Hydroconversion of methyl palmitate over Ni-phosphide catalysts on SAPO-11 and ZSM-5 composite supports.

Zeolite materials (SAPO-11 or ZSM-5) were used to prepare modified Al 2 O 3 supports by mixing with Al oxide hydroxide, peptization with HNO 3 and subsequent extrusion. The obtained Al 2 O 3 -SAPO-11 and Al 2 O 3 -ZSM-5 (with 30 wt% zeolite content) were impregnated by solutions containing Ni and P precursors: phosphate (A), phosphite (I), and hypophosphite (H). Ni-phosphide catalysts were prepared by temperature-programmed reduction in hydrogen flow and characterized by ICP-AES chemical analysis, low-temperature N 2 physisorption, H 2 -TPR, NH 3 -TPD, XRD, 27Al MAS NMR, XPS. The catalysts were tested in methyl palmitate (MP) hydroconversion (HC, i.e. hydrodeoxygenation (HDO) + hydroisomerization/hydrocracking). 100% MP conversion was achieved over all catalysts (flow reactor at 340 °C, 2.0 MPa, 5.3 h−1). For Ni 2 P/Al 2 O 3 -SAPO-11 catalysts the overall yield of iso-alkanes (iso-C 15 and iso-C 16) increased in the following order of precursors: A < I < H. The highest yield of iso-alkanes was 21% over Ni 2 P/Al 2 O 3 -SAPO-11 H catalyst. Ni 2 P/Al 2 O 3 -ZSM-5 samples possessed high cracking activity. Alkanes from MP HDO as well as the solvent (n-dodecane) were almost completely transformed to C 6 –C 9 alkanes at 340 °C. Decreasing temperature (290, 270 °C) did not result in significant yield of iso-alkanes over Ni 2 P/Al 2 O 3 -ZSM-5 catalysts. [Display omitted] • Ni 2 P/Al 2 O 3 -SAPO-11 and Ni 2 P/Al 2 O 3 -ZSM-5 were prepared from different precursors. • Reduction processes start at different temperatures for different precursors. • Phosphite and hypophosphite precursors give smaller particles. • SAPO-11-containing catalysts produce n- and iso-alkanes (at 340 °C). • ZSM-5 containing catalysts showed high cracking activity at the same conditions. [ABSTRACT FROM AUTHOR]