Lee Ilkeun, Zaera Francisco
Department of Chemistry, University of California, Riverside, California 92521, USA.
J Phys Chem B. 2005 Feb 24;109(7):2745-53. doi: 10.1021/jp045443u.
The thermal chemistry of a number of C4 hydrocarbons (1,3-butadiene, 1-bromo-3-butene, 1-bromo-2-butene, trans-2-butene, cis-2-butene, 1-butene, 2-iodobutane, 1-iodobutane, and butane) was investigated on clean and hydrogen- and deuterium-predosed Pt(111) single-crystal surfaces by temperature-programmed desorption and reflection-absorption infrared spectroscopy. A combination of rapid beta-hydride eliminations from alkyls to olefins and the reverse insertions of those olefins into metal-hydrogen bonds explains the hydrogenation, dehydrogenation, and H-D exchange products that desorb from the surface. A preference for hydrogenation at the end carbons and dehydrogenation from the inner carbons also explains the extent of the isotope exchange and the preferential isomerization of 1-butene to 2-butene observed on this Pt(111) surface. The reactions of more dehydrogenated C4 species is also discussed.
通过程序升温脱附和反射吸收红外光谱法，在清洁的以及预先吸附了氢和氘的Pt(111)单晶表面上，研究了多种C4碳氢化合物（1,3 - 丁二烯、1 - 溴 - 3 - 丁烯、1 - 溴 - 2 - 丁烯、反式 - 2 - 丁烯、顺式 - 2 - 丁烯、1 - 丁烯、2 - 碘丁烷、1 - 碘丁烷和丁烷）的热化学性质。从烷基到烯烃的快速β - 氢消除以及这些烯烃反向插入金属 - 氢键的过程共同解释了从表面解吸的氢化、脱氢和H - D交换产物。在末端碳原子处优先氢化以及从内部碳原子处脱氢，这也解释了同位素交换的程度以及在此Pt(111)表面上观察到的1 - 丁烯优先异构化为2 - 丁烯的现象。还讨论了更多脱氢C4物种的反应。
