Reaction of a Lignin Model Dimer Sequentially with Chlorine and Sodium Hydroxide

Abstract

Dimer 9, which is representative of diaryl methane structures reported present in residual lignin, was reacted with aqueous chorine at 50 o C. The major product was identified as the tetrachloroquinone dimer 13 (x=2, y= 2). Similar reaction of the tetrachorocatechol dimer 12 with aqueous chorine gave a mixture of the tetrachloroquinones 15 and 16. When the mixture of the quinones was reacted with 2.5% sodium hydroxide, an intramolecular oxidation-reduction (Cannizzaro) reaction with the simultaneous loss of two chlorine atoms occurred as the main reaction. The products, 21, were characterized as having a chlorine-free muconic acid lactone group attached to a dichlorocatechol