The Alkaline Reactions of Some Simple Quinonemethide-Anthrahydroquinone Adducts

Abstract
The rapid delignification rates associated with anthraquinone-alkaline pulping could be due to the formation and reactions of lignin qulnonemethide-anthrahydroquinone (QM-AHQ) adducts. The chemistry of some simple QM-AHQ adducts is examined here. Upon heating in aqueous alkali, the QM-AHQ adducts fragment to QMs and AHQ. At 100° the adducts are reduced by AHQ dianion to afford QM-anthrone adducts and anthraquinone. At typical pulping temperatures (173°), the adducts are extensively, but not completely, decomposed, releasing AHQ and/or anthraquinone.