Controllable synthesis of polyoxymethylene dimethyl ethers by ionic liquids encapsulated in mesoporous SBA-16

The promising combustion and emission properties of polyoxymethylene dimethyl ethers (PODEn) are of significant interest. However, the synthesis of PODEn products with desired chain lengths is still a prob-lem facing synthetic PODEn. Herein, a series of unique IL@SBA-16-Cx solid catalysts are prepared by encapsulation of ionic liquids (ILs) within the nanocage of SBA-16 through a silylation method. The struc-ture of the encapsulated catalyst was characterized by UV–vis spectra, Fourier transform infrared (FT-IR), N2 adsorption–desorption isotherms, Powder X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Elemental analysis. The encapsulated catalysts show similar catalytic activity to the homoge-neous counterparts and display higher selectivity to the targeted PODE3–5 products than their homoge-neous counterparts in the synthesis of PODEn from methanol (MeOH) and trioxymethylene (TOM). The encapsulated catalysts exhibit a superior PODE3–5 selectivity and could be the promising catalysts for PODEn synthetic reaction.