A NEW ENVIRONMENTALLY BENIGN TECHNOLOGY FOR TRANSFORMING WOOD PULP INTO PAPER - ENGINEERING POLYOXOMETALATES AS CATALYSTS FOR MULTIPLE PROCESSES

A new environmentally benign technology, based on the use of polyoxome talate (POM) salts and oxygen, is being developed to bleach wood pulps for use in the manufacture of paper. Details of POM chemistry relatin g to the unit operations of an effluent-free bleaching process are rep orted. These include anaerobic delignification of wood pulp, aerobic r eoxidation of reduced POMs for their cyclic reuse and POM catalyzed an d initiated aerobic mineralization (wet oxidation) of lignin fragments removed from pulp during bleaching. The results of bleaching trials u sing a series of isostructural POM complexes of the Keggin family are reported, Key structural components of the POMs are varied to determin e the effects of these changes on POM performance, Homogeneous reactio ns of lignin-model compounds with select POMs are used to help interpr et kinetic data obtained in the heterogeneous reaction of POM solution s with pulp fibers. Finally, new directions in catalyst design that pr omise to expand the potential of the technology are discussed.