Cascade aldol condensation of an aldehydeviathe aerobic oxidation of ethanol over an Au/NiO composite

Abstract

Synthesis of liquid biofuels (C 11 -C 13 ) from cellulosic ethanol is regarded as a promising and versatile protocol. In this study, oxide-supported nanogold catalysts exhibit good catalytic performance in ethanol conversion with cinnamaldehyde and finally give rise to the C 11 -C 13 hydrocarbon. High selectivity (70%) for C 11 -C 13 hydrocarbons is achieved over Au/NiO via a one-pot cascade reaction, viz. cross-aldol condensations in the presence of oxygen and base (K 2 CO 3 ) and then full hydrodeoxygenation with hydrogen gas. EtOH-TPD and TGA analyses show that the ethanol is activated to acetaldehyde (CH 3 CHO*) over the surface oxygen vacancies of the NiO support. The CH 3 CHO* then reacts with cinnamaldehyde at the interfacial perimeter of the Au/NiO composite during the cascade reactions, as evidenced by comparison of the catalytic performance with that over another oxide-supported Au NP, chemo-adsorption investigations, and in situ infrared spectroscopy investigations. This work may provide new guidelines for designing efficient catalysts to convert bioethanol into biofuels with high energy density. a Reaction conditions: 10 mg of 1 wt% Au catalysts, 26 mL of cinnamaldehyde, 10 mg of base, 3 mL of ethanol, 4 h, and 1 MPa air. b The cinnamaldehyde conversion and product selectivity were determined by GC-MS analysis.3656 | Nanoscale Adv., 2019, 1, 3654-3659This journal is

Recent Progress in Heterogeneous Catalysis by Atomically and Structurally Precise Metal Nanoclusters

“…Furthermore, the application extended to one‐pot cascade coupling in ethanol conversion with cinnamaldehyde in the presence of oxygen, which follows a hydrodeoxygenation with hydrogen to giving rise to the C11–C13 hydrocarbons (liquid biofuels), Figure 8 [62] . A high selectivity of 70 % toward C 11 –C 13 hydrocarbons was achieved on the Au/NiO catalysts.…”

“… The conversion pathway of cinnamaldehyde to oxygenates and C 11 and C 13 hydrocarbons via the one‐pot cascade reactions of oxidative esterification, aldol condensation and Michael addition over the Au/NiO catalysts, followed by the hydrodeoxygenation process [62] . Reprinted with permission from ref [62].…”

Continuous dimethyl carbonate synthesis from CO2 and methanol over BixCe1−xOδ monoliths: Effect of bismuth doping on population of oxygen vacancies, activity, and reaction pathway

“…TPD was applied to study the adsorption properties of the Bi0.12Ce0.88Oδ nanocomposite for methanol and carbon dioxide [39,43]. As shown in Fig.…”

Butterfly‐Like Tetranuclear Copper(I) Clusters for Efficient Alkyne Homocoupling Reactions

“…Specifically, the catalytic activity over Cu 4 / TiO 2 , Cu 4 /CeO 2, and Cu 4 /MgO catalysts was higher than that of the Cu 4 /SiO 2 (Table 2, entries 1-3 vs entry 4). And the activity was improved when using the basic NiO as the support, 10 Table 2, entry 5. These experimental results suggest that the basic property of the oxides can promote the catalysis, which is maybe due to the easy deprotonation of alkynes over the copper cluster catalysts with aid of the basic oxides.…”