High-silica Hβ zeolites for catalytic hydration of hydrophobic epoxides and alkynes in water

We investigated the hydration of hydrophobic epoxides and alkynes in water using 24 types of heterogeneous and homogeneous catalysts and found that Hbeta (H beta) zeolite with a relatively high Si/Al ratio (Si/Al = 75), H beta-75, is an effective catalyst. H beta-75 showed wide substrate scope, good reusability, and applicability in gram-scale synthesis for both types of reactions. The effects of hydrophobicity, acidity, and the size of zeolite pores were also comprehensively studied through the hydration of hydrophilic and hydrophobic epoxides and alkynes with different molecular sizes using two types of zeolite (H beta and HZSM5). The high yields obtained using the H beta-75 catalyst in the hydration of hydrophobic epoxides and alkynes are attributed to the hydrophobic interaction between zeolite pores with the substrates, as well as the relatively large pore size. (C) 2018 Elsevier Inc. All rights reserved.