论文部分内容阅读
考察了由亚磷酸改性的HZSM 5在673、873和1073K温度下100%水蒸气处理样品的物化和催化性质。采用XRD表征了样品的结构。通过吸附吡啶红外光谱和NH3 TPD进行了酸性和酸分布研究。XPS的研究结果表明,P由+3价氧化成了+5价,并提出了可能的改性的表面结构模型。通过N2吸附 脱附等温线研究了样品的孔结构,样品的吸附 脱附等温线为Ⅰ型和Ⅳ型的复合型,滞后环为IUPAC分类的H4型。Al的状态由27AlMASNMS表征。采用AM1(AustinModelⅠ)半经验量子化学方法和模型簇法筛选了磷改性可能的两种结构模型,其区别在于磷上的桥氧与铝配位还是端氧与铝配位,结果表明端氧与铝配位的可能性更大。以正庚烷裂化反应为探针反应考察了样品的活性。
The physico-chemical and catalytic properties of 100% steam-treated samples of phosphorated HZSM 5 at 673, 873 and 1073 K were investigated. The structure of the sample was characterized by XRD. The acidity and acid distribution were studied by adsorption of pyridine and infrared spectroscopy and NH3 TPD. The results of XPS show that P is oxidized by the +3 valence to the +5 valence, and a possible modified surface structure model is proposed. The pore structure of the samples was studied by N2 adsorption-desorption isotherms. The adsorption-desorption isotherms of the samples were of type I and type IV, and the hysteresis loop was H4 type classified by IUPAC. The state of Al is characterized by 27AlMASNMS. AM1 (AustinModelⅠ) semi-empirical quantum chemical method and the model cluster method were screened for phosphorus modification possible two structural models, the difference is that phosphorus on the bridge of oxygen with aluminum or aluminum and oxygen terminal coordination results show that end-oxygen The possibility of coordination with aluminum is greater. The n-heptane cracking reaction as a probe reaction investigated the sample activity.