Since their discovery, microporous materials have been broadly exploited as shape-selective catalysts and sorbents in different research fields, 1 accompanied by an ongoing search for novel molecular sieve structures and new synthesis methods. For example, Morris and co-workers have recently developed a novel method (ionothermal synthesis) for preparing molecular sieves, which involves the use of ionic liquid as both the solvent and structuredirecting agent. 2 By using this method, Morris et al. have prepared several aluminophosphate and cobalt aluminophosphate structures in an imidazolium-based ionic liquid (1-ethyl-3-methylimidazolium bromide ([emim]Br)). Compared with the traditional hydrothermal or solvothermal methods, 1,3 preparations using the ionothermal method can take place at or near ambient pressure because of the negligible vapor pressure of ionic liquids. 4 This eliminates safety concerns associated with high pressures.The synthesis of molecular sieves often requires the addition of organic molecules, such as amines and quaternary ammonium ions, into the synthesis mixture. The role of these molecules has been described as a structure-directing effect, referring to the complementary shapes of the structure-directing agents and the frameworks they direct. Normally the addition of structure-directing agents to molecular sieve synthesis can affect the rate at which a particular structure is formed. In this work, we report the study of the structure-directing role of amines in the ionothermal synthesis of molecular sieves in 1-butyl-3-methylimidazolium bromide ionic liquid ([bmim]Br). 5 We show that the original crystallization process can be altered by the addition of amine, as summarized in Scheme 1.In the absence of amine, AlPO 4 -11 molecular sieves (AEL-type structure) 6 with minor AlPO 4 -5 (AFI-type structure) 7 were formed after a short induction period at a temperature between 190 and 280°C in [bmim]Br ( Figure 1a and Table 1). Increasing the crystallization time leads to further growth of the AEL structure, while the amount of the AFI structure passed through a maximum and eventually disappeared after 4 h. Both of the two structures are composed of straight one-dimensional channels with AFI containing 12-membered ring (MR) pores (7.3 × 7.3 Å in size) and AEL containing 10-MR pores (6.5 × 4.0 Å). To date, the only ionic liquid used in ionothermal synthesis was [emim]Br. The pore sizes of all the AlPO and CoAlPO products synthesized ionothermally in [emim]Br are no larger than 10-MR. 2,8 The fact that the 12-MR large-pore AFI structure was formed when [bmim]Br was used as the reaction media instead of [emim]Br suggests the possible structure-directing effect of ionic liquid. ( 13 C CP-MAS NMR indicates that the cation of [bmim]Br is occluded in the pores of AlPOs; see Supporting Information.) Moreover, the cation of ionic liquid may have the major influence on the frameworks it directs. Nevertheless, it seems that [bmim] + is still suitable for filling the 10-MR channels because the AEL structu...

AlPO4-11 and AlPO4-5 molecular sieves are ionothermally prepared without addition of water by using anhydrous starting materials, such as NH4H2PO4, pseudoboehmite (AlOOH), and NH4F. The synthesis appears to be an autocatalytic process. Water has a remarkable effect on the synthesis process. Addition of reagent quantities of water (H2O/Al = 1, molar ratio) can enhance the crystallization kinetics greatly.

Crystalline porous materials with large or extralarge pores continue to be of particular significance in both industry and academia for their potential applications in shape-selective catalysis and adsorption/separation. [1][2][3] Of these zeolitic materials, especially aluminosilicate-and aluminophosphate-based molecular sieves are of prime interest because of their high stability associated with their widespread use in many established process and emerging applications.[4] The materials VPI-5 (VFI framework type, 18-ring) [5] and UTD-1 (DON framework type, 14-ring) [6] were the first extra-large pore (pores constructed of more than 12 T atoms) aluminophosphate and aluminosilicate materials discovered. The oxide frameworks are built up by corner-sharing [AlO 4 ] and [PO 4 ] tetrahedra as well as [AlO 4 ] and [SiO 4 ] tetrahedra. In the search for materials with even larger pores, an anionic open-framework aluminophosphate JDF-20 (20-ring) was reported; however, it could not be classified as a zeolite because its framework (with an Al/P ratio of 5:6) is unstable upon removal of the occluded protonated templates by calcination. [7] Larger pore openings were also achieved using Ge or Ga as the framework T atom in a high amount, for example in ECR-34 (ETR framework type, 18-ring), [8] ITQ-33 (18-ring), [9] cloverite (-CLO framework type, 20-ring), [10] and ITQ-37 (30-ring). [11] In this context, the use of Ge or Ga as framework atoms as well as fluoride has been found to facilitate the formation of a double four-ring (D4R) unit. [12,13] This is in agreement with the prediction by Brunner and Meier that structures with extra-large pores should contain a large number of three-and four-membered rings. [14] Ionothermal synthesis, in which ionic liquids act as both the solvent and template, is a novel method that has attracted great interest in the synthesis of zeolitic and other porous materials. [15][16][17] Besides the advantage of experimenting at ambient pressure, ionic liquids offer different chemistry and structural variety associated with the use of additional amines as structure-directing agents (SDA), and therefore open up new vistas for the synthesis of new porous materials. [15][16][17][18][19][20] Herein, we report the ionothermal synthesis of the first aluminophosphate molecular sieve with 20-ring pore openings, denoted as DNL-1 (Dalian National Laboratory Number 1). This molecular sieve was confirmed as a structural analogue to the gallophosphate molecular sieve cloverite by using a combination of Rietveld refinement of powder X-ray diffraction (PXRD) data and NMR analysis. Moreover, in comparison to cloverite, DNL-1, as-synthesized and calcined, exhibits excellent stability.DNL-1 was synthesized in the ionic liquid 1-ethyl-3-methylimidazolate bromide ([emim]Br) with 1,6-hexanediamine (HDA) as the co-SDA. The detailed synthetic procedure is described in the Experimental Section. The assynthesized DNL-1 material displays uniformly globular agglomerates of grainlike nanocrystals with a diameter of about 2...