Lignin, a component of plant cell walls, gives plants the strength to grow tall but this strength is a barrier to turning plants into biofuels. So researchers in the UK have devised an efficient way to make complex model compounds of lignin to help them figure out the best way to break lignin down.
Unlike cellulose, a plant cell wall component with a repeating polymer structure, lignin is a complex and random polymer. The chemical units are linked by different connectivities, so one single process cannot attack all of these bonds. Previously, monomers and dimers were used to model chemical linkages of lignin, but were too simple for the study of lignin itself. More complex trimers, tetramers and hexamers have been synthesised, but with inefficient, low-yielding methods.
Work undertaken in Gary Sheldrake’s group at Queen’s University Belfast looks set to significantly advance the study of lignin with the development of a new scalable synthetic route for complex model lignin oligomers that produces several grams of product, and can easily be performed in a standard lab. ‘The ultimate aim was to get a synthesis that worked, but we tried as far as possible to avoid ungreen solvents and harsh conditions,’ notes Sheldrake.
Read the original journal article in Green Chemistry:
An efficient and flexible synthesis of model lignin oligomers
W. Graham Forsythe, Mark D. Garrett, Christopher Hardacre, Mark Nieuwenhuyzen and Gary N. Sheldrake
Green Chem., 2013, DOI: 10.1039/C3GC41110A, Paper