Study Of Synthesizing α-Tetralone

As an important pharmaceutical intermediate, the annual demand of a-tetralone is more than 1 billion U.S. dollars all ove the word, so the study on their synthesis was of great practical significance. The synthesis of a-tetralone was the major work of this paper from Tetralin The final products were identified by Mass Spectrometry.SiO₂ supported Cr-based catalysts (denoted as Cr(L)/SiO₂ or Cr(H)/SiO₂, respectively) were prepared by an impregnation method. For comparison, K₂O modified Cr(L)/SiO₂ (K-Cr(L)/SiO₂) and Na₃Mo₁₂P₄₀ heteropoly salt was also prepared. The UV-vis results revealed that Cr(L)/SiO₂ possessed the highest ratio of low valence Cr species (Cr[â…¢]) to high valence Cr species (Cr[â…¥]), and the introduction of K₂O hindered the formation of Cr[â…¢]. It is suggested that oxidation of tetralin toα-tetralol can be the rate limiting step, which may be catalyzed by Cr[â…¢] species. Cr(L)/SiO₂ and Cr(H)/SiO₂ behaved similarly when O₂ was used as the oxidant, suggesting that O₂ transfer between the phase interfaces and/or adsorption of O₂ over the catalysts can be the rate limiting step in this case. The XRD results revealed that Cr was well dispersed on the surface of SiO₂.The catalytic performances of the three catalysts in oxidation of tetralin toα-tetralone were investigated using tert-butyl hydroperoxide (TBHP),O₂ or cumene hydroxy peroxide (CHP) as the oxidants. The results indicated that when TBHP was used as reagent, Cr(L)/SiO₂ showed the highest activity and the selectivity toα-tetralone, whereas K-Cr(L)/SiO₂ and Cr(H)/SiO₂ exhibited similar catalytic behavior. the repeatability of the catalyst and fixed-bed reactivity were discussed in the paper.