Strong templating effect of TEAOH in the hydrothermal genesis of the AlPO4-5 molecular sieve: Experimental and computational investigations

The hydrothermal genesis of AlPO4-5, in the presence of four different organic templates, viz., methyldicyclohexylamine (MCHA), triethylamine (TEA), tripropylamine (TPA), and tetraethylammonium hydroxide (TEAOH), has been monitored by XRD. It is shown that TEAOH has the best templating ability to the formation of AlPO4-5 structure under the different synthesis conditions considered in this study. Density functional calculations on periodic models of AlPO4-5 indicate the strongest nonbonding interaction energy between the template and the framework in the case of TEAOH. Therefore, a new approach correlating the nonbonding interaction energy to the template ability to form a porous structure is proposed as a step toward a better understanding of the role of the organic template in the synthesis of porous molecular sieves.

Graphical abstractMonitoring the hydrothermal genesis of AlPO4-5 by means of XRD and DFT calculations shows that TEAOH has the best templating effect toward the formation of AlPO4-5 structure from the synthesis gels among the investigated organic templates series, viz., MCHA, TEA, TPA, and TEAOH.Figure optionsDownload full-size imageDownload as PowerPoint slide