Ethylene inhibition, first observation

It has been reported that use of a suitable co-solvent increases the concentration of the olefin in water (catalyst) while retaining the biphasic nature of the system. It has been shown that using co-solvents like ethanol, acetonitrile, methanol, ethylene glycol, and acetone, the rate can be enhanced by several times [27, 28], However, in some cases, a lower selectivity is obtained due to interaction of the co-solvent with products (e.g., formation of acetals by the reaction of ethanol and aldehyde). The hydroformylation of 1-octene with dinuclear [Rh2(/t-SR)2(CO)2(TPPTS)2] and HRh(CO)(TPPTS)3 complex catalysts has been investigated by Monteil etal. [27], which showed that ethanol was the best co-solvent. Purwanto and Delmas [28] have reported the kinetics of hydroformylation of 1-octene using [Rh(cod)Cl]2-TPPTS catalyst in the presence of ethanol as a co-solvent in the temperature range 333-353 K. First-order dependence was observed for the effect of the concentration of catalyst and of 1-octene. The effect of partial pressure of hydrogen indicates a fractional order (0.6-0.7) and substrate inhibition was observed with partial pressure of carbon monoxide. A rate eqution was proposed (Eq. 2). 

The spectra of alkene selenides persists for several minutes after flashing. A spectrum observed in flashed COSe and ethylene mixture is identical to that produced in flashed CSe2 and ethylene mixture. In Ar or N2, flash photolysis of COSe produces Se2 but no CSe. An added alkene inhibits Se2 formation in experiments either with COSe or CSe2. In flashed CSe2, the rate of decay of Se (4 P) is identical to the rate of appearance of the far ultraviolet bands, within an experimental scatter of + 20% in the pseudo first-order rate constant. Therefore the absorption in the far... 

Hydroformylation of ethylene using a water-soluble Rh-TPPTS catalyst system has been investigated [22] using a toluene-water solvent system at 353 K. The effect of TPPTS concentration on rate passes through a maximum of at a P/Rh ratio of 8 1. The effect of the catalyst precursor concentration on the rate of reaction first increases and above a certain concentration it remains constant. The effect of aqueous-phase hold-up shows a maximum in the rate (ela = 0.4). The apparent reaction orders for the partial pressure of hydrogen and ethylene were found to be 1 and zero respectively. A strong inhibition in the rate with an increase in Pco was observed. 

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