晶化条件对MnAPO-36分子筛合成的影响

Effects of Crystallization Condition on Synthesis of MnAPO-36

以拟薄水铝石、质量分数85%的正磷酸、四水合醋酸锰为原料,三正丙胺为模板剂,采用原位水热法合成了MnAPO-36分子筛,利用FT-IR、SEM、XRD、TG-DSC及NH3-TPD等方法对MnAPO-36分子筛进行了表征.考察了晶化温度和晶化时间对原位水热法合成MnAPO-36的结晶度的影响.研究结果表明,用三正丙胺为模板剂在水热条件下制备MnAPO-36分子筛,容易共生MnAPO-5的晶型.采用先在100℃晶化50 h,然后在150℃晶化24 h的两步晶化方法,能得到纯度相对较高的MnAPO-36.

Manganese aluminophosphate of type 36 （MnAPO-36） molecular sieve was hydrothermally synthesized in situ using pseudo-boehmite, phosphoric acid （85 % ）, tetrahydrate manganese acetate as raw material and tripropylamine as templating agent. Characterization of the synthetic products was performed using FT-IR, SEM, XRD, TG-DSC and NH3-TPD. The influence of crystallization temperature and crystallization time on the crystallinity of MnAPO-36 molecular sieve were investigated. The results showed that small amounts of MnAPO-5 always crystallinzed parallel to the MnAPO-36 material under hydrothermal conditions when tripropylamine was used as organic template. Highly crystalline MnAPO-36 molecular sieve was crystallized in two temperature steps, namely at 100 ℃ for 50h and subsequently at 150 ℃ for 24 h.