Aerobic Oxidation of 2,3,6-Trimethylphenol with Reusable Homogenized Copper Catalysts

The oxidation of 2,3,6-trimethylphenol(TMP) can produce both 2,3,5-trimethyl-1,4-benzoquinone(TMQ) and 2,3,5-trimethyl-1,4-hydroquinone(TMHQ) as important intermediates of vitamin E. With a soluble and porous polymer of intrinsic microporo-sity(PIM-1), we developed a highly active and reusable CuO@PIM-1 catalyst for the aerobic oxidation of TMP to TMQ and TMHQ. The CuO@PIM-1 catalyst is high active and selective for the aerobic oxidation of TMP, and TMQ and TMHQ can be obtained in yields of 81% and 19%, respectively. The CuO@PIM-1 catalyst has both advantages of homogeneous and heterogeneous and the CuO@PIM-1 catalyst showed a higher activity than homogeneous(CuCl₂) and heterogeneous(supported CuO) catalysts. Moreover, CuO@PIM-1 catalyst can be recovered easily and reused at least 5 times without deactivation.