An Efficient and Reusable Embedded Ru Catalyst for the Hydrogenolysis of Levulinic Acid to γ‐Valerolactone

Abstract

To achieve a higher activity and reusability of a Ru-based catalyst, Ru nanoparticles were embedded in N-doped mesoporous carbon through a hard-template method. The catalyst showed excellent catalytic performance (314 h turnover frequency) and recyclability (reusable five times with 3 % activity loss) for the hydrogenolysis of levulinic acid to γ-valerolactone. Compared with the mesoporous carbon without N-doping and conventional activated carbon, the introduction of N-dopant effectively improved the dispersion of Ru nanoparticles, decreased the average size of Ru nanoparticles to as small as 1.32 nm, and improved the adsorption of levulinic acid, which contributed to the increase in the activity of the catalyst. Additionally, the embedding method increased the interaction between Ru nanoparticles and carbon support in contrast with the conventional impregnation method, thus preventing the Ru nanoparticles from migration, aggregation, and leaching from the carbon surface and therefore increasing the reusability of the catalyst.

Selective Levulinic Acid Hydrogenation in the Presence of Hybrid Dendrimer‐Based Catalysts. Part I: Monometallic

“…The close proximity of Ru surface to reacting species in the catalyst structure facilitates further hydrogenation to γ‐valerolactone (the C=C double bond is reduced much easier than C=O). Therefore, the introduction of dendrimer amino groups has not only effectively improved the dispersion of Ru nanoparticles, decreased the average size of Ru nanoparticles to as small as 1–2 nm, but also facilitated the adsorption of levulinic acid, the latter contributing the increase in the activity of the catalyst as well as in the case of N‐doped mesoporous carbon …”

Cascade catalytic hydrogenation–cyclization of methyl levulinate to form γ-valerolactone over Ru nanoparticles supported on a sulfonic acid-functionalized UiO-66 catalyst

“…[5][6][7][8][9] Indeed, many reports exist into the catalytic conversion of LA using both homogeneous and heterogeneous noble and non-noble metal catalysts in liquid and vapor phase systems. [5][6][7][8][9][11][12][13][14][15][16][17][18] Among the various metals investigated, ruthenium appears to be the most active and selective metal for the conversion of LA to GVL, mainly due to its selective hydrogenation of carbonyl groups without altering other unsaturated functionalities. [11][12][13][14][15][16][17][18] However, traditional catalysts, such as commercial Ru/C, oen exhibit leaching of the ruthenium species through the formation of metal-carboxylate complexes with LA, which is likely caused by the weak acidity of LA (pK a ¼ 4.59), [19][20][21] results in a low catalytic activity and poor catalyst reusability.…”

Highly stable Ru nanoparticles incorporated in mesoporous carbon catalysts for production of γ-valerolactone

“…Although supported Ru on carbon (Ru/C) catalysts have excellent initial catalytic performance, their activity decreases sharply in a batch hydrogenation process. Wei [21] pointed out that at least four factors were reported to be responsible for Ru/C catalysts deactivation in water: (I) Ru leaching into the reaction bulk; (II) Ru aggregation on the carbon surface; (III) carbon deposition on Ru nanoparticles and (IV) the phase transformation of Ru nanoparticles and support. To improve stability, many different strategies are applied in recent studies.…”

“…Jamal [22] and Wen [20] used metallic oxide supports to increase the interaction between Ru NPs and supports to gain higher stability. Wei [21] used embedding method to decelerate the deactivation of Ru catalyst in methanol system. The embedded structure could prevent the Ru NPs from migration, aggregation, and leaching during reaction process.…”