Hydrogenation Of Cinnamaldehyde Research Articles

CNTs-promoted Co-Cu Catalyst for Efficient Synthesis of Cinnamyl Alcohol from Hydrogenation of Cinnamaldehyde

CNTs-promoted Co-Cu Catalyst for Efficient Synthesis of Cinnamyl Alcohol from Hydrogenation of Cinnamaldehyde

Pd-N-doped carbons for chemoselective hydrogenation of cinnamaldehyde: Unravelling the influence of particle size and support in multiphase batch and continuous-flow systems

The chemoselective hydrogenation of the CC bond of cinnamaldehyde (CAL) was investigated under batch and continuous flow conditions, by comparing the performance of two ad-hoc prepared palladium-based catalysts supported on N-doped carbons to that of a commercial Pd/C system. An impregnation (I) and a solution-mediated (S) protocols were used for the synthesis of the catalytic materials, Pd-N/Ci and Pd-N/Cs, respectively, in the presence of chitin as a precursor of the support. The S method afforded palladium nanoparticles of 2.0±0.5 nm, while by impregnation, a wider size distribution was achieved with particles mostly belonging to two groups displaying a mean radius of 3.0±0.5 nm and 8.4±0.5 nm, respectively. A parametric analysis of the hydrogenation reaction showed that both the reaction conditions and the nature of the catalysts played a role to steer the selectivity towards the formation of the desired product, 3-phenylpropanal (hydrocinnamaldehyde, HCAL). At 50 °C and 1 bar H2, in a triphasic (liquid-liquid-liquid) batch reactor where the catalyst was compartmentalized in an ionic liquid layer, Pd-N/Ci and commercial Pd/C were almost equally active and allowed to obtain HCAL in a 90–96 % selectivity at complete conversion. On the other hand, at the same T and p (50 °C/1 bar), Pd-N/Cs was more effective in the continuous-flow mode: the process was quantitative yielding HCAL with a selectivity and a productivity of 91 % of 16 mmol (gcat h)−1, respectively, while the catalyst proved highly stable showing no loss of activity over 300 min of time on-stream. The reaction environment, the size and dispersion of the metal active sites, and the nature of the catalyst support were major contributors to such results, acting synergistically to each other to tune the energetics of adsorption/desorption of reactants/products, of the interfacial interactions/ barriers, and in the last analysis, of the process kinetics/selectivity.

Fabrication of SBA-15-supported nanoscale Co3O4 and its use in the catalytic hydrogenation of cinnamaldehyde

Fabrication of SBA-15-supported nanoscale Co3O4 and its use in the catalytic hydrogenation of cinnamaldehyde

Co-Ti Bimetallic Complex-Induced Phase Modulation of Co@Black TiO2 for Catalytic Hydrogenation of Cinnamaldehyde.

Transition-metal-doped black titania, primarily in the anatase phase, shows promise for redox reactions, water splitting, hydrogen generation, and organic pollutant removal, but exploring other titania phases for broader catalytic applications is underexplored. This study introduces a synthetic approach using a Co-Ti bimetallic complex bridged by a 1,10-phenanthroline-5,6-dione ligand as a precursor for the synthesis of cobalt-doped black titania [Co@L2N@b-TiO2]. The synthesis involves precise control of pyrolysis conditions, yielding a distinct structure dominated by the rutile phase over anatase, with active cobalt encapsulated within a nitrogen-doped graphitic layer, primarily as Co0 rather than CoII and CoIII. The synthesized material is employed for the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) under industrially viable conditions. The efficiency and selectivity of Co@L2N@b-TiO2 was compared with other catalysts, including cobalt-doped rutile TiO2 (Co@r-TiO2), anatase TiO2 (Co@a-TiO2), and black titania (Co@b-TiO2) as well as materials pyrolyzed under different atmospheres and temperatures, materials with phenanthroline ligands, and materials lacking any ligands. The superior performance of Co@L2N@b-TiO2 is attributed to its high surface area, stable Co0 within the nitrogen-doped graphitic layer, and composition of rutile and anatase phases of TiO2 and Ti2O3 (referred to as RAT), along with the synergistic interaction between RAT and Co0. These factors significantly influence the efficiency and selectivity of COL over hydrocinnamaldehyde (HCAL) and hydrocinnamyl alcohol (HCOL), indicating potential for broader applications beyond catalysis, particularly in designing of black titania-based materials.

Dually functional NiSi intermetallic compounds for the efficient hydrogenation and oxidation of cinnamaldehyde

Intermetallic compounds (IMCs) are promising catalysts for upgrading biomass-derived platform chemicals. Herein, bifunctional NiSi IMCs catalysts were developed for the hydrogenation and oxidation of cinnamaldehyde (CAL). A solvent-free arc-melting method was employed for the synthesis of NiSi IMCs within 5 min. The NiSi IMCs catalysts afforded 99 % conversion of CAL and presented ∼ 71 % yield of 2-phenyl propanol and ∼ 34 % yield of benzaldehyde for the hydrogenation and base-free oxidation of CAL, respectively. Moreover, NiSi IMCs could be used for five runs without deactivation. Characterizations and theoretical calculation results indicated the formation of intermetallic structure and the existence of Si vacancy sites, which could not only facilitate the efficient hydrogenation of CAL but also expose NiOx species as catalytic centers for the oxidation of CAL, leading to the high performance and stability in both hydrogenation and oxidation process.

Continuous-flow hydrogenation of cinnamaldehyde over catalysts derived from modified CoAl4 layered double hydroxides incorporating Mn, Ni, Cu and Zn ions

Series of CoxM1-xAl4 layered triple hydroxides, LTHs were prepared as catalyst precursors for hydrogenation of biomass compound cinnamaldehyde under flow and batch reaction conditions. To this end, we have successfully extended the eco-friendly family of Al-rich layered double hydroxides (LDHs) by synthesizing MnAl4-LDHs, furthermore Co3Al-, Co2Al-LDHs were also exploited. Both the magnetic Co-rich and Al-rich reduced forms behaved as robust, efficient and reusable catalysts with significantly different selectivities correlated with their acid-base properties. Al-rich solids showed increased acidity and lower basicity resulting in high hydrocinnamaldehyde selectivity (∼75 %), while the Co-rich catalysts attested enhanced hydrocinnamyl alcohol production (∼80 % selectivity) due to their low acidity and high basicity (mapped by NH3/CO2 temperature programmed desorption tests). Incorporation of Mn, Ni, Cu and Zn ions generally decreased the total acidity of Al-rich catalysts, while their Lewis basicity largely increased: the highest was found for Mn, resulting in activity similar to that of Co-rich catalysts.

Precise regulation of Mo2N–TiO2 deposited Pt nanoparticles induced synergistic effect for the hydrogenation of cinnamaldehyde

The amalgamation of an appropriate cocatalyst is a proficient technique to expand the efficacy of precious Pt-based catalytic materials. In this study, Mo2N–TiO2 with regularly distributed Mo2N particles were simply prepared for the deposition of precious Pt nanoparticles (NPs). Numerous techniques were implemented to thoroughly explore, how synthesis method influence the bulk structural, interfacial and cata1ytic features of the as-prepared 3 wt%Pt/TiO2 and 3 wt%Pt/Mo2N–TiO2 catalytic materials. The catalytic results obviously show that the 3 wt%Pt/Mo2N–TiO2 catalyst has exceptional hydrogenation performance when compared to 3 wt%Pt/TiO2 catalyst. The 3 wt%Pt/Mo2N–TiO2 catalyst displayed high conversion (72.4 %) of cinnamaldehyde (CAL) with a maximum selectivity (82.1 %) towards CO bond. The excellent hydrogenation performance is attributed to the synergistic interaction taking place between Pt NPs and Mo2N entities of 3 wt%Pt/Mo2N–TiO2. Also, the enhanced standardized dispersal of Pt NPs on the Mo2N–TiO2 surface causes more exposed Pt0 sites on the 3 wt%Pt/Mo2N–TiO2 surface, which is productive for the improved activation and conversion of CO bond of CAL to yield COL. In addition, the 3 wt%Pt/Mo2N–TiO2 catalyst retained its higher catalytic activity for consecutive five successive rounds without substantial loss in either conversion or selectivity.

Schiff Base Functionalized Cellulose: Towards Strong Support-Cobalt Nanoparticles Interactions for High Catalytic Performances.

A new hybrid catalyst consisting of cobalt nanoparticles immobilized onto cellulose was developed. The cellulosic matrix is derived from date palm biomass waste, which was oxidized by sodium periodate to yield dialdehyde and was further derivatized by grafting orthoaminophenol as a metal ion complexing agent. The new hybrid catalyst was characterized by FT-IR, solid-state NMR, XRD, SEM, TEM, ICP, and XPS. The catalytic potential of the nanocatalyst was then evaluated in the catalytic hydrogenation of 4-nitrophenol to 4-aminophenol under mild experimental conditions in aqueous medium in the presence of NaBH4 at room temperature. The reaction achieved complete conversion within a short period of 7 min. The rate constant was calculated to be K = 8.7 × 10-3 s-1. The catalyst was recycled for eight cycles. Furthermore, we explored the application of the same catalyst for the hydrogenation of cinnamaldehyde using dihydrogen under different reaction conditions. The results obtained were highly promising, exhibiting both high conversion and excellent selectivity in cinnamyl alcohol.

Silica-modified Pt/TiO2 catalysts with tunable suppression of strong metal–support interaction for cinnamaldehyde hydrogenation

Tuning Strong Metal-support Interactions (SMSI) is a key strategy to obtain highly active catalysts, but conventional methods usually enable TiOx encapsulation of noble metal components to minimize the exposure of noble metals. This study demonstrates a catalyst preparation method to modulate a weak encapsulation of Pt metal nanoparticles (NPs) with the supported TiO2, achieving the moderate suppression of SMSI effects. The introduction of silica inhibits this encapsulation, as reflected in the characterization results such as XPS and HRTEM, while the Ti4+ to Ti3+ conversion due to SMSI can still be found on the support surface. Furthermore, the hydrogenation of cinnamaldehyde (CAL) as a probe reaction revealed that once this encapsulation behavior was suppressed, the adsorption capacity of the catalyst for small molecules like H2 and CO was enhanced, which thereby improved the catalytic activity and facilitated the hydrogenation of CAL. Meanwhile, the introduction of SiO2 also changed the surface structure of the catalyst, which inhibited the occurrence of the acetal reaction and improved the conversion efficiency of C=O and C=C hydrogenation. Systematic manipulation of SMSI formation and its consequence on the performance in catalytic hydrogenation reactions are discussed.

Design of Pt@Sn core–shell nanocatalysts for highly selective hydrogenation of cinnamaldehyde to prepare cinnamyl alcohol

The selective hydrogenation of cinnamaldehyde (CAL) to prepare cinnamyl alcohol (COL) is challenging as the unwanted hydrogenation of CC bond in CAL is thermodynamically more favorable than the hydrogenation of CO bond. We herein designed core–shell structured nanoparticles (NPs) that consisted of Pt cores and Sn shells to catalyze the CAL to COL conversion. By simply changing the amount of Sn precursor, we generated Pt@Sn NPs with different Sn shell thickness and catalytic performance. Among the samples, Pt@Sn/SiO2 with Pt/Sn of 1/1 achieved the highest CAL conversion (87.2 %) as well as the COL selectivity (95.4 %), which were 5-fold and 6-fold, respectively, higher than those of Pt/SiO2. This catalyst was also applicable to the hydrogenation of other α, β-unsaturated aldehyde and unsaturated carbonyl compounds. Both experiments and theoretical calculations indicated that the strong Pt-Sn interaction and the partial coverage of Pt by Sn facilitated their adsorption of CO bonds, thus enhancing the conversion of CAL and the selectivity towards COL.

Water-promoted selective hydrogenation of cinnamaldehyde over hydrotalcite-derived Co catalysts

Non-noble metal-catalyzed selective CO hydrogenation of α,β-unsaturated aldehydes to corresponding alcohols is chemically atom economic and practically feasible. This work reports hydrotalcite-derived Co-based catalysts for catalyzing aqueous phase selective hydrogenation reaction of cinnamaldehyde to cinnamyl alcohol. The structure characterizations demonstrate the phase transition from hydrotalcite to co-existed CoOx and metallic Co0 in the optimal Co2Al-H2-400 catalyst. It exhibits superior catalytic activity and selectivity relative to other as-obtained Co catalysts, because of the synergy effect of Co2+ sites to promote the adsorptive activation of CO group and small-size Co0 sites to facilitate the activating dissociation of hydrogen. Furthermore, the catalytic role of water has also been explored. Adopting water as pure solvent and partially adding water into organic solvent can both effectively enhance the activity and selectivity. Such reaction environment may induce creation of more intermolecular hydrogen bonds for promoting the hydrogen transfer and thus boosting the hydrogenation reaction.

Unravelling the synergy of platinum-oxygen vacancy in CoOx for modulating hydrogenation performance

Constructing high-efficiency catalysts with high activity and selectivity is the long-term pursuit in heterogeneous catalysis field. Metal–oxygen vacancy (Ov) synergy provides a promising route to realizing the goal. In this study, the Pt/CoOx catalysts with Pt–Ov dual sites are designed by atomic layer deposition (ALD) for selective hydrogenation of cinnamaldehyde, and the Ov property, Pt size and the spatial relationship of Pt and CoOx can be well modulated. Experimental and theoretical investigations indicate that the substrate and hydrogen can be activated on Ov and Pt nanoparticles, respectively. The Ov introduced by ALD not only preferentially activates CO bond of CALD to achieve high selectivity to CALA, but also enhances the ability to dissociate hydrogen on Pt nanoparticles through Pt-Ov electron transfer. Importantly, the optimized Pt40/CoOx-Ov catalysts with suitable Ov coordination and Pt sizes (2.5 nm) show lower adsorption energy for reactant molecules, obtaining significantly enhanced activity with a turnover frequency value of 202.5 molCALD·molPt-1·min−1 and obviously improved selectivity of desired products (93 %). This work offers a fundamental understanding of Pt–Ov synergy toward hydrogenation of unsaturated compounds.

Hydrogenation of cinnamaldehyde over palladium nanoparticles supported on functionalized N-doped solid carbon spheres

Hydrogenation of cinnamaldehyde over palladium nanoparticles supported on functionalized N-doped solid carbon spheres

High Active Catalyst of the Cu–Ag Bimetal Supported on Defect KTaO3 Nanosheets for the Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol

High Active Catalyst of the Cu–Ag Bimetal Supported on Defect KTaO₃ Nanosheets for the Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol

Multilayer Nb2CTx (MXene) Supports CoB for the Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol: Effect of the Electron-Modified CoB Site and Lewis Acid Site

Multilayer Nb2CTx (MXene) Supports CoB for the Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol: Effect of the Electron-Modified CoB Site and Lewis Acid Site

Highly Selective Hydrogenation of Unsaturated Aldehydes in Aqueous Phase.

Chemoselective hydrogenation of carbonyl in unsaturated aldehydes is a significant process in the chemical industry, in which the development of aqueous-phase reaction systems as a substitution to organic ones is challenging. Herein, we report Ir atomic cluster catalysts anchored onto WO3-x nanorods via a reduction treatment at various temperatures (denoted as Ir/WOx-T, T = 200, 300, 400, and 500 °C), which accelerates the chemoselective hydrogenation of carbonyl groups in aqueous solutions. The optimal catalyst Ir/WOx-300 exhibits exceptional activity (TOF value: 1313.7 min-1) and chemoselectivity toward cinnamaldehyde (CAL) hydrogenation to cinnamyl alcohol (COL) (yield: ∼98.0%) in water medium, which is, to the best of our knowledge, the highest level compared with previously reported heterogeneous catalysts in liquid-phase reaction. Ac-HAADF-STEM, XAFS, and XPS verify the formation of interface structure (Irδ+-Ov-W5+ (0 ≤ δ ≤ 4); Ov denotes oxygen vacancy) induced by metal-support interaction and the largest concentration of interfacial Ir (Irδ+) in Ir/WOx-300. In situ studies (Raman, FT-IR), isotopic labeling measurements combined with DFT calculations substantiate that the hydrogenation of the C=O group consists of two pathways: water-mediated hydrogenation (predominant) and direct hydrogenation via H2 dissociation (secondary). In the former case, W5+-Ov site accelerates the activation adsorption of H2O, while Ir0 site facilitates the H-H bond cleavage of H2 and Irδ+ promotes the CAL adsorption. H2O molecule, as the source of hydrogen species, participates directly in the hydrogenation of the carbonyl group through a hydrogen-bonded network, with a largely reduced energy barrier relative to the H2 dissociation path. This work demonstrates a green catalytic route that breaks the activity-selectivity trade-off toward the selective hydrogenation of unsaturated aldehydes, which shows great potential in heterogeneous catalysis.

Screening support effect of Pt/MOx for selective hydrogenation of cinnamaldehyde

In supported metal catalysts, solid support material is of great importance for immobilizing and dispersing metal species, which can affect the catalytic performance of supported metal catalysts in terms of selectivity. Rational design of supported metal catalysts with tailored performance, in particular with controlled catalytic performance, is highly desired yet poses challenges in chemoselective hydrogenation reactions. Here, platinum nanoparticles (Pt NPs) supported on a series of commercial oxides were synthesized by a facile wet impregnation and thermal treatment under the air. The catalytic performance of as-prepared catalysts was evaluated in chemoselective hydrogenation of cinnamaldehyde. The varied product distribution demonstrates that supports affect markedly on selectivity. Fourier transform infrared spectra (FTIR) spectroscopy reveals that the high selectivity towards cinnamyl alcohol could be attributed to the preferential adsorption of aldehyde group. Meanwhile, the existence of Ptδ+ could enhance activity markedly by facilitating the spillover of activated H species.

Constructing a Highly Active Pd Atomically Dispersed Catalyst for Cinnamaldehyde Hydrogenation: Synergistic Catalysis between Pd–N3 Single Atoms and Fully Exposed Pd Clusters

Constructing a Highly Active Pd Atomically Dispersed Catalyst for Cinnamaldehyde Hydrogenation: Synergistic Catalysis between Pd–N₃ Single Atoms and Fully Exposed Pd Clusters

Hydrogenation of Cinnamaldehyde Using Carbon Dots Reduced Palladium Nanoparticles

Carbon dots (CDs) with a size range of 0.2 to 2 nm were prepared using a hydrothermal treatment of sucrose and oleic acid. The as-synthesized CDs were used to reduce H2PdCl4 to metallic Pd nanoparticles with dPd = 9.3 ± 3.7 nm, as confirmed by PXRD and HRTEM data. Pd particles were made to be larger than the CDs, to observe any inverse support effects, however, TEM data revealed that the CDs were transformed to carbon sheets in the reduction reaction at 100 °C. The synthesized Pd-CDs catalysts (0.81 wt. % loading) and CDs were both tested for the liquid phase hydrogenation of cinnamaldehyde. The influence of mass, temperature, and hydrogen flow rate on the activity and selectivity of the CDs and Pd-CDs catalyst on the hydrogenation of cinnamaldehyde was investigated. The CDs gave a cinnamaldehyde conversion (40%, 4 h) with selectivity towards the reduction of the C = O bond (cinnamyl alcohol) while the Pd-carbon catalyst was only selective to the reduction of the C = C bond (conversion 78%) indicating the dominance of Pd in the reaction. Post analysis of the deactivated catalysts indicated formation of carbon sheets and sintering of the Pd nanoparticles. It is thus shown that the presence of Pd induces the CDs to carbon sheet formation and thus indicates the limited use of CDs as a support for the olefin hydrogenation reaction with the CDs produced carbon support. This finding has implications for other studies using CDs as supports.Graphical abstract

Solvent effect in selective hydrogenation of cinnamaldehyde over Pd–Ni nanoclusters encapsulated within siliceous zeolite

Selective hydrogenation of unsaturated-organic compounds derived from biomass sources is a key step for producing chemicals and fuels, but it faces challenges in enhancing product selectivity and energy efficiency. Metal nanoparticles (NPs) encapsulated in zeolite crystals (metal@zeolite) are desirable and robust materials that can control catalytic activity and selectivity by tuning their structure. However, the solvent effect on selective hydrogenation over metal@zeolite has been unexplored, which plays a significant role in the reaction process. Here, the solvent effect on the selective hydrogenation of cinnamaldehyde (CAL), a representative substrate, over Pd–Ni bimetallic clusters encapsulated inside S-1 zeolite (Pd0.6Ni@S-1) was first reported. The results showed that Pd0.6Ni@S-1 effectively converted CAL into hydrocinnamaldehyde (HCAL) under mild conditions and that the product distribution was solvent-dependent by correlating the selectivity with solvent properties. The polarity of polar solvents affected the solvent-CAL interaction and thus the hydrogenation pathway. Our study reveals the importance of solvent engineering for selective hydrogenation over metal@zeolite catalysts and provides insights for designing efficient and robust materials for biomass conversion.