Kinetics of one-stage Wacker-type oxidation of C2-C4 olefins catalysed by an aqueous PdCl2-heteropoly-anion system

The steady-state kinetics of the one-stage Wacker oxidation of gaseous olefins such as ethene, propene, and 1-butene by oxygen (1:2 stoichiometric mixture of O(2) and olefin) to form acetaldehyde, acetone, and methyl ethyl ketone, respectively, was studied in a semicontinuous reactor. The catalytic system involves an aqueous solution of Pd(II) chloride (0.05-2 mM Pd(II), [Pd(II)]/[Cl(-)] = 1:50) and Keggin-type heteropoly anions [PMo(9)V(3)O(40)](6-) (50 mM), at 20-50degreesC. Under these conditions in a steady state, the reactivity of olefins increases in the order ethene less than or equal to1-butene <propene, but the total range is only a factor of 3. The oxidation of 1-butene is accompanied by the double-bond migration to form 2-butene. (C) 2002 Elsevier Science (USA).