The HERON reaction — Origin, theoretical background, and prevalence

2005 ◽  
Vol 83 (9) ◽  
pp. 1492-1509 ◽  
Author(s):  
Stephen A Glover ◽  
Arvi Rauk ◽  
Jeanne M Buccigross ◽  
John J Campbell ◽  
Gerard P Hammond ◽  
...  
Keyword(s):  
Gas Phase ◽  
Theoretical Basis ◽  
Historical Perspective ◽  
Theoretical Background ◽  
Amide Bond ◽  
Chemical Transformations ◽  
Amide Nitrogen ◽  
Gas Phase Reactions ◽  
Physical Organic ◽  
Computational Work

The origin of the HERON reaction is reviewed from a historical perspective and shown to have its foundation in the unusual properties of bisheteroatom-substituted amides, so-called anomeric amides. The reaction involves migration of anomerically destabilized oxo-substituents on an amide nitrogen to the amide carbon and dissociation of the amide bond. Computational work providing a theoretical basis for the reaction is presented, together with physical organic measurements that support results therefrom. The rearrangement has been observed in a number of chemical transformations of N-alkoxy-N-aminoamides, reactions of 1-acyloxy-1-alkoxydiazenes, N-alkoxy-N-aminocarbamates, N-alkoxyhydroxamic acids, as well as in the gas-phase reactions of N-acyloxy-N-alkoxyamides.Key words: HERON reaction, anomeric amides, rearrangements, hindered esters, concerted reactions.

Thermodynamics of some model reactions useful for understanding theoretical background of correlation analysis

1990 ◽  
Vol 55 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Zdeněk Slanina
Keyword(s):  
Correlation Analysis ◽  
Gas Phase ◽  
Energy Characteristic ◽  
Room Temperature ◽  
Vibrational Mode ◽  
Theoretical Background ◽  
Partition Functions ◽  
Gas Phase Reactions ◽  
Model Reactions

Six isodesmic gas-phase reactions have been studied out of which three reactions represent a redistribution of two methyl substituents and the other three represent a redistribution of two chloro substituents between two benzene nuclei. The thermodynamics of these reactions has been evaluated on the basis of the partition functions and observed heats of formation at room temperature. The partition functions have been constructed with the help of observed structural and vibrational data. If the internal rotation was present, the frequence of the corresponding torsional vibrational mode has been determined by a fit to the observed thermodynamic data.The energy characteristic calculated for these reactions (the standard change of Gibbs free energy ΔGT0, enthalpy ΔHT0, enthalpy at absolute zero ΔH00, and potential energy change ΔE) have been evaluated from the standpoint of their applicability to organic correlation analysis. The studies form a part of a wider project, and, in accordance with the findings already presented within this project elsewhere and concerning reactions of fluorobenzenes, they indicate a certain preferred role of the term ΔH00 in these contexts.

The theoretical background for the effective development of beef raising

2020 ◽  
Vol 18 (9) ◽  
pp. 1738-1749
Author(s):  
N.L. Titov ◽  
M.M. Nizamutdinov ◽  
G.S. Klychova
Keyword(s):  
Beef Cattle ◽  
Economic Efficiency ◽  
Performance Indicators ◽  
Theoretical Basis ◽  
Theoretical Background ◽  
Theory And Practice ◽  
Cattle Breeding ◽  
Cattle Industry ◽  
Effective Development ◽  
Cattle Husbandry

Subject. This article explores the theoretical basis of the economic efficiency of production and classifies the performance figures of beef cattle husbandry. Objectives. The article aims to define a system of indicators of beef cattle husbandry economic efficiency. Methods. For the study, we used a comparative analysis. Conclusions and Relevance. To assess the economic efficiency of agriculture production, it is necessary to use a set of indicators by beef cattle breeding sub-sector. The system of economic performance indicators of production needs to be transformed into a summarizing indicator. The results of the study can be applied in the theory and practice of determining the economic efficiency of the beef cattle industry.

Gas-Phase Reactions

1981 ◽  
Author(s):  
Victor N. Kondratiev ◽  
Evgeniĭ E. Nikitin
Keyword(s):  
Gas Phase ◽  
Gas Phase Reactions

Influence of Gas Mixing and Heating on Gas-Phase Reactions in GaN MOCVD Growth

2012 ◽  
Vol 1 (1) ◽  
pp. P46-P53 ◽  
Author(s):  
Ran Zuo ◽  
Haiqun Yu ◽  
Nan Xu ◽  
Xiaokun He
Keyword(s):  
Gas Phase ◽  
Gas Mixing ◽  
Gas Phase Reactions ◽  
Mocvd Growth

Gas Phase Reactions Activated by Nuclear Processes

1957 ◽  
Vol 79 (17) ◽  
pp. 4609-4616 ◽  
Author(s):  
Adon A. Gordus ◽  
John E. Willard
Keyword(s):  
Gas Phase ◽  
Gas Phase Reactions ◽  
Nuclear Processes

Nanocomposite ceramic powder production by laser-induced gas-phase reactions

1993 ◽  
Vol 168 (2) ◽  
pp. 177-181 ◽  
Author(s):  
E Borsella ◽  
S Botti ◽  
R Alexandrescu ◽  
I Morjan ◽  
T Dikonimos-Makris ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ceramic Powder ◽  
Gas Phase Reactions ◽  
Powder Production

Methylene. III. Gas phase reactions with 1-chloropropane

1969 ◽  
Vol 312 (1509) ◽  
pp. 141-161 ◽  
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Hydrogen Abstraction ◽  
The Other ◽  
Gas Phase Reactions ◽  
Other Hand ◽  
Chlorine Substituent ◽  
High Degree ◽  
Singlet Methylene

The work described in this and the following paper is a continuation of that in parts I and II, devoted to elucidation of the mechanism of the reactions of methylene with chloroalkanes, with particular reference to the reactivities of singlet and triplet methylene in abstraction and insertion processes. The products of the reaction between methylene, prepared by the photolysis of ketene, and 1-chloropropane have been identified and estimated and their dependence on reactant pressures, photolysing wavelength and presence of foreign gases (oxygen and carbon mon­oxide) has been investigated. Both insertion and abstraction mechanisms contribute significantly to the over-all reaction, insertion being relatively much more important than with chloroethane. This type of process appears to be confined to singlet methylene. If, as seems likely, there is no insertion into C—Cl bonds under our conditions (see part IV), insertion into C2—H and C3—H bonds occurs in statistical ratio, approximately. On the other hand, the chlorine substituent reduces the probability of insertion into C—H bonds in its vicinity. As in the chloroethane system, both species of methylene show a high degree of selectivity in their abstraction reactions. We find that k S Cl / k S H >7.7, k T Cl / k T H < 0.14, where the k ’s are rate constants for abstraction, and the super- and subscripts indicate the species of methylene and the type of atom abstracted, respectively. Triplet methylene is discriminating in hydrogen abstraction from 1-C 3 H 7 Cl, the overall rates for atoms attached to C1, C2, C3 being in the ratios 2.63:1:0.

scholarly journals Gas-Phase Reactions between Urea and Ca2+:  The Importance of Coulomb Explosions

2004 ◽  
Vol 108 (46) ◽  
pp. 10080-10088 ◽  
Author(s):  
Inés Corral ◽  
Otilia Mó ◽  
Manuel Yáñez ◽  
Jean-Yves Salpin ◽  
Jeanine Tortajada ◽  
...  
Keyword(s):  
Gas Phase ◽  
Gas Phase Reactions
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