Heats of Organic Reactions. IV. Hydrogenation of Some Dienes and of Benzene

Kistiakowsky, G. B.; Ruhoff, John R.; Smith, Hilton A.; Vaughan, William E.

doi:10.1021/ja01292a043

Cited by 232 publications

(141 citation statements)

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“…It is also interesting to note that exaltation is observed in styrene (XVIII), for which Amax = A, exaltation = 0-6 unit, and in propenyl benzene (XIX), but not in allyl benzene (XX) (Eisenlohr 1912, p. 105). a number of heats of hydrogenation; but the values so obtained are not in agreement with recent measurements by Kistiakowsky (1936), who finds, for instance, that whereas the hydrogenation of many unsaturated systems (e.g. cyclohexene, cycZopentadiene, butadiene) proceeds exothermically, the formation of 1 : 3-cycZohexadiene by hydrogenation of benzene is endothermic.…”

Section: C6 H 5-c H = C H -C H = C H -Ceh 5 C6h 5-c H^c H -C H = C H contrasting

confidence: 92%

Refractive dispersion of organic compounds IX—Optical exaltation in unsaturated hydrocarbons containing conjugated double bonds

1937

Proc. R. Soc. Lond. A

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One of the ultimate aims of the present investigations of refractive dispersion is to elucidate the phenomenon of “optical exaltation” in organic compounds containing conjugated systems of alternate single and double bonds, as observed by Gladstone in 1881 and defined by Brühl in 1907. A first step was taken in Part IV (Allsopp 1934 a ) when dispersion curves were plotted over a wide range of wave-lengths for two compounds of the cyclohexane series, viz. cyclohexene (I), which contains a single olefinic double bond, and cyclohexadiene (II), with two conjugated olefinic double bonds:

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Section: C6 H 5-c H = C H -C H = C H -Ceh 5 C6h 5-c H^c H -C H = C H contrasting

confidence: 92%

Refractive dispersion of organic compounds IX—Optical exaltation in unsaturated hydrocarbons containing conjugated double bonds

1937

Proc. R. Soc. Lond. A

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“…For the standard heat of formation from the elements at 25° C, values for the diolefins, C3 to C5, were obtained as follows: 1,3-Butadiene, from reference [27]; 1,2-butadiene, from reference [28]; propadiene, cis-and trans-1,3-pentadiene, and 1,4-pentadiene, from combination of the data on heats of hydrogenation from references [36,37] with the values for the heats of formation of the corresponding paraffin hydrocarbons from reference [29]; by calculation, using the relations between energy content and molecular structure given in references 129, 30,31,32,33]. The values so calculated are believed to be uncertain by not more than about ±0.75 kcal/mole.…”

Section: Heat Of Formation Free Energy Of Formation and Equilibmentioning

confidence: 99%

Heats, equilibrium constants, and free energies of formation of the C3 to C5 diolefins, styrene, and the methylstyrenes

Kilpatrick¹,

Beckett²,

Prosen³

et al. 1949

J. RES. NATL. BUR. STAN.

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For th e C3 to Cs diolefins, styrene, and the m ethylstyrenes, values are presented for t he followin g thermody namic prop er t ies to 1,500° K : H eat-conte nt fun ction, free-energy fun ction, entropy, heat conten t , hea t capacity, heat of forma tion from the clements, free energy of fonnatio n from t he elem ents, an d loga rit hm of the equilibrium constant of format ion from the elem ents. Equili brium con tants and concent rat ions are given in tabular and graphica l form for some reactions of isomerizat ion a nd dehydrogenat ion .

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“…The selected value previously used [1] for the heat of hydrogenation of 1,3-butadiene to n-butane, at 25° C, was obtained from the selected value for the heat of h) drogenation at 82° C [2] corrected to the new atomic weight of carbon and converted to 25° C [1], using an estimated value for the difference in heat capacities of 1,3-butadiene and n-butane, with the known heat capacity of hydrogen [23]. The conversion of the heat of hydrogenation from 82° to 25° Chad previously been taken as C4H6(gas, 1,3-butadiene)+2H2(gas)=C4H IO (gas, n-butane) (1) !J.H0355 .16-!J.H0298.16= -0.500 ± 0.100 kcaljmole.…”

Section: 3-butadienementioning

confidence: 99%

“…The previously published value from this laboratory for the heat of formation of 1,3-butadiene from its elements [1) 2 is based on a combination of values of the heat of hydrogenation of 1,3-butadiene to n-butane [2), the heat of combustion of n-butane (3), the heat of formation of water from its elements [4), and the heat of formation of carbon dioxide from its elements [5). Because a new "best" value for the heat of formation of carbon dioxide ~6) and new data on the heat capacities of n-butane f7) and 1,3-butadiene [8,25,26)lu.ve become available, a revised value for the heat of forma tion of 1,3-butadiene can be calculated .…”

Section: Introductionmentioning

confidence: 99%