Recent Catalytic Advances in the Chemistry of Substituted Furans from Carbohydrates and in the Ensuing Polymers

Liquid‐Phase Catalytic Processing of Biomass‐Derived Oxygenated Hydrocarbons to Fuels and Chemicals

“…Selective dehydration of hexoses leads to formation of HMF, a polyfunctional chemical intermediate that has the potential to be a substitute for petroleum-based building blocks for various types of polymers (e.g., polyamides, polyesters). [20,22] The formation of HMF occurs by the loss of three water molecules in an acid-catalyzed dehydration of fructose or glucose. However, HMF production is generally more selective from ketohexoses (fructose) as compared to aldohexoses (glucose).…”

“…[18] On the other hand, selective hydrogenation of the C=O bond of furfural or HMF leads to furfuryl alcohol (e.g., for furanic resins, plastics) [39] or 2,5-dihydroxymethylfuran (a monomer used in the production of new polymeric material). [22] Selectivity for the hydrogenation reaction depends on factors such as solvent, partial pressure of hydrogen, and the nature of the catalyst. Production of tetrahydrofurfuryl alcohol (THFA), a solvent in various industrial applications, requires hydrogenation of all the unsaturated bonds in furfural.…”

“…[19] However, HMF is not yet a high-volume chemical in view of difficulties in cost-effective production, even though many researchers have shown promising results in a wide range of potential applications. [6,[20][21][22] Production of HMF from sugars is a problem that illustrates the selectivity challenges involved in the processing of highly functionalized carbohydrate molecules. Dehydration of hexoses has been studied in water, organic solvents, biphasic systems, ionic liquids, and near-or supercritical water, using a variety of catalysts such as mineral and organic acids, organocatalysts, salts, and solid acid catalysts such as ion-exchange resins [23] and zeolites [24] in the temperature range of 370-470 K. Although evidence exists that supports both the open-chain and the cyclic fructofuransyl intermediate pathways (Scheme 1), it is clear that the reaction intermediates and the HMF product degrade by means of various processes.…”

Synergy of boric acid and added salts in the catalytic dehydration of hexoses to 5-hydroxymethylfurfural in water

“…The molecule constitutes a platform compound that can be converted into a wide range of industrially important chemicals. 7, 8 In this context, the oxidation product of HMF, 2,5-furandicarboxylic acid (FDA), is of specific interest as it can potentially replace terephthalic acid in polyester manufacturing (Scheme 1). 9 Currently the most successful efforts to produce HMF have been done in ionic liquids, 10-12 high-boiling organic solvents (e.g.…”

Process Options for the Catalytic Conversion of Renewables into Bioproducts

“…Furan Derivatives Catalytic processes used to obtain furan derivatives from carbohydrates and the catalytic routes from furan intermediates to chemicals and polymers have been reviewed by Moreau et al [27]. Some of the main reactions are summarized in Fig.…”