The temperature-dependence of the structure-directing effect of 2-methylpiperazine in the synthesis of open-framework aluminophosphates

Abstract

The heating temperature can affect the crystallization process of the initial mixture and the structure-directing effect of 2-methylpiperazine by altering its structure, changing the equilibrium of the reactions, and modifying the assembly of the building oligomers.

In situ growth and assembly of microporous aluminophosphate nanosheets into ordered architectures at low temperature and their enhanced catalytic performance

“…42,43 It is well acknowledged that the crystallization temperature has a great inuence on the zeolite nucleation and growth rate, which may alter the reaction intermediate/process, and lead to different crystal phases, morphologies, and sizes. [44][45][46][47][48] Synthesis at lower temperature tends to reduce the crystallization rate and achieve nanosized zeolites. 44,47,48 However, although the lowtemperature syntheses have been studied by several groups, 44,[48][49][50][51] very few cases by simply employing low temperature to build ordered hierarchical structures have been achieved.…”

Temperature-dependence of the influence of the position-2-methyl group on the structure-directing effect of piperazine in the synthesis of open-framework aluminophosphates

“…The present study confirmed that the structure of AP2pip is also synthesis condition-dependent. In the crystallization of APMeP200, a shoulder peak at −29.7 ppm was observed, which was not observed in the crystallization of APMeP200 from the initial mixture with the same composition at 200 °C 29 . This signal can be assigned to the P sites coordinated by four Al atoms via an oxygen bridge.…”

“…These phenomena have made the explanation of the template effect or structure-directing role of organic species by calculation of their non-bonding interactions with the final inorganic open-framework less convincing. Although significant efforts have been made in investigating the structure-directing effect 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 , the origin of the structure-directing effect and how the structure-directing agent directs the corresponding structure are not fully understood.…”

Cationic surfactant-assisted hydrothermal synthesis: an effective way to tune the crystalline phase and morphology of SAPO molecular sieves

“…Recently, a series of work concerning the crystallization mechanism of open-framework aluminophosphates and the structure-directing effect in the crystallization of such materials have been reported. [15][16][17][18][19] The investigations demonstrate once again that the crystallization of inorganic microporous materials is a very complicated process. Even though the structure-directing effect of a template is the most important key for the formation of an open-framework structure, there are still many other factors that can change the reaction results, such as the solvent or the other additives.…”