can further convert into hydroperoxides or peroxides. The downward liquid convective flow transports these hydroperoxides and peroxides to the bottom section of the column. In this region, where the temperature is comparatively higher, a fraction of the hydroperoxides and peroxides decompose, turning into peroxyl and alkoxyl radicals and becoming the source of trace oxygen compound contamination despite negligible dissolved molecular oxygen, as shown in Fig. . In all trays, the radical reaction timescales are shorter than the residence time, so most radicals react. However, radical slows into and out of trays are often significant relative to the slow net radical formation reactions. In the liquid-phase system, in addition to the Diels-Alder (DA) polymerization and radical polymerization in the base case scenario, the presence of dissolved oxygen gives rise to alkylperoxyl propagation chain, as illustrated in Fig. . For conciseness, the illustration omits the substituent groups of the monomers. For radical polymerization, monomers can be non-conjugated alkenes as well as dienes. The growing chain can either be alkyl or alkylperoxyl.