Detail of "779-51-1"

Reference

Studies on thermal degradation of synthetic polymers

Studies on thermal degradation of synthetic polymers. V. Thermal degradation of polystyrene. Kuroki, Takeshi; Honda, Tsutomu; Sekiguchi, Yuuki; Ogawa, Taichi; Sawaguchi, Takashi; Ikemura, Tadashi (Coll. Sci. Technol., Nihon Univ., Tokyo, Japan). Nippon Kagaku Kaishi, (6), 894-901 (Japanese) 1977. CODEN: NKAKB8. DOCUMENT TYPE: Journal CA Section: 35 (Synthetic High Polymers) When polystyrene (I) [9003-53-6] was thermally degraded, the reaction proceeded in 2 steps at <370 and >370.degree. with activation energies 54.7 and 73.7 kcal/mol, resp.; when I was preheated 1 h at 280.degree., the activation energy of the reaction at <370.degree. became 30.2 kcal/mol, and that at >370.degree. became 63.8 kcal/mol. The main high-boiling products in a fixed bed depolymn. reactor of molten I at 350-500.degree. were diphenylmethane [101-81-5], 1,2-diphenylethane [103-29-7], 1,2-diphenyl-1-propene [779-51-1], 1,3-diphenylpropane [1081-75-0], 2,4-diphenyl-1-butene [16606-47-6], and 1,3-diphenylpropene [5209-18-7]. The mechanism of the degrdn. was discussed.

Energetics of twisting in the lowest stilbene triplet state

Energetics of twisting in the lowest stilbene triplet state. Saltiel, Jack; Rousseau, Alan D.; Thomas, Babu (Dep. Chem., Florida State Univ., Tallahassee, FL 32306, USA). J. Am. 588-59-0 and 779-51-1 are cas registry numbers. These chemicals are also mentioned in this article. Chem. Soc., 105(26), 7631-7 (English) 1983. CODEN: JACSAT. ISSN: 0002-7863. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) The temp. dependence of the azulene (I) effect on the Ph2CO-sensitized photoisomerization of the stilbenes is reported in PhMe, C6H6, Me3COH and MeCN. The data are consistent with formation of identical stilbene triplets from the 2 isomers. Predictions concerning the shape of the potential-energy curve for twisting about the central bond depend on the detailed mechanism assumed for the quenching interaction. A lower enthalpy for the twisted triplets is predicted, DHtp = -2.1 and -1.6 kcal/mol in PhMe and Me3COH, resp., if it is assumed that the equil. population of transoid triplet geometries, 3T*, is negligible and that quenching follows encounters of twisted stilbene triplets, 3P*, with I when they achieve 3T* geometries in the encounter cage. On the other hand, if quenching is assumed to occur only by direct interaction between 3T* and I, equil. consts. for the 3T* t 3P* process are obtained which predict a lower enthalpy content for transoid triplets: DHtp = 0.5 and 2.9 kcal/mol for PhMe and Me3COH, resp. In the latter case entropy is predicted to favor twisted geometries so that for both mechanisms the free energy favors 3P* at the temps. normally employed for photochem. studies. Reasons for favoring the 3P* quenching mechanism are presented. .