Pd/SAPO-5的制备及其在合成甲基正戊基酮中的应用

Preparation of Pd/SAPO-5 Bifunctional Catalysts for One-step Synthesis of Methyl Amyl Ketone

以三乙胺为模板剂,采用水热法制备了Pd/SAPO-5双功能催化剂,并用H2-TPR,XRD,SEM,XRF,^（29）Si MASNMR等手段对催化剂进行了表征。结果表明：钯的加入并不能改变分子筛的晶体结构;而不同的硅铝比（SiO2与Al2O3的物质的量比,下同）会导致SAPO-5分子筛晶体结构以及形貌上的差异。将所制备的催化剂用于丙酮和丁醛气相一步法合成甲基正戊基酮（MAK）的反应中,考察了硅铝比、反应温度和金属负载量对催化活性的影响,在SAPO-5分子筛结构完整的前提下,Pd/SAPO-5催化活性随硅铝比的上升而增加。在硅铝比为1.5、反应温度180℃、w（Pd）=0.25%时,MAK的收率最高,可达57.86%,并可运行500 h以上而不明显失活。

A series of Pd/SAPO-5 bifunctional catalysts were prepared through hydrothermal method by using triethylamine as template and were characterized by H2-TPR, XRD, SEM, XRF and ^（29） Si MAS NMR. The results revealed that the doping of Pd didn＇t change the molecular sieve crystalline structure of SAPO-5, while the alteration of molar ratio of Si O2 to Al2 O3 could induce the changes in crystalline structure and morphology of SAPO-5. Subsequently, the Pd/SAPO-5 bifunctional catalysts were applied for one-step synthesis of methyl amyl ketone（MAK） from acetone and butyraldehyde. The influences of SiO2/Al2 O3 molar ratio, reaction temperature and amount of palladium loading on the catalytic activity of catalyst were investigated. When the SAPO-5 crystalline structure kept intact, the activity of Pd/SAPO-5 increased with increasing the SiO2/Al2 O3 molar ratio. When the SiO2/Al2 O3 molar ratio was 1.5, the reaction temperature was 180 ℃, and the amount of Pd loading was 0.25%, the catalytic activity reached the best. The highest yield of MAK was 57.86%. Moreover, the catalytic activity was rather stable under 500 h time-on-stream test.