Studies on the Kinetics of Addition Reactions of Carbon Monoxide with Organic Compounds in Hydroiodic Acid under High Pressure (Part 2)

The addition reaction of carbon monoxide with ethylene in aqueous hydroiodic acid was investigated under high pressure in the range of 30 to 90kg/cm2. The yield of propionic acid was fairly high and the overall rate equation was:ln[C2H4]0/[C2H4]0-[C2H5COOH]=k1k2HCOPCOt/k-1+k2HCOPCO=KtNamely, the apparent reaction was a pseudo first order with respect to carbon monoxide and ethylene, and the apparent rate constants mere 3.0×10-5, 13.1×10-5 and 26.8×10-5sec-1 at 100, 120 and 140°C, respectively. From these values, K/PCO's calculated were 0.05×10-5, 0.21×10-5 and 0.43×10-5kg-1•cm2•sec-1 comparable to 0.08×10-5, 0.20×10-5 and 0.30×10-5kg-1•cm2•sec-1 obtained in the reaction of carbon monoxide with ethyl iodide. The overall activation energy has been found to be 16.6kcal/mole, as opposed to that of the latter reaction, i. e., 13kcal/mole. From these results the authors concluded that ethyl iodide was formed as an intermediate product in the reaction of carbon monoxide with ethylene.