Trace amounts of Cu(OAc)2 boost the efficiency of cumene oxidation catalyzed by carbon nanotubes washed with HCl†
The oxidation of hydrocarbons to high value-added intermediates is significant in industrial manufacture. It is of great significance to develop low-cost, high-activity catalytic systems. In this study, carbon nanotubes (CNTs) were used as catalysts and cumene was used as a substrate to be oxidized into high value-added peroxides, alcohols, and ketones. By adding trace amounts of Cu(OAc)2 (1 ppm of CNTs), the conversion of cumene greatly increased to 54.2% from 38.5%, and the selectivity of alcohol increased from 25.1% to 44.7%, indicating that the trace amounts of Cu(OAc)2 could significantly modulate the reactivity and product selectivity. The mechanism study has shown that this promoting effect results from the presence of chlorine adsorbed on the carbon surface caused by HCl washing. This adsorbed chlorine is extremely unstable during the reaction and interacts with Cu(OAc)2 to form a Cu–Cl component, thus accelerating the decomposition of peroxides and promoting the activity of the reaction. This study demonstrates that the pretreatment of carbon materials might significantly impact their catalytic performance.