Preparation of hierarchical MWW-type titanosilicate by interlayer silylation with dimeric silane

• Dimeric silane pillared MWW zeolite was prepared through pre-swelling and silylation processes.
• The obtained interlayer expanded structure possessed a large d-spacing of  30.9 Å.
• Interlayer expanded Ti-MWW serves as active catalyst for the epoxidation of cyclohexene.

An interlayer expanded zeolite structure with dimeric silane as the pillars was constructed by a combination of pre-swelling and silylation. The pre-swelling process was carried out on the lamellar precursor of MWW-type borosilicate, which created enough interlayer space for accommodating the dimeric silane molecules with a relatively large molecular dimension. An appropriate amount of dimeric silane was important to prepare an ordered interlayer expanded structure pillared by monomolecular silane agent. The d-spacing of interlayer expanded MWW zeolite by dimeric silane reached 30.9 Å, which is larger than that of the conventional 3-dimentional (3D) MWW (25.0 Å) as well as the silylated sample pillared by monomeric silane (27.5 Å). Ti cations were isomorphously incorporated into the interlayer expanded MWW zeolite pillared by dimeric silane. The obtained titanosilicate was highly active in the epoxidation of alkenes with hydrogen peroxide, especially in the case of cyclohexene.

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