Synthesis and catalytic activity in selective hydrogenation of palladium complexes anchored in montmorillonite

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90090-Q· OSTI ID:5564226

Choudary, B M; Kumar, K R; Kantam, M L ^[1]

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1. Indian Institute of Chemical Technology, Hyderabad (India)

Functional groups such as diphenylphosphine, triphenylphosphine, and 4-picoline have been intercalated in montmorillonite, a swelling smectite clay; subsequent complexation with palladium has led to syntheses of various interlamallar montmorillonite-anchored palladium(II) complexes. These montmorillonite ligands and their complexes are characterized by elemental analyses, IR, XRD, and ESCA. Diphenylphosphinomontmorillonite-palladium(II) complex 4B(ii), the best catalyst of the series for hydrogenation reactions, hydrogenated alkynes to alkenes and to alkanes selectively, yields are quantitative. Catalyst 4B(ii) has shown consistent activity for a number of recycles in the hydrogenation of styrene, and hex-1-ene. Data indicates that transient homogeneous complex species formed in the pretreatment remain unchanged during the recycles. Catalyst 4B(ii) hydrogenated mono and disubstituted alkynes and alkenes in ethanol. On the other hand, diphenylphosphinite-montmorillonite-palladium(II) complex (2B) selectively hydrogenated monosubstituted alkynes and alkenes only under identical conditions. Catalyst 2B, with its lower initial interlamellar spacings, has induced size selectivity as evidenced in the selective hydrogenation of monosubstituted reactants only, because the preferred perpendicular orientation of the transient reactant-palladium complex formed with monosubstituted olefins in the interlayer spacings of montmorillonite requires a space smaller than that expected for disubstituted ones. Easy adjustment of interlayer spacings by the incorporation of complex moieties of different sizes in the interlayers makes montmorillonite a practical alternative to zeolites for inducing size selectivity.

• OSTI ID: 5564226
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 130:1; ISSN 0021-9517; ISSN JCTLA
• 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
ABSORPTION
ALKANES
ALKENES
ALKYLATED AROMATICS
ALKYNES
AROMATICS
AZINES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHEMICAL COMPOSITION
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CLAYS
COHERENT SCATTERING
COMPLEXES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
HETEROCYCLIC COMPOUNDS
HEXENES
HYDROCARBONS
HYDROGEN
HYDROGENATION
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MONTMORILLONITE
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PALLADIUM COMPLEXES
PHOSPHINES
PHOSPHORUS COMPOUNDS
PICOLINES
PYRIDINES
RECYCLING
SCATTERING
SPECTRA
SPECTROSCOPY
STYRENE
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION
YIELDS