Eero Iiskola

Studies on the synergetic effect of group viii transition metal carbonyls on homogeneous catalysis of the water-gas shift reaction

Abstract Homogeneous catalysis of the water-gas shift reaction by Group VIII mixed metal carbonyls and by mixtures of Group VIII metal carbonyls in pyridine solution was examined under mild conditions (T= 100°C, P co = 0.42–0.60 atm). A weak synergetic effect of Group VIII metals was observed between iron and iridium carbonyls. A stronger synergetic behaviour of mixed metal Fe/Ru catalyst precursors (Fe2Ru(CO)12 and FeRu2(CO)12) was noted. The effect of phosphine and phosphite substitution on Fe2Ru(CO)12 and FeRu2(CO)12 was examined. Only monosubstitution on Fe2Ru(CO)12 was found to have an enhancing effect on catalytic activity. Rhodium carbonyls, which were found to produce the most active catalyst solution under homogeneous water-gas shift conditions, did not show a synergetic behaviour with other Group VIII metals.

Aminosilane as a coupling agent for cyclopentadienyl ligands on silica

Abstract Aminosilane has been used as a coupling agent for cyclopentadienyl (Cp) ligands on silica surfaces. First the silica surface was functionalized with aminopropyldimethylethoxysilane (APDMES) by using saturated gas–solid reactions. Secondly two different (tetramethylcyclopentadienyl)chlorosilanes, Me 2 Si(C 5 Me 4 H)Cl and MeHSi(C 5 Me 4 H)Cl, were immobilised on the APDMES-functionalized silica by utilising n -BuLi ( n -butyllithium). The amine groups react with n -BuLi by producing lithiated amine groups. Furthermore, the lithiated amine reacts with chloride of the silane and a chemical bond between nitrogen and silicon of the silane is formed. These stepwise prepared surfaces were characterised with 1 H-, 13 C- and 29 Si- solid state NMR and FTIR spectroscopy.

Preparation of new modified catalyst carriers

Abstract Novel modified catalyst carriers have been prepared. First, aminopropyltriethoxysilane (APTES) was immobilized on the silica surface by using the saturated gas–solid reactions. Secondly, two different (tetramethylcyclopentadienyl)chlorosilanes, (Me2Si(C5Me4H)Cl and MeHSi(C5Me4H)Cl), were synthesized and anchored on the amine surface using liquid-phase reactions. Characterization of these stepwise prepared surfaces was carried out by 1 H , 13 C and 29 Si solid state NMR and FTIR spectroscopy.

Immobilization of CrCl3(THF)3 on a cyclopentadienyl surface of silica

Abstract Heterogeneous cyclopentadienylchromium catalysts were synthesized by adsorbing chromiumtrichloride CrCl3(THF)3 on a cyclopentadienyl modified silica surface. The obtained catalysts and the homogeneous model compound, [CpCrMe(μ-Cl)]2 (Cp=η5-C5H5), were tested in the polymerization of ethylene with the presence of the methylaluminoxane (MAO) cocatalyst. The heterogeneous catalyst showed a good activity toward ethylene but the main products were oligomers, mainly n-butene. The homogeneous catalyst was a better polymerization catalyst but it also produced oligomers. Heterogeneous catalysts were characterized with FTIR and 13C and 29Si CP MAS NMR.

IMMOBILIZATION OF ZIRCONIUM AMIDE ON A CP-MODIFIED SILICA SURFACE AND ITS USE AS A CATALYST FOR ETHYLENE POLYMERIZATION

Abstract Heterogeneous ethylene polymerization catalysts were prepared by supporting tetrakis(dimethylamino)zirconium on chemically modified silica surface. The silica was modified with a silane coupling agent, Cp(CH 2 ) 3 Si(OEt) 3 , using ALCVD-technique. On the resulting cyclopentadienyl surface zirconium amide, Zr(NMe 2 ) 4 , was immobilized with and without using methyllithium. Depending on the use of methyllithium the immobilization resulted in either mono- or bis-cyclopentadienyl zirconium complexes, which were characterized using chemical analysis, FT-IR, 13 C- and 29 Si-NMR results. Moreover, a homogeneous model compound, (Me 3 SiCp) 2 Zr(NMe 2 ) 2 , was synthesized with a reaction between Zr(NMe 2 ) 4 and Me 3 SiCp. The preliminary results of ethylene polymerization with these supported and unsupported organometallic complexes are presented.

Catalysis of the water gas shift reaction by a Ru3(CO)12-2,2′-bipyridine complex

Reaction of Ru3(CO)12 with 2,2′-bipyridine in water under a carbon monoxide atmosphere affords a high activity low-temperature catalyst for the water gas shift reaction.

Synthesis of supported titanocene amide complex and its use as a catalyst in ethylene polymerization

Abstract Heterogeneous ethylene polymerization catalysts were prepared by supporting tetrakis(dimethylamino)titanium, Ti[N(CH 3 ) 2 ] 4 , on chemically modified silica surface. The modification of silica was made using a silane coupling agent, Cp(CH 2 ) 3 Si(OCH 2 CH 3 ) 3 and atomic layer chemical vapor deposition (ALCVD). Titanium amide was also immobilized straight on the silica and on a methyllithium-treated modified silica. The aim of methyllithium treatment was to alkylate the unreacted ethoxy groups of the silane coupling agent on the silica. Methyllithium methylates, besides ethoxy groups, also silica surface and surface cyclopentadienyl groups. A model compound for these heterogeneous catalysts was prepared using a reaction of Ti[N(CH 3 ) 2 ] 4 with trimethylsilylcyclopentadienyl yielding a monocyclopentadienyl titanium compound, Me 3 SiCpTi[N(CH 3 ) 2 ] 3 . The preliminary results of ethylene polymerization using the prepared heterogeneous and homogeneous titanocene amide complexes and the effect of amount of MAO are presented.

Preparation and characterization of immobilized constrained-geometry hafnium complexes

Heterogeneous constrained-geometry hafnium complexes were prepared by anchoring Hf(NMe2)4 on a heterogenized ansa-cyclopentadienylamino ligand of type (RN)R′R′′Si(C5R′′′4), surface 1: R=OMe2Si(CH2)3; R′, R′′, R′′′=Me; surface 2: R=OMe2Si(CH2)3; R′, R′′′=Me, R′′=H. Preparation of the constrained-geometry catalyst ligand on silica surface was carried out in two steps: functionalizing of the silica surface with aminopropyldimethylethoxysilane (APDMES) by using saturated gas–solid reactions and immobilizing of (tetramethylcyclopentadienyl)chlorosilanes, Me2Si(C5Me4H)Cl or MeHSi(C5Me4H)Cl, on the functionalized silica by utilizing n-butyllithium (n-BuLi). Hf(NMe2)4 was immobilized on the heterogeneous surfaces by the amine elimination route. The complexes were characterized by 1H, 13C, and 29Si solid state NMR and FTIR spectroscopy.