Abstract
Through the phase-separation system, lignocellulosics (western hemlock < Tsuga heterophylla > and unbleached mechanical pulps) were converted and separated to lignin-based polymers (lignophenols) and hydrolyzed carbohydrates. This system composed of phenol derivatives and a concentrated acid includes a simple stirring operation for about 60 minutes at ambient temperature in open system. To improve and control the phenolic/aqueous phase-separation reaction, the ultrasonic energy was applied to the reaction system. The ultrasonication greatly accelerated the hydrolysis of carbohydrates and the phenol grafting to native lignin to give lignophenols. The yields of ligno-p-cresols, especially from pulps, were increased dramatically at the early stage of the treatment. The resulting ligno-p-cresols had almost the same structural properties.
