ARTICLE IN PRESS JID: JTICE [m5G;April 7, 2016;21:42] Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–12 Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice Experimental and modelling approach to the catalytic coproduction of glycerol carbonate and ethylene glycol as a means to valorise glycerol Jesús Esteban a , Miguel Ladero b,∗ , Elena Fuente b , Ángeles Blanco b , Félix García-Ochoa b a School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. b Department of Chemical Engineering, College of Chemical Sciences, Complutense University of Madrid, 28040 Madrid, Spain. a r t i c l e i n f o Article history: Received 29 December 2015 Revised 7 March 2016 Accepted 15 March 2016 Available online xxx Keywords: Glycerol carbonate Ethylene glycol Kinetic model Solventless synthesis FBRM a b s t r a c t Due to the current scenario of biodiesel industry facing a challenge in the management of its by-product glycerol, its conversion into value-added products is of the greatest significance. This work presents an experimental and modelling approach to the simultaneous production of glycerol carbonate and ethylene glycol, two highly valuable chemicals, under mild operating conditions reaching yields to the products as high as 96% using the inexpensive catalyst K 2 CO 3 . Physical (focused beam reflectance measurement) and chemical (HPLC) analyses were employed to monitor the evolution of the chemical reaction between glycerol and ethylene carbonate, finding that the reacting system evolves from liquid–liquid dispersion to single-liquid system at a conversion of glycerol of 0.34. After minimising mass transfer limitations (800 rpm), a study of the reaction kinetics was performed varying temperature, molar ratio of reactant species and catalyst concentration. The model offering the best fit reflected with high accuracy the phys- ical transition of the system, the reversibility of the reaction and the deactivation of the catalyst, with the following parameters: 91.7 ± 2.7 kJ/mol and 93.9 ± 15.9 kJ/mol for the direct and reverse reactions, respectively, with the deactivation constant having a value of 0.36 ± 0.06 s −1 . © 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Policies aimed at increasing gradually the share of use of en- ergy based on renewable sources have been promoted all over the world during the early years of the present century, especially in the European Union. Subsequently, a boom of the biodiesel indus- try has taken place, which has led to an oversaturation of the glyc- erol (Gly) market and a subsequent price drop [1]. Awareness of this situation has led to multiple efforts being undertaken to em- ploy this by-product of biodiesel as feedstock in order to improve the economics of the process and approach the Green Chemistry principle of preventing waste generation. The chemical features of glycerol have made it subject to very diverse transformations to obtain many interesting products, which have been accounted for in a significant number of thorough reviews [2,3]. Some examples of the synthetic pathways followed to valorise glycerol include es- terification of different organic acids [4,5], hydrogenolysis to 1,2- propanediol [6] or dehydration reactions [7]. The synthesis of glycerol carbonate (GC) has been lately pur- sued through the transesterification of glycerol with organic car- ∗ Corresponding author. Tel.: +34 913944164; fax: +34 913944179. E-mail address: mladero@quim.ucm.es, mladerog@ucm.es (M. Ladero). bonates, for they present the advantages of (i) being an indirect manner of CO 2 fixation and (ii) allowing the use of milder oper- ating conditions [8]. Operation with dimethyl carbonate (DMC) at atmospheric pressure from 60 to 75 °C has been described with quantitative yield to product [9–18]. Likewise, synthesis with di- ethyl carbonate has been performed with positive results, though the reaction conditions were more severe: large molar excesses of diethyl carbonate to Gly have been used (17:1 to 21:1) and use of temperatures of 130 °C have been described using different types of hydrotalcites as catalysts [19,20]. Finally, ethylene carbonate (EC) has been put to use in this reaction in a procedure in absence of any catalyst at temperatures ranging from 100 to 140 °C [21] and also in catalytic processes with Mg/Al hydrotalcites and MCM41 based materials at temperatures between 50 and 80 °C and molar excess of EC to Gly of 2 to 1 [22,23]. The interest of GC as a biobased product has been notorious in the past few years bearing in mind its broad spectrum of applica- tions in several fields, mainly as a green solvent in analytical ap- plications [24], Li-ion batteries [25] or as reaction media [26,27]. In addition, it has been supported on immobilised liquid membranes for CO 2 separation [28] or as an additive in construction materials [29]. As a building block, it has been used in the synthesis of fur- ther products like polymers for adhesives [30] or esters with sur- factant features [31]. http://dx.doi.org/10.1016/j.jtice.2016.03.031 1876-1070/© 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Please cite this article as: J. Esteban et al., Experimental and modelling approach to the catalytic coproduction of glycerol carbonate and ethylene glycol as a means to valorise glycerol, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.03.031