Catalysis of Organic..

Puckette 314. Halophosphite Ligands for the RhodiumCatalyzed Low-PressureHydroformylation ReactionAbstractThomas A. PucketteEastman Chemical Company, Texas Eastman Division,P.O. Box 7444, Longview TX 75607-7444Tapucket@eastman.comThe discovery and use of fluorophosphites and chlorophosphites as trivalentphosphorus ligands in the rhodium catalyzed, low-pressure hydroformylationreaction are described. The hydroformylation reaction with halophosphite ligandshas been demonstrated with terminal and internal olefins. For the hydroformylationof propylene, the linear to branched ratio of the butyraldehyde product shows astrong dependency on the ligand to rhodium molar ratios, the reaction temperature,and the carbon monoxide partial pressure.IntroductionThe hydroformylation reaction, also known as the oxo reaction, is used extensivelyin commercial processes for the preparation of aldehydes by the reaction of one moleof an olefin with one mole each of hydrogen and carbon monoxide. The mostextensive use of the reaction is in the preparation of normal- and iso-butyraldehydefrom propylene. The ratio of the amount of the normal aldehyde product to theamount of the iso aldehyde product typically is referred to as the normal to iso (N:I)or the normal to branched (N:B) ratio. In the case of propylene, the normal- and isobutyraldehydesobtained from propylene are in turn converted into manycommercially-valuable chemical products such as n-butanol, 2-ethyl-hexanol,trimethylol propane, polyvinylbutyral, n-butyric acid, iso-butanol, neo-pentyl glycol,2,2,4-trimethyl-1,3-pentanediol, the mono-isobutyrate and di-isobutyrate esters of2,2,4-trimethyl-1,3-pentanediol.Slaugh and Mullineaux (1) disclosed a low pressure hydroformylation processusing trialkylphosphines in combination with rhodium catalysts for the preparationof aldehydes as early as 1966. Trialkylphosphines have seen much use in industrialhydroformylation processes but they typically produce a limited range of productsand frequently are very oxygen sensitive.