Energy partitioning in flourine-atom bimolecular reactions with saturated and unsaturated hydrocarbons

Nonstatistical dynamics is important for many chemical reactions. The Rice-Ramsperger-Kassel-Marcus (RRKM) theory of unimolecular kinetics assumes a reactant molecule maintains a statistical microcanonical ensemble of vibrational states during its dissociation so that its unimolecular dynamics are time independent. Such dynamics results when the reactant's atomic motion is chaotic or irregular. Intrinsic non-RRKM dynamics occurs when part of the reactant's phase space consists of quasiperiodic/regular motion and a bottleneck exists, so that the unimolecular rate constant is time dependent. Nonrandom excitation of a molecule may result in short-time apparent non-RRKM dynamics. For rotational activation, the 2J + 1 K levels for a particular J may be highly mixed, making K an active degree of freedom, or K may be a good quantum number and an adiabatic degree of freedom. Nonstatistical dynamics is often important for bimolecular reactions and their intermediates and for product-energy partitioning of bimolecular and unimolecular reactions. Post–transition state dynamics is often highly complex and nonstatistical.

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Semi-empirical calculation of activation energy for a number of bimolecular reactions. Part I

Journal de Chimie Physique ◽

10.1051/jcp/1971680753 ◽

1971 ◽

Vol 68 ◽

pp. 753-757 ◽

Cited By ~ 1

Author(s):

M.B. Pahari ◽

Rama Basu

Keyword(s):

Activation Energy ◽

Bimolecular Reactions ◽

Semi Empirical

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Intramolecular interactions in N-methylsalicylaldimine and its anion. A semi-empirical energy partitioning analysis

Journal de Chimie Physique ◽

10.1051/jcp/1981780127 ◽

1981 ◽

Vol 78 ◽

pp. 127-130 ◽

Cited By ~ 4

Author(s):

Salavatore Millefiori ◽

Arcangelo Millefiori

Keyword(s):

Energy Partitioning ◽

Intramolecular Interactions ◽

Semi Empirical

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Nickel-Catalyzed Regioselective Hydroalkylation of 1,3-Dienes with Hydrazones

10.26434/chemrxiv.8266643.v1 ◽

2019 ◽

Author(s):

Leiyang Lv ◽

Dianhu Zhu ◽

Zihang Qiu ◽

Jianbin Li ◽

Chao-Jun Li

Keyword(s):

Catalytic Method ◽

Unsaturated Hydrocarbons ◽

Carbon Nucleophiles ◽

Aryl Aldehydes ◽

Aldehydes And Ketones ◽

Sterically Hindered

Hydroalkylation of unsaturated hydrocarbons with unstablized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydroalkylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acted as both the sources of unstabilized carbanions and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a novel and reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.

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Estimate of Hyperconjugation Strength in Alkylaromatics and Unsaturated Hydrocarbons Derived from Refractometric Data

Current Organic Chemistry ◽

10.2174/1385272823666191108100747 ◽

2020 ◽

Vol 23 (23) ◽

pp. 2598-2613

Author(s):

Boris A. Zaitsev

Keyword(s):

Quantitative Estimation ◽

Physical Phenomenon ◽

Unsaturated Hydrocarbons ◽

Resonance Effects ◽

Alkyl Derivatives ◽

Retrospective View ◽

Scientific Papers ◽

Polycyclic Aromatic ◽

Qualitative Measure ◽

Steric Inhibition Of Resonance

: A retrospective view of exaltation of refraction observed for many unsaturated and aromatic compounds demonstrates that this physical phenomenon is undeservedly considered only as a qualitative measure of conjugation. This mini-review discusses numerous papers by the author that have been published earlier in inaccessible periodicals and collections of scientific papers. Using a great number of illustrations, the author shows that this parameter can be successfully used for quantitative estimate of resonance effects in organic and polymer chemistry. The methods for derivation of strictly additive atomic and group refraction constants are described; these constants were subsequently used as a tool that allowed quantitative estimation of resonance effects in mono-, di-, tri- and polyalkylbenzenes, alkylnaphthalenes, some alkyl derivatives of unsaturated hydrocarbons. These effects cause strictly fixed increase in refraction of carbon atoms in different structural modifications (graphene, fullerene, diamond) and in polycyclic aromatic hydrocarbons. The relevant results regarding quantitative estimation of degree of steric inhibition of resonance in sterically hindered ortho-dialkylbenzenes, 1,2,3- trialkyl-, 1,2,3,4-tetraalkyl-, and 1,2,3,4,5-polyalkylbenzenes accumulated by the author are summarized.

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Selfhydrogenation of unsaturated hydrocarbons on transition metals partially covered with preadsorbed oxygen

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19711205 ◽

1971 ◽

Vol 36 (3) ◽

pp. 1205-1211 ◽

Cited By ~ 2

Author(s):

H. Kadlecová ◽

V. Kadlec ◽

Z. Knor

Keyword(s):

Transition Metals ◽

Unsaturated Hydrocarbons

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Intermolecular hydrogen transfer in unsaturated hydrocarbons induced by dimeric titanocene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19832924 ◽

1983 ◽

Vol 48 (10) ◽

pp. 2924-2936 ◽

Cited By ~ 5

Author(s):

Karel Mach ◽

Lidmila Petrusová ◽

Helena Antropiusová ◽

Vladimír Hanuš ◽

František Tureček ◽

...

Keyword(s):

Hydrogen Transfer ◽

Titanium Content ◽

Esr Spectra ◽

Stable Complex ◽

Catalytic Complex ◽

Substitution Reactions ◽

Unsaturated Hydrocarbons ◽

Linear Alkanes ◽

Saturated And Aromatic Hydrocarbons ◽

Intermolecular Hydrogen Transfer

μ-(η5 : η5-Fulvalene)-di-μ-hydrido-bis(η5-cyclopentadienyltitanium) and μ-(η5 : η5-fulvalene)-μ-chloro-μ-hydrido-bis(cyclopentadienyltitanium) form a thermally stable complex which catalyzes the intermolecular hydrogen transfer in unsaturated hydrocarbons, in addition to isomerizations and cyclizations. Cyclic hydrocarbons disproportionate under catalysis to saturated and aromatic hydrocarbons, while linear olefins yield predominantly linear alkanes and high molecular weight tar. The catalyst enables the hydrocarbon system to approach the thermodynamic equilibrium through a series of substitution reactions between alkyl- and allyltitanocene-like species and olefins and dienes. The catalytic complex was characterized by UV and ESR spectra. About one half of overall titanium content could be converted to mononuclear η3-allyltitanocene-like species, stable up to 400 °C. This exceptional thermal stability is ascribed to a firmly bound allyl containing ligand.

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Hydrogenation-dehydrogenation and cleavage functions of hydrorefining catalysts studied by the reaction of tetrahydrothiophene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19862770 ◽

1986 ◽

Vol 51 (12) ◽

pp. 2770-2780 ◽

Cited By ~ 1

Author(s):

Alexandra Drahorádová ◽

Miroslav Zdražil

Keyword(s):

Activated Carbon ◽

Catalyst Surface ◽

Bond Cleavage ◽

Unsaturated Hydrocarbons ◽

Cleavage Reactions

The reaction of tetrahydrothiophene in a stream of nitrogen was used to study the relations between dehydrogenation and C-S cleavage reactions on sulphided Co-Mo/Al2O3 catalysts. The course of the reaction was compared for Co-Mo catalysts supported on alumina and activated carbon, for alumina alone as well as for a Pt/C catalyst. The effect of substitution of nitrogen for hydrogen, of the addition of water to the feed, of pre-sulphidation of catalysts and their deactivation by coking on the rate and selectivity of the reaction were also investigated. The results showed that hydrogenation-dehydrogenation and dehydrosulphurization activity of the sulphide catalysts have the same origin. Hydrogen accelerates dehydrosulphurization on the sulphide catalysts by removing sulphur and unsaturated hydrocarbons formed on catalyst surface by C-S bond cleavage reactions.

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Bimolecular Reactions, Transition-State Theory

10.1093/oso/9780198805014.003.0006 ◽

2018 ◽

Author(s):

Niels Engholm Henriksen ◽

Flemming Yssing Hansen

Keyword(s):

Transition State ◽

Saddle Point ◽

Transition State Theory ◽

Classical Mechanics ◽

Small Degree ◽

State Theory ◽

Reaction Coordinate ◽

Partition Functions ◽

Bimolecular Reactions ◽

Activated Complex

This chapter discusses an approximate approach—transition-state theory—to the calculation of rate constants for bimolecular reactions. A reaction coordinate is identified from a normal-mode coordinate analysis of the activated complex, that is, the supermolecule on the saddle-point of the potential energy surface. Motion along this coordinate is treated by classical mechanics and recrossings of the saddle point from the product to the reactant side are neglected, leading to the result of conventional transition-state theory expressed in terms of relevant partition functions. Various alternative derivations are presented. Corrections that incorporate quantum mechanical tunnelling along the reaction coordinate are described. Tunnelling through an Eckart barrier is discussed and the approximate Wigner tunnelling correction factor is derived in the limit of a small degree of tunnelling. It concludes with applications of transition-state theory to, for example, the F + H2 reaction, and comparisons with results based on quasi-classical mechanics as well as exact quantum mechanics.

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