A series of mesoporous solid acid catalysts (PDS-x) with large BET surface area, superior thermal stability, strong sulfonic acid groups and tunable Brønsted acidity were synthesized by the copolymerization of divinylbenzene (DVB) and sodium p-styrenesulfonate (SPSS). The PDS-x catalysts showed high activity on the direct and efficient production of triacetylglycerol (TAG) via acyl exchange reaction of oils (fats) and acetic acid. The highest TAG yield of 93.0 mol% was obtained on the PDS-x catalysts at a mild condition of 200 °C. By combining SEM, TEM, FT-IR/DRIFTS, BET, XRD , XPS , EA, 31 P MAS NMR and TG-DTG, the key factors that affected the TAG yield were clarified on the PDS-x catalysts. Moreover, the origin of the slow deactivation on these catalysts was elucidated. The large BET surface area and abundant mesopores of catalysts allowed the contact of large-sized oils (fats) with the strong sulfonic acid groups, accounting for the high TAG yield.
Shi Qiqi,Guo Heqin,Chen Congbiao,Hou Bo,Jia Litao,Li Debao
In the present work, a series of sulfonic polymer-based acid catalyst PDS-x’s was obtained by hydrothermal method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction, N 2 adsorption–desorption isotherms, thermogravimetric analysis, Fourier transform infrared spectrometer, pyridine-adsorbing IR, acid–base titration, X-ray photoelectron spectroscopy, and CHNS elemental analysis. The carbonylation of formaldehyde was chosen as a probe reaction to test the catalytic performance. The results show that the content of acid sites and specific surface area can be adjusted by changing the molar ratio of sodium 4-vinylbenzenesulfonate (SVBS) to divinylbenzene (DVB). The catalyst performance results show that the PDS-x’s can efficiently catalyze glycolic acid synthesis. And a high glycolic acid yield up to 96% was obtained on PDS-2.1 due to its large specific surface area, plentiful mesoporosity as well as suitable acid concentration. This data are even higher than those on super-strong CF 3 SO 3 H and commercial resin Amberlyst-15. Moreover, the carbonylation of formaldehyde is a structure-sensitive reaction, the isolated and monolayer dispersed -SO 3 H is much more active than aggregated −SO 3 H. Furthermore, the catalyst has high stability.