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Zeolite β is an important material in catalysis, however the material with molar ration of silicon and aluminum more than 200 is difficult to synthesize. Typically, the pure silica β and heteroatom zeolite β are prepared at near neutral pH using HF as the mineralization agent. However, the HF is highly toxic and corrosive, and the zeolites formed are usually more than 10 μm. In this paper, alkaline and fluorine-containing salts was applied, and pure silica β was hydrothermally synthesized from a basic precursor. The silica resource and alkali metal cations in the precursor would influence the crystallization process, tetraethyl orthosilicate and sodium cations are preferred. The pure silica β is plate-like, the crystals formed on the third day are about 50 × 300 × 300 nm, which keep growing with the time, and pure silica zeolite β with uniform size of about 200 × 700 × 700 nm are synthesized in a week. More importantly, the pure silica β is defects-free, and it's highly hydrophobic.

The silanization is an important approach for hierarchical zeolite preparation. Although the influences of the silanization conditions have been detailed studied, the differences in the reactivity of the zeolite precursor should further be analyzed. In this paper, hierarchical titanium silicalite-1 (HTS) was prepared with trimethoxy[3-(phenylamino)propyl]silane (TMPAPS) under the nTMPAPS:nSi = 0.04–0.20 and nTi:nSi = 0.005–0.04 conditions, the changes of the corresponding physicochemical properties were analyzed, and the influences of the condensation activities between silicon/titanium to the organosialne were deduced and verified by density functional theory (DFT) calculations. Generally, more supermicropores and mesopores can be created in the metastable sponge-like HTS crystals with higher TMPAPS and titanium contents. In comparison, the free energy barrier in the condensation reaction with titanium (1.31 eV) is lower than silicon (1.55 eV), it's preferential to prepare HTS with more intracrystalline secondary porosity by increasing the nTi:nSi. More importantly, the titanium can be isolated by the organosilane, and HTS with more framework titanium can be synthesized by silanization.

CHHP is the main product of the cyclohexane oxidation process, the rational design and preparation of solid catalysts are vital important for the development of an environmental benign CHHP conversion process. Herein, cobalt oxide encapsulated hydrophilic hierarchical Silicalite-1 was developed for CHHP conversion. In the presence of an organosilane, the encapsulation of cobalt oxide, creation of intracrystalline secondary porosity, and introduction of surface silanols were simultaneously achieved via hydrothermal synthesis. The particle size of the encapsulated cobalt oxide was about 4.7–6.3 nm, while the SBET, VT and VME are 527 m2/g, 0.417 cm3/g and 0.3 cm3/g, respectively. Moreover, the SBET further increases to 692 m2/g when the silanization process was intensified by surfactants, and the hydrophilic substrates could more easily be adsorbed by the catalyst for the abundant terminal silanols. Then, the dilute CHHP could selectively be adsorbed and activated by the catalyst, and a CHHP conversion of more than 99% could be achieved in 20min. More importantly, the catalyst exhibits outstanding activity in both the CHHP decomposition reactions and cyclohexane oxidation reaction with CHHP as the oxidant, the oxygen utilization efficiency (60%) and KA oil selectivity (120%) were notably improved. The stability of the catalyst is excellent, the activity retained after recycling for 20 times. This strategy is general, which could further be applied for the development of heterogeneous catalysts for more environmental benign chemical processes.