A Highly Active In Situ Zn(CH3COO)2-NC Catalyst for the Acetoxylation of Acetylene

Preparation of High-Performance Zn-Based Catalysts Using Printing and Dyeing Wastewater and Petroleum Coke as a Carrier in Acetylene Acetoxylation

In this study, novel Zn catalysts were prepared by the wet impregnation method using printing and dyeing wastewater (PDW)-modified petroleum coke (petcoke) as a carrier, and they were applied to the acetylene acetoxylation. The pretreated petroleum coke has a high specific surface area which provides sufficient space for the loading of Zn. Calcination further increases catalyst activity, but when calcination temperatures exceed 1000 °C, a significant loss of Zn occurs, resulting in a dramatic decrease in catalyst activity. This enables the conversion of acetic acid up to 85%. X-ray photoelectron spectroscopy confirmed that a large amount of N is introduced into PC from PDW, which changes the electron transfer around Zn. Temperature-programmed desorption (TPD) analysis revealed that the nitrogen-doped Zn(OAc)2 catalyst enhanced the catalytic activity by modulating the intensity of the catalyzed adsorption of acetic acid and acetylene. This study provides a new way to reuse petroleum coke and printing and dyeing wastewater to support the sustainable development of the vinyl acetate industry.

Solvent Effects in the Preparation of Catalysts Using Activated Carbon as a Carrier

The role of solvents is crucial in catalyst preparation. With regard to catalysts prepared with activated carbon (AC) as the carrier, when water is used as a solvent it is difficult for the solution to infiltrate the AC. Because AC comprises a large number of C atoms and is a nonpolar material, it is more effective for the adsorption of nonpolar substances. Since the water and active ingredients are polar, they cannot easily infiltrate AC. In this study, the dispersion of the active component was significantly improved by optimizing the solvent, and the particle size of the active component was reduced from 33.08 nm to 15.30 nm. The specific surface area of the catalyst is significantly increased, by 10%, reaching 991.49 m²/g. Under the same reaction conditions, the conversion of acetic acid by the catalyst prepared with the mixed solvent was maintained at approximately 65%, which was 22% higher than that obtained using the catalyst prepared with water as the solvent.

Enhanced nonlinear optical properties of a π-conjugated porphyrin dimer–graphene nanocomposite

A more conjugated nanocomposite and a potential NLO candidate with a strong intrasystem interaction were constructed using a rarely mentioned porphyrin dimer and graphene.