Investigation of the Synthesis of Alcohols Byproducts in Fischer-Tropsch Synthesis on Modified Fe-Cu Catalyst: Reactivity and Mechanism

The influence of copper promoters and reaction conditions on the formation of alcohols byproducts of a common Fischer-Tropsch synthesis used iron-based catalysts were investigated. A good compromise of 28%Cu/FeKLaSiO2 can lead to the optimization of an improved Fischer-Tropsch catalyst. The product distribution shifts towards hydrocarbons with increasing the reaction temperature, while pressure promotes the formation of alcohols. It was found that the production of either alcohols or hydrocarbons followed A-S-F distributions, and their α parameters were essentially different which indicated a competition in the growing chain between the two species. TPD after acetaldehyde adsorption gave strong evidence of the insertion of a C1 oxygen-containing species into an alkyl chain.

Authors:

• Wanyu Mao
• Qiwen Sun
• Weiyong Ying
• Dingye Fang

Keywords:

• Fischer-Tropsch synthesis
• Fe-Cu catalyst
• alcohols byproducts
• reaction pathways

References:

[1] M. Ichikawa, T. Fukushima, "Mechanism of syngas conversion into
C2-oxygenates such as ethanol catalysed on a SiO2-supported Rh-Ti
catalyst", J. Chem. Soc. Chem. Comm., vol. 1985, pp. 321-323, 1985.
[2] M. Pijolat, V. Perrichon, "Synthesis of alcohols from CO and H2 on a
Fe/A12O3 catalyst at 8-30 bars pressure", Appl. Catal., vol. 13, pp.
321-333, Jan. 1985.
[3] J. Hackenbruch, W. Keim, M. Roper, H. Strutz, "Mechanistic
considerations for the formation of oxygenated species in the
Fischer-Tropsch synthesis", J. Mol. Cat., vol. 26, pp. 129-134, Feb. 1985.
[4] T. Tatsumi, A. Muramatsu, K Yokota, H. Tominaga, "Mechanistic study
on the alcohol synthesis over molybdenum catalysts: Addition of probe
molecules to CO-H2", J. Catal., vol. 115, pp. 388-398, Feb. 1989.
[5] A. Takeuchi, J.R. Katzer, "Mechanism of methanol formation", J. Phys.
Chem., vol. 85, pp. 937-939, Apr. 1981.
[6] A. Takeuchi, J.R. Katzer, "Ethanol formation mechanism from carbon
monoxide + molecular hydrogen", J. Phys. Chem., vol. 86, pp.
2438-2441, June 1982.
[7] A. Kiennemann, C. Diagne, J.P. Hindermann P. Chaumette, Ph. Courty,
"Higher alcohols synthesis from CO+2H2 on cobalt-copper catalyst: Use
of probe molecules and chemical trapping in the study of the reaction
mechanism", Appl. Catal., vol. 53, pp. 197-216, Sep. 1989.
[8] H. Orita, S. Naito, K. Tamaru, "Mechanism of acetaldehye formation
from the carbon monoxide-hydrogen reaction below atmospheric
pressure over supported Rh catalysts", J. Chem. Soc. Chem. Comm., vol.
1984, pp. 150-151, 1984.
[9] D.G. Castner, R.L. Blackadar, G.A. Somorjai, "CO hydrogenation over
clean and oxidized rhodium foil and single crystal catalysts. Correlations
of catalyst activity, selectivity, and surface composition", J. Catal., vol.
66, pp. 257-266, Dec. 1980.
[10] P. Biloen, M.W.H. Sachtler, "Mechanism of hydrocarbon synthesis over
Fischer-Tropsch catalysts", Adv. Catal., vol. 30, pp. 165-216, 1981.
[11] M. Shimokawabe, H. Asakawa, N. Takezawa, "Characterization of
copper/zirconia catalysts prepared by an impregnation method", Appl.
Catal., vol. 59, pp. 45-58, Mar. 1990.
[12] R. Zhou, T. Yu, X. Jiang, F Chen, X. Zheng, "Temperature-programmed
reduction and temperature-programmed desorption studies of CuO/ZrO2
catalysts", Appl. Surf. Sci., vol. 148, pp. 263-270, July 1990.
[13] G. Munteanu, L. Ilieva, D. Andreeva, "Kinetic parameters obtained from
TPR data for ╬▒-Fe2O3 and Au/╬▒-Fe2O3 systems", Thermochimica Acta,
vol. 291, pp. 171-177, Apr. 1997.
[14] C.H. Zhang, H.J. Wan, Y. Yang, H.W. Xiang, Y.W. Li, "Study on the
iron-silica interaction of a co-precipitated Fe/SiO2 Fischer-Tropsch
synthesis catalyst", Catal. Comm., vol. 7, pp. 733-738, Apr. 2006.
[15] F. del Monte, M.P. Morales, D. Levy, A. Fernandez, M. Ocana, A. Roig,
E. Molins, K. O-Grady, "Formation of ╬│-Fe2O3 isolated nanoparticles in a
silica matrix", C.J. Serna. Langmuir, vol. 13, pp. 3627-3634, July 1997.
[16] T. Matsuzaki, K. Takeuchi, T.Hanaoka, H. Arakawa, Y. Sugi,
"Hydrogenation of carbon monoxide over highly dispersed cobalt
catalysts derived from cabalt(II) acetate", Catalysis Today, vol. 28, pp.
251-259, May 1996.
[17] L.M. Tau, R. Robinson, R. D. Ross, B.H. Davis, "Oxygenates formed
from ethanol during Fischer-Tropsch synthesis", J. Catal., vol. 105, pp.
335-341, June 1987.
[18] X.D. Xu, E.B.M. Doesburg, J.J.F. Scholten, "Synthesis of higher alcohols
from syngas - recently patented catalysts and tentative ideas on the
mechanism", Catalysis Today, vol. 2, pp. 125-170, Dec. 1987.
[19] Y. Liu, B.T. Teng, X.H. Guo, Y. Li, J. Chang, L. Tian, et al., "Effect of
reaction conditions on the catalytic performance of Fe-Mn catalyst for
Fischer-Tropsch synthesis", J. Mol. Catal. A: Chemical, vol. 272, pp.
182-190, July. 2007.
[20] H. Schulz, H. Gokcebay, "Catalysis of organic reactions", vol. 18, J.R.
Kosak, Ed. New York: Marcel Dekker, 1984, pp.153-169.
[21] M.E. Dry, "Catalysis-science and technology", vol. 1, Anderson and
Boudart, Ed. New York: Springer Verlag, 1981, p. 159.
[22] A. Kiennemann, A. Barama, S. Boujana, M.M. Bettahar, "Higher alcohol
synthesis on modified iron based catalysts: Copper and molybdenum
addition", Appl. Catal. A, vol. 99, pp. 175-194, June. 1993.