The Reactions of Lignins with High Temperature Hydrogen Peroxide Part 2. The Oxidation of Kraft Lignin

Abstract

A technical pine kraft lignin was subjected to alkaline hydrogen peroxide oxidation in the presence of DTMPA and molecular oxygen at various temperatures. In the presence of DTMPA the lignin was found to undergo increasing levels of oxidation and degradation with increasing temperature. At 110°C over 80 % of the kraft lignin was degraded. Analyses of the degraded lignins indicated that both phenolic and nonphenolic lignin moieties were degraded. At 90°C the addition of molecular oxygen resulted in further lignin demethoxylation, but did not decrease the amount of phenolic hydroxyl groups or hydrogen peroxide consumed. In the absence of DTMPA the hydrogen peroxide was rapidly degraded, and accompanied by only minimal lignin oxidation.

Evaluation of the enzyme manganese peroxidase in an industrial sequence for the lignin oxidation and bleaching of eucalyptus kraft pulp

“…This is a slight improvement of the PO stage against P, perhaps due to the higher stability of peroxide radicals responsible of the ligninolytic effect of these processes. This result is in agreement with the work of Kadla et al, 42 who applied a P stage at 138 kPa (20 psig) of oxygen pressure and 908C to the treatment of pine kraft pulp. The use of oxygen pressure during a P stage for the delignification of chemical pulp is a process currently used on an industrial scale, 43 so its application in an enzymatic-chemical process will be straightforward.…”

Ammoxidized Fenton-Activated Pine Kraft Lignin Accelerates Synthesis and Curing of Resole Resins

“…The effects of a Fenton-type treatment of lignin can be manifold due to its heterogeneous chemical composition including cleavage of β-O-1 and β-O-4 bonds [15], demethoxylation, aromatic and aliphatic hydroxylation [16,17], side-chain oxidation under the formation of aromatic aldehydes, ketones and carboxylic acids [15,18], aromatic ring cleavage, and condensation reactions [17]. Reduction of steric limitations by lignin depolymerization, along with the increase of functional group density, is considered beneficial for both homo-and copolymerization reactions.…”

“…Ammoxidation of lignin, i.e., its joint treatment with oxygen and ammonia [19], has been intensively studied for decades in an attempt to produce nitrogen-rich organo-mineral fertilizers featuring long-lasting nitrogen release (high-pressure approaches; up to 25% N) or artificial humid substances featuring C/N ratios typical for humified soil organic matter (10)(11)(12)(13)(14)(15) and moderate nitrogen contents bound in different types of nitrogenous moieties which mineralize in soil at different rates (ambient-pressure approaches; ca. 5%-6% N) [20].…”

Physicochemical characterisation of sugar cane bagasse lignin oxidized by hydrogen peroxide

“…The oxidation can be carried out in mild acidic or alkaline solution, and in both cases, different types of oxidisers like oxygen and hydrogen peroxide can be used [16]. Advantages of delignification with hydrogen peroxide are low investment and strong bleaching effect [2,17].…”