Deoxygenation of Methyl Laurate as a Model Compound to Hydrocarbons on Ni2P/SiO2, Ni2P/MCM-41, and Ni2P/SBA-15 Catalysts with Different Dispersions

The deoxygenation of methyl laurate as a model compound to diesel-like hydrocarbons was performed on Ni 2 P/SiO 2, Ni 2 P/MCM-41, and Ni 2 P/SBA-15 catalysts. The effect of Ni 2 P dispersion on the catalyst structure and performance was investigated. The average Ni 2 P crystallite sizes varying from 3 to 12 nm were obtained. In correlation with the Ni/P ratio, the catalyst acid amount was mainly determined by the surplus P species. The deoxygenation was tested at 300–340 °C, 2.0 MPa, weight hourly space velocity of 10 h –1, and H 2 /methyl laurate ratio of 50. For different catalysts, the conversion of methyl laurate followed the different sequence from the turnover frequency (TOF). The TOF increased with the Ni 2 P crystallite size. The lower TOF on smaller crystallites can be attributed to the stronger interaction between Ni and P. Both hydrodeoxygenation and decarbonylation pathways occurred on the Ni 2 P catalysts. As indicated by the ratio between n -undecane ( n -C 11 ) and n -dodecane ( n -C 12 ) being larger than 1.0, the main deoxygenation pathway was decarbonylation. We suggested that the deoxygenation pathway was affected by Brönsted acidity and Ni 2 P crystallite size (i.e., the interaction between the Ni and P atoms). The Brönsted acid sites because of P–OH groups and the Ni sites having less interaction with P favored the decarbonylation pathway. With an increasing reaction temperature, the conversion, the selectivity to n -C 11 and n -C 12, and the n -C 11 / n -C 12 ratio increased. At 340 °C, the conversion and the selectivity to n -C 11 and n -C 12 on all Ni 2 P catalysts exceeded 97 and 99%, respectively.