双模板剂调控SAPO-34对1-丁烯催化裂解的影响

Effects of SAPO-34 regulated by double templates on catalytic cracking of 1-butene

利用水热合成法,通过调控模板剂吗啡啉和四乙基氢氧化铵物质的量比[n(MOR)∶n(TEAOH)]合成出不同SAPO-34分子筛。采用XRD、SEM、NH_(3)-TPD等测试方法对合成样品进行表征,并考察其在1-丁烯催化裂解制丙烯反应中的催化性能。结果表明,双模板剂相比单模板剂制得的SAPO-34分子筛具有不同的酸性和颗粒尺寸,适宜的[n(MOR)∶n(TEAOH)]可以协同SAPO-34分子筛有更弱的酸强度和B酸酸位,从而抑制裂解过程中氢转移反应的发生。当n(MOR)∶n(TEAOH)=2.0∶0.5时可以最大程度的提升丙烯产率和选择性,在1-丁烯催化裂解制丙烯中具有最高的丙烯产率和丙烯选择性,分别为37.03%和45.78%,可以有效应用于1-丁烯催化裂解反应。

Different SAPO-34 molecular sieves were synthesized by modulating the molar ratio of templating agent morpholine and tetraethylammonium hydroxide[n(MOR)∶n(TEAOH)]via hydrothermal synthesis and characterized by XRD,SEM,NH_(3)-TPD and other testing methods.Their catalytic performance in cracking of 1-butene to propylene was systematic investigated.The results showed that SAPO-34 molecular sieves obtained by dual templating agents had different acidity and particle size compared to single templating agent method.Suitable n(MOR)∶n(TEAOH)can get weaker acidic strength and B-acidic site in SAPO-34 to inhibit hydrogen transfer reaction during the cracking process.In cracking of 1-butene to propylene,the highest propylene yield and propylene selectivity were 37.03%and 45.78%respectively when n(MOR)∶n(TEAOH)=2.0∶0.5.The catalyst could be effectively used in the catalytic cracking reaction of 1-butene.