Green synthesis of hydrocalumite-type compounds and their evaluation in the transesterification of castor bean oil and methanol Manuel Sánchez-Cantú a,⇑ , Lydia M. Pérez-Díaz a , Nancy Tepale-Ochoa a , Valeria J. González-Coronel a , María E. Ramos-Cassellis a , David Machorro-Aguirre a , Jaime S. Valente b a Benemérita Universidad Autónoma de Puebla, Facultad de Ingeniería Química, Avenida San Claudio y 18 Sur, C.P. 72570 Puebla, Mexico b Instituto Mexicano del Petróleo, Eje Central #152, C.P. 07730 México D.F., Mexico highlights " Hydrocalumite-like compounds prepared by a simple and environmentally-friendly method. " Catalyst precursor for biodiesel production. " Thermal treatment enhanced biodiesel obtaining. " Full conversion of the raw materials was achieved with the annealed sample at 700 °C. " The catalyst deactivation was caused by the active phase leaching. graphical abstract article info Article history: Received 14 March 2012 Received in revised form 15 June 2012 Accepted 19 June 2012 Available online 2 July 2012 Keywords: Transesterification Biodiesel Anionic clay Hydrocalumite abstract The search for alternative sources of energy is more important than ever as the extraction of petroleum, the greenhouse gas emissions and the climate changes are getting extremely complicated an unsafe for mankind. In order to find renewable, cheaper and easier methods to obtain energy, a hydrocalumite-type compound was synthesized by a green method here presented and evaluated in the transesterification of castor oil with methanol to obtain biodiesel. The pristine material and its thermally decomposed prod- ucts were analyzed by X-ray powder diffraction, thermogravimetric analysis and Scanning Electron Microscopy. Biodiesel conversion was determined by 1 H NMR. The effect of the precursors’ thermal acti- vation on biodiesel production was evaluated at 300, 500 and 700 °C. Similar results were obtained with the solids produced by a conventional method, demonstrating that the materials prepared by the new technique disclosed not only comparable physicochemical properties, but also analogous catalytic activ- ity; revealing the feasibility of producing high active catalyst’s precursors by a simple, economic and environmentally-friendly method. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction In 2009 the European Union parliament through the approval of the Commission and Social Committee, issued the Directive 2009/ 28/EC, which mandates a 20% share of energy from renewable sources and a 10% share of energy from renewable sources in trans- port in Community energy consumption, which will have to be achieved by 2020 [1]. This tendency is expected to gradually be ac- cepted worldwide. In this sense, biodiesel (BD) has become an alternative for the partial or total substitution of petrodiesel. In the vast literature reported it is generally found that BD production is based on edible oils such as sunflower, canola, soybean, olive, cotton, rapeseed, and palm [2–7]. In fact, in 2008 about 84% of the world’s biodiesel production was covered by rapeseed oil. The remaining portion was from sunflower oil (13%), palm oil (1%), soybean oil and others (2%) [2]. The former has originated a severe controversy since nowadays it has to be decided whether these oils must be used for human consumption or for BD 0016-2361/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2012.06.078 ⇑ Corresponding author. Tel.: +52 55 2295500x7265. E-mail address: manuel.sanchez@correo.buap.mx (M. Sánchez-Cantú). Fuel 110 (2013) 23–31 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel