磷酸和水蒸汽联合改性Hβ分子筛的表征及催化性能

应用BET、XRD和IR等技术研究了磷和水蒸汽联合改性的Hβ分子筛的物化性能。系统考察了FCC汽油在Hβ为基质的改性沸石分子筛上的烯烃转化反应。BET结果表明，磷改性引起分子筛比表面积由417 m²·g^-1减小到401 m²·g^-1，单独经过水蒸汽处理的分子筛的比表面积随处理温度的升高也明显下降。XRD和IR研究表明，磷与水蒸汽改性前后没有新的晶相出现，并且联合改性后Hβ沸石保留了合适的酸含量，总酸量均保持在038 mmol·g^-1以上。改性前后样品的活性评价在微型反应装置上进行，结果表明，联合改性样品在973 K的高温条件下,烯烃转化率仍可达到42%,远高于仅仅由水蒸汽改性分子筛的催化活性(后者烯烃转化率仅为33％)，显示出磷物种对沸石分子筛高温水蒸汽脱铝的抑制作用。

Characterization and catalytic properties of steam-phosphorus modified Hβ zeolites

Physicochemical properties of steam-treated and phosphorus-modified Hβ zeolites were studied using BET, XRD and IR technique. Olefin conversionreaction of FCC gasoline over the Hβ-based modified zeolites was investigated. BETresults showed that surface area of the Hβ zeolites modified by solely phosphorus decreased from 417 m²·g^-1 to 401 m²·g^-1, and that of theHβ zeolites modified by solely steam remarkably decreased with the treatment temperature. XRD and IR results showed that no new crystalline phase formed and proper acidity ofover 0.38 mmol·g^-1 was retained in the samples modified by steam and phosphorus. The microreactor activity test results showed that olefin conversion of up to42% was attained over steam-phosphorus modified-Hβ zeolite, much higher thanthat of Hβ zeolite treated by solely steam (olefin conversion=33％), indicating the inhibiting effects of phosphorus against dealumination at higher temperature by steam.