Dehydrogenation of propane over Pt/KL catalyst: Investigating the role of L-zeolite structure on catalyst performance using isotope labeling
摘要:
Dehydrogenation of propane using an equimolar mixture of propane-do and propane d(8) was investigated over 1%Pt/KL and 1%Pt/SiO2 at atmospheric pressure and different reaction temperatures A normal kinetic isotope effect exists (k(H)/k(D) = 1 4-1 5) when the reaction is conducted on Pt/KL at different temperatures (400 500 and 600 degrees C) suggesting that C-H bond activation is involved in the kinetically relevant steps Furtheremore there is hardly any H-D exchange in the recovered propane during dehydrogenation at temperatures above 400 degrees C suggesting that adsorption and subsequent dehydrogenation of propane are essentially irreversible and that C-H bond activation is the rate determining step Unlike the case of hexane aromatization the unique structure of L-zeolite does not help in controlling the entry of propane molecules Into the lobes of the L-zeolite containing the active sites hence bimolecular reactions do occur leading to coke formation and catalyst deactivation (C) 2010 Elsevier B V All rights reserved
Kinetic and photochemical studies of FeC5H6+ in the gas phase
作者:Yongqing Huang、Ben S. Freiser
DOI:10.1021/ja00169a014
日期:1990.6
collisionally cooling the FeCsub 5}Hsub6}sup +} ions in a high-background pressure of argon and yield a rate constant of 5 plus minus} 2 times} 10sup minus}10} cmsup 3}/(molecule times} s), corresponding to a reaction efficiency of about 0.4. Photodissociation of the cyclopentadienyallyliron ion yields two product ions, FeCsub 8}Hsub 8}sup +} and FeCsub6}Hsub6}sup +}, with the latter pathway
Hydrocarbon activation by gas-phase lanthanide cations: interaction of praseodymium (Pr+), europium (Eu+), and gadolinium (Gd+) with small alkanes, cycloalkanes, and alkenes
作者:J. Bruce. Schilling、J. L. Beauchamp
DOI:10.1021/ja00209a002
日期:1988.1
reactivity. Gd/sup +/ can be thought of as having two valence electrons, and indeed it reacts similarly to Sc/sup +/ and the other group 3 metal ions Y/sup +/ and La/sup +/, yielding products corresponding to elimination of hydrogen, alkanes, and alkenes. The elimination of neutral alkenes in the reaction of Gd/sup +/ with alkanes results in the formation of metal dialkyl or hydrido-alkyl complexes. This finding
Tracing the Hydrogen Source of Hydrocarbons Formed by Vanadium Nitrogenase
作者:Chi Chung Lee、Yilin Hu、Markus W. Ribbe
DOI:10.1002/anie.201100869
日期:2011.6.6
Hydrocarbons from CO: The vanadium‐nitrogenase‐catalyzed reduction of carbon monoxide involves the adenosine triphosphate (ATP)‐dependent protonation of CO and the subsequent formation of CC bonds, leading to the production of small hydrocarbons, such as C2H4, C2H6, C3H6, and C3H8 (see picture). Isotope‐substitution studies monitored by GC–MS analysis show that protons are the source of hydrogen for
一氧化碳中的碳氢化合物:钒氮酶催化的一氧化碳还原涉及三磷酸腺苷(ATP)依赖的一氧化碳质子化和随后形成的CC键,从而导致生成小分子碳氢化合物,例如C 2 H 4,C 2 H 6,C 3 H 6和C 3 H 8(见图)。通过GC-MS分析监测的同位素替代研究表明,质子是减少CO的氢源。
Isotope Studies in Oxidation of Propane over Vanadium Oxide
The oxidation of propane has been studied over silica‐supported vanadium oxide and polycrystalline, bulk MoVTeNb oxide with M1 structure. Temperature‐programmed reaction experiments were performed, and the reactivity of propane molecules labeled with deuterium and 13C, respectively, was analyzed under steady‐stateconditions. The measurement of kinetic isotope effects reveals fundamental differences
Reactions of cyclopropane and deuterium over supported metal catalysts
作者:Ronald Brown、Charles Kemball
DOI:10.1039/ft9908603815
日期:——
The reaction of cyclopropane and deuterium has been studied at low temperatures over a number of supported metalcatalysts. The main reaction was normally ring-opening, yielding a mixture of isotopic propanes which were analysed mass-spectrometrically and by deuterium NMR spectroscopy. The patterns of isotopic propanes varied substantially with the nature of the metal and provided information about