ZSM-5酸改性对甲醇芳构化性能的影响

利用硝酸、草酸和酒石酸溶液对ZSM-5分子筛进行改性，并采用XRD、SEM、NH₃-TPD、XRF、²⁷Al MAS NMR、吡啶吸附红外光谱和N₂吸附-脱附对ZSM-5分子筛结构、酸量、比表面积及孔体积等物化性质进行表征分析。在反应温度为422℃，甲醇质量空速为4.74 h^-1的条件下，考察了ZSM-5分子筛的催化活性。结果表明，采用不同酸改性ZSM-5分子筛，影响了分子筛的比表面积、酸性及孔体积，从而改变了催化剂的催化性能。在甲醇芳构化（MTA）反应中，酸改性后的分子筛表现出良好的催化活性，且草酸改性后的催化剂表现出较高的催化活性及选择性，反应8 h时，芳烃及BTX收率分别达到57.40%和39.40%。

Effect of ZSM-5 acid modification on aromatization performance of methanol

ZSM-5 zeolites were modified with tartaric acid, oxalic acid and nitric acid. The physicochemical properties of ZSM-5 zeolites, such as crystal structure, acid content, surface area and pore volume, were characterized by XRD, SEM, NH₃-TPD, XRF, ²⁷Al MAS NMR, pyridine adsorption infrared spectroscopy and N₂ adsorption-desorption isotherms. The catalytic activity of ZSM-5 zeolites were investigated under the condition of reaction temperature 422 ℃ and methanol mass space velocity of 4.74 h^-1. The specific surface area, acidity, pore volume and catalytic performance of the catalyst are affected by acid modification. The acid-modified zeolites show good catalytic activity in methanol aromatization (MTA) reaction, and oxalic acid modified catalyst shows higher catalytic activity and selectivity. The yield of aromatic hydrocarbons and BTX reaches 57.40% and 39.40% for reaction time at 8 h, respectively.