Ordered mesoporous titanium phosphate material: A highly efficient, robust and reusable solid acid catalyst for acetalization of glycerol

In the present work, a series of ordered mesoporous titanium phosphate (M-TiPO) materials with controllable composition are prepared by a simple one-pot method. The introduced Ti and P species are homogeneously dispersed in the skeleton of M-TiPO. Moreover, the influence of P content in mesoporous structure and existing states of Ti species is detailedly discussed. The result shows that the mesoporous structure is successfully improved by the introduction of P species. The M-TiPO-0.5 material (P/Ti=0.5) exhibits outstanding textural properties (specific surface area (215 m(2)center dot g(-1)), pore size (6.6 nm) and volume (0.34 cm(3)center dot g(-1))). Also, with the increasing of P species, the crystalline structure of mesoporous skeleton gradually changes from anatase TiO2 to amorphous phase, and the bonds in the materials transfer from Ti-O-Ti to Ti-O-P. The electron density of Ti decreases, and the acidic property is gradually enhanced. The gotten M-TiPO samples are utilized as catalyst for acetalization of glycerol with acetone. The M-TiPO-0.75 with excellent textural and acidic properties exhibits the best catalytic effect (the glycerol conversion is 91.3% and the acetal selectivity is 94.7%). More importantly, the M-TiPO-0.75 solid acid catalyst shows attractive reusability, and there is no decline in catalytic activity even after ten cycles. Consequently, M-TiPO material is a promising catalyst for the acetalization of glycerol.