| Abstract
| - Hydroformylation of 1,4-diacetoxy-2-butene was studied using a water-soluble Rh complex catalyst preparedin situ from [Rh(COD)Cl]2 complex and trisodium salt of tri-(m-sulfophenyl)phosphine (TPPTS) in a biphasicsystem. The sequence of addition of catalyst precursor, ligand, and reactant/solvent showed a significanteffect on leaching of Rh from aqueous to organic phase, and hence, the procedure was optimized to developa nonleaching and stable biphasic catalyst system. The only hydroformylation product (1,4-diacetoxy-2-formylbutane, DAFB) formed was found to deacetoxylate completely to 2-formyl-4-acetoxybutene (FAB), thusallowing a one-pot synthesis of FAB, an important intermediate for Vitamin A. Experimental data on theconcentration−time and CO/H2 consumption−time profiles were obtained, and the effects of DABconcentration, CO partial pressure, H2 partial pressure, and catalyst concentration were studied in a stirredbatch reactor over a temperature range of 338−358 K. The effect of aqueous phase holdup on the initial rateof hydroformylation and analysis of gas−liquid and liquid−liquid mass transfer effects were also investigatedto identify the reaction rate data operating in a kinetic regime. A rate equation based on the knownhydroformylation reaction mechanism was used to fit the experimental rate data and to evaluate kineticparameters. The agreement between the model prediction and the experimental data was found to be excellent.The activation energy was calculated as 30.1 kJ/mol. The biphasic catalyst system reported here is not onlyefficient for catalyst−product separation but also provides a tandem synthesis of Vitamin A intermediate,FAB.
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