Large-scale cultivation of microalgae is an effective and sustainable measure to achieve multiple targets of carbon dioxide emission reduction and chemicals/fuels production. We cultivated microalgae using CO2-enriched air and maximal biomass productivity reached approximated 1.0 g/L/day with substantial composition of carbohydrate, which can serve as the substrate for some commodity chemicals. Relatively high percentage of nitrogen- and sulfur-contained components in microalgae provided serious challenge for effective catalytic conversion. Here, an interesting catalytic process was reported to convert microalgae (<i>Chlorococcum sp.</i>) into 1,2-propanediol (1,2-PDO) and ethylene glycol (EG) in water over nickel-based catalysts. The influences of reaction temperature, initial H2 pressure and reaction time on the product distribution were systematically investigated by using a batch reactor. Under optimal reaction conditions (at 250 ºC for 3 h with 6.0 MPa of H2 pressure), microalgae was directly and efficiently converted over Ni-MgO-ZnO catalyst and a total yield of polyols was up to 41.5%. Such excellent catalytic activity was attributed to the smaller size and better dispersion of Ni particles on MgO-ZnO supporter based on the characterization results as well as its tolerance to nitrogen-contained compounds. Besides, the reaction pathway was proposed based on the formation of reaction intermediates and the results of model compound conversion. Because the process uses green feedstock and free of organic solvent, such catalytic utilization of microalgae for chemicals’ production should provide a potential renewable route for the production of valuable chemicals from microalgae.

One-pot catalytic conversion of microalgae to glycol in water over nickel-based catalysts

250th National Meeting (2015)

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