Deuterium tracer study of alkane formation in the palladium-catalyzed hydrogenation of propadiene and of 1,2-butadiene and its implications concerning the breakdown of selectivity in ethyne hydrogenation

Journal Article · Wed Jun 15 04:00:00 EDT 1977 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(77)90185-3· OSTI ID:5426570

Oliver, R G; Wells, P B

Reactions of propadiene (allene) and of 1,2-butadiene (methylallene) with deuterium catalyzed at 293/sup 0/K by palladium--alumina are reported. Reactions are selective for alkene formation at low conversions and low deuterium pressures, but at higher conversions and deuterium pressures considerable alkane yields are observed. Selective hydrogenation of 1,2-butadiene gives cis-2-butene (approx.60%) and 1-butene (approx.40%), each having a deuterium number (D.N.) of 2.0, by a mechanism identical to that described previously for reactions catalyzed by nickel. The appearance of butane (D.N. = 5.0) is accompanied by trans-2-butene (D.N. = 3.0); both products are highly exchanged. A mechanism for their formation is proposed which involves the participation of an ..cap alpha cap alpha..-diadsorbed intermediate. This mechanism has implications regarding the mode of ethane formation from ethylene (acetylene) under conditions in which palladium behaves unselectively.

• Research Organization: The Univ. Hull, Eng.
• OSTI ID: 5426570
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 47:3; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400303* -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
ALKANES
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DEUTERATION
DIENES
ELEMENTS
HYDROCARBONS
KINETICS
METALS
ORGANIC COMPOUNDS
PALLADIUM
PLATINUM METALS
POLYENES
REACTION KINETICS
TRANSITION ELEMENTS
YIELDS