REACTIONS OF DIBENZO-P-DIOXIN AND DIBENZOFURAN WITH ELECTROPHILIC REAGENTS

The levels of polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) formed during chlorine bleaching of pulp may be reduced if pre cursors such as dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) are dest royed prior to chlorination. Research was undertaken to find reagents that react effectively with DBD and DBF and to better understand the c hemistry of dioxin precursors. The reactivities of DBD and DBF toward ozone, nitrogen dioxide, hydrogen peroxide, oxygen under ultraviolet l ight, and nitric acid were examined. The precursors reacted with radic al, charged, and neutral electrophiles. In many cases, the degradabili ty of the precursors depended on whether they were dissolved in water or adsorbed to lignin-free fibers. Ozone was the most effective reagen t tested for destroying DBD and DBF; nitrogen dioxide was the next mos t effective.