Influence of Noble Metals on the Direct Oxidation of Ethylene to Acetic Acid over NM/WO3-ZrO2 (NM = Ru, Rh, and Pd) Catalysts

✍ Scribed by Lixia WANG; Shuliang XU; Wenling CHU; Weishen YANG

• Publisher: Elsevier Science
• Year: 2009
• Weight: 267 KB
• Volume: 30
• Category: Article
• ISSN: 1872-2067
• DOI: 10.1016/s1872-2067(08)60144-8

✦ Synopsis

Ru-, Rh-, and Pd/WO 3 -ZrO 2 catalysts were studied for the direct oxidation of ethylene to acetic acid. The catalytic activity and selectivity depended strongly on the noble metals used. Rh/WO 3 -ZrO 2 gave the highest conversion of ethylene, whereas Ru/WO 3 -ZrO 2 was almost inactive. The higher catalytic activity was attributed to a better metal dispersion. Pd/WO 3 -ZrO 2 gave the highest selectivity for acetic acid (75%), with the selectivity of the other two catalysts being rather low (~10%). Temperature-programmed oxidation and H 2 reduction experiments were used to show that the strength of the noble metal-oxygen bond played an important role in product distribution. A weak metal-oxygen bond favored the formation of acetic acid, while a strong metal-oxygen bond favored the combustion of ethylene to CO x .