Four kinds of modified niobic acids were synthesized by potassium hydroxide melting method using different inorganic acid treatments. The structure and surface acidity of this niobic acid were studied by XRD, N2 adsorption-desorption and NH3-TPD. The catalytic activity of modified niobic acid in the synthesis of tebelon had been studied. The experimental results indicated that H2SO4-Nb2O5 has the better performance and stability. The optimal conditions of etherification reaction are as follows: catalyst amount used for raw material 1.0% (weight ratio), reaction temperature 110？C, mole ratio of alcohol to acid 2:1 and reaction time 8 h.
Fazal, M.A., Jaceria, M.R. and Haseeb, A.S.M.A. (2014) Effect of Copper and Mild Steel on the Stability of Palm Biodiesel Properties: A Comparative Study. Industrial Crops and Products, 58, 8-14.
Jain, S. and Sharma, M.P. (2011) Correlation Development for Effect of Metal Contaminants on the Stability of Jatropha Curcas Biodiesel. Fuel, 90, 2045-2050. http://dx.doi.org/10.1016/j.fuel.2011.02.002