Transesterification Route Esterfip

The classical route involves very active soluble catalysts, with the major drawback of a difficult purification of the glycerol produced, as discussed above. A simple way to avoid the problem is to turn to heterogeneous catalysis. Such a process has been developed by IFF and is being commercialized by Axens [4]. The first industrial unit started in 2006, at Sete, in the south of France. 

In this new continuous process, the transesterification reaction is promoted by a completely new heterogeneous catalyst. This catalyst consists of a mixed oxide (a zinc aluminate) that promotes the transesterification reaction without catalyst loss [5j. The reaction is performed at higher temperature and pressure than in the homogeneous catalyst process, due the lower activity of the solid catalyst. 

This new heterogeneous catalyst process offers the main following advantages (Table 9.3)  

Homogeneous biodiesel process Heterogeneous biodiesel process 

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