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Viscosity η and density ρ of binary mixtures of coconut + colza and coconut + soybean biodiesel have been measured over the whole composition range at T = (293.15, 313.15, 333.15, 353.15, and 373.15) K and at atmospheric pressure. Densities and viscosities data were correlated with R-square adjustment and the Andrade equation, respectively, with good agreement. The deviations of viscosities (Δη) have been calculated from the experimental data. To predict the density and viscosity we have used Joback’s method and a group contribution model proposed by Ceriani et al. (J. Chem. Eng. Data 2008, 53, 877−880), respectively.

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This work investigates the use of a layered Ca-Al double hydroxide (hydrocalumite) as precursor, after its thermal activation, of base catalysts for the methanolysis of sunflower oil. Above 750 °C, hydrocalumite is transformed into a mixture of CaO and mayenite (Ca 12 Al 14 O 33 ). Another Ca-Al material obtained under similar experimental conditions was also studied, but using the Ca/Al molar ratio of the mayenite, 12:14. A sunflower oil conversion of 97% has been reached with a methanol/oil molar ratio of 12:1, a reaction temperature of 60 °C, and 1 wt % of the CaAl-2:1 catalyst. This catalyst needs to be previously activated at 500 °C in helium atmosphere, which is an activation temperature at least 200 °C lower than that required to revert the CO 2 poisoning in bulk and supported CaO catalysts.