9

Levulinic acid (LA) has long been identified as a potentially significant bio-platform molecule, being highlighted in the 2004 US Department of Energy report as one of 12 bioderived compounds of interest. LA contains both carboxylic acid and ketone functionality, both of which can be further converted to give a range of products. The main interest in LA is as a route to liquid fuels and oxygenated additives via cyclisation to lactones or through reactions with bio-derived alcohols to give a variety of esters. These compounds can also all be applied as bio-derived solvents, an area which continues to grow in significance, especially in relation to increasing legislation around conventional compounds. LA has also been shown to be a feedstock for the production of pharmaceuticals, food additives, agri-products and polymers.

Like FDCA (BioChem 10 – 2), LA is formed from acid hydrolysis of cellulose via HMF (BioChem 10 – 4) and as such is based on the same well established routes to production. LA can be produced from free sugars, with the earliest synthesis reported being from fructose, as it this most easily converted to HMF. Any C6 sugar can act as feedstock as it can be isomerised to fructose under acidic conditions and aided further by certain catalysts. However the employment of 1st generation feedstock sugars is not an economically viable for low value products such as fuels in addition to being better utilised as a food stuff. As such, the majority of recent LA research has focused on pure cellulose or lignocellulosic biomass as feedstock due to both low cost and high abundance, especially for the latter.

LA market is currently small, with GFBiochemicals producing 10kt per annum and is the only industrial scale producer utilising biomass as feedstock. However LA has current applications in the pharmaceutical sector, where the calcium salt is incorporated into a number of medications. The alkyl esters can be applied in the flavour and fragrance industry.