【摘要】 以三乙烯四胺为模板剂,采用水热合成法,以磷酸、正硅酸乙酯、氢氧化铝、乙酸镁及三乙烯四胺为原料,各原料配比为n(P)∶n(Si)∶n(Mg)∶n(Al)∶n(H2O)∶n(TETA)=1∶0.11∶0.38∶0.49∶82∶0.89,在(150~170)℃、晶化时间24 h和pH=6.0~6.2条件下,合成得到纯度较高和热稳定较好的含镁磷酸硅铝分子筛。采用扫描电子显微镜和粉末X射线衍射对分子筛进行晶体结构和形貌分析,所得分子筛在合成范围内具有较高的纯度和结晶度。DSC-TG热分析表明,分子筛具有较好的热稳定性。对分子筛进行甲醇转化反应评价,结果表明,在载气流速10 mL·min-1、进料体积空速5.0 h-1和300℃条件下,甲醇转化反应中气相产物甲烷体积分数可达80%,乙烯和丙烯含量约为13%。通过Vario ELⅢ型元素分析仪测定C、N、H和Mg质量分数分别为6.51%、5.53%、3.19%和3.39%。更多还原

【Abstract】 Using phosphoric acid,tetraethyl orthosilicate,aluminum hydroxide,magnesium acetate and triethylenetetramine( TETA) as raw materials,the silicoaluminophosphate molecular sieve containing magnesium with high purity and good thermal stability was synthesized by hydrothermal synthesis method under the condition as follows: raw materials n( P) ∶ n( Si) ∶ n( Mg) ∶ n( Al) ∶ n( H2O) ∶ n( TETA) = 1∶ 0. 11∶ 0. 38∶ 0. 49∶ 82∶ 0. 89,crystallization time 24 h,crystallization temperature( 150- 170) ℃ and pH = 6. 0- 6. 2. The as-synthesized molecular sieve was characterized by SEM,XRD and DSC-TG and was evaluated in methanol conversion reaction. The characterization results indicated that the molecular sieve possessed high purity and crystallinity,and its framework collapsed at 600 ℃. The evaluation results indicated that under the reaction condition of carrier gas flow rate 10 mL·min- 1,feeding volume space velocity 5. 0 h- 1 and 300 ℃,methane content of gasous product reached 80% and the content of ethylene and propylene was about 13%. The results of elemental analysis by Vario EL Ⅲ elemental analyzer indicated that the contents of C,N and H were 6. 51wt%,5. 53wt%,and 3. 19wt%,respectively.更多还原