AbstractsChemistry

Bleaching of wood pulp with alkaline hypochlorite is of great economical importance in the pulp and paper industry. Considerable work has been done on the problem of such bleaching but mainly from an industrial point of view with the object of effecting economies in the chlorine consumption while at the same time maintaining high quality in the pulps. All of this work, too, was hampered by the necessity of studying the reactions of bleaching either on whole wood or on isolated lignins known to be altered in structure in obscure but probably drastic ways. Some years ago it was found possible to isolate most of the lignin from wood in a state that was only slightly chemically changed. The product, periodate lignin, was a light brown powder preserving much of the original morphological detail, and differing from most other isolated lignins in retaining the original insolubility of lignin in all liquids investigated. The availability of "periodate" lignin encouraged the writer to study the actions of a typical bleaching agent, sodium hypochlorite, and a closely related substance, sodium hypoiodite, upon it. This work supplements earlier results that were complicated by the presence of carbonydrates of wood or by the use of a less suitable type of lignin.[...]