Microwave-Assisted Conversion of Lignin

LigninLignin is the most abundant natural aromatic compounds in the world consisting of three phenylpropane unitsPhenylpropane units : coumaryl alcoholCoumaryl alcohol , coniferyl alcoholConiferyl alcohol and syringylSyringyl alcohol, which are cross-linked to each other with a variety of different chemical bondsChemical bonds . Although the compositional property of lignin has great potential as a feedstockFeedstock for high-value chemicalsChemicals , its complex structure requires development of efficient procedures. The application of microwave to the transformation of lignin by microwaveMicrowave pyrolysisMicrowave pyrolysis to produce bio-oilBio-oil with or without catalystsCatalysts has proven to be feasible and efficient, which will be as the emphasis in this chapter. In addition, lignin (or lignin model compoundsLignin model compounds ) degradationDegradation to produce phenolPhenol , acetovanillone or other phenolic compoundsPhenolic compounds with microwave as Microwave as heating heatingMicrowave as heating source will also be introduced. The objective of this chapter is to introduce the major works in microwave-assisted conversion of lignin and the methods to summarize the methods for microwave direct chemical (or catalytic) conversion of lignin to high value-added products.