?-Hydrohexafluoroisobutyryl fluoride ? A new system with a labile hydrogen atom

1964 ◽  
Vol 13 (2) ◽  
pp. 339-341
Author(s):  
Yu. A. Cheburkov ◽  
M. D. Bargamova ◽  
I. L. Knunyants
Keyword(s):  
Hydrogen Atom ◽  
Labile Hydrogen ◽  
Labile Hydrogen Atom ◽  
New System

Reactions of polyfluoronitroalkanes that contain a labile hydrogen atom

1974 ◽  
Vol 23 (11) ◽  
pp. 2421-2424 ◽  
Author(s):  
A. M. Krzhizhcvskii ◽  
N. S. Mirzabekyants ◽  
Yu. A. Cheburkov ◽  
I. L. Knunyants
Keyword(s):  
Hydrogen Atom ◽  
Labile Hydrogen ◽  
Labile Hydrogen Atom

The Interaction of Tetramethylthiuram Disulfide with Rubber and with Compounds Containing a Labile Hydrogen Atom

1960 ◽  
Vol 33 (2) ◽  
pp. 401-411 ◽  
Author(s):  
B. A. Dogadkin ◽  
V. A. Shershnev
Keyword(s):  
Hydrogen Atom ◽  
Carbon Disulfide ◽  
Three Dimensional ◽  
Radical Mechanism ◽  
Labile Hydrogen ◽  
Paramagnetic Resonance ◽  
Tetramethylthiuram Disulfide ◽  
Dimensional Network ◽  
Sulfur Addition ◽  
Labile Hydrogen Atom

Abstract In the interaction of TMTD with rubber, sulfur and nitrogen from the TMTD add to the rubber, a maximum being exhibited on the rate curve for sulfur addition. At the same time dimethyldithiocarbamic acid is formed which, in mixtures containing zinc oxide, becomes bound in the form of Zn-DDC but which decomposes to carbon disulfide and dimethylamine in mixtures containing magnesium and calcium oxides and in the absence of metallic oxides. In the absence of oxides or in the presence of CaO or MgO a less dense three dimensional network is formed and reversion takes place which is accelerated by carbon disulfide and dimethylamine. The degree of crosslinking increases with increase in content of 1,4 structural units while the amount of combined sulfur and the rate of accumulation of zinc dithiocarbamate diminish. Dithiocarbamic acid also forms in the interaction of TMTD with geraniol and isopropylbenzene. The thermal decomposition of TMTD to thiuram monosulfide, sulfur, tetramethylthiourea and carbon disulfide takes place in the absence of compounds with a labile hydrogen atom. The reaction proceeds through the stage of rupture of the S—S and C—;S bonds of TMTD to form free radicals. The radical mechanism of the reaction is confirmed by electronic paramagnetic resonance specta.

Absolute rate constants for hydrocarbon autoxidation. 25. Rate constants for hydrogen atom abstraction from alkanes by the tert-butylperoxy radical

1978 ◽  
Vol 56 (24) ◽  
pp. 3047-3053 ◽  
Author(s):  
J. H. B. Chenier ◽  
S. B. Tong ◽  
J. A. Howard
Keyword(s):  
Hydrogen Atom ◽  
Rate Constants ◽  
Kinetic Isotope Effect ◽  
Peroxy Radical ◽  
Hydrogen Atom Abstraction ◽  
Labile Hydrogen ◽  
Absolute Rate ◽  
Steric Strain ◽  
Kinetic Isotope ◽  
Tert Butyl Hydroperoxide

Rate constants for abstraction of secondary and tertiary hydrogens from structurally different alkanes by the tert-butylperoxy radical in solution at 30 °C have been determined by competitive experiments in the presence of tert-butyl hydroperoxide. Rate constants fall in the range 1 × 10−4to 9 × 10−4and 1 × 10−3–2 × 10−2 M−1 s−1 for secondary and tertiary aliphatic C—H bonds, respectively. The most reactive secondary hydrogen is, therefore, almost as reactive as the least reactive tertiary hydrogen. Differences in reactivity within a type of aliphatic C—H bond are governed by differences in steric hindrance to attack by the peroxy radical and by relief of steric strain upon removal of the labile hydrogen. Rate constants for reaction of perdeuterated methylcyclohexane and 3-methylpentane are much smaller than the values calculated from the maximum primary kinetic isotope effect for this reaction.

scholarly journals Synthesis and Properties of Peroxy Oligomers Obtained by Telomerization Effects of the Presence of Bases

2016 ◽  
Vol 5 (4) ◽  
pp. 261
Author(s):  
Michael M. Bratychak ◽  
Volodymyr B. Vostres ◽  
Marc J.M. Abadie
Keyword(s):  
Unsaturated Polyester ◽  
Diglycidyl Ether ◽  
Labile Hydrogen ◽  
Hydrogen Atoms ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Direct Titration ◽  
Mobile Hydrogen ◽  
One Step ◽  
Labile Hydrogen Atom

<p>New bifunctional oligomers bearing peroxy groups have been synthesized by telomerization in one step reaction. For obtaining oligoperoxides (PO) by telomerization method, epoxide compounds will react with substances containing labile hydrogen atom. Using the principle of stochiometric imbalance between diepoxy compounds and substances with mobile hydrogen atoms and employing a functional peroxide as telogen, the synthesis of PO was studied. 2,2–Di[4–(2,3–epoxy–1-propoxy)phenyl]–propane (diglycidyl ether of diphenylol propane - DGEDPP), 1,2–Di (2,3–epoxy–1-propoxy) ethane (diglycidyl ether of ethylene glycol - DGEEG) and 1,2–Epoxy–3–tert–butylperoxypropane (EP) have been synthesized by methods reported in the literature. Chemical structures have been confirmed by NMR and FTIR, number-average molecular weights M<sub>n</sub> of PO<sub>s</sub> by cryoscopy, active oxygen content [O]<sub>act</sub>. for PO<sub>s</sub> was determined by iodometry and epoxy number (<em>e.n</em>.) for PO<sub>s</sub> was measured via direct titration of PO samples. A 50% solution of potassium or sodium isopropylates in 2-propanol is used to catalyze the telomerisation. Different parameters such as ratio of components, temperature, reaction time have been optimized in vu to get well defined peroxy oligomers. The presence of peroxy groups in synthesized POs allows us to employ these compounds as curing agents for polymers containing unsaturated double bonds and may be used to improve performance of unsaturated polyester GFR systems.</p>

Alkyne oxidation III. Competitive features and degenerate branching

1970 ◽  
Vol 317 (1528) ◽  
pp. 41-53 ◽  
Keyword(s):  
Hydrogen Abstraction ◽  
Reactive Intermediates ◽  
Labile Hydrogen ◽  
Acyl Radical ◽  
Radical Species ◽  
Abstraction Reaction ◽  
Labile Hydrogen Atom ◽  
A Chain ◽  
Hydrogen Abstraction Reaction ◽  
Radical Attack

A comparison is made between the slow com bustions of propyne and butyne-2 which are degenerately branched and acetylene which is not. The relative rates of ‘oxidation’ radical attack on these alkynes and a number of the reactive intermediates formed in their slow combustions have been obtained from their separate and competitive oxidations. The results confirm that the same electrophilic radical species (hydroxyl or hydroperoxyl) is involved in the oxidations of acetylene, propyne and butyne-2. It is concluded that the branching intermediate is a peracid formed from an aldehyde in the case of propyne and an acyl radical in butyne-2 oxidation, which produces only traces of aldehydes, by the sequence: RCHO + X˙→ RĊO + HX ; RĊO + O 2 → RCO˙ 3 ; RCO˙ 3 + RʹH→ RCO 3 H + Rʹ˙ ; RCO 3 H → R˙ + CO 2 +˙OH, where X˙ is a chain carrier and RʹH a molecule with a labile hydrogen atom. In acetylene oxidation the hydrogen abstraction reaction is too slow to compete with alternative reactions of the acyl radical and hence it is not branched.

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