Suppression method of the condensation reaction during phenol liquefaction of woody material

Abstract

The liquefaction of woody materials in the presence of phenol and acid catalyst is a promising method to utilize the waste woody materials into phenolic resin. However, the condensation reaction is a major problem for its practical applications. In order to suppress condensation reactions, methanol was added to the liquefaction medium. Even the intense condensation reactions were suppressed by the addition of 50% methanol (mol% to phenol). The effect of methanol was further confirmed by the measurement of molecular weight distribution. In the case of mild condensation, addition of 5% methanol suppressed the production of the residues. At the same time, the liquefaction rates overall were faster than the case without methanol. It was inferred that the existence of methanol lowered the amount of combined phenol which could be the reaction site of the condensation reaction. On the other hand, larger amounts of methanol (100%) retarded the liquefaction rate and the consumption rate of phenol. The actual reaction temperature in the reactor was lower than the setup temperature of the oil bath when the methanol was added. The investigation of the IR spectra showed that there were almost no differences between the functional groups of the liquefied products obtained with and without methanol. The addition of small amounts of methanol could be applicable because the disadvantages of methanol addition could be reduced.