Deuterium enrichment and the kinetic isotope effect during ruthenium catalyzed Fischer-Tropsch synthesis.

摘要

Fischer Tropsch Synthesis is a highly researched field that is still widely debated today. Research in this field could lead to many different advances, such as alternative fuel sources, explanations of abiogenic hydrocarbons and the formation of organic matter in the solar nebula. Analysis of this synthesis was carried out with a ruthenium catalyst at controlled temperatures and pressures. Two types of experiments were performed: H 2/D2 switching and competitive methods. The products showed that the hydrocarbon production rate was slightly increased when syngas was switched to D2/CO. Also, the H/D ratios of the hydrocarbons produced by the FT reaction using equal amount of H2 and D2 are always less than 1 indicating deuterium enrichment. We also observed that the ratios of [2-alkene]H/[2-alkene]D is about 1.4, indicating a normal isotope effect. However, the ratio of [1-alkene] H/[1-alkene]D was around 0.9, indicating a different pathway for production than 2-olefins. We attempt to explain these experimental facts by the modified alkylidene mechanism.