Efficient One-Pot Synthesis of 1,2-Pentanediol from 1-Pentene over a Zirconium Sulfate-Loaded Ti-MWW Bifunctional Catalyst

The one-pot synthesis of 1,2-pentanediol from 1-pentene is a route featuring environmental benignity, cost-effectiveness, and high atom economy. In this study, a bifunctional zirconium sulfate-loaded titanosilicate molecular sieve (ZS/Ti-MWW) catalyst was prepared via the impregnation method and used in the one-pot synthesis of 1,2-pentanediol. The effects of reaction conditions, zirconium sulfate loading, and calcination temperature on the catalytic performance for the oxidative hydration of 1-pentene were systematically investigated. On the basis of the NH3-TPD characterization results, the acid amounts of different catalysts were quantitatively analyzed. The results confirmed that zirconium sulfate could introduce abundant acidic sites into the catalyst, and the acid amount varied with the loading amount of zirconium sulfate and the calcination temperature. With the increase in acid sites in the ZS/Ti-MWW catalyst, its catalytic activity in epoxide hydration was markedly improved. Thus, the 1-pentene epoxidation and epoxide hydration were efficiently carried out in one system without additional separation. Under the optimal reaction conditions, the conversion rate of 1-pentene, the selectivity, and the yield of 1,2-pentanediol reached 95.65%, 80.72%, and 77.21%, respectively. This work offers new insights into the design and preparation of bifunctional titanosilicate molecular sieve catalysts as well as the efficient and green synthesis of 1,2-diols from olefins.