YXY is a brand name for furan based building blocks developed by the high throughput company Avantium. Furanics (e.g. 2,5-Furandicarboxylic acid, HMF, furfural) have been referred to as “Sleeping Giants” because of their enormous market potential, as evidenced by the research of DuPont and DSM in this area and its position in the US Department of Energy top 12 of high-potential biobased products.[1] YXY building blocks have a different manufacturing process than the traditional pursued routes towards HMF (minimizing the water content without using exotic solvents such as ionic liquids and DMSO/MIBK). YXY is a trademark of Avantium of the Netherlands.
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HMF and MMF are key molecules into the conversion of carbohydrates into liquid biofuels, polymers and chemicals. Oxidation of HMF and MMF results in the formation of 2,5-furandicarboxylic acid, which has been proposed as a replacement of terephthalic acid for the production of a wide range of plastics including polyesters and polyamides. The potential applications of furan based building blocks for polymer applications has been extensively reviewed by Gandini.[2] In collaboration with NatureWorks (subsidiary of Cargill) the development of YXY polyesters was initiated. This collaboration has already demonstrated that YXY polyesters have properties that are very similar or even better (barrier properties) than regular PET, allowing to develop a green version of this bulk polymer. Avantium has entered into a partnership with Teijin Aramid, producer of Twaron, to develop YXY for aramides. HMF and MMF can be converted to a wide range of mono- and dialkoxymethyl ethers.[3] The compounds can also further converted to 2,5-dimethylfuran (DMF) and valeric biofuels.[4] Several heavy duty Diesel engine tests have demonstrated the potential of YXY molecules as a green component to blend with Diesel fuel.[5]
Already for many decades, the potential of furanic products, obtained from carbohydrates, has been identified. However, despite the impressive array of useful furfural and HMF-derived intermediate chemicals in literature,[1][6] HMF is still not produced on an industrial scale. Historically it is interesting to look at the two earlier HMF commercialization attempts that made it to the pilot plant stage. The main problem associated with producing HMF is that in principle HMF is an intermediate in the dehydration of hexoses to Levulinic acid and formic acid. In other words, HMF is not stable under the acidic conditions required for its formation. Both attempts used different strategies to handle this problem. The first of these is by Roquette Freres in France[7] who introduced a two-phase process in which the polar phase contained the hexose feed and an organic phase such as methylisobutyl ketone (MIBK) or dimethoxyethane (DME) to extract the HMF out of the reactive phase directly after formation. The second approach by Südzucker was based on water as diluent and conditions that maximized HMF selectivity, rather than maximizing HMF yield or hexose conversion. The process involved the use of a homogeneous catalyst such as sulfuric acid and an ion-exchange resin to separate the catalyst from the reaction product.[8] When under these conditions sucrose or glucose was used as a feed, no conversion to HMF is observed, which is a distinct disadvantage given the lower price and abundant availability of sucrose and glucose. Only in the presence of dimethylsulfoxide (DMSO), dimethylformamide (DMF) and dimethylacetamide (DMA), ionic liquids or in a sub- and supercritical mixture of acetone and water reasonable HMF yields from starting materials other than fructose were obtained.[9] Concluding, the known methods for the synthesis of HMF with economic potential mostly start from fructose and typically do not give high yield, partly attributable to the instability of HMF under the acidic reaction conditions required for HMF formation. Low conversion routes in water and in biphasic solvent systems both have disadvantages and no commercial process could be developed using these approaches.
Furanics were never commercialized because they could not be produced in an economic fashion. Avantium has discovered a revolutionary chemical, catalytic process that enables the economic production of Furanics on basis of a wide range of carbohydrates. Its patented YXY technology[3] that converts biomass into YXY building blocks (Figure 1) for both polymers as well as biofuels applications. It uses carbohydrates (C6 sugars) as feedstock to make biomaterials through a catalytic process of dehydration, oxidation and polymerization. To make biofuels both C5 and C6 sugars can be used. Via dehydration and etherification / hydrogenation you make components for Diesel, jetfuels and gasoline (Figure1). The necessary co-reactants (H2, methanol, ethanol) can be produced through gasification/Fischer Tropsch synthesis of the humins/lignin fraction. YXY shows attractive economics and a very promising environmental footprint. The process has a good fit with existing chemical production assets, allowing to retrofit existing production assets to switch from fossil feedstock to renewable resources. Currently a pilot plant is being built on the Chemelot Campus in Geleen[10], the Netherlands[11] (Figure 2). The objective of this pilot plant is to optimize the production process and to demonstrate the process at larger scale, as well as the production of trial quantities of YXY for product development purposes.