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Steady state and transient behavior in 1‐butene reactions over bismuth molybdate
Author(s) -
Oliveira Margarida,
Portela M. Farinha,
Pires Maria Joäo,
Ribeiro F. Ramôa
Publication year - 1983
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450610115
Subject(s) - dehydrogenation , molybdate , selectivity , chemistry , oxygen , steady state (chemistry) , isomerization , bismuth , butene , photochemistry , inorganic chemistry , catalysis , organic chemistry , ethylene
Pulse and continuous flow techniques were used to study 1‐butene reactions in the presence of oxygen over bismuth molybdate. At 280°C and low 1‐butene partial pressures (2.1‐5.6 kPa), the activity increases with the pulse number and tends towards a constant level. At high 1‐butene partial pressures (40‐68 kPa), the activity decreases at the same conditions but tends also to stabilize. The butadiene selectivity increases and 2‐butene selectivities decrease in both cases and tend towards the selectivities observed with a continuous flow technique in steady state conditions. At 350°C, the activity has a similar behavior for low pressures of 1‐butene, but for high pressures increasing activity occurs. For such a temperature the oxidative dehydrogenation selectivity decreases and the isomerization selectivities increase with respect to the pulse number, but tend also towards the values found in steady state flow operation. Experiments at intermediate temperatures (300 and 320°C) show a coherent evolution. On other side, experimental results obtained using only 1‐butene as reactant in the absence of oxygen contributed greatly to clarification of the observed situation. The results are discussed and interpreted in the context of the reaction mechanism.