Effect of Size and Distribution of Ni Nanoparticles on γ-Al2O3 in Oleic Acid Hydrodeoxygenation to Produce n-Alkanes

Abstract

Abstract:To contribute to the search for an oxygen-free biodiesel from vegetable oil, a process based in the oleic acid hydrodeoxygenation over Ni/γ-Al 2 O 3 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-C 17 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-C 17 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-C 17 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.

Fatty Acid Deoxygenation in Supercritical Hexane over Catalysts Synthesized Hydrothermally for Biodiesel Production

“…This dependence can be attributed to a first‐order reaction, as for the noncatalytic process. The change in the reaction order for the Ni‐containing catalyst indicates higher substrate adsorption on the catalyst surface in comparison with the Co‐containing catalyst , . This can also explain the higher activity of 10 % Ni/HPS.…”

“…The rate of stearic acid consumption in deoxygenation in the presence of the Ni‐containing catalyst is slightly higher than that for the Co‐containing catalyst. The higher activity of the Ni‐containing catalyst can be explained by the fact that nickel has a higher impact on the protonation/dissociation of the proton‐donor solvent .…”

Physicochemical effect of Pt nanoparticles/γ‐Al2O3 on the oleic acid hydrodeoxygenation to biofuel

“…Three polynomial models were developed to predict the yield of n‐ C 17 regarding to temperature ( T ), reaction time ( t ), and any of the following three variables that complete this statistical study, i.e., wt % of Pt ( W ), average particle size ( S ), and dispersion of Pt nanoparticles ( V ), where S and V were calculated statistically from TEM images of the catalyst (Figure ). In the reviewed literature, there is a comparison of these important catalytic parameters ( W , S, and V ) related to Ni catalytic performance on biofuel production . Hence, an analysis of response surface including these three variables and three models with different independent variables was performed: Model A) with T , t , and W , as variables; Model B) with T , t , and S , as variables; Model C) with T , t, and V , as variables.…”

Catalytic Deoxygenation of Hexadecyl Palmitate as a Model Compound of Euglena Oil in H2 and N2 Atmospheres

“…Both, C15H31COOC16H33 conversion and the C10-C16 yield obtained in N2 atmosphere, were much lower than those obtained in H2 atmosphere ( Figure 6) over Pd/Mg(Al)O after reaction at 300 °C for 2 h. This indicates that H2 greatly improves the deoxygenation of C15H31COOC16H33, and that it is difficult to produce hydrocarbons from C15H31COOC16H33 in N2 atmosphere. The use of basic hydrotalcite, acidic H-ZSM-5, and Pd/C has been reported for the deoxygenation of triglycerides or fatty acids in N2 or Ar atmospheres [14,17,18]. As shown in Table 1, the basic catalyst Mg(Al)O without Pd gave low conversion (23.3%) and a low yield of C10-C16 hydrocarbons (15.1%) for the reaction in N2 atmosphere.…”

“…)-supported catalysts possess high activities for the deoxygenation of triglycerides and fatty acids in H 2 atmosphere [15][16][17]. However, the deoxygenation of triglycerides in N 2 atmosphere (without H 2 ) is an important subject, because H 2 is expensive and may be difficult to obtain in areas of vegetable and algae cultivation.…”