The valuable products produced from glycerol transformation have become a research route that attracted considerable benefits owing to their huge volumes in recent decades (as a result of biodiesel production as a byproduct) as well as a myriad of chemical and biological techniques for transforming glycerol into high-value compounds, such as fuel additives, biofuels, precursors and other useful chemicals, etc. Biodiesel has presented another challenge in the considerable increase in its byproduct (glycerol). This review provides a recent update on the transformation of glycerol with an exclusive focus on the various catalysts’ performance in designing reaction operation conditions. The different products observed and cataloged in this review involved hydrogen, acetol, acrolein, ethylene glycol, and propylene glycol (1,3-propanediol and 1,2-propanediol) from reforming and dehydration and hydrogenolysis reactions of glycerol conversions. The future prospects and critical challenges are finally presented.

2-Methyltetrahydrofuran (MTHF) is a desirable biomass-based platform chemical with excellent potential as an ideal biofuel, green solvent, and raw material for synthesizing downstream chemicals. In this work, a series of copper nanoparticles encapsulated on SiO₂ were prepared by the wet impregnation method and evaluated as efficient non-noble metal catalysts for the vapour-phase hydrogenation of γ-valerolactone (GVL) to MTHF in a fixed-bed reactor under mild reaction conditions. The obtained catalyst properties were determined by XRD, FE-SEM, TEM, UV-DRS, TPR, NH₃-TPD, N₂O decomposition and pore size distribution measurements. Meanwhile, the parameters/variables tuning their catalytic performance (activity, conversion, selectivity and stability) were examined. Various Cu loadings featured on the SiO₂ support are essential for tuning the catalytic activity. Among the catalysts tested, a 5 wt% Cu/SiO₂ catalyst showed a 97.2% MTHF selectivity with 71.9% GVL conversion, and showed a stability for 33 h time-on-stream, achieved at 260 °C and atmospheric pressure conditions. It was found that a huge dispersion of Cu metal in support, hydrogen activation ability, abundant acidic sites and surface area are all beneficial for improved MTHF selectivity.

Conversion of biomass-derived furfural (FFA) platform molecule to value-added tetrahydrofurfuryl alcohol (THFA) molecule is a sustainable route using an efficient non-noble metallic catalyst in water solvent. In this work, Ni in various loadings on mesoporous titanium dioxide (m-TiO₂) was synthesized in one pot by Evaporation-Induced Self-Assembly (EISA). The synthesised catalysts were evaluated for the hydrogenation of furfural to tetrahydrofurfuryl alcohol. The catalysts were characterised using a combination of spectroscopic techniques such as XRD, H₂-TPR, H₂-TPD, XPS, SEM-EDX, TEM, and HR-TEM. The characterization results show that the Ni/m-TiO₂ materials exhibit enhanced electron-rich active sites, facilitated hydrogen spillover, uniform dispersion of small Ni particles (~5 nm), and strong metal support interaction between Ni and TiO₂. Among the various Ni dopings, 7.5 wt.% Ni/m-TiO₂ catalyst exhibited the best performance and achieved 99.9% FFA conversion and 93.2% THFA selectivity in water solvent at 100 °C and under 2 MPa H₂. Additionally, detailed kinetic studies, process parameters, the stability and reusability of the catalyst were also studied. The results demonstrated that the 7.5 wt.% Ni/m-TiO₂ catalyst is highly active and stable.

A direct alkaline hydrothermal method was used to synthesize mono- and bimetallic Ni and Cu on mesoporous silica (m-SiO₂) as catalysts for the hydrogenation of furfural (FAL) to cyclopentanone (CPO). The catalysts were characterized by XRD, FTIR, H₂-TPR, SEM, TEM, HR-TEM, XPS, ICP, BET, and CHN analysis. The results demonstrate that the addition of Cu metal improved the reducibility of Ni catalysts and revealed Ni-Cu alloy formation over m-SiO₂. Furthermore, XPS and FTIR results reveal that the silanol groups on the catalyst surface play an important role in the ring rearrangement of furfuryl alcohol. Hence, the effect of silanol groups in the FOL rearrangement was studied in detail. Among the catalysts at fixed metal loading of 20 wt.%, Ni₅Cu₁₅/m-SiO₂ catalyzed the formation of CPO as the main product due to the synergy of Ni-Cu alloy and surface silanol groups. Ni₅Cu₁₅ supported on a commercial mesoporous silica (Ni₅Cu₁₅/C-SiO₂) showed inferior performance compared with the Ni₅Cu₁₅/m-SiO₂ catalyst for the FAL hydrogenation. Reaction temperature and time were also optimized for the enhanced CPO yield over Ni₅Cu₁₅/m-SiO₂. The Ni₅Cu₁₅/m-SiO₂ catalyst is durable, as demonstrated by stability tests over multiple reuses. This effective and flexible Ni_xCu_y on m-SiO₂ catalyst provides an effective candidate for efficient upgrading of furanics in selective hydrogenation reactions.