硼改性对纳米HZSM-5分子筛催化甲醇制丙烯的影响

采用浸溃法制备了一系列不同硼含量的改性纳米HZSM-5分子筛催化剂。利用X射线衍射、氮气吸附／脱附和氨-程序升温脱附技术对硼改性前后纳米HZSM-5分子筛催化剂的结构和酸性进行了表征，并在常压、500℃和甲醇空速为1．0／h的反应条件下，在连续流动固定床微型反应器上考察了其催化甲醇制丙烯反应的性能。结果表明，随硼含量的增加，改性纳米HZSM-5分子筛的比表面积和孔容均减小，酸强度降低，强酸量减少，弱酸量先减少后增加，从而使丙烯选择性不断提高和催化剂的稳定性先提高后降低。

The Effect of Boron Modification on Catalytic Performance of Nanosized HZSM-5 Zeolite for Conversion of Methanol to Propene

A series of nanosized HZSM- 5 zeolite catalysts modified with different boron contents were made by impregnation method. The structures and acidic properties of the samples before and after boron modification were investigated by XRD, N2 adsorption/desorption and NH3-TPD techniques. Their performance for conversion of methanol to propene was tested in a continuous flow fixed-bed micro-reactor at atmospheric pressure, 500℃, and methanol space velocity （WHSV） of 1.0/h. The results showed that with the increase of boron content in the modified nano-HZSM - 5 zeolites, their surface areas decreased gradually,as well as the pore volume, the strength of the acidic sites and the amount of strong acidic sites, but the amount of weak acidic sites reduced firstly and then increased. Accordingly, the selectivity for propene increased continuously and the catalyst stability was enhanced firstly and then deteriorated.