Hydrothermal Synthesis and Characterization of Aluminum-Free Mn‑β Zeolite: A Catalyst for Phenol Hydroxylation

• Published in: ACS applied materials & interfaces Vol. 7; no. 4; pp. 2424 - 2432
• Main Authors: He, Zhen, Wu, Juan, Gao, Bingying, He, Hongyun
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.02.2015
• Subjects: phenol hydroxylation; hydrothermal synthesis; Al-free; beta zeolite; catalytic activity
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/am507134g

Zeolite beta, especially heteroatomic zeolite beta, has been widely used in the industries of fine chemicals and petroleum refining because of its outstanding thermal stability, acid resistance, and unique 3-D open-frame structure. In this paper, aluminum-free Mn-β zeolite was hydrothermally synthesized in the SiO2–MnO2–(TEA)2O–NaF–H2O system. The effect of the chemical composition of the precursor mixture to the crystallization of the Al-free Mn-β zeolite was investigated. The synthesized Al-free Mn-β zeolite was characterized by inductively coupled plasma (ICP), XRD, thermogravimetric/differential thermal analysis (TG/DTA), N2 adsorption–desorption, FT-IR, UV–vis, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The results show that the synthesized zeolite has a structure of β zeolite with good crystallinity and Mn ions present in the framework of the zeolite. The synthesized Al-free Mn-β zeolite shows great catalytic activity toward the phenol hydroxylation reaction using H2O2 as the oxidant. Approximately 35% of phenol conversion and ∼98% of dihydroxybenzene selectivity can be obtained under the optimal conditions.