Layered Aluminophosphate Research Articles

Carbon dioxide selective mixed-matrix membranes formulation and characterization using rubbery substituted polyphosphazene

Substituted polyphosphazene (PPZ) used in the formulation of mixed-matrix membranes conforms to make good interface contact with the molecular sieve particles due to its rubbery nature. The methoxy ethoxy ethanol (MEE) substituted polyphosphazene is CO 2 selective with CO 2/N 2 and CO 2/CH 4 ideal separation factors of 43 and 15, respectively, at 22 °C. This study shows the improvement of the CO 2 separation factor over light gases by formulating mixed-matrix membranes using silicoaluminophosphate (SAPO-34) and modified 2D layered aluminophosphate (ALPO). The synthesis and characterization of these molecular sieve materials is described. The CO 2/CH 4 and CO 2/N 2 ideal separation factors increase to 17 and 54 for the membrane formed by PPZ and SAPO-34. A more significant increase in separation factors is observed with decreasing membrane temperature. The pore blocking effect by CO 2 in the PPZ–SAPO mixed-matrix membranes was not observed even though this behavior was reported in literature for SAPO-34 molecular sieve membranes. This is potentially due to lower adsorption of CO 2 in the pores of SAPO-34 when dispersed in the continuous polymer phase as compared to SAPO-34 particles. The layered aluminophosphate zeolite was exfoliated to create particles with high aspect ratio that were dispersed in the PPZ polymer to form composite membranes. The CO 2/H 2 separation factor observed in these composite membranes was 12.0 as compared to a value of 8.5 for PPZ membrane at 22 °C. The structure of these membranes is expected to be CO 2 selective flakes with high aspect ratio dispersed in the polymer which retard the transport of less interactive gases resulting in the improvement of separation factors. A comparison of gas transport data between the two types of mixed-matrix membranes also provides information regarding the structure of these membranes.

Transport properties of aluminophosphate nanocomposite membranes prepared by in situ polymerization

Nanocomposite membranes containing 5 wt% microporous layered aluminophosphate in a polymer matrix were fabricated using in situ polymerization. The gas transport properties of these membranes were evaluated. Polyetherimide was combined with aluminophosphate swelled with several different surfactants. The glass transition temperature of these membranes increased as a result of adding the layered aluminophosphate, however, gas pair selectivity was not improved. A second experiment involved the addition of as-synthesized layered aluminophosphate, which was ball milled to small sizes, to a linear and branched polyimide based on 4,4′-oxydiphthalic anhydride (ODPA), 2,4,6-triaminopyrimidine (TAP), and 4,4′-oxydianiline (ODA) via in situ polymerization. In some cases the gas pair selectivities were improved as a result of adding the layered aluminophosphate. DMTA data suggest no mechanical enhancement with the addition of AlPO, which means that the layers were likely not exfoliated. For this reason, it is most likely that the selectivity enhancements in these samples were not due to molecular sieving through the microstructure of the aluminophosphate.

Layered Assembly of Organic Molecules and Host–Guest Interactions in a CAL‐1 Chabasite‐Type Precursor of H‐SAPO‐34 Catalysts

Filling the holes: CAL-1, a novel precursor for the acidic solid-state catalyst H-SAPO-34, was characterized by X-ray diffraction and Fourier transform IR spectroscopy. Synthesis starting from a layered aluminophosphate precursor yields a product with a layered organization of the organic templates n-butylammonium (nBA, blue/gray), and hexamethylenimine (HMI, yellow). (Figure Presented) © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

Hydrothermal transformation of a layered aluminophosphate into a mesoporous structure

A new mesoporous aluminophosphate (AlPO4) has been synthesized through hydrothermal transformation of a lamellar mesostructured aluminophosphate prepared in the presence of a neutral surfactant dodecylamine (DDA) under mild alkaline pH conditions and using water–ethanol mixture as the synthesis medium. Post-synthesis hydrothermal treatment was carried out at 448 K for 72 h in the presence of dilute aqueous phosphoric acid, which results this phase transformation. Lamellar and mesoporous phases of these samples were revealed from powder X-ray diffraction, SEM-EDS, transmission electron microscopic image analysis, 31P MAS NMR a FT IR spectroscopic studies and thermal analysis. N2 sorption studies revealed the existence of pores with dimension of small mesopores after H3PO4 treatment. Pillaring of the interlayers through PO4 units during post-synthesis hydrothermal treatment could be responsible for the transformation of lamellar to mesoporous phase.

The CAL family of molecular sieves: Silicoaluminophosphates prepared from a layered aluminophosphate

Abstract Among the synthesis methods to prepare zeolites, the sol–gel processes are the ones most known and used. The same may be said about the aluminophosphate-based molecular sieves. This work reviews the preparation of zeolites from layered silicates and discusses the synthesis of molecular sieves using an aluminophosphate with kanemite-type layered structure as precursor. The role of the structure directing agent and of the water content on the structure-type of each silicoaluminophosphate prepared is reviewed. In the cases focussed herein, there are two features affected by this new procedure: the acidity of the silicon substitution sites and the morphology of the particles. Concerning the acidity of these solids, a larger amount of silicon can be substituted in the framework before the onset of silicon island formation. At comparable SiO2/Al2O3 molar ratios, the samples prepared by the altered procedure possess a larger number of acid sites in the borders of silicon islands than in the silicoaluminophosphates prepared by the traditional procedures(e.g. by using phosphoric acid and a source of aluminum, as precursors). In relation to the morphology, this new route leads to particles shape with vestiges of the lamellar morphology of the layered reactant, thus introducing the possibility of reduced mass transport difficulties.

Synthesis and Characterization of a New Layered Fluoroaluminophosphate (C4H11NOH)3.5 [Al4(PO4)5F]×0.5H3O with Extra‐Large 16‐Rings.

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Synthesis and Characterization of a New Layered Fluoroaluminophosphate (C4H11NOH)3.5[Al4(PO4)5F]·0.5H3O with Extra-Large 16-Rings

A new two-dimensional-layered fluoroaluminophosphate (C4H11NOH)3.5[Al4(PO4)5F] x 0.5H3O (denoted as AlPO-CJ20) with an Al/P ratio of 4:5 has been synthesized solvothermally by using 2-amino-2-methyl-1-propanol as the structure-directing agent. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by solid-state NMR techniques, including 27Al, 19F --> 27Al cross-polarization, and 31P magic angle spinning NMR. The alternation of Al-centered tetrahedra (AlO4 and AlO3F) and PO3(=O) tetrahedra gives rise to a new type of 4.6.16-net sheet. The inorganic sheets are stacked in an ABAB sequence along the [010] direction and further held together through strong H bonds between protonated template molecules and P=O groups in the inorganic layers. Except for Mu-4, AlPO-CJ20 is the second layered aluminophosphate with an Al/P ratio of 4:5, and it contains the largest pore opening of 16-rings in the known layered aluminophosphates. Furthermore, the coordination of Al and P of fluoroaluminophosphates is summarized. Crystal data: (C4H11NOH)3.5[Al4(PO4)5F] x 0.5H3O, monoclinic, C2/c (No. 15), a = 32.678(7) A, b = 12.956(3) A, c = 21.045(4) A, beta = 115.17(3) degrees, V = 8064(3) A3, Z = 8, R1 = 0.0837 [I > 2sigma(I)], and wR2 = 0.2428 (all data).

A new nickel complex-templated layered aluminophosphate [Ni(C 4N 3H 13)(C 4N 3H 14)H 2O][Al 3P 4O 16

A new layered aluminophosphate [Ni(C 4N 3H 13)(C 4N 3H 14)H 2O][Al 3P 4O 16] has been prepared from a hydrothermal system Al( i-PrO) 3 Ni(OAc) 2 H 3PO 4 diethylenetriamine H 2O, and characterized by single-crystal X-ray diffraction, ICP, CHN and TG analyses. Its structure is built up from the alternation of AlO 4 and PO 3( O) tetrahedra to from 4.6.8-net sheets stacked in an ABAB sequence. The nickel complex Ni(C 4N 3H 13)(C 4N 3H 14)H 2O that is formed under hydrothermal conditions locates in the interlayer region and interacts with the inorganic sheets through H-bonds.

The ionothermal synthesis of SIZ-6—a layered aluminophosphate

A new layered open framework aluminophosphate has been prepared by ionothermal synthesis using an ionic liquid as the reaction solvent and structure-directing agent.

Assembly of Helical Hydrogen Bonds in a New Layered Aluminophosphate [C6N3H17] [Al2(HPO4)(PO4)2

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Synthesis and structure of Mu-33, a new layered aluminophosphate [formula omitted

Mu-33, a new layered aluminophosphate with an Al/P ratio of 0.66, was obtained from a quasi non-aqueous synthesis in which tert-butylformamide ( tBF) was the main solvent and only limited amounts of water were present. During the synthesis, tBF decomposed and the resulting protonated tert-butylamine is occluded in the as-synthesized material. The approximate structure was determined from data collected on a microcrystal (200 × 25 × 5 μm 3) at the European Synchrotron Radiation Facility (ESRF) in Grenoble, but the quality of these data did not allow satisfactory refinement. Therefore the structure was refined using high-resolution powder diffraction data, also collected at the ESRF. The structure ( P2 1/ c, a = 9.8922(6) Å, b = 26.180(2) Å, c = 16.729(1) Å and β = 90.4(1)°) consists of anionic aluminophosphate layers that can be described as a six-ring honeycomb of alternating corner-sharing AlO 4 and PO 4 tetrahedra with additional P-atoms above and below the honeycomb layer bridging between Al-atoms. The tert-butylammonium ions and water molecules located in the interlayer spacing interact via hydrogen-bonds with the terminal oxygens of the P-atoms. The characterization of this new aluminophosphate by 13C, 31P, 1H– 31P heteronuclear correlation (HETCOR) and 27Al 3QMAS solid state NMR spectroscopy is also reported.

Synthesis, characterization and structure determination of two isotypes of a layered aluminophosphate with a new 2D network topology

Two isotypes of a new layered aluminophosphate, further denoted MDAP-3 and MDAE-1, have been synthesized under hydrothermal conditions using N-methyl-1,3-propanediamine and N-methyl-ethylenediamine, respectively. MDAP-3, with the empirical formula [Al 2(HPO 4)(PO 4) 2](C 4N 2H 14)(H 2O), crystallizes in the orthorhombic space group Pna 2 ( 1 ) (No. 33) with a = 9.602 ( 16 ) Å , b = 9.26 ( 2 ) Å , c = 16.03 ( 3 ) Å , Z = 4 , R 1 = 0.0498 and w R 2 = 0.1217 . The second solid, MDAE-1, with the empirical formula [Al 2(HPO 4)(PO 4) 2](C 3N 2H 12)(H 2O), crystallizes in the same space group with a = 9.4250 ( 19 ) Å , b = 9.3170 ( 19 ) Å , c = 15.907 ( 3 ) Å , Z = 4 , R 1 = 0.0407 and w R 2 = 0.0954 . The two compounds possess the same layer topology. Inorganic layers contain PO 3=O, PO 3OH, AlO 4 and AlO 6 polyhedra, linked together to generate a new 4×8 net. MDAP-3 and MDAE-1 represent the first examples of two-dimensional layered aluminophosphates with the Al 2P 3O 12 stoichiometry, and containing AlO 6 octahedra.

Assembly of Helical Hydrogen Bonds in a New Layered Aluminophosphate [C6N3H17][Al2(HPO4)(PO4)2

A new layered aluminophosphate, [C6N3H17][Al2(HPO4)(PO4)2] (denoted AlPO-CJ21), has been prepared in an alcoholic system by the use of N-(2-aminoethyl)-piperazine (AEPP) as the template. Its inorganic layer containing a series of bridged six-membered rings (MRs) is a new type of 4.6-net sheet built up from AlO4, PO2(OH)(=O), and PO3(=O) tetrahedra. Interestingly, inorganic helical chains of right- or left-handedness are presented in the aluminophosphate layers, and fascinating hydrogen-bonded helices are self-assembled under solvothermal conditions between organic templates and inorganic sheets via strong hydrogen bondings of O...N atoms. Crystal data: monoclinic, P2(1) (No. 4), a = 10.069(2) A, b = 8.0875(16) A, c = 10.598(2) A, beta = 94.71(3) degrees, z = 2, R(1) = 0.0325 [I > 2sigma(I)], and wR(2) = 0.0807 (all data); Flack parameter: 0.03.

Lamellar Mesostructured Aluminophosphates: Intercalation of n-Alkylamines into Layered Aluminophosphate by Ultrasonic Method

A family of lamellar mesostructured aluminophosphates, denoted Mu-4-Ln (L stands for lamellar, n = 4, 8, 12, 16, the number of carbon atoms for n-alkyl chain) has been prepared through intercalating n-alkylamines into the layered aluminophosphate [(C2H5)2NH2]4[Al8P10O40H2]·[H2O]2.5 (Mu-4) using an ultrasonic method. The intercalation compounds are characterized by XRD, IR, TG, NMR, as well as compositional analyses. The results show that the intact sheet structure of Mu-4 retains while the n-alkylamines are intercalated into the layers. A linear relationship is observed between the interlayer distance and the number of carbon atoms in n-alkyl chains. A possible arrangement of the n-alkylamines in the interlayer space has been proposed using computer simulations.

Delamination and aromatic amine intercalation of layered aluminophosphate with [Al 3P 4O 16] 3− stoichiometry

The delamination and intercalation of a layered microporous aluminophosphate, [Al 3P 4O 16] 3−⋅3[CH 3(CH 2)NH 3] + (AlP), with aromatic amine have been carried out and were followed by XRD and SEM measurements. The basicity of the amine plays an important role in this process, as do the dielectric constant of the solution and the amount of amine added. A saturated benzylamine (p K a of 9.34) intercalate of the aluminophosphate are obtained in solutions with dielectric constant of 50–70 and an amine concentration of 10 mmol/g AlP, while no aniline (p K a of 4.60) intercalates are formed under similar conditions. The remarkable effect of basicity of the amine can be explained by a metathetical balanced reaction model, which was proved by the results of the intercalation processes of 4-methylpiridine (p K a = 6.00 ) and 4-methylimidazole (p K a = 7.55 ).

Fabrication of Polymer/Selective-Flake Nanocomposite Membranes and Their Use in Gas Separation

Here, we report for the first time the fabrication of polymer/selective-flake nanocomposite membranes which can, in principle, be scaled down to submicrometer structures. A layered aluminophosphate with a porous net layer is used as a selective phase and a polyimide as a continuous phase. The microstructures of the nanocomposite membranes are investigated using various characterization techniques including X-ray diffraction, NMR, transmission electron microscopy, small-angle neutron scattering, and dynamic mechanical thermal analysis. Nanocomposite membranes with 10 wt % layered aluminophosphate show substantial enhancement in performance with oxygen selectivity over nitrogen as high as 8.9 (as compared to 3.6 for pure polymer) and carbon dioxide selectivity over methane as high as 40.9 (as compared to 13.4 for pure polymer) in room-temperature permeation measurements. This improved performance, along with permeability estimation through the aluminophosphate layers with a semiempirical model, suggests tha...

Hydrogen‐Bonded Helices in the Layered Aluminophosphate (C2H8N)2 [Al2(HPO4)(PO4)2

AbstractFor Abstract see ChemInform Abstract in Full Text.

Hydrogen‐Bonded Helices in the Layered Aluminophosphate (C2H8N)2[Al2(HPO4)(PO4)2

In the Communication “Hydrogen-Bonded Helices in the Layered Aluminophosphate (C2H8N)2[Al2(HPO4)(PO4)]” by J. Yu, R. Xu, et al. (1), on page 2400, left column, line 27, an oxygen atom was inadvertently mislabeled. The sentence should be: P(1) shares two O atoms with adjacent Al atoms and has one terminal POH group (P(1)O(12) 1.563(4) Å) and one terminal PO group (P(1)O(1) 1.470(3) Å), while P(2) and P(3) each share three oxygen atoms with adjacent Al atoms and have one terminal PO group (P(2)O(2) 1.493(3) Å, P(3)O(5) 1.489(3) Å).

Synthesis and crystal structure of a new layered aluminophosphate [Al 3P 4O 16][C 6N 3H 17][H 3O

A new layered aluminophosphate denoted AlPO-AEPP has been synthesized under hydrothermal conditions using N-(2-aminoethyl)-piperazine (AEPP) as structure directing molecule. The compound, with the empirical formula Al 3 P 4 O 16 C 6 N 3 H 17 H 3 O crystallizes in the orthorhombic space group P2 12 12 1 (No. 19) with a=14.550(8) Å, b=16.163(8) Å, c=18.677(9) Å, Z=4, R 1=0.0253 and w R 2=0.0644. Inorganic sheets contain a 4×6 network previously found in a layered compound synthesized with 1,2-dimethylimidazole molecules. Layers stack in the ABAB sequence and are held together by doubly protonated organic molecules and H 3O + cations. AlPO-AEPP represents the second example of layered aluminophosphate for which protonated water acts as a co-template along with organic molecules.

Synthesis and crystal structure of a new layered aluminophosphate 6Al3P4O1696C6N3H1796H3O9

A new layered aluminophosphate denoted AlPO-AEPP has been synthesized under hydrothermal conditions using N-(2-aminoethyl)-piperazine (AEPP) as structure directing molecule. The compound, with the empirical formula Al3P4O16C6N3H17H3O crystallizes in the orthorhombic space group P212121 (No. 19) with a=14.550(8) Å, b=16.163(8) Å, c=18.677(9) Å, Z=4, R1=0.0253 and wR2=0.0644. Inorganic sheets contain a 4×6 network previously found in a layered compound synthesized with 1,2-dimethylimidazole molecules. Layers stack in the ABAB sequence and are held together by doubly protonated organic molecules and H3O+ cations. AlPO-AEPP represents the second example of layered aluminophosphate for which protonated water acts as a co-template along with organic molecules.