No abstract

The conversion of bio-mass into bio-fuel using solvents that come from bio-mass itself is being more and more important for the concern of renewable development and CO 2 -netural. Formic acid was used as an in situ hydrogen donor for the liquefaction of wheat straw alkali lignin. It was found that the addition of ethanol improved the yield of mono-phenols remarkably. Although ethanol exhibited a poor effect in the liquefaction of lignin, it was found to be a good assistant solvent for improving the mono-phenol yield of formic acid system significantly.

Dilute lignin solution was successfully digested into colorless and clarified liquor under microwave-assisted oxidative digestion with hydrogen peroxide. High dosage of hydrogen peroxide is needed to effectively digest lignin, but excessive hydrogen peroxide may lead to recondensation of formed fragments in digested lignin. Microwave irradiation greatly facilitates the oxidative digestion of lignin. Compared with conventional heating technique, microwave-assisted digestion achieves the same or higher digestion rate within a shorter time and/or at lower temperature. After digestion, total organic carbon content of lignin solution decreases by 93.9%, and a small amount of aliphatic alkane, alcohol, acid and ester are formed via the cleavage of aromatic rings as well as the deprivation of side chains in original lignin. This work provides an alternative way to efficiently treat spent pulping liquor.