Chem. J. Chinese Universities ›› 2009, Vol. 30 ›› Issue (9): 1748.

• Articles • Previous Articles     Next Articles

Autoxidation of Monoterpenes with Oxygen Catalyzed by Co(acac)2 Supported on Silica Functionalized Imidazole

FANG Zhao, TANG Rui-Ren*, HUANG Ke-Long, ZHANG Rui-Rong   

  1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
  • Received:2009-01-20 Online:2009-09-10 Published:2009-09-10
  • Contact: TANG Rui-Ren. E-mail: trr@mail.csu.edu.cn
  • Supported by:

    中国博士后基金(批准号: 2008431027)资助.

Abstract:

Selective oxyfunctionalization of monoterpenes is an interesting route to utilize these inexpensive natural products for a number of applications, such as pharmaceutical, flavor and perfumery industry as well as useful synthetic intermediates. The use of solid materials in catalytic oxidations in the liquid-phase has recently been extensively investigated because of their easy recovery and the possibility of regeneration which results in a reduction of the environmental impact. In this work, a new heterogeneous catalyst Co(acac)2/SiIm was prepared with supporting Co(acac)2 on silica gel modified with 3-chloropropyltrimethoxysilane and imidazole, and the structure of catalyst was characterized by IR, UV-Vis and ICP-AES. Oxidation reactions of limonene, α-pinene and β-pinene with dioxygen in acetonitrile solutions containing catalytic amounts of Co(acac)2/SiIm were studied. The results show that the higher conversion and products chemoselectivities were obtained. Limonene and α-pinene gave epoxides as predominant products with chemoselectivities 62% and 79% at 58% and 72% conversion, respectively. On the other hand, β-pinene gave allylic oxides as major products with chemoselectivity 85% at a 55% conversion rate. In addition, the reaction mechanism and competition were simply discussed.

Key words: Acetylacetone cobalt(Ⅱ); Silica gel; Catalysis oxidation; Monoterpenes; Oxygen

TrendMD: