ABSTRACT
Molybdenum oxide-modified ruthenium on titanium oxide (Ru-(y)MoO x /TiO2; y is the loading amount of Mo) catalysts show high activity for the hydroconversion of carboxylic acids to the corresponding alcohols (fatty alcohols) and aliphatic alkanes (biofuels) in 2-propanol/water (4.0/1.0 v/v) solvent in a batch reactor under mild reaction conditions. Among the Ru-(y)MoO x /TiO2 catalysts tested, the Ru-(0.026)MoO x /TiO2 (Mo loading amount of 0.026 mmol g-1) catalyst shows the highest yield of aliphatic n-alkanes from hydroconversion of coconut oil derived lauric acid and various aliphatic fatty acid C6-C18 precursors at 170-230 °C, 30-40 bar for 7-20 h. Over Ru-(0.026)MoO x /TiO2, as the best catalyst, the hydroconversion of lauric acid at lower reaction temperatures (130 ≥ T ≤ 150 °C) produced dodecane-1-ol and dodecyl dodecanoate as the result of further esterification of lauric acid and the corresponding alcohols. An increase in reaction temperature up to 230 °C significantly enhanced the degree of hydrodeoxygenation of lauric acid and produced n-dodecane with maximum yield (up to 80%) at 230 °C, H2 40 bar for 7 h. Notably, the reusability of the Ru-(0.026)MoO x /TiO2 catalyst is slightly limited by the aggregation of Ru nanoparticles and the collapse of the catalyst structure.
ABSTRACT
Bimetallic Ni-Sn alloys have been recognised as promising catalysts for the transformation of furanic compounds and their derivatives into valuable chemicals. Herein, we report the utilisation of a supported bimetallic RANEY® nickel-tin alloy supported on aluminium hydroxide (RNi-Sn(x)/AlOH; x is Ni/Sn molar ratio) catalysts for the one-pot conversion of biomass-derived furfural and levulinic acid to 1,4-pentanediol (1,4-PeD). The as prepared RNi-Sn(1.4)/AlOH catalyst exhibited the highest yield of 1,4-PeD (78%). The reduction of RNi-Sn(x)/AlOH with H2 at 673-873 K for 1.5 h resulted in the formation of Ni-Sn alloy phases (e.g., Ni3Sn and Ni3Sn2) and caused the transformation of aluminium hydroxide (AlOH) to amorphous alumina (AA). The RNi-Sn(1.4)/AA 673 K/H2 catalyst contained a Ni3Sn2 alloy as the major phase, which exhibited the best yield of 1,4-PeD from furfural (87%) at 433 K, H2 3.0 MPa for 12 h and from levulinic acid (up to 90%) at 503 K, H2 4.0 MPa, for 12 h. Supported RANEY® Ni-Sn(1.5)/AC and three types of supported Ni-Sn(1.5) alloy (e.g., Ni-Sn(1.5)/AC, Ni-Sn(1.5)/c-AlOH, and Ni-Sn(1.5)/γ-Al2O3) catalysts afforded high yields of 1,4-PeD (65-87%) both from furfural and levulinic acid under the optimised reaction conditions.
