Wincenty Skupiński

Investigation of catalytic systems containing nickel supported on alumina-silica bonded with organic ligands and complexed by lewis acids

Abstract The influence of inorganic carriers on the catalytic activity of immobilized homogeneous catalysts in the oligomerization of propylene on system I formed in the reaction of bis-allyl nickel with hydroxyl groups of alumina—silica was studied. The catalytic activity was ascertained for the systems containing the strongest acid sites (alumina—silica, 50 – 80 wt.% of Al2O3). The carriers act similarly to, although worse than the MeAlCl2·O group in the catalytically-active surface nickel complexes. Modification of the carriers by addition of WO3 did not increase the activity of system I. The mechanism of the catalytic transformations on the active system I is proposed. Systems I were modified by MeAlCl2. An order of catalysts exhibiting different activities and similar selectivities was established.

(η5-C5H5)TiCl2(OC6H4X): synthesis and properties (X = NO2, Cl, CH3)

Abstract The compounds (η 5 -C 5 H 5 )TiCl 2 (OC 6 H 4 X), where X = NO 2 , Cl, CH 3 , have been obtained from the reaction of CpTiCl 3 with suitable substituted phenols in 1 : 1 ratio. Some of the IR and NMR bands of the compounds correlate directly with Hammett σ factors.

Polarographic studies of CpTiCl2(OC6H4X-p)/MAO and EPR studies of CpTiCl2(OC6H4X-p)/MAO/styrene systems

Cyclopentadienyl-titanium complexes containing OC6H4X ligands (X=NO2, Cl, H, C(CH3)3, OCH3) were synthesized. The “X” substituents at the phenoxy ligands have different electron donor properties, which are described by Hammett’s factors. Mixtures of CpTiCl2(OC6H4X-p) and MAO were investigated by polarography. The amount of Ti(III) ions have been noticed. EPR spectra were recorded for mixtures of CpTiCl2(OC6H4X-p) with MAO and styrene. The shape and the parameters of the EPR spectra were found to be related to the nature of OC6H4X-p ligands.

Carrier influence on the paramagnetic and catalytic properties of supported titanium complexes

Abstract Alumina-silica possessing various Al 2 O 3 /SiO 2 ratios was used as a carrier of surface titanium complexes. The systems obtained were examined as models for the investigation of the macroligand (inorganic gel) influence on the physicochemical properties of supported transition metal complexes. The titanium complexes were prepared first by the reaction of CpTiCl 3 , with the hydroxyl groups of the gel and then reduced by an excess of BuLi. The influence was established of the basic gel properties on: (a) the amount of titanium(IV) and titanium(III) complexes on the alumina-silica gel surfaces; (b) the symmetry of the surface Ti III surface complexes; (c) the electron density around the surface-Ti III ions, ionic or covalent bonds character in a complex; and (d) the catalytic activity in olefin hydrogenation.

Nitrogen fixation on supported titanium complexes

Abstract The fixation of nitrogen on the system CpTiCl3/Al2O3 reduced with various agents for varying conditions of temperature, reducing atmosphere, reduction time and reducing agent-to-Ti ratio has-been studied. EPR spectra of the investigated system are also discussed.

Alumina supported CpTiCl3 catalytic system

Abstract The system obtained by treating CpTiCl3 with hydroxyl groups of alumina gel followed by reduction with BuLi was found to catalyze olefin hydrogenation at room temperature under normal pressure.

Influence of carrier (Al2O3 and SiO2) calcination temperature on physicochemical and catalytic properties of supported titanium complexes

Abstract CpTiCl3 reacts with the surface hydroxyl groups of Al2O3 and SiO2 calcined at 773, 873 and 973 K to give the surface complex CpTiCl2-O-M-xxx (M = Al, Si; xxx is the carrier surface; Cp = cyclopentadienyl). The surface complexes were reduced with BuLi (Bu = butyl) and surface Ti(III) complexes were formed. The influence of the carrier calcination temperature on the amount of supported Ti(IV) complexes, the amount of supported Ti a.r. (a.r. = after reduction), the relative content of Ti(III) complexes, and the catalytic activity of supported Ti a.r. complexes in propylene hydrogenation is established.