纳米薄层SAPO-5分子筛的离子热合成及催化性能

以小剂量的丁二酸、氯化胆碱和四乙基溴化铵复配形成的低共熔混合物为溶剂和模板,以水热法合成的纳米薄层SAPO-5分子筛作为晶种,使用离子热法在微波加热功率为400 W、温度为180℃和晶化时间为20 min的条件下,高效合成了具有六角花瓣状的纳米薄层SAPO-5分子筛。采用XRD、SEM、N2物理吸/脱附和NH3-TPD对合成样品的物相、形貌、孔结构和酸性进行了分析。结果表明,所合成的样品SC2-T180-t20-P400是一种同时含有微孔-介孔-大孔结构的多级孔SAPO-5分子筛,其外表面积高达85m2/g。分子筛产物中无机物的原子利用率达到88%。该样品在苯与苯甲醇的烷基化反应中,苯甲醇转化率和二苯甲烷选择性分别达到99.9%和94.0%,表现出比传统水热法合成的纳米薄层SAPO-5催化剂更为优异的催化性能。

Ionothermal synthesis of nanosheets SAPO-5 molecular sieves and its catalytic performances

Hexagonal petal SAPO-5 zeolite was synthesized by ionothermal method with high efficiency under the conditions of microwave heating power of 400W, temperature of 180 °C and crystallization time of 20 min, in which a low-dosage eutectic mixture based on succinic acid, choline chloride and tetraethyl ammonium bromide was used as the solvent and template, nanosheets SAPO-5 molecular sieve synthesized by hydrothermal method acted as seeds.The product phase, morphology, pore structure and acidity of the synthesized samples were fully analyzed by XRD, SEM, N2 physical adsorption/ desorption and NH3-TPD techniques. The results of N2 physical adsorption/desorption analysis show that the synthesized sample SC2-T180-t20-P400 is a hierarchically porous SAPO-5 molecular sieve with micro-meso-macropore structure inside, and its external surface area is up to 85 m2/g.The atomic utilization efficiency of inorganic substances in zeolite products can reach 88%. Most importantly, the conversion of benzyl alcohol and the selectivity of diphenylmethane in the alkylation of benzene with benzyl alcohol reached 99.9% and 93.9% respectively, showing better catalytic performance than the traditional hydrothermally synthesized counterpart.