Sulfonic acid group modified ZSM-5 zeolite as a highly active catalyst for the hydration of cyclohexene to cyclohexanol

Abstract

In this work, sulfonic acid group modified ZSM-5 (SFZ-x, x presents the weight percentage of mercaptopropyltrimethoxysilane during preparation) has been prepared by introducing sulfydryl on ZSM-5 and then oxidizing them into the sulfonic acid group. The obtained samples were characterized by XRD, N₂ adsorption/desorption, FTIR, and SEM and studied the catalytic performance in the hydration of cyclohexene to produce cyclohexanol. The characterization results showed that with the introduction of -SO₃H, the crystallinity of SFZ-15 decreased slightly, and the Brønsted acid sites obviously increased, while the pore structure was almost unchanged inside the ZSM-5 zeolites. Therefore, SFZ-15 exhibits better catalytic performance in the hydration of cyclohexene to produce cyclohexanol compared to commercial ZSM-5. Furthermore, this SFZ-15 catalyst kept the conversion of cyclohexene over 12% and the selectivity of cyclohexanol over 99% even after five runs, demonstrating the benefit of –SO₃H functionalization on the activity improvement of traditional ZSM-5 catalyst.

Graphical abstract

The sulfonic acid group modified ZSM-5 zeolite has been prepared by introducing sulfydryl on ZSM-5 and then oxidizing them into the sulfonic acid group. The prepared catalyst exhibits excellent catalytic performance in the hydration of cyclohexene to produce cyclohexanol.