Lignin is a complex polymer that is a potential feedstock for aromatic compounds and carboxylic acids by cleaving the β-O-4 and 5-5' linkages. In this work, a syringe pump atomizes an alkaline solution of lignin into a catalytic fluidized bed operating above 600 K. The vanadium heterogeneous catalysts convert all the lignin into carboxylic acids (up to 25 % selectivity), coke, carbon oxides, and hydrogen. Aluminum-vanadium-molybdenum mostly produced lactic acid (together with formic acid, acrylic acid, and maleic anhydride), whereas the vanadium pyrophosphate catalyst produced more maleic anhydride.
We combine thermo-chemical processes with oxidative catalysis to convert lignin to aliphatic carboxylic acids mainly C4 acids. Acid selectivity changed with catalyst.
Integrating a high-pressure syngas step with Fischer-Tropsch synthesis (FT) in a single vessel reduces investment and operating costs for Gas-toLiquids technology (GtL). Methane catalytic partial oxidation (CPOX) to produce syngas for FT is an economic opportunity for micro-refineries. Many metals and metal oxides selectively convert natural gas to CO and H 2 , but they also form coke, which must be removed intermittently, otherwise it deactivates the catalyst and can foul the reactor and process lines. Here, we prepared a 1 % mass fraction (0.01 g/g) Pt/Rh (Pt/Rh = 9) catalyst supported on MgO over FeCralloy woven fibre via solution combustion synthesis. At 900 • C, from 0.1-2 MPa, and with a 2:1 feed composition of CH 4 to O 2 , the reaction consumed all the oxygen and we obtained a H 2 /CO ratio of 2 (ideal for FT). At low pressure and a 0.1 s residence time the catalyst converted 90 % of the methane at 90 % CO selectivity. At 2 MPa, CO yield reached 50 % (< 80 % conversion and 57 % selectivity). Based on thermodynamic calculations, less than 5 % coke forms below 900 • C. At high pressure and short residence time (0.1 s), the coke yield (presumed to be coke crystallites) was 24 %. Increasing the residence time to 0.3 s reduced the amount of coke by 33 % because it is metastable.
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