Rate of the retro‐Diels‐Alder dissociation of 1,2,3,6‐tetrahydropyridine over a wide temperature range

Sidhu, Sukh; Kiefer, J. H.; Lifshitz, Assa; Tamburu, Carmen; Walker, James A.; Tsang, Wing

doi:10.1002/kin.550230304

Cited by 14 publications

(1 citation statement)

References 28 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…KKS noted that Arrhenius extrapolation of either the Roquitte or the Herndon et al highpressure limit rate coefficient ͑k ϱ ͒ data to higher temperatures lies on or below the lowest temperature shocktube data, which are clearly in the fall-off regime. Similarities with the earlier shock-tube LS studies of the retro-DielsAlder decompositions of 1,2,3,6-tetrahydropyridine 14 and cyclohexene 3 were noted. In these two investigations, extrapolation of reliable low temperature k ϱ data also lies on or below the shock-tube fall-off k uni data.…”

Section: B Shock-tube Experiments and Resultssupporting

confidence: 84%

Vibrational energy transfer in shock-heated norbornene

Barker

King

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

Recently, Kiefer et al. ͓J. H. Kiefer, S. S. Kumaran, and S. Sundaram, J. Chem. Phys. 99, 3531 ͑1993͔͒ studied shock-heated norbornene ͑NB͒ in krypton bath gas using the laser-schlieren technique and observed vibrational relaxation, unimolecular dissociation ͑to 1,3-cyclopentadiene and ethylene͒, and dissociation incubation times. Other workers have obtained an extensive body of high-pressure limit unimolecular reaction rate data at lower temperatures using conventional static and flow reactors. In the present work, we have developed a vibrational energy transfer-unimolecular reaction model based on steady-state RRKM calculations and time-dependent master equation calculations to satisfactorily describe all of the NB data ͑incubation times, vibrational relaxation times, and unimolecular rate coefficients͒. The results cover the temperature range from ϳ300 to 1500 K and the excitation energy range from ϳ1 000 to 18 000 cm Ϫ1 . Three different models ͑based on the exponential step-size distribution͒ for the average downward energy transferred per collision, ͗⌬E͘ down were investigated. The experimental data are too limited to enable the identification of a preferred model and it was not possible to determine whether the average ͗⌬E͘ down is temperature dependent. However, all three ͗⌬E͘ down models depend linearly on vibrational energy and it is concluded that standard unimolecular reaction rate codes must be revised to include energy-dependent microcanonical energy transfer parameters. The choice of energy transfer model affects the deduced reaction critical energy by more than 2 kcal mol Ϫ1 , however, which shows the importance of energy transfer in determining thermochemistry from unimolecular reaction fall-off data. It is shown that a single set of Arrhenius parameters gives a good fit of all the low temperature data and the shock-tube data extrapolated to the high pressure limit, obviating the need to invoke a change in reaction mechanism from concerted to diradical for high temperature conditions. Some possible future experiments are suggested.

show abstract

Section: B Shock-tube Experiments and Resultssupporting

confidence: 84%

Vibrational energy transfer in shock-heated norbornene

Barker

King

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

The Retro–Diels–Alder Reaction PartI.CCDienophiles

Rickborn

1998

Organic Reactions

View full text Add to dashboard Cite

The Diels–Alder (“DA”) reaction is so familiar to organic chemists that the retro‐Diels–Alder or retro‐diene reaction (hereafter “rDA”) requires no conceptual introduction. However, a working definition is needed to indicate the coverage of this review. The intent is to include all reported examples of the general skeletal process excluded in this chapter. Any of the atoms in the starting material (cycloadduct) may be carbon or heteroatom, and substituents on all positions are allowed. In addition, any bond order available to the element in any oxidation state is included, as well as bonding to non‐nearest neighbor atoms (bicyclics, etc.). The volume of literature required separation of this review into two parts. Part I covers all expelled C–C dienophiles, i.e. those reactions that generate a new carbon‐carbon double or triple bond in the dienophile that is formed. Part II, to appear later, covers those expelled dienophiles in which one or both atoms is a heteroatom. Certain specific topics are intentionally omitted. These are: rDA reactions invoked under mass spectral conditions; rDA reactions of polymeric substrates; Electrocyclic processes, some of which are arguably very similar to rDA reactions (these are not addressed unless needed for clarification of an rDA sequence); and a thorough discussion of homo‐rDA reactions. CAS‐Online searches resulted in ca. 1,300 references, of which ca. 900 proved pertinent to the rDA topic as defined and delimited above. Active literature searching was halted in April 1995, but occasional more recent articles are included. Over 2,500 pertinent references were eventually found. Most were obtained by perusal of primary literature (articles) and secondary sources (books and reviews). Computer based search success was limited mainly by the failure of authors or abstractors to key‐word this topic, an especially common occurrence when the expelled dienophile was a simple substance such as N 2 or CO 2 . Overall, approximately 3,500 books, chapters, reviews, articles, and abstracts were consulted in an effort to make this review as comprehensive as possible. This was done with the certainty that some pertinent literature would be missed, tempered by the view that these omissions are probably also lost to any future rational search method. Many secondary sources proved valuable not only for in‐depth discussion of certain rDA reaction types, but also for providing comparisons with related topics. To assist the reader, these secondary sources are referenced (alphabetically by first author within broad subject areas) with a title or brief note on the topic(s) addressed. The first group lists earlier reviews with primary focus on rDA reactions, followed by items of Historical/General Interest, reviews that deal with Experimental Methods, DA reactions (general and specific), reviews of Related Topics (these impinge in more or less significant ways on rDA reactions), and general treatments of Theory and Mechanism.

show abstract

The Retro–Diels–Alder Reaction PartII. Dienophiles with One or More Heteroatom

Rickborn

1998

Organic Reactions

View full text Add to dashboard Cite

This review (Part II) is topically organized around the dienophile that is generated in a retro [4 + 2] reaction, and to the extent possible follows the principles adopted for Part I, which covers reactions in which both dienophile bonding centers are carbon atoms. The present chapter encompasses retro–Diels–Alder (rDA) reactions in which one or both of the dienophile reaction centers are heteroatoms. Any of the other atoms in the starting material (cycloadduct) may be carbon or heteroatom. Substituents on all positions are encompassed, and any bond order available to any oxidation state of an element is included, as is bonding to non‐nearest neighbor atoms (e.g., bicyclics). The reader is directed to Part I (Vol. 52) for general discussion of the rDA reaction, the features that affect rates and outcome, and the use of acids, bases, other catalysts, and scavengers. Certain subclassifications (e.g., processes proposed under MS conditions, polymer applications) of rDA reactions have been omitted from both sections; these topics are listed in the Introduction to Part I. Citations to over 100 reviews on various aspects of the rDA reaction are collected at the beginning of the References to Part I. Those that are especially pertinent to Part II will be repeated here, in the context of the particular dienophile under discussion. The decision to split the review of the rDA reaction into two parts was based on the volume of literature encountered, as outlined in the Introduction to Part I. Active literature searching was concluded for both Parts in April 1995, although occasional more recent references have been included.

show abstract

Rate of the retro‐Diels‐Alder dissociation of 1,2,3,6‐tetrahydropyridine over a wide temperature range

Cited by 14 publications

References 28 publications

Vibrational energy transfer in shock-heated norbornene

Vibrational energy transfer in shock-heated norbornene

The Retro–Diels–Alder Reaction PartI.CCDienophiles

The Retro–Diels–Alder Reaction PartII. Dienophiles with One or More Heteroatom

Contact Info

Product

Resources

About