Furfural, hydroxymethylfurfural (HMF), levulinic and formic acids are natural precursors that can be employed for the synthesis of a range of bio-products as chemicals, fuel precursors and solvents. They can be obtained from biomass, a sustainable resource that is gaining importance as an alternative industrial feedstock to limit the dependence on non-renewable feedstocks. Then, these platform chemicals can be produced in lignocellulosic biorefineries, with are focused in the sustainable processing of biomass into a spectrum of marketable products and bioenergy.
Currently, the research developed by EQ2 group regarding these topics is focused in:
Furfural is produced by hydrolysis and dehydration of pentosans that constitute biomass hemicelluloses. Xylan is the most important pentosane, and its hydrolysis results in the formation of xylose, which can be dehydrated into furfural at high temperatures. The main drawback of the commercial furfural production processes is the participation of parallel reactions leading to the formation of black, resinous products, denoted as humins. These side reactions include furfural condensation and reactions of furfural with its intermediates (furfural resinification) which are responsible for decreased yields.
Then, the development of new technologies for furfural production is essential to improve yields. As alternative, furfural production in aqueous media can be improved by using biphasic systems, where the furfural generated in the aqueous phase is continuously transferred to the organic one, limiting the extent of parallel reactions. Some proposals to improve furfural yields are the use of selective solvents in modified aqueous media, new catalyst or distillation as a technology for furfural recovery and solvent recycling.
HMF, formic and levulinic acids
HMF is obtained from hexoses that constitute lignocellulosic biomass. Glucose units constitute cellulose, and galactose and mannose are present in hemicelluloses of softwood. Hexoses dehydration in aqueous acidic media lead to HMF formation. However, parallel reactions lead to the formation of non-desired byproducs, particularly humins, that affect negatively to HMF yields and selectivities.
In aqueous media, HMF can rehydrate to levulinic acid, then, HMF is an intermediate of the reaction. Since HMF and levulinic are platform chemicals that generate high interest, their obtaining is focused to the development of specific technologies for each case. Between the multiple alternatives, the use of different solvents and catalysts is proposed.
Additionally, formic acid is a co-product generated with levulinic acid by HMF rehydration that can be considered for its valorization to multiple industrial applications as formaldehyde, plasticizers, textile and pharmaceutical products.
Three R&D projects are focused in this line, funded by the Ministry of Science and Innovation