Higher alcohol synthesis (HAS) from syngas using highly active CoCu catalysts has attracted extensive interest, but there still exist problems such as the low coordination between Co and Cu phases and poor catalytic stability. Here, a series of highly dispersed bimetallic CoCu catalysts with different Co/Cu ratios (x = 1–4) encapsulated in KIT-6 were proposed and showed high performances in HAS. The best is Co3Cu1/KIT-6 with a space-time yield toward C2+OH of 31.9 mmol gcat –1 h–1 and excellent stability over 200 h. Notably, these catalysts had well-dispersed metal particles and abundant CoCu alloy sites that were maintained during the reaction, which was benefited from the preparation method of ethylene glycol (EG)-assisted impregnation combined with stepwise pyrolysis. The EG-derived glyoxylate dianion could effectively anchor Co and Cu species in the same precursor, enabling them in atomic close interaction, which also favored their synergistic catalysis in HAS. In addition, the stepwise pyrolysis and the confinement of KIT-6 promoted the high dispersion of CoCu species, facilitating the catalytic activity. Meanwhile, the maintenance of highly dispersed and atomic close interacted CoCu bimetallic sites ensured good stability of the catalyst for HAS. These results may provide new ideas for the design and fabrication of high-performance HAS catalysts.

No abstract

A catalytic asymmetric [3+2] cycloaddition reaction of chiral palladium-containing N(1) -1,3-dipoles with methyleneindolinones has been successfully developed. The reaction allows an efficient construction of 3,3'-pyrrolinyl spirooxindoles with high yields and excellent stereoselectivities (up to 93 % yield, 19:1 d.r. and >99 % ee). A synthetic application of this methodology is demonstrated and a stereocontrol mechanism is proposed.

In this study, the impact of ultrasound on the adsorption and desorption features of blueberry anthocyanins on macroporous resins were studied. Sonication was performed at 106-279 W/L and 20-30 °C in a pulsed mode, respectively. Generally, ultrasound treatments within the selected experimental range enhanced the adsorption/desorption process of anthocyanins on macroporous resins. The recovery of blueberry anthocyanins after ultrasound-assisted adsorption/desorption process at 279 W/L and 20 °C was 82.12%, which was 52.84% higher than that obtained after adsorption/desorption with shaking at 100 rpm. Meanwhile, higher acoustic energy density (AED) levels and lower temperatures benefited the adsorption process through enhancing the adsorption capacity and shortening the equilibrium time, whereas higher temperatures promoted the desorption process. Furthermore, malvidin-3-galactoside had the highest adsorption and desorption capacities among all the studied monomeric anthocyanins. No organic acids and sugars were detected after adsorption/desorption processes, indicating the successful improvement of anthocyanin purification. Sonication mainly enhanced the adsorption process by means of strengthening the formation of hydrogen bond on resins surface and increasing their surface roughness. Overall, ultrasound can be an effective tool to improve the purification of anthocyanins using macroporous resins.

No abstract