The Acetalization Of Glycerol With Solid Acid Catalyst

With the rapid development of biodiesel, it has been applied in many fields. But the by-product----glycerol has become the main problem for the further development of biodiesel. In this paper, glycerol has been applied to the acetalization with acetone to obtain solketal.Acetalization of glycerol with acetone was examined by using M-AIPO4 solid acid catalysts with enlarged surface areas. So we introduce Zn, Cu, Ni and Co atom into M-AIPO4, respectively. The synthesized catalysts were systematically analyzed using various techniques, namely, XRD, SEM, EDX, BET surface area, pore size distribution, UV-vis spectrophotometer and NH3-TPD. XRD results suggested formation of mesostructure amorphous materials. SEM results showed that these materials had ordered structure. All the materials exhibited uniform pore size and high specific surface area. The strength of the acid sites of solid acid catalysts was studied by NH3-TPD. The amount of the acid sites of solid acid catalysts was studied by UV-vis spectrophotometer, a novel method to measure the exact amount of the acid sites. The resulted materials were found to exhibit excellent catalytic activity for the acetalization of glycerol with acetone. The reaction with M-NiAlPO4 showed the highest yield (75.44%) and the best selectivity (75.12%).Acetalization of glycerol with acetone was examined by using M-ZrPO solid acid catalysts with enlarged surface areas. We changed ratios of P/Zr (from 0.25 to 1.25), calcination temperature (from 500℃ to 700 ℃) of M-ZrPO, replaced P atom with Sn and W atoms and Zr atom with Ti and La atoms to substitute framework charges. The synthesized catalysts were systematically analyzed using the same techniques. The resulted materials were found to exhibit excellent catalytic activity for the acetalization of glycerol with acetone. The reaction with M-ZrPO-0.75-500 showed the highest yield (78.91%) and the best selectivity (88.51%).The optimized reaction conditions in the acetalization of glycerol, such as the catalyst amount, reaction temperature and molar ratio of glycerol to acetone, were investigated by simple variable methods. The results show that T= 80 ℃, glycerin:acetone= 8, m= 0.2 g, T= 1 h is the best reaction conditions.