Synthesis of γ-valerolactone from different biomass-derived feedstocks: Recent advances on reaction mechanisms and catalytic systems

Recent Advances in Ruthenium-Catalyzed Hydrogenation Reactions of Renewable Biomass-Derived Levulinic Acid in Aqueous Media

“…In the last decade, the hydrogenation reactions of LA into γ-valerolactone (GVL, Figure 2), which is a key intermediate compound, and beyond GVL to yield 1,4-pentanediol (1,4-PDO, Figure 2) and valeric acid (VA, Figure 2), have gained considerable attention. Numerous heterogeneous catalytic systems based on precious and non-noble metals and water-soluble transition metal catalytic complexes have been developed in the absence and presence of organic or aqueous solvents (Serrano-Ruiz et al, 2011Tang et al, 2014;Yan et al, 2015a,b;Omoruyi et al, 2016;Pileidis and Titirici, 2016;Osatiashtiani et al, 2017;Makhubela and Darkwa, 2018;Xue et al, 2018;Dutta et al, 2019;Yu et al, 2019;Ye et al, 2020). The catalytic hydrogenation reaction of LA in the aqueous solvent is a more attractive and promising processing mode because the use of water combines several advantages: (i) the highly polar nature of the aqueous solvent makes it an ideal medium to convert polar, with high oxygen content, and hydrophilic platform chemicals such as the water-soluble starting material LA; (ii) water is involved as a byproduct to obtain the GVL intermediate, which is further hydrogenated into 1,4-PDO in the aqueous medium and, after dehydration and cyclization reactions 2-methyltetrahydrofuran (2-MTHF, Figure 2), is formed creating an aqueous/organic twophase system which provides for the easy separation of the polar aqueous reaction medium from a polar organic product 2-MTHF by a simple phase separation.…”

Heterogeneous Catalytic Hydrogenation of Levulinic Acid to γ‐Valerolactone with Formic Acid as Internal Hydrogen Source

“…The participation of water is inevitable in the degradation of cellulosic carbohydrates, the hydrolysis of 5‐HMF, and the dehydration of LA, and aqueous solvent has also shown significant effects on the catalytic performance of the FA/LA catalytic system for the synthesis of GVL (Figure ). The catalytic hydrogenation of LA was performed using FA as an internal hydrogen source in an aqueous solution (LA/FA/H 2 O=1:5:1), and water was considered to be conducive to the generation of GVL .…”

“…However, most of the research attempts have been focused on LA conversion with fossil‐fuel‐derived H 2 , whereas FA‐assisted LA hydrogenation remains to be explored further. In prior studies, the basic raw feedstocks, homogeneous and heterogeneous catalysts, and reaction conditions for GVL synthesis from LA have been summarized thoroughly. Although research progress on LA conversion under FA hydrogen supply has also been reported, these reviews have paid more attention to summarizing the basic information such as catalysts and reaction conditions.…”

Transformation of Levulinic Acid to Valeric Biofuels: A Review on Heterogeneous Bifunctional Catalytic Systems

“…Nevertheless, challenges still exist: new‐generation biofuels need to be continuously developed to cope with the increasingly urgent energy demand. However, the exploration of efficient synthetic strategies for high‐value biofuels based on inexpensive lignocellulosic feedstocks still faces technical challenges …”