Rate determining step and kinetics of oxygen delignification

A differentially operated, continuous stirred tank reactor (CSTR) was used to study the kinetics of oxygen delignification. The delignification kinetics and reaction rate were determined at different temperatures, oxygen pressures and caustic concentrations on softwood kraft Pulps. The kinetics are first order in residual lignin content (HexA corrected). The kinetics of phenolic delignification can be described by assuming that the decomposition of the hydroperoxide anion at carbon 3 of the aromatic ring is the rate determining step. The cellulose degradation. kinetics were described by two contributions: one due to radicals produced by phenolic delignification, and the other due to alkaline hydrolysis.