The heat of oxidation of 1,2-di-n-butylhydrazine to azo-n-butane

Engel, Paul S.; Owens, Walter H.; Wang, Chengrong

doi:10.1021/j100142a036

Cited by 7 publications

(3 citation statements)

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“…The degree to which “hydrazyl resonance” accelerates cyclization of 14 might be evaluated if one knew the thermochemistry of simple intermolecular additions like methyl radical to ethylene and to diimide. Experimental values for the ethylene case are readily available, but the heats of formation (Δ H f ) of both diimide − and hydrazyl radicals − are not well established. Even if Δ H f of hydrazyl itself were well known, it is possible that methyl substitution would stabilize this radical, similar to MeNHCH 2 • versus H 2 NCH 2 • …”

Section: Discussionmentioning

confidence: 99%

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Thermolysis and Photolysis of a γ-Azoperester. Cyclization of γ-Azo and γ-Perester Radicals

Engel

Smith

1997

J. Am. Chem. Soc.

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Thermolysis of azoperester 5 affords γ-azo radical 14, which cyclizes to hydrazyl radical 15 at a rate of 1.3 × 109 M-1 s-1 at 110 °C. Our experimental results are consistent with loss of a methyl radical from 15 to afford 2-pyrazoline 9, which is oxidized in situ by the starting 5 to pyrazole 6. This unusual and endothermic β-scission can be rationalized if the odd electron in 15 is better aligned with the CH3−C bond than with the weaker t-Bu−N bond. The fact that 5-endo cyclization of 14 is 5 × 107 faster than that of the analogous olefinic radical 30 led us to carry out ab initio calculations on simplified structures. ΔH ⧧ for methyl radical addition to diimide is only 0.84 kcal/mol lower than for addition to ethylene and the exothermicity is only 3.5 kcal/mol greater. However, the smaller CNN than CCC bond angle leads to a ΔH ⧧ 13.3 kcal/mol lower for 5-endo cyclization of 4,5-diazapenten-1-yl than for the analogous 4-pentenyl radical. Photolysis of 5 selectively cleaves the azo group, producing γ-perester radical 20. This species undergoes intramolecular attack on the peroxide linkage to form lactone 23 at a rate of 1.5 × 104 s-1 at 22 °C. The cyclization rate of 20 is slow enough that 5 could be used as a photochemical bifunctional initiator, but cyclization of 14 to the azo group is so rapid that this radical would only rarely attack a monomer.

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Section: Discussionmentioning

confidence: 99%

“…1 H NMR (C6D6): δ 0.99 (s, 6H), 1.12 (s, 9H), 1.15 (s, 9H), 2.05 (m, 2H), 2.15 (m, 2H). 13 C NMR: δ 24.37 (Me 2), 26.14 (t-Bu), 26.27 (CH2), 26.75 (t-Bu), 35.17 (CH2), 66.51 (C), 67.00 (C), 83.30 (C), 171.3 (CO). IR (neat): 2975, 1779 cm -1 .…”

Section: Methodsmentioning

confidence: 99%

Thermolysis and Photolysis of a γ-Azoperester. Cyclization of γ-Azo and γ-Perester Radicals

Engel

Smith

1997

J. Am. Chem. Soc.

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“…In accord with earlier studies, the results of these calculations revealed that further investigations of the thermochemistry of hydrazines and amines are necessary. As acknowledged by the authors, data on the enthalpy of formation of alkyl hydrazines are sparse; for example, data are available for 1,2-di-n-butylhydrazine [124] but are not available for any other butylated species. Data are available, however, for mono-, di-and tributyl amine.…”

Section: Issuementioning

confidence: 99%

Interplay of thermochemistry and structural chemistry, the journal (volume 24, 2013, issues 5–6) and the discipline

2014

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Electronic Structure of Hydrazo, Azo and Azoxy Compounds

Basch

Hoz

2009

Patai's Chemistry of Functional Groups

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Introduction Methods A VB Description of NH 2  NH 2 A VB Description of NH  NH Azoxy Compounds: Structure and Energetics Azoxy: Isomerization Reaction Mechanism Azoxy: Synthesis Reaction Mechanism Acknowledgements

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The heat of oxidation of 1,2-di-n-butylhydrazine to azo-n-butane

Cited by 7 publications

References 1 publication

Thermolysis and Photolysis of a γ-Azoperester. Cyclization of γ-Azo and γ-Perester Radicals

Thermolysis and Photolysis of a γ-Azoperester. Cyclization of γ-Azo and γ-Perester Radicals

Interplay of thermochemistry and structural chemistry, the journal (volume 24, 2013, issues 5–6) and the discipline

Electronic Structure of Hydrazo, Azo and Azoxy Compounds

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