Rhodium-catalyzed biphasic hydroformylation of olefins. The Ruhrchemie-Rhone Poulenc process for manufacturing butyraldehyde

2 Rhodium-catalyzed biphasic hydroformylation of olefins. The Ruhrchemie-Rhone Poulenc process for manufacturing butyraldehyde 

In 1975 Kuntz has described that the complexes formed from various rhodium-containing precursors and the sulfonated phosphines, TPPDS (2) or TPPTS (3) were active catalysts of hydroformylation of propene and 1-hexene [15,33] in aqueous/organic biphasic systems with virtually complete retention of rhodium in the aqueous phase. The development of this fundamental discovery into a large scale industrial operation, known these days as the Ruhrchemie-Rhone Poulenc (RCH-RP) process for hydroformylation of propene, demanded intensive research efforts [21,28], The final result of these is characterized by the data in Table 4.2 in comparison with cobalt- or rhodium-catalyzed processes taking place in homogeneous organic phases. 

The process itself is stunningly simple [1, 6-8], Propene and syngas are fed to a well stirred tank reactor containing the aqueous solution of the 

There are many important points and lessons to be learned from the development and operation of the Ruhrchemie-Rhone Poulenc process and we shall now have a look at the most important ones. 

Solubility of the reactants and products in the catalyst-containing aqueous phase is another factor to be considered. The solubility of C3 terminal olefins rapidly decreases with increasing chain length [7] as shown in Table 4.3. The solubility data in the middle column of Table 4.3 refer to room temperature, therefore the values for ethene through 1-butene show the solubility of gases, while the data for 1-pentene through 1-octene refer to solubilities of liquids. For comparison, the solubilities of liquid propene and 1-butene are also shown (third column), these were calculated using a known relation between aqueous solubility and molar volume of n-alkenes [60], 

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