more efficient anti-fatigue agents than the free amine precursors of the nitroxyl radicals (4). Therefore, the diarylamines in general, such as the BLE and AOare more efficient anti-fatigue agents than the TMQ.

Title of Thesis: The Behavior of Substituted Diaryl Nitroxyl Radicals and Their Derivatives as Antifatigue Agents for Rubbers The University of Aston in Birmingham, England; Supervisor: * No Access to this Thesis for Two Years. From March 83 to March For Patent Registration.

it was Financed by (NRDC). Type part of your institution name for a list of matches. If your institution is not listed, please contact your librarian. Mechanism of Alcohol Oxidation Mediated by Copper(II) and Nitroxyl Radicals Bradford L. Ryland, Scott D. McCann, Thomas C.

Brunold, and Shannon S. Stahl Journal of the American Chemical Society (34), Chiral nitroxyl radicals could be simultaneously visualized with the labeling of isotopic nitrogen. Chiral nitroxyl radicals, hydroxylmethyl-2,2,5,5-tetramethylpyrrolidineoxyl, were visualized using the method of simultaneous EPR imaging, which refers to the visualization of two kinds of molecules with unpaired electrons in a single image scan.