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Evaluation of surfactant templates for one-pot hydrothermal synthesis of hierarchical SAPO-5
Microporous and Mesoporous Materials ( IF 5.2 ) Pub Date : 2020-06-20 , DOI: 10.1016/j.micromeso.2020.110364
Daniel Ali , Caren Regine Zeiger , Muhammad Mohsin Azim , Hilde Lea Lein , Karina Mathisen

Hierarchical SAPO-5 molecular sieves were synthesized with three different mesopore structure directing agents (meso-SDAs) (cetyltrimethyl-ammonium bromide (CTAB), myristyltrimethyl-ammonium bromide (MTMAB) and [3-(trimethoxysilyl) propyl] dimethyloctadecylammonium chloride (TPOAC)) based on a soft-template hydrothermal synthesis procedure. To investigate the modified porosity of the hierarchical SAPO-5s, they were characterized thoroughly with the results being compared to the conventional microporous SAPO-5. Nitrogen sorption measurements revealed considerable hysteresis loops for the hierarchical SAPO-5s as well as larger mesopore volumes (≥0.15 cm3 g-1) compared to the conventional SAPO-5 (0.05 cm3 g-1). The relative number of acid sites were calculated from FTIR adsorption data and were in the order of C-SAPO-5>H-CTAB > H-MTMAB > H-TPOAC. The hierarchical SAPO-5s had a significantly increased lifetime (>150 h) in the methanol to hydrocarbons (MTH) model reaction compared to the conventional SAPO-5 (<10 h), with TPOAC producing the most stable catalyst and MTMAB producing the catalyst with the largest product distribution. The modified porosity of the hierarchical SAPO-5 was additionally verified by an enhanced lifetime and increased production of large products in a shape selective process as well as a lower rate of coke formation compared to the conventional SAPO-5.



中文翻译:

一锅水热合成分级SAPO-5的表面活性剂模板的评估

使用三种不同的介孔结构导向剂(meso-SDA)(十六烷基三甲基溴化铵(CTAB),十四烷基三甲基溴化铵(MTMAB)和[3-(三甲氧基甲硅烷基)丙基]二甲基十八烷基氯化铵(TPOAC))合成SAPO-5分子筛)基于软模板水热合成程序。为了研究分级SAPO-5的改进孔隙率,将其彻底表征,并将结果与​​常规微孔SAPO-5进行比较。氮吸附测量显示,与常规SAPO-5(0.05 cm 3  g -1)相比,分层SAPO-5具有相当大的磁滞回线,并且中孔体积更大(≥0.15cm 3  g -1)。根据FTIR吸附数据计算酸位的相对数,其顺序为C-SAPO-5> H-CTAB> H-MTMAB> H-TPOAC。与传统的SAPO-5(<10 h)相比,分层的SAPO-5在甲醇制烃(MTH)模型反应中具有显着增加的寿命(> 150 h),其中TPOAC产生最稳定的催化剂,而MTMAB产生催化剂产品分销量最大。与常规的SAPO-5相比,分层的SAPO-5的改进的孔隙率还通过延长形状选择过程中的使用寿命和增加大型产品的产量以及更低的焦炭生成率得到了验证。

更新日期:2020-06-23
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