Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (04): 770-776.doi: 10.3866/PKU.WHXB201301152

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of Silver Content on Catalytic Performances of SiO2-Supported Silver Tungstophoric Acid for the Synthesis of Polytetrahydrofuran

ZHANG Po, HUANG Ming, CHU Wei, LUO Shi-Zhong, LI Tong   

  1. Department of Chemical Engineering, Sichuan University, Chengdu 610065, P. R. China
  • Received:2012-11-08 Revised:2013-01-15 Published:2013-03-25
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20776089) and National Key Technology R&D Program of China (2010BAC67B02).

Abstract:

A series of supported silver salts of heteropolyacid AgxH3-xPW/SiO2 (x=0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized and showed high reactivity and stability in tetrahydrofuran polymerization, which were due to the salts' insolubility in polar solvent. The amount of Ag ion replaced in the salt and the amount of the salt loaded on the silica significantly influenced the catalytic performance. Change in the Ag content of the supported silver salt altered the crystal phase composition of the silver tungstophoric acid and catalyst's acid strength. The AgxH3-xPW/SiO2 catalyst had the highest acid strength and the highest polymerization activity when x=2.0. When the Ag2HPW loading was 30% (mass fraction), the catalyst exhibited the best dispersion and highest activity for the polymerization of tetrahydrofuran. Compared with the conventional silica supported heteropolyacid (HPW/SiO2) catalyst, the present 30%Ag2HPW/SiO2 displayed excellent reusability, with its reactivity only slightly declining after 4 reuses. Through the introduction of the Ag ion, the stability of the novel supported 30%Ag2HPW/SiO2 was significantly improved and the obtained polymer product, polytetrahydrofuran, had a stable average molecular weight.

Key words: Polytetrahydrofuran, Supported catalyst, Silver salt, Tungstophoric acid, Reusability

MSC2000: 

  • O643