592-41-6Relevant articles and documents
Role of Defects in Radiation Chemistry of Crystalline Organic Materials. 3. Geometrical and Electronic Structures of Alkene Radical Anion and Cation in Alkene/n-Alkane Mixed Crystals As Studied by ESR Spectroscopy
Matsuura, Kaoru,Muto, Hachizo,Nunome, Keichi
, p. 9481 - 9487 (1991)
An ESR study has been made in order to elucidate the electronic structures of alkene radical anion and cation, the former radical being first detected in the hexene/n-hexane mixed crystals irradiated at 4.2 K along with the cation.The present work extended to the hexene and butene isomers has resulted in evidence that both anions with vinylene and vinylidene groups have pyramidal structures with ?-character, which differ from the planar or twisted structures of corresponding cations.The proton hyperfine couplings of their anions were only about one-third as large asthose of the cations: A(two α-H) = 0.45, 0.1, -0.25 mT; a(two pairs of β-H) = 1.38 and 0.56 mT for the 3-hexene anion, and a(two α-H) = 1.3 mT and a(two pairs of β-H) = 4.6 and 2.9 mT for the cation.The differences in the geometrical structures and in the sizes of the proton couplings of the anion and cation radicals were discussed on the basis of a simple molecular orbital calculation.It has been found that the anion is stabilized by admixing 2s;C atomic orbitals (AO) with a lower core integral than 2p;C AO to the unpaired electron orbital and that the small β-proton couplings mainly originate from low extent of hyperconjugation due to a wide energy separation of C=C ?-antibonding and C-H pseudo-?-bonding orbitals.
LIGANDS FOR PRODUCTION OF 1-HEXENE IN CHROMIUM ASSISTED ETHYLENE OLIGOMERIZATION PROCESS
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Paragraph 0054-0056, (2022/01/12)
Catalyst compositions and processes for the oligomerization of ethylene to 1-hexene are described. The catalyst composition includes a triamino bisphospino (NPNPN) ligand system with specific phosphorous and nitrogen ligands. The terminal nitrogen atoms include linear alkyl hydrocarbons that differ in the number of carbon atoms by 3.
Phosphorus and nitrogen-doped palladium nanomaterials support on coral-like carbon materials as the catalyst for semi-hydrogenation of phenylacetylene and mechanism study
Ma, Lei,Jiang, Pengbo,Wang, Kaizhi,Lan, Kai,Huang, Xiaokang,Yang, Ming,Gong, Li,Jia, Qi,Mu, Xiao,Xiong, Yucong,Li, Rong
, (2021/02/26)
In this work, two types of polyporous and coral-like materials (CN) with high specific surface area are prepared using sodium glutamate as a carrier. At the same time, a CN-supported phosphorus-nitrogen-doped palladium nanomaterial CN-P-Pd is synthesized and applied to the preparation of styrene by selective hydrogenation of phenylacetylene under mild conditions. As shown in the TEM images, Pd nanoparticles with a particle size of about 4.4 nm are uniformly dispersed on the surface of the carrier. The results of N2 adsorption–desorption reveal that the surface area of the prepared catalyst (CN-P-Pd) is 1307 m2g?1. In addition, the experimental exploration shows the intervention of P in carbon-nitrogen materials can contribute to improve the selectivity of the reaction, which can be attributed to the fact that P element can change the electron density of Pd. Meanwhile, it is found that the solvent not only affects the activity of catalyst, but also the selectivity of the reaction. Kinetic study shows the activation energy of the reaction is 4.5 kJ/mol. With the increase of the reaction temperature, the dissolution rate of hydrogen in the solvent gradually slows down, which inhibits the progress of the reduction reaction. Mechanistic studies demonstrate that the carbon-nitrogen materials have strong adsorption capacity for substrates, and also provide more adsorption sites for phenylacetylene. Additionally, the optimal catalyst (CN-P-Pd) also has high reaction activity to other alkynes and the conversion can reach at 95%. Moreover, the optimal catalyst can be reused several times without significant reduction in reaction activity.