Heat content, free-energy function, entropy, and heat capacity of ethylene, propylene, and the four butenes to 1,500 degrees-K

Kilpatrick, John E.; Pitzer, Kenneth S.

doi:10.6028/jres.037.008

Cited by 57 publications

(5 citation statements)

References 12 publications

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“…It was indicated earlier that the values of V predicted by these NMR relaxation studies agreed favorably with literature values for cis-2butene, trans-2-butene, and isobutene (see Table V). [22][23][24][25] Calculated values agree within 15-20% (generally 0.1-0.3 kcal low) of reported literature values. The applicability of the method to more complex molecules where standard optical microwave techniques are not amenable however is emphasized.…”

Section: Resultssupporting

confidence: 76%

Carbon-13 spin relaxation and methyl rotation barriers in the methylethylenes

Collins¹,

Alger²,

Grant³

et al. 1975

J. Phys. Chem.

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Methylethylene Nuclear Relaxation Times 2031 viously reported for this transition. A definitive placement of the 1La band in this crystal, however, will have to await a somewhat higher resolution and probably low-temperature study of the type reported here. Moreover, the location of the band in phenazine itself will have to rest on a more detailed study of the uncomplexed material than has been reported to date.11,15,19 Until such a study has been carried out, it is probably somewhat premature to speculate on the ordering of the 1Lb and 1La bands in phenazine on the basis of more-or-less qualitative observations of the crystal absorption of phenazine currently available.24 References and Notes(1) This work has been partially supported by a grant from the National Institutes of Health.

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Section: Resultssupporting

confidence: 76%

Carbon-13 spin relaxation and methyl rotation barriers in the methylethylenes

Collins¹,

Alger²,

Grant³

et al. 1975

J. Phys. Chem.

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“…The magnitude of transition state torsional energy contributions to ΔΔ G * from substrate bonds can be estimated by comparing ground state CH 3 −C torsional barriers for methyl-substituted alkenes with the barriers of the corresponding epoxides: propylene oxide, 2.56 kcal/mol;31c 1-propene, 1.95 kcal/mol;31a trans -2-butene oxide, 2.44 kcal/mol;31d trans -2-butene 1.95 kcal/mol;31a cis -2-butene oxide, 1.61 kcal/mol;31e cis -2-butene, 0.75 kcal/mol 31b. According to these examples, the torsional component of ground state energy will increase by ca.…”

Section: Torsional Effects In Epoxidationsmentioning

confidence: 99%

Torsional, Rotor, and Electronic Effects in 4-tert-Butylmethylenecyclohexane Epoxidations and Osmylations

et al. 1996

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The axial epoxidation preference for 2-substituted 4-tert-butylmethylenecyclohexanes is attributed to a combination of small effects, including existing bond torsion and rotor effects. Contributions from developing bond torsion are smaller and may be negligible. Cieplak (σ-σ*) effects are too small to identify in most of the epoxidations, but a marginal effect could be present according to comparisons of isosteric systems 11a and 15a or 19a and 19b. Dimethyldioxirane epoxidations and osmylations are more sensitive to steric factors, resulting in a trend for equatorial attack.

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“…These phenomena remind us of the old concept of gear motion, which Pitzer and his collaborators devised a long time ago to explain the thermodynamical data of some organic molecules. 4 A classical example of the molecule, in which Pitzer anticipated a gear motion was taking place was cis-2-butene: CH 3 CHQCHCH 3 . However, Kondo et al 5 concluded by a careful study of microwave spectroscopy that the most stable conformation of the methyl groups in this molecule was such that one of the C-H bonds of each of the two methyl groups eclipsed the CQC double bond, namely of C 2v symmetry.…”

Section: Introductionmentioning

confidence: 99%

Chirality of and gear motion in isopropyl methyl sulfide: A Fourier transform microwave study

Hirota

Sakieda

Kawashima

2010

Phys. Chem. Chem. Phys.

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Isopropyl methyl sulfide (CH(3))(2)CHSCH(3) was investigated by Fourier transform microwave spectroscopy. Two rotational isomers gauche and trans were detected. The rotational spectra of gauche were found fit to an asymmetric rotor pattern, except for being split by the internal rotation of CH(3) attached to S with the potential barrier V(3) of 601.642 (65) cm(-1) and for exhibiting the effect of tunneling between the two equivalent gauche forms in a few high-K transitions. The tunneling was discussed from a viewpoint of chirality. The trans spectra appeared generally similar to those of gauche, with V(3) to the S-CH(3) internal rotation of 559.00 (11) cm(-1), but satellite lines accompanied the ground torsional state lines in some high-K transitions. These satellites were ascribed to the excited state of the C(isop)-S torsion. In fact, the potential function for this torsion was shown by an ab initio calculation to be flat or even of double minima around the trans position, which was presumably caused by a gear coupling between the two methyl groups of the isopropyl group and the one in the S-CH(3).

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Heat content, free-energy function, entropy, and heat capacity of ethylene, propylene, and the four butenes to 1,500 degrees-K

Cited by 57 publications

References 12 publications

Carbon-13 spin relaxation and methyl rotation barriers in the methylethylenes

Carbon-13 spin relaxation and methyl rotation barriers in the methylethylenes

Torsional, Rotor, and Electronic Effects in 4-tert-Butylmethylenecyclohexane Epoxidations and Osmylations

Chirality of and gear motion in isopropyl methyl sulfide: A Fourier transform microwave study

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