Influences of Different Active Carbons on the Catalytic Performance of Ni/C Catalysts for Vapor-Phase Carbonylation of Ethanol

Different active carbons, i.e. bamboo charcoal, cylindrical coal, fruit carbon. wood charcoal, and coconut charcoal, were used to prepare Ni/C catalysts for vapor-phase carbonylation of ethanol. The results revealed that the Ni/CC catalyst showed the highest catalytic activity for ethanol carbonylation with 96.1% of ethanol conversion and 93.2% of propionic acid selectivity, but the Ni/BC catalyst showed the lowest activity with 63.0% of ethanol conversion and 32.7% of propionic acid selectivity. The Ni/C catalysts were characterized by CO adsorption and temperature-programmed reduction. Meanwhile, N-2 physical adsorption, X-ray photoelectron spectroscopy, and temperature-programmed desorption were used to investigate the structural properties, the species and quantities of surface oxygen functional groups of active carbons. It was found that the catalytic performance of the Ni/C catalysts depended on the nature of active carbons greatly

Promoting effect of CeO2 addition to Ni/AC catalyst for vapor phase carbonylation of ethanol to propionic acid

Ni/AC catalysts promoted with or without CeO2 for vapor phase carbonylation of ethanol to propionic acid were tested and investigated by CO chemisorption, XRD and H-2-TPR techniques. The catalytic test results showed that the proper amount of CeO2 addition could remarkably enhance the activity and stability of Ni/AC catalyst. The characterization results indicated that CeO2 added can improve the dispersion and metal area of Ni on the catalyst, suppress the sintering of Ni crystallite and benefit the reduction of Ni, which are closely related to high performance of the Ni/AC catalyst promoted with CeO2. (c) 2009 Elsevier B.V. All rights reserved.Ministry of Science and Technology of China [2004CB217805]; Colleges Cooperation Projects [0042-K81009

Study on Ni/C catalysts for vapor phase carbonylation of ethanol

Activated carbon-supported Ni catalysts for vapor phase carbonylation of ethanol to propionic acid in the presence of ethyl iodide as promoter were investigated. Under Optimum reaction conditions, the conversions of carbon monoxide and ethanol were measured to be 81.4% and 98.4%, respectively. while the selectivity for propionic acid was found to be 98.65%. The catalyst was stable within 48 h on stream. XRD and XPS methods were used to characterize the structures and surface properties of the fresh and tested catalysts. The characterization results indicated that aggregation of nickel particles and formation of nickel iodide on the catalyst surface should be responsible for the deactivation of the catalysts.Colleges Cooperation Projects [0042-K81009