Preparation and characterisation of montmorillonite-supported palladium hydrogenation catalysts possessing molecular sieving properties

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1174· OSTI ID:6153541

Crocker, M; Herold, R H.M.; Buglass, J G; Companje, P ^[1]

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1. Koninklijke/Shell-Laboratorium, Amsterdam (Netherlands)

Highly dispersed palladium metal has been deposited in the interlayer space of montmorillonite clay by the reduction of intercalated palladium complexes. The use of the highly electrophilic Pd(II) precursor complexes [Pd(PPh[sub 3])(NCMe)[sub 3]][sup 2+] and [PdL[sub 4]][sup 2+] (L = NCM3, (CH[sub 3])[sub 2]CO) is shown to facilitate the reduction step under very mild conditions (0[degrees]C; MeOH as a reaction medium). TEM analysis of reduced [Pd(PPh[sub 3])(NCMe)[sub 3]][sup 2+]/clay and [Pd(NCMe)[sub 4]][sup 2+]/clay samples reveals that the palladium is present largely in the intellamellar regions of the clay, in the latter case as particles of platelet morphology. A procedure for depositing palladium metal exclusively in the interlamellar region of the clay particles is also described. Transmission electron micrographs of the resulting material (containing 1 wt% Pd) reveal a very narrow size distribution for the palladium crystallites formed, the median particle diameter being ca. 8 [angstrom]. Consistent with this is an observed basal spacing of 8-10 [angstrom] for the intercalated regions of the clay. Molecular sieving effects are observed when this material is used as a catalyst for the hydrogenation of cyclic and monosubstituted alkenes of varying critical dimension. In contrast, catalysts prepared by simple reduction of Pd(II) complexes homogeneously dispersed in montmorillonite show significantly less shape selectivity towards olefinic reactants. 35 refs., 7 figs., 2 tabs.

• OSTI ID: 6153541
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 141:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKENES
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CLAYS
COMPLEXES
ELECTRON MICROSCOPY
ELEMENTS
HETEROGENEOUS CATALYSIS
HYDROCARBONS
HYDROGENATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MICROSCOPY
MONTMORILLONITE
MORPHOLOGY
ORGANIC COMPOUNDS
PALLADIUM
PALLADIUM COMPLEXES
PARTICLES
PLATINUM METALS
REDUCTION
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY