The Oligomerization of Butadiene with Iron Complex Catalysts. II. The Effects of Additives

Abstract

Abstract In the oligomerization of butadiene with the catalyst composed of iron(III) acetylacetonate and triethylaluminum, the degree of digomerization and the structures of the oligomers were strongly affected by the addition of an electron donor as a catalyst component. When triphenylphosphine was added, linear dimers composed of 3-methylhepta-1, 4, 6-triene and n-octa-1, 3, 6-triene were formed, while the addition of 2, 2′-dipyridyl produced cyclic dimers composed of cycloocta-1, 5-diene and 4-vinylcyclohex-1-ene. Besides the above donors, triphenylphosphite, tri(o-tolyl)-phosphite, tri(p-tolyl)phosphite, phosphorus trichloride, triethylamine and pyridine as monodentate, and o-phenanthroline, 2(2′-pyridyl)imidazoline and oxine as bidentate ligands, were tried, and the effects of those donors upon the reaction were studied. The transition states in these catalyst systems were also considered by means of studies of the effects of the molar ratio of catalyst components and by the measurements of infrared, ESR and visible light absorption spectra or magnetic susceptibilities of the reaction solutions.