Study On Solid Catalysts Modified By Introduction Of Rare-earth Through Solid-state Ion Exchange

The core of the developing green catalysizing technology is that the study on the friendly catalysts both protects environment and improves economic efficiency.At present, the solid B acid catalysts have been used widely for the etheriflcation of catechol with methanol. But, their selectivity, especially the catalytic stability, is still need to be improved. Therefore, we try to use the ZnCl2 modified solid L acid catalysts to catalyze this reaction for the first time.The results have shown that the ZnCl2 modified Al2O3 or NaY catalysts has great efficiency to the reaction, which precede to the HY catalyst with B acid sites. The modifications of the ZnCl2 to A12O3 or NaY, which are to increase the acidity of the catalyst, increased the catalytic activities greatly, especially increased the selectivity for the guaiacul and also improved the stability of the catalysts. Further studies on the ZnCl2/Al2O3 and ZnCl2/NaY catalysts have shown that the former displayed the better catalytic activity and the selectivity for the guaiacul (at the optimum conditions, the conversion and selectivity are 81.5% and 90.9%, respectively), but its stability is worse (it will lose the activity after running 30 h), the cause is that the ZnCl2 active component of this catalyst is easy to lose in the running process; while the latter not only has the improved activity and selectivity (at the optimum conditions, theconversion and selectivity are 86.7% and 99.3%, respectively) , but also has a distinct improvement of the stability (it will lose the activity after running 70 h), the cause of its improved stability is that the active component of this catalyst is not easy to lose in the running process, the coke of the catalyst' surface is the main reason for the inactivation.In order to look for a better catalyst with longer use-life, we have studied the catalytic interactions of the non-framework-aluminium in NaY to this reaction and the modifications of the accessory ingredient to this catalyst. After studying we found that the non-framework-aluminium NaY molecular sieve was very active to this reaction (catechol conversion: 76.4%, guaiacul selectivity: 91.9%, stability of the catalyst: 20h), after adding a small of accessory ingredient into the non-framework-aluminiu-m NaY we found its catalytic activity and stability have been improved distinctly (catechol conversion: 94.0%, guaiacul selectivity: 90.4%, stability of the catalyst: 100h).All the three kinds of catalysts have presented better catalytic activity. They will be used widely if their use-life can be prolonged. The previous works will provide research foundation for the application of the solid acid catalysts in the organic synthesis.