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

Journal Article · Tue Jun 01 00:00:00 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]

---

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), Vol. 141:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

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