| In this paper,different modification methods was studied for the improvement of HZSM-5 zeolite catalyst.It's found that hydrothermal treatment,the loading of phosphorus oxide modification and the loading of rare earth metal oxides all can adjust the strength and the quantity of acid sites of HZSM-5 zeolite and regulate the pore size of the zeolite,and the modifications all can improve p-DEB selectivity during the alkylation of ethylbenzene.But hydrothermal treatment and phosphorus oxide modification have little contribution to the yield of p-DEB.In contrast,rare earth metal oxide modification can improve the yield of p-DEB and the yield of p-DEB increased with the loading of the oxides of rare earth elements increasing.On the basis of modification,catalyst EA-6 was obtained,which has the following catalytic performance:1) In the alkylation of ethylbenzene with ethylene and the alkylation of ethylbenzene with ethanol,EA-6 shows an initial yield of DEB of about 19%,a yield of DEB of 7%after 300 hours TOS.The catalyst has a selectivity to p-DEB of above 98%in the two reactions.2) Catalyst EA-6 has good regeneration performance.The catalyst which regenerated after 11 times can display the same catalytic performance as the catalyst which regenerated for the first time.In the alkylation of ethylbenzene,the initial yield of DEB of the repeatedly regenerated catalyst is about 19%.The yield of DEB can still achieve 5%after 300 hours TOS.The selectivity of p-DEB of it can be achieved more than 98%through the entire time course of operation.3) In the alkylation of ethylbenzene with ethylene,the initial yield of DEB of the catalyst which regenerated for one time is about 20%.The yield of DEB in the middle and final period of the reaction can be maintained at 11-10%.The selectivity of p-DEB can be maintained above 98%in the whole 550 hours' operation.Results confirm that the highly active shape-selective catalyst is easily reproduced.
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