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通过正交实验,研究了硅源(记为SiO_2)、铝源(记为Al_(2)O_3)、磷源(记为P_(2)O_5)、模板剂(记为R)和水对SAPO-18分子筛合成的影响,根据极差分析得到各因素对SAPO-18分子筛合成的影响顺序为:P_(2)O_5>Al_(2)O_3>R>H_(2)O>SiO_2。结合单因素实验,确定合成SAPO-18分子筛初始凝胶的最优摩尔比为:0.9P_(2)O_5:0.8Al_(2)O_3:1.8R︰50H_(2)O︰0.6SiO_2。利用XRD、SEM和FTIR等检测技术对样品进行表征,并考察样品对甲醇制烯烃(MTO)反应的催化活性。结果表明,所得SAPO-18分子筛样品纯净,并具有优良的催化性能,在甲醇转化率100%的情况下,总低碳烯烃选择性为86.97%,而且产物中C_2~C_4烷烃以及C_(5+)选择性较低。
Orthogonal experiments were carried out to investigate the effect of water on SAPO (denoted as SiO_2), aluminum source (denoted as Al_ (2) O_3), phosphorus source (denoted as P_ (2) O_5) -18 molecular sieve synthesis, the order of influence of each factor on the synthesis of SAPO-18 molecular sieve is as follows: P 2 O 5> Al 2 O 3> R> H 2 O> SiO 2. Combined with single factor experiments, the optimal molar ratio of the initial gel of SAPO-18 zeolite was determined: 0.9P_ (2) O_5: 0.8Al_ (2) O_3: 1.8R︰50H_ (2) O︰0.6SiO_2. The samples were characterized by XRD, SEM and FTIR. The catalytic activity of the samples on MTO reaction was also investigated. The results showed that the sample of SAPO-18 molecular sieve was pure and had excellent catalytic performance. The selectivity of total light olefins was 86.97% under the condition of methanol conversion of 100%, and the products of C_2 ~ C_4 alkanes and C_ (5+ ) Less selective.