Please cite this article in press as: D.A. Cantero, et al., Selective transformation of fructose and high fructose content biomass into lactic acid in supercritical water, Catal. Today (2014), http://dx.doi.org/10.1016/j.cattod.2014.11.013 ARTICLE IN PRESS G Model CATTOD-9354; No. of Pages 7 Catalysis Today xxx (2014) xxx–xxx Contents lists available at ScienceDirect Catalysis Today j our na l ho me page: www.elsevier.com/locate/cattod Selective transformation of fructose and high fructose content biomass into lactic acid in supercritical water Danilo A. Cantero a,b , Luis Vaquerizo a , Celia Martinez a , M. Dolores Bermejo a , M. José Cocero a,∗ a High Pressure Processes Group, Department of Chemical Engineering and Environmental Technology, EII Sede Mergelina, University of Valladolid, 47011 Valladolid, Spain b Department of Applied and Industrial Chemistry, Faculty of Exact, Physical and Natural Sciences, National University of Cordoba, Av. Velez Sarsfield 1611, 5000 Cordoba, Argentina a r t i c l e i n f o Article history: Received 23 September 2014 Received in revised form 3 November 2014 Accepted 5 November 2014 Available online xxx Keywords: Biomass Biorefinery Inulin Lactic acid Molasses Pyruvaldehyde a b s t r a c t The reactions of fructose in sub- and supercritical water were analyzed changing the chemical properties of the reaction medium (Kw, ε, pH and free radical kidnapers). The reactions were performed in a contin- uous reactor at 260 ◦ C, 330 ◦ C and 400 ◦ C, at 23 MPa and 27 MPa using water as reaction medium. The pH of the medium was modified using oxalic acid and sodium hydroxide. Also, scavengers (TEMPO and BHT) were tested in order to determine its influences in the radical reactions. The main product of fructose hydrolysis in supercritical water was pyruvaldehyde (>80%, w·w -1 ) at 400 ◦ C and 23 MPa with a reaction time of 0.7 s. Furthermore, the reactions of fructose were analyzed in combination with glucose. It was determined that different retro-aldol condensation products can be obtained depending on the start- ing material. Fructose produced mainly C-3 molecules (pyruvaldehyde) and glucose produced mainly C-2 molecules (glycolaldehyde). The isomerization of fructose to glucose was negligible and so was the production of C-2 when the starting material was fructose. The yield of 5-HMF was negligible when the starting material was glucose. Three different biomass enriched in fructose (sugar cane molasses, beet molasses and inulin) were tested as starting material for the hydrolysis process. It was determined that lactic acid (50%, w·w -1 ) was the main product of molasses and inulin hydrolysis in a supercritical water medium modified with basic catalysts. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Processes that involve the use of biomass as raw material have been intensively studied in the near past looking for new processes capable of producing biocompounds, biofuels and bioenergy using “green” solvents. One way to achieve these processes is by using selective and efficient reaction mediums. The vegetal biomass is an alternative as raw material, being cellulose (glucose resource) one of the main component of biomass [1,2]. A method to break cellu- lose into sugars (mainly glucose and fructose) was developed in a previous work obtaining as product a solution of sugars with low formation of derived products, such as 5-hydroxymethylfurfural (5-HMF) in a supercritical water medium [3]. Another interesting raw materials for the production of chemicals are the by-products ∗ Corresponding author. Tel.: +34 983423166; fax: +34 983423013. E-mail addresses: da.cantero@iq.uva.es (D.A. Cantero), mjcocero@iq.uva.es (M.J. Cocero). of the food and agriculture industry with high amounts of carbo- hydrates, such as the sugar cane and beetroot molasses produced in the sugar manufacturing process. These by-product streams are composed mainly of sucrose, glucose and fructose. Lactic acid is a product of interest of many industries; it is used in food, chemical, pharmaceutical and cosmetic industries. Nowadays, the most valuable alternative for the use of lactic acid would be the production of the biodegradable lactic acid polymer [4]. The lactic acid can be produced by chemical synthesis or by carbohydrates fermentation. However, lactic acid is industrially produced mainly by fermentation [4]. Glucose can be modified in a hot pressurized water medium in order to obtain added value products like lactic acid [5–10]. The production of lactic acid was achieved in a previous work of our group by using NaOH as medium modifier [9]. The production of lactic acid was also studied using by-products streams like sugar cane molasses [11,12]; paper sludge [13] or other cellulosic biomass [14,15] as raw materials. Also the production of lactic acid was studied using fructose as raw mate- rial [16]. However, several works in literature attempt to produce http://dx.doi.org/10.1016/j.cattod.2014.11.013 0920-5861/© 2014 Elsevier B.V. All rights reserved.