Effect of alcohol addition on fischer-tropsch synthesis over cobalt-based catalysts

Abstract

CnH2n+1OH (n=2, 3, 5, 6) primary alcohol activation, hydrogenation and its additional effects on the performance of the Fischer-Tropsch (FT) synthesis over a cobalt catalyst were investigated in a fixed bed micro-reactor. All products were analyzed using an on-line gas chromatography. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to investigate intermediates on the catalyst surface. In the presence of argon or hydrogen, CnH2n+1OH underwent two main reactions: direct de-carbonylation to produce (CH2)n-1hydrocarbons, and dehydration to produce (CH2)nhydrocarbons. The addition of lower carbon number alcohol (ethanol or 1-propanol) into the FT synthesis reaction had no significant effect on the hydrocarbon product distribution. While co-feeding higher carbon number alcohol (1-pentanol or 1-hexanol) into the FT synthesis reaction, the selectivity to hydrocarbons with carbon numbers greater than or equal to n-1 increased markedly because of the additive's chain initiation on the catalyst surface. © Editorial office of Acta Physico-Chimica Sinica.