Abstract
Liquid-phase oxidation of acrolein into acrylic acid by oxygen in the presence of metal catalyst of cobalt laurate has been studied.
There are several papers which reported on the formation of a considerable amount of polymer during the oxidation, but the discussions were not enough in detail.
Authors made clear quantitatively the effect of oxygen, acrolein and concentration of catalyst affecting the formation of the polymer. When oxygen was dissolved enough in the solution no polymer formed.
The formation of polymer is expressed by the following equation;
1/IP (P) =K (AL) 1.75 (O2) -1
where, IP (P) is induction period (min.) of polymer formation given by the time for formation of a turbid solution, and AL is concentration of acrolein (M). IP (P) increased with increase of concentration of catalyst.
Elementary, functional and thermal analyses of the polymers were carried out as well as IR measurement. The contents of -CHO and -C=C- were high, and -COOH increased with increase of oxygen concentration though the content was low. Approximately, an amount of 86% of the polymers was formed by radical polymerization via acyl radical, and not via peracid radical. The above equation well explains the initiation of the oxidation and the mechanism of the polymerization.
