ON THE NATURE OF RESIDUAL LIGNIN

摘要

In a recent study,the results of oxygen delignification trials on kraft,prehydrolysis kraft and magnesium sulphite pulps were compared,thus providing the basis for a theory on the nature of the lignin residual lignin remaining in pulp after cooking,and particularly after oxygen delignification,the so-called residual lignin.It is suggested that,at least after oxygen delignification,the residual lignin effectively consists of LCC-bound monolignins,a theory relating to the efficiency of oxygen delignification and bleaching,and indicating possible strategies for improving the efficiency of such processes.An efficient means of breaking the LCC bonds would lead to a more efficient bleaching,known as requiring either a complete oxidation of the LCC-bound monolignins or a peeling off the carbohydrate binding to the LCC.In any case,a mere breaking of one unsaturated bond in an aromatic ring is not sufficient to achieve depolymerisation of the residual lignin or an efficient kappa reduction.