文档介绍：4
Studies on Modification of Solid Super Acid SO 2-
/TiO2 and Synthesis
of Tri-n-butyl Citrate with the catalyst
Abstract
Tri-n-butyl citrate(TBC) was synthesized with solid super acid as catalyst, and the catalytic properties of the catalyst SO42-/TiO2 in esterification of citric acid with n-butanol were studied. A new catalyst Tm-SO42-/TiO2 was prepared by modification on which the rare earth element Tm was loaded. The correlation between its structure and properties was also investigated. All these above strongly support the industrialization
of TBC synthesis catalyzed by solid super acid.
This paper reported the esterification synthesis of TBC under no catalyst, H2SO4, or solid super acid SO42-/TiO2. The correlation between reaction conversion, water yield and reaction time was surveyed. The effects of initial molar ratio and catalyst quantity were investigated and the optimum synthesis conditions were found. Tri-n-butyl citrate was synthesized with solid super acid SO42-/TiO2 as catalyst, and the activity and stability of the catalysts in esterification of citric acid with n-butanol were studied. The
effects of (NH4)2SO4 quantity and calcination temperature on the catalysts were studied and the correlation between their structure and properties was also investigated. The results showed that (NH4)2SO4 was better than H2SO4 as promoter. The catalytic
selectivity amounted to 99% while 20% (NH4)2SO4 added and 600℃ calcinated. On
this condition the conversion of citric acid was %, and the ester yield was %. The formation and growth of anatase crystalline phase was the key factor in the improvement of catalytic selectivity. The deactivation of catalysts in TBC synthesis
2-
resulted from the carbon deposition and the loss of SO4 .
2-
In order to improve catalytic properties, Tm-SO4
/TiO2 was prepared by
modification, the rare earth element Tm was loaded on SO42-/TiO2. Loading Tm effectively promoted catalytic stability, improved catalytic a