沸石分子筛的制备及其在异丁烷/丁烯烷基化反应中的应用

【作者】 施维；

【导师】 孙闻东；

【作者基本信息】 东北师范大学 ， 物理化学， 2004， 硕士

【摘要】 异丁烷和丁烯在酸催化剂作用下反应生成的烷基化油，是车用汽油的理想调和组分。工业上的烷基化过程采用硫酸和氢氟酸作为催化剂，存在着设备腐蚀、废酸处理和毒性等问题，因此开发对环境友好的固体酸催化剂具有重要意义。 以四乙基溴化铵（TEABr）为模板剂，硅胶为硅源，铝酸钠为铝源，采用水热晶化法合成β沸石。研究了各种因素（晶化温度、晶化时间、硅铝比、铵浓度、碱度、水含量等）对晶化过程和产物性质的影响。得出适宜的初始凝胶组成为n（SiO₂）／n（Al₂O₃）=25～60，n（TEABr）／n（SiO₂）=0.32～0.4，n（OH^-）／n（SiO₂）=0.2～0.23，n（H₂O）／n（SiO₂）=8.6～18。通过XRD、ICP、IR、SEM和NH₃-TPD分别对样品的结构和酸性进行了表征。 用浸渍法和离子交换法制备了含碱金属、碱土金属和稀土金属的Hβ分子筛固体强酸催化剂M_xO_y／Hβ，利用XRD和NH₃-TPD方法对样品进行了结构表征和酸性测定，并在相同条件下比较了样品对异丁烷／丁烯烷基化反应的催化性能。结果表明，M_xO_y／Hβ仍然保持了Hβ的基本特性，但酸性和催化性能发生了不同程度的改变，这与负载金属的本性有很大关系。其中Sm₂O₃／Hβ样品具有很好的稳定性，烷基化产物C₈比例也有所增加。更多还原

【Abstract】 From the isobutane alkylation with butene at the presence of acidic catalyst, alkylate is the ideal blend composition of gasoline. H2SO4 and HF used as catalysts in alkylation process bring serious environmental pollution, it is helpful to develop environment friendly solid acid catalyst.The zeolite beta used in this study was synthesized hydrothermally from the corresponding aluminosilicate gels. Tetraethylammonium bromide was used as the organic template, silica gel was the silica source and sodium aluminate was the aluminum source. The effect of the gel SiO2/Al2O3 ratio, gel alkalinity, gel dilution, template concentration, and time and temperature of the synthesis was investigated. The optimized gel composition was found to be within the range n(SiO2)/n(Al2O3)=25~60, n(TEABr)/n(SiO2)=0.32~0.4, n(OH -)/n(SiO2)=0.2~0.23, n(H2O)/n(SiO2) = 8.6~8. The samples of zeolite beta were characterized by XRD, ICP, IR, SEM and NHs-TPD.H ?molecular sieve solid acid catalyst loaded with alkali metal, alkali-earth metal and rare earth metal (MxOy/H {3 ) were synthesized by impregnation and ion exchange process. The structural characterization and measurement of acidic property were carried out by XRD and NH3-TPD. Catalytic behaviors were investigated under the same conditions. The basic character of MxOy/H and H sample are similar, however, the catalytic activity and acidic property which are related to the nature of loaded metal have changed. The Sm2O3/H samplehas better stability, and the proportion of alkylate is increased.更多还原