The Liquid Phase Oxidation of Acrolein. III. Decompositions of Peracrylic Acid by Catalysts and with Acrolein

Abstract Peracrylic acid was decomposed by four kinds of catalysts in a benzene solution at 30°C. The order of the catalysts’ effect on the decomposition was: Mn>Co>Fe>Ni; this agreed, except for the reverse order of Co and Mn, with that of the effective catalysts in the oxidation of acrolein (Co>Mn>Fe>Ni). The empirical rate equation, −d(CH2=CHCOO2H)⁄dt=k(CH2=CHCOO2H)0.58(catalyst)0.56 was obtained from the decomposition by Co(acac)3. On the other hand, from the stationary-state treatment of elementary steps adequate to the reaction and some assumptions, and from the experimental data, the following equation was derived: −d(CH2=CHCOO2H)⁄dt=1.3×10−1(CH2=CHCOO2H)(Co3+)+9.6×10−3(CH2=CHCOO2H)1⁄2(Co3+)1⁄2 The above two equations have been confirmed as agreeing with each other over the range of reaction conditions used. The interaction of peracrylic acid with acrolein was carried out in the absence of a catalyst under an oxygen or nitrogen atmosphere. In this case, there was formed a complex consisting of both peracrylic acid and acrolein. The complex was mainly decomposed through the ionic mechanism, but in part through the radical mechanism at a higher temperature, namely, through the homolytic cleavage of its peroxy group, followed by the induced decomposition of peracrylic acid. Furthermore, the formation mechanism of acrylic acid in the oxidation of acrolein was discussed in view of the activation energy of the decomposition of peracrylic acid.