Ia. Weinstock et al., A NEW ENVIRONMENTALLY BENIGN TECHNOLOGY FOR TRANSFORMING WOOD PULP INTO PAPER - ENGINEERING POLYOXOMETALATES AS CATALYSTS FOR MULTIPLE PROCESSES, Journal of molecular catalysis. A, Chemical, 116(1-2), 1997, pp. 59-84
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.