Mechanistic Investigations into the Brightness Stabilization Effects of Hexadienol

ABSTRACT

The total amounts of 3,4,5-trimethoxyacetophenone and 2,6-dimethoxyphenol formed via the photocleavage of 3,4,5-trimethoxy-α-(2′,6′-dimethoxyphenoxy)-acetophenone (1) in benzene and 3:2 ethanol/benzene, have been quantified in the presence and absence of 2,4-hexadienol, a potential photostabilizing agent for mechanical pulps. Photodegradation of 1 in ethanol/benzene solutions was shown to be reduced by the addition of hexadienol. Photolysis of bleached chemithermomechanical pulp (BCTMP) treated with trans,trans-2,4-hexadienol was shown to yield all four possible geometric isomers of the hexadienol. These results suggest that a potential mode of stabilization of mechanical pulps by the hexadienol is triplet quenching of the excited state of lignin chromophores such as the α-carbonyl groups of phenacyl aryl ethers.