多级孔道ZSM-22分子筛的合成及其正庚烷加氢 异构反应性能

In order to convert n-heptane into single-branched or multi-branched isoparaffins with a higher octane number to improve the octane number and combustion efficiency of gasoline components, a hierarchical porous ZSM - 22 - M - R - 2 molecular sieve was prepared by a ball milling - recrystallization method and a ZSM - 22 - C molecular sieve was synthesized by a conventional hydrothermal method. Then, a catalyst with a Pt content of 0.5% was prepared by an impregnation method. The structure and acidity of the catalyst samples were analyzed by means of X-ray powder diffraction, scanning electron microscopy, N2 physical adsorption, ammonia adsorption - temperature-programmed desorption, and pyridine infrared spectroscopy. In a fixed-bed reactor, the performance of these two catalysts in the hydroisomerization reaction of n-heptane was studied. The results show that the ZSM - 22 - M - R - 2 molecular sieve has an acid amount comparable to that of the ZSM - 22 - C molecular sieve, but has a smaller particle size; its isomerization reaction activity, selectivity and yield of isomerization products are all higher than those of the conventional ZSM - 22 - C molecular sieve. At a reaction temperature of 300 °C, the maximum yield of isomerization products is 68%.

为了将正庚烷变成辛烷值较高的单支链或多支链异构烷烃来提高汽油组分的辛烷值和燃烧效率，采用球磨-重结晶的方法制备了多级孔道 ZSM-22-M-R-2 分子筛和常规水热法合成了 ZSM-22-C 分子筛，进而通过浸渍法制备了含 Pt 量为 0.5%的催化剂。借助 X 射线粉末衍射、扫描电镜、N2物理吸附、氨吸附-程序升温脱附、吡啶红外光谱表征手段分析了催化剂样品的结构和酸性。在固定床反应器中，研究了这两种催化剂的正庚烷加氢异构反应性能。结果表明：ZSM-22-M-R-2 分子筛具有的酸量和 ZSM-22-C 分子筛相当，但具有更小的粒径；其异构化反应活性、异构产物的选择性和收率均高于常规 ZSM-22-C 分子筛。在反应温度为300 ℃时，异构产物的最大收率为 68%。