The Synthesis Of New Type Solid Alkali And Catalytic Transesterification Performance Research

The transesterification is one of the most important ways to produce biodiesel.There are many kinds of catalysts used to catalyze the transesterification. But theresearchers are always seeking the catalysts which are highly active, environmentalprotection and reusable. The supported solid base catalysts with the merits of the fastcatalytic rate, strong basicity and reusable are received more and more attention.In this paper we have successfully synthesized two series of the supported solidbase catalysts KF/M_xO_y、LiOH/M_xO_y. Combined with a series characterization such asXRD、CO₂-TPD、SEM, we have exposited the relationship between the catalytic activityand the structure、basicity of the catalyst. The results of experiments showed that whenLa₂O₃was used as the catalyst carrier, it has better catalytic activity、stability thanSm₂O₃、CeO₂rare-earth oxides carriers, and Al₂O₃、TiO₂、ZrO₂nonrare-earth oxidescarriers. The experiments results also showed that when LiOH was used as activeconstituent, the catalyst had superior activity than KF used as active constituent.When KF was loaded on La₂O₃, new phase LaOF appeared, and the LaOF leadnew basic center to appear. The basicity of the catalyst increased, the catalytic activityenhanced. And the LaOF can control the loss of activity site, keep the stability ofcatalysts. Under the suitable reaction conditions,15%KF/La₂O₃catalyze thetransesterification, the tributyrin conversion was nearly100%, and the methyl butyrateyield was98.0%are obtained.When LiOH was loaded on La₂O₃, the catalyst showed good activity. Under thesuitable reaction conditions,15%LiOH/La₂O₃catalyze the transesterification, the methylbutyrate yield was98.2%, and the tributyrin conversion was nearly100%. Theexperiments results certified that it was Li that dispersed in the catalyst promoted thetransesterification, increased the catalytic activity. Because of Li was not easy to loss inthe reaction system, the catalyst had good stability, after use five times, the methylbutyrate activity was above90.0%.