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    叶丽萍, 胡浩, 曹发海, 孙启文, 应卫勇, 房鼎业. SAPO-34分子筛的合成及其对甲醇制低碳烯烃反应的催化性能[J]. 华东理工大学学报（自然科学版）, 2010, (1): 6-13.
    引用本文: 叶丽萍, 胡浩, 曹发海, 孙启文, 应卫勇, 房鼎业. SAPO-34分子筛的合成及其对甲醇制低碳烯烃反应的催化性能[J]. 华东理工大学学报（自然科学版）, 2010, (1): 6-13.
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    Synthesis of SAPO-34 molecular sieves and their catalytic performances in methanol-to-olefins reaction[J]. Journal of East China University of Science and Technology, 2010, (1): 6-13.
    Citation: Synthesis of SAPO-34 molecular sieves and their catalytic performances in methanol-to-olefins reaction[J]. Journal of East China University of Science and Technology, 2010, (1): 6-13.
    shu

    SAPO-34分子筛的合成及其对甲醇制低碳烯烃反应的催化性能

    Synthesis of SAPO-34 molecular sieves and their catalytic performances in methanol-to-olefins reaction

      摘要
    • 摘要: 制备具有适宜酸性能和最佳物理性质的催化剂是甲醇制低碳烯烃（MTO）工艺的关键。采用水热晶化法，考察了不同模板剂、模板剂用量、pH、晶化时间和温度等因素对SAPO-34分子筛制备的影响，并采用XRD、SEM、BET和NH3-TPD等方法进行表征，从而考察分子筛结构、表面酸性等性质对分子筛催化剂在MTO反应中的催化性能的影响。结果表明：四乙基氢氧化铵（TEAOH）为合成SAPO-34的最佳模板剂，与二乙胺相比，TEAOH制得的SAPO-34比表面积大（＞400 m2/g），呈立方晶形，颗粒尺寸较小且分布均匀，具有比例适宜的强、弱酸中心；而以二乙胺为模板剂合成的SAPO-34具有较多的强酸中心，酸性较强。采用TEAOH为模板剂，当n(TEAOH)∶n(Al2O3)为2.02~1.35时，减少模板剂用量，合成产物仍为SAPO-34，相对结晶度减小；当n(TEAOH)∶n(Al2O3)为1.35~1.01时，减少模板剂用量会导致SAPO-5与SAPO-34共生。直接、快速的升温过程不利于晶粒的成长；先升温至90~150 ℃并维持这一温度，待过渡相态稳定后再继续升温至170~250 ℃晶化，有利于得到更高结晶度的SAPO-34晶体，此时SAPO-34分子筛在MTO反应中显示了最优的催化性能，甲醇转化率100%，对低碳烯烃的选择性为83.40%，活性时间为220 min。

       

      Abstract: SAPO-34 molecular sieves were synthesized hydrothermally. The effects of templates, template amounts, pH, crystallization temperature and time on the synthesis were investigated. By means of XRD, SEM, BET and NH3-TPD techniques, the influences of the molecular sieve structure and surface acidity on the catalytic properties were also studied. The results show that compared with DEA, TEA and TMAOH, TEAOH is the most proper template for synthesis of SAPO34 with large BET surface areas (＞400 m2/g), homogeneous cubic crystals of narrow size distribution and proper ratio of strong to weak acid sites, while the SAPO34 prepared by using DEA as template shows strongger acidity. Using TEAOH as template with its amount in the range of n(TEAOH)∶n(Al2O3) of 2.02-1.35, the crystallinity of product SAPO34 decreases upon reducing the amount of template. Reducing TEAOH amount in the range of n(TEAOH)∶n(Al2O3) of 1.35-1.01 leads to SAPO-5 co-generating with SAPO-34. A directly fast heating is unfavorable for the growth of crystals. The procedure of preheating to 90-150 ℃, keeping this temperature until the transition state becomes stable and then heating to 170-250 ℃ for crystallization is favorable for the synthesis of SAPO-34 with higher crystallinity which shows the best catalytic performances with a 100% methanol conversion, a selectivity of 83.40% for C=2-C=3, and a life time of 220 min.

       

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