Search

Small-pore zeolites catalyze the methanol-to-olefins (MTO) reaction via a dual-cycle mechanism, encompassing both olefin- and aromatic-based cycles. Zeolite topology is crucial in determining both the catalytic pathway and the product selectivity of the MTO reaction. Herein, we investigate the mechanistic influence of MCM-35 zeolite on the MTO process. The structural properties of the as-synthesized MCM-35 catalyst, including its confined cages (6.19 Å), were characterized, confirming them as the catalytic centers. Then, the MTO reactions were systematically performed and investigated over a MCM-35 catalyst. Feeding pure methanol to the reactor yielded minimal MTO activity despite the formation of some aromatic species within the zeolite. The results suggest that the aromatic-based cycle is entirely suppressed in MCM-35, preventing the simultaneous occurrence of the olefin-based cycle. However, cofeeding a small amount of propene in methanol can obviously enhance the methanol conversion under the same studied reaction conditions. Thus, the exclusive operation of the olefin-based cycle in the MTO reaction, independent of the aromatic-based cycle, was demonstrated in MCM-35 zeolite.

A series of Zr-based catalysts were prepared using various commercial and cheap organic acids as the coordination agents, and these as-synthesized samples exhibited superior activities to produce lactic acid (LaA) from carbohydrates. Using humic acid (HA) as a typical coordination agent, LaA yield was up to 76% over the resultant Zr-HA, outperforming the most recent reported works. Deeper studies revealed that Zr-HA possessed both acid sites and base sites, and these dual active sites can simultaneously activate xylose, resulting in high yield production of LaA. Besides, Zr-HA also showed excellent reusability and can be reused at least five times.

A novel catalyst prepared by a facile ‘one-pot’ solvothermal method was developed for the efficient production of lower polyols from glucose solution. Under the optimal reaction conditions, the yield of diols was up to 50.7%, outperforming the recent works reported in the literature (

Carbonaceous catalysts with sulfonic acid (-SO3H) groups are showing promising performances in the conversion of mono- and poly-saccharides, however, their applications in the hydrodeoxygenation (HDO) of oxygen-rich lignin derivatives are rarely reported. Herein, we report a facile synthetic approach for one-step preparation of porous carbonaceous solid acids with –SO3H groups (OHCA) where monosaccharide, polysaccharide, and raw biomass can be used as carbon precursors. These porous carbonaceous solid acids supported ultrafine palladium nanoparticles (Pd/OHCA) exhibited excellent performances in the HDO of vanillin (VAN) in water. We found that Pd nanoparticles (Pd NPs) were responsible for the hydrogenation of VAN to vanillyl alcohol (VAL) and acidic groups were crucial for the hydrogenolysis of generated VAL to 2-methoxy-4-methylphenol (MMP). Importantly, VAL once generated can be immediately converted to MMP via synergistic catalysis between acidic groups and Pd NPs, avoiding the formation of by-products. Pd/OHCA catalyst also exhibited excellent stability in the HDO of VAN and retained its activities in the six consecutive runs. The findings of this work provide a new thought for the HDO of biomass derivatives over biomass-based carbon catalysts.