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To contribute to the search for an oxygen-free biodiesel from vegetable oil, a process based in the oleic acid hydrodeoxygenation over Ni/γ-Al2O3 catalysts was performed. In this work different wt % of Ni nanoparticles were prepared by wetness impregnation and tested as catalytic phases. Oleic acid was used as a model molecule for biodiesel production due to its high proportion in vegetable oils used in food and agro-industrial processes. A theoretical model to optimize yield of n-C17 was developed using size, distribution, and wt % of Ni nanoparticles (NPs) as additional factors besides operational conditions such as temperature and reaction time. These mathematical models related to response surfaces plots predict a higher yield of n-C17 when physical parameters of Ni NPs are suitable. It can be of particular interest that the model components have a high interaction with operation conditions for the n-C17 yields, with the size, distribution, and wt % of Ni NPs being the most significant. A combination of these factors statistically pointed out those conditions that create a maximum yield of alkanes; these proved to be affordable for producing biodiesel from this catalytic environmental process. [ABSTRACT FROM AUTHOR]

Abstract: Thin films of paramelaconite, tenorite and their mixtures were deposited on fiberglass substrate by chemical vapor deposition and catalytically evaluated by isopropanol oxidation at low temperatures between 150 and 275°C. Copper oxides were deposited using bis(2,4-pentanedionato)copper(II) as a precursor and oxygen as carrier-reactant gas. Original crystalline phases deposited on fiberglass at different temperatures or formed subsequently were characterized by several analytical techniques. Films gave crystallite sizes from 6.5 to 8.4nm and a thickness around 230nm. The fiberglass with a paramelaconite film showed a relatively high catalytic activity, more than 40%, at 250°C. Nevertheless, the fiberglass with a tenorite film exhibited a catalytic activity of only 10% at the same temperature. Above 250°C the paramelaconite experienced a notable deactivation after which the catalytic activity decreased to 6.7% at 350°C and after this, the catalyst could not be reused. This activity loss was probably due to changes in the chemical phases on fiberglass by effect of temperatures above 250°C. [Copyright &y& Elsevier]

Cu2O–CuO and CuO thin films on a fiberglass substrate were prepared by chemical vapor deposition (CVD) and then catalytically evaluated by cyclohexane oxidation. The fiber with a Cu2O–CuO film showed a high catalytic activity at low temperatures, for example 43% at 350 °C, and a good selectivity to cyclohexanol production (37% at 300 °C). The fiber with a CuO film exhibited a higher catalytic activity, for example 48% at 350 °C, with a high yield of cyclohexanone (37% at 250 °C). A CuO/SiO2 catalyst with the same CuO content gave a result similar to the CuO/fiberglass system under the same conditions examined but, on the other hand cyclohexane was cleaved giving a higher selectivity to hexenes, 30% at 250 °C. The effect of reaction temperature on the catalytic activity and selectivity of cyclohexane oxidation were investigated. At 300 °C the steady-state catalytic performance of the CuO/fiberglass experienced a slight deactivation after 4 h time-on stream from 40% to 38% of conversion, after which, the catalyst could be reused apparently without any activity loss. [Copyright &y& Elsevier]