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Catalysis by intermetallic compounds I. A comparison of the catalytic behaviour of CePd 3 , ZrPd 3 and Pd sponge for buta‐1,3‐diene hydrogenation and but‐1‐ene hydroisomerisation
Author(s) -
Bahia Amrik,
Winterbottom John M.
Publication year - 1994
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280600312
Subject(s) - isomerization , diene , intermetallic , catalysis , selectivity , chemistry , palladium , hydrogen , photochemistry , organic chemistry , natural rubber , alloy
The hydrogenation of buta‐1,3‐diene and more briefly, the hydroisomerisation of but‐1‐ene catalysed by powdered CePd 3 , ZrPd 3 and Pd sponge has been studied in a fixed bed continuous flow microreactor at 1 bar (101·5 k Pa) total pressure and in the temperature range 45–225°C. The two intermetallics (CePd 3 , ZrPd 3 ) exhibited greater selectivity for butene formation than palladium, especially at high buta‐1,3‐diene conversions. The superior selectivity of the intermetallics was demonstrated further under the more demanding conditions, whereby but‐1‐ene was added to the feed buta‐1,3‐diene in the ratio C 4 H 8 /C 4 H 6 = 24. The kinetics and apparent energies of activation were determined for the hydrogenation and isomerisation reactions. In the case of buta‐1,3‐diene hydrogenation, the kinetics suggest that for Pd sponge, hydrogen and buta‐1,3‐diene adsorb on similar sites, whereas in the case of the intermetallics different sites may be involved for hydrogen and buta‐1,3‐diene adsorption, which may result from palladium—metal oxide interactions. In the case of but‐1‐ene isomerisation, double bond migration appears to occur via addition–abstraction mechanisms on all three catalysts but in the case of the intermetallics hydrogenation and isomerisation involve different rate determining steps.