Synthesis of Aluminophosphate Molecular Sieves in Alkaline Media

Abstract

Unlike conventional aluminosilicate zeolites synthesized in alkaline media, aluminophosphate molecular sieves (AlPOs) have always been prepared under acidic conditions in the past three decades; this has been regarded as one of essential factors for synthesis, except for the case of silica‐substituted analogues (SAPOs). For the first time, we demonstrate herein a simple and generalized route for synthesizing various types of aluminophosphate molecular sieves in alkaline media. A series of aluminophosphate sieves and their analogues have been prepared with different quaternary ammonium cations as structure‐directing agents in this manner. The above successes have extended the systematic media from acidic or neutral to alkaline for the preparation of a series of aluminophosphate molecular sieves, which possibly open an alternative route for the synthesis of aluminophosphate molecular sieves.

A series of novel phosphites/phosphates with deep-ultraviolet cut-off edges from 0D polar to 3D non-polar architectures

“…Aluminophosphate molecular sieves have been extensively studied for their structural diversity as well as their wide range of applications as functional materials. 29 Generally, those frameworks were made up of alternating Al-centered polyhedra (AlO 4 , AlO 5 , AlO 6 ) and PO 4 tetrahedra. For comparison, aluminophosphites are scarcely reported, 30 due to the HP III O 3 2− group being easily oxidized into (P V O 4 ) 3− under open air conditions.…”

Nonclassical Approaches and Behaviors in Synthesis, Structure Characterization, and Catalysis of Zeolites

“…A series of aluminophosphate sieves and their analogues with various framework (AEI, POR, AFI, CHA, FAU, AFX) have been synthesized using various quaternary ammonium cations as templates in alkaline media. 30 As a typical example, the crystallization process of AlPO 4 -18 (AEI) has been intensively investigated. In the early stage of the crystallization process there was no solid product, but 18 h later a small amount of solid product appeared, exhibiting characteristic peaks associated with AEI structure.…”

“…To solve the problems resulted from classical hydrothermal synthesis, e.g. the employment of a large amount of water or organic templates resulting in the formation of polluted water and harmful gases, green routes for synthesis of zeolites have been significantly developed in the past few decades. , In addition, the change in the acidic or alkaline media for the synthesis of aluminosilicate zeolites or aluminophosphate molecular sieves has been also reported in recent years, , which would offer new opportunities for synthesis of zeolites with new structure or enhanced properties.…”

“…Recently, Sheng et al demonstrated a simple and generalized route for synthesizing various types of aluminophosphate molecular sieves in alkaline media. A series of aluminophosphate sieves and their analogues with various framework (AEI, POR, AFI, CHA, FAU, AFX) have been synthesized using various quaternary ammonium cations as templates in alkaline media . As a typical example, the crystallization process of AlPO 4 -18 (AEI) has been intensively investigated.…”

“…(A) XRD patterns, (B) SEM images, (C) UV-Raman curves, and (D) N 2 sorption isotherms of AlPO 4 -18 samples crystallized at (a) 18, (b) 24, (c) 28, (d) 36, (e) 48, and (f) 96 h in the alkaline media. Reprinted with permission from ref . Copyright 2020 Wiley-VCH.…”