DOI: 10.1002/cssc.201300531 Biomass-Derived Chemicals: Synthesis of Biodegradable Surfactant Ether Molecules from Hydroxymethylfurfural Karen S. Arias, Maria J. Climent,* Avelino Corma,* and Sara Iborra [a] Introduction In recent years, the search for new pathways to obtain chemi- cals from renewable feedstocks has considerably intensified. The transformation of selected platform molecules is the most appropriate approach to identifying molecules that can replace those obtained from petrochemistry, giving products with dif- ferent molecular structure but with similar function, or gener- ating molecules that display new or improved properties. The transformation of 5-hydroxymethylfurfural (HMF) in valuable furan derivatives for biofuel and fine chemical industries is a clear example of this approach. [1–4] HMF can be produced by acid-catalyzed dehydration of lignocellulosic building blocks such as glucose and fructose. The nonedible nature of lignocel- lulose, which implies no competition with food, makes this an important raw material for future biorefineries. Following our ongoing program for identifying new environ- mentally benign routes for transformations of HMF into valua- ble chemicals, [5] we have herein studied the conversion of HMF into a new class of biodegradable anionic surfactants with the structure of 5-alkoxymethylfuroate. Surfactant agents containing a nonpolar hydrophobic tail and a hydrophilic head are present in many products com- monly used in our society, such as in food production, agricul- tures, textile, cosmetic products, detergents, and others. Among them, anionic surfactants which include sulfonates, car- boxylates, phosphonates, and sulfates are used predominantly in detergents industries. Their ecological impact is especially important when they are used as detergents. For example, the high utilization of linear alkylbenzene sulfonates may be par- tially linked to their high biodegradability. [6] Biodegradability of surfactants could be even improved when they are prepared from renewable biomass feedstocks, and important work de- veloping biomass-derived surfactants has been performed in the last years and recently reviewed. [6, 7] Considering that 5-hydroxymethylfurfural and fatty alcohols obtained from carbohydrates and triglycerides, respectively, are completely based on natural resources and biodegradable compounds, we hypothesized that their combination into a 5-alkoxymethylfuroate molecule would lead to a biodegradable surfactant. Furthermore, it has been previously reported that 5-hydroxymethylfurfural-derived structures such as 2,5-furandi- carboxylic acid or its mono-n-decyl ester sodium salt, [8] and 5-alkoxymethyl-alpha-hydroxyfuranmethane sulfonic acid sodi- um salts [9] are considered as biodegradable anionic surfactants. Notably, the synthesis of 5-alkoxylfuroic acids have been pre- viously reported in patent literature through the Williamson synthesis, starting from 5-chloro-2-furoic acid and fatty alco- hols using stoichiometric amounts of alkaline hydrides. [10] Here, we present a new sustainable and more efficient one-pot–two- steps catalytic process to produce 5-alkoxymethyl furoic acid salts starting from HMF. The process involves the selective etherification of the 5-hydroxymethyl group with a fatty alco- hol, followed by a selective oxidation of the formyl group to the alkaline carboxylate (Scheme 1). Concerning HMF etherification, Avantium has recently intro- duced a new bio-based chemical etherification of HMF with methanol or ethanol [11] or fatty alcohols for valuable compo- nents for biodiesel. For instance, 5-(ethoxymethyl)furfural-2-car- A new class of biodegradable anionic surfactants with struc- tures based on 5-alkoxymethylfuroate was prepared starting from 5-hydroxymethylfurfural (HMF), through a one-pot–two- steps process which involves the selective etherification of HMF with fatty alcohols using heterogeneous solid acid, fol- lowed by a highly selective oxidation of the formyl group with a gold catalyst. The etherification step was optimized using aluminosilicates as acid catalysts with different pore topologies (H-Beta, HY, Mordenite, ZSM-5, ITQ-2, and MCM-41), different active sites (Bronsted or Lewis) and different adsorption prop- erties. It was shown that highly hydrophobic defect-free H-Beta zeolites with Si/Al ratios higher than 25 are excellent acid catalysts to perform the selective etherification of HMF with fatty alcohols, avoiding the competitive self-etherification of HMF. Moreover, the 5-alkoxymethylfurfural derivatives ob- tained can be selectively oxidized to the corresponding furoic salts in excellent yield using Au/CeO 2 as catalyst and air as oxi- dant, at moderated temperatures. Both H-Beta zeolite and Au/CeO 2 could be reused several times without loss of activity. [a] K. S. Arias, Prof. M. J. Climent, Prof. A. Corma, Prof. S. Iborra Instituto de Tecnología Química (UPV-CSIC) Universitat Politcnica de Valncia Avda dels Tarongers s/n, 46022, Valencia (Spain) Fax: (+ 34) 963877809 E-mail: acorma@itq.upv.es mjcliol@qim.upv.es Supporting Information for this article is available on the WWW under http://dx.doi.org/10.1002/cssc.201300531.  2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim ChemSusChem 0000, 00, 1 – 12 &1& These are not the final page numbers! ÞÞ CHEMSUSCHEM FULL PAPERS