RECENT DEVELOPMENTS IN THE FIELD OF HYDROFORMYLATION OF OLEFINS OF HIGHER MOLECULAR-WEIGHT INTO OXO-ALCOHOLS

60 years after its discovery by Otto Roelen, the hydroformylation reac tion has remained a focus of interest in the scientific and industrial fields of chemistry. From the very beginning, the synthesis of ''fatt y alcohols'' for the surfactants industry has been an important field of application for the hydroformylation reaction. Until today rhodium- catalysed processes have still been shunned in favour of cobalt-cataly sed processes for the hydroformylation of olefins of higher molecular weight into oxoalcohols. This is due to the higher yields of unbranche d oxoalcohols which can be obtained with cobalt catalysts, even when u sing olefins with an internal double bond, and to the difficulties in achieving a loss-free recycling of the expensive homogeneous rhodium c atalyst systems. Today the more branched oxoalcohols are also widely u sed for the synthesis of surfactants. Significant improvements have al so been achieved in the loss-free separation and recycling of rhodium catalyst systems. The advantages of the more active and more selective rhodium catalysts can therefore plow also be utilised for the hydrofo rmylation of olefins of higher molecular weight. This review paper, wh ich includes experimental results which have not been published until today, presents new techniques for the hydroformylation of olefins of higher molecular weight and the recycling of the catalyst system. It p articularly deals with the scope and limits of applications for hetero genised hydroformylation catalyst systems, micellar two-phase hydrofor mylation using surfactant phosphine ligands, an innovative so-called h omogeneous-heterogeneous method using rhodium catalyst systems which a re highly soluble in water and methanal while remaining insoluble in o ther solvents, the hydroformylation with non-ionic surfactant phosphin e catalyst systems, which are olefin-soluble at increased temperature only (above their cloud point) but are water soluble at normal tempera ture and thus facilitate the separation of the oxoproducts considerabl y. The paper closes with a discussion of a synthesis process for oxoal cohols in a single stage with rhodium carbonyl/tertiary amine/H2O cata lyst sytems.