M Di Girolamo

A review of low temperature methanol synthesis

It has been more than ten years since the discovery of highly active catalysts which allow low temperature (< 150°C), single pass conversion of syngas to methanol. Detailed studies including catalyst refinements, reactor engineering, and process development have been conducted at the Snamprogetti and Amoco laboratories. The presence of electron-rich metal hydrides is the key to the unusual activity of these catalytic systems. Catalyst deactivation phenomena have till now hampered the development of a commercially viable process.

Organometallic nickel catalysts anchored on polymeric matrices in the oligomerization and/or polymerization of olefins. Part II. Effect and role of the components of the catalytic system

Abstract Organometallic nickel complexes with bidentate P∩O chelating ligands of ylidic (C(O)HPPh 3 ) and phosphino-acetic (CH(PPh 2 )COOH) type heterogenized on polystyrene resins by anchoring through the carbon atom of the ligand have been prepared and used in the polymerization and/or oligomerization of ethylene. Their catalytic behaviour has been compared with those of corresponding homogeneous models and with heterogeneous species with the phosphine and oxygenated ligand bound in a non-chelated arrangement. The catalytic activity and selectivity are strongly dependent on the chelating strength of the ligand. The polymerization of ethylene to HDPE occurs with replica of the support morphology. The role of the ancillary ligand (phosphine, nitrogen bases, etc.) added to the systems has also been studied and clarified.

Organometallic nickel catalysts bound to polymeric matrices in the oligomerization and/or polymerization of olefins with a replica of the support morphology

Abstract Organometallic nickel complexes with bidentate P O ⌢ chelating ligands of type Ph(PPh3)Ni(Ph2PCHCOPh) were heterogenized according to a new strategy — through the =CH— group of the ylidic ligand — and their behaviour in the polymerization and/or oligomerization of ethylene investigated. When anchored to polystyrene resins the catalytic systems showed a high and very selective activity in ethylene polymerization (1–2.5 kg of polymer (g Ni)−1 h−1) working in slurry or in gas—solid phase with reproduction of the morphology of the starting resins. When the matrix is a microspherical resin (0.1–0.3 mm diameter) the HDPE (high-density polyethylene) obtained is in the form of regular and very compact spheres of 3–7 mm diameter. Depending on the physical characteristics of the matrix (crosslinking, surface area, porosity, existence of spacing groups), compact spheres, hollow spheres (‘eggs’), geminates, polymer powders, or liquid oligomers were obtained.

Alcohols carbonylation to alkyl formates catalyzed by strongly basic resins

Heterogeneous basic polymeric resins were checked as catalysts for the carbonylation of methanol and higher alcohols to alkyl formates and their activity compared with that of the conventional homogeneous systems. The data were interpreted in terms of different morphology, basicity and swelling degree of the strongly basic resins.