1.H2SO4
2.p-CH3-phSO3H
3.JK008 resin
Ion Exch. Adsorp.2000,16,362-365
4.H2SO4 /TiO2
China Condiment,2007,41-45
5.TiSiW12O40/TiO2
China Surfact. Deterg. Cosmetics 2000,20-25
6. [HSO3-p-MIM]HSO4

 
7. [HSO3-p-MIM]p-TSA
 
J Am. Chem Soc.2002,124,5962-5963
Ind. Eng. Chem. Res. 2006, 45,7982-7984
Catal. Commun 2004,5,473-478