Fischer-Tropsch Reaction Mechanism Involving Stepwise Growth of Carbon Chain

Abstract

Expressions are derived which predict satisfactorily the observed isomer and carbon number distribution of products from iron and cobalt catalysts in the Fischer-Tropsch synthesis. These expressions are based on three schemes of stepwise addition of one carbon atom to the end or adjacent-to-end carbons of the longest carbon chain of the growing group at the catalyst surface. The implications of these schemes to some general aspects of the reaction mechanism are considered.

Effects of Adding Cobalt and Potassium to MoS₂-based Catalysts on Mixed Alcohol Synthesis

“…The probability of chain growth was determined using the Anderson-Schultz-Flory (ASF) distribution, where Yn is the molar composition of an alcohol or a hydrocarbon with a carbon number of n 28) .…”

The product distribution in Fischer–Tropsch synthesis: An extension of the ASF model to describe common deviations

“…It was adapted to the Fischer-Tropsch synthesis by Herington (1946) and Anderson (Friedel and Anderson, 1950;Anderson et al, 1951;Storch et al, 1951;Anderson, 1956). Assuming that the chain-growth probability α is independent of the chain length, the well-known Anderson-Schulz-Flory where yn is the mole fraction of components with the carbon number or chain length n. Due to its assumption of a constant chain growth probability, the ASF distribution is an idealized distribution function with limited applicability; in particular, several experimental results show deviations for C 1 and C 2 components, as outlined in more detail below.…”

A New Approach to the Mechanism of Fischer–Tropsch Syntheses Arising from Gas Phase NMR and Mass Spectrometry

“…They evidenced the incorporation of the carbidec arbon atoms into the reactionp roducts (initialf raction of 13 Ci nC 2 -C 4 :1 0-16 %), but the isotope distribution in the C 2 -C 4 fraction led them to conclude that the carbidem ay play the role of ac hain growth initiator.T he enol mechanism [8] deals with the nondissociative chemisorption of CO that reacts with adsorbed hydrogen to form enolic units. Ac ombination of surface polymerization, condensation, andw ater elimination steps by adjacent groups leads to the formation of hydrocarbons.…”