Susan C. Koster

Synthesis and characterization of the 12-ring zeolites UZM-4 (BPH) and UZM-22 (MEI) via the charge density mismatch approach in the Choline-Li2O-SrO-Al2O3-SiO2 system

Abstract The Charge Density Mismatch (CDM) approach to zeolite synthesis employs zeolitic reaction mixtures which cannot easily crystallize, which are then perturbed by the addition of small amounts of crystallization-inducing agents to achieve crystallization. This approach allows great control over crystallization and extends the utility of any organic template. In this work, choline hydroxide derived aluminosilicate solutions were treated with solutions containing Li + , Sr 2+ , or both, resulting in the isolation of useful forms of the structurally similar 12-ring zeolites UZM-4 (BPH) and UZM-22 (MEI). UZM-4 is isolated in the Li-Choline system at Si/Al = 2.66, the highest ratio achieved by direct synthesis. UZM-22 is the first example of an MEI aluminosilicate prepared with a simple organic template, making this an accessible material.

UZM-13, UZM-17, UZM-19 and UZM-25: synthesis and structure of new layered precursors and a zeolite discovered via combinatorial chemistry techniques

Abstract A combinatorial chemistry investigation screening the abilities of the diethyldimethylammonium (DEDMA), ethyltrimethylammonium (ETMA), and [Me 3 N(CH 2 ) 4 NMe 3 ] 2+ (diquat-4, DQ-4) cations to form zeolites over a range of conditions was carried out. Each of the templates formed a layered precursor; UZM-13, UZM-17, and UZM-19 forming in the DEDMA, ETMA, and DQ-4 systems, respectively. The layered materials are distinct from, but similar to MCM-47 by XRD. The structure of UZM-13 was solved from powder data and was confirmed to contain MCM-47-like aluminosilicate layers. Calcination of these layered materials led to condensation along the b-axis, forming similar 3-dimensional zeolitic species designated UZM-25. However, the UZM-25 derived from the UZM-13 material was superior in crystallinity and had the only XRD pattern that could be indexed. The structure of UZM-25 was determined to be of the CDO structure type, which contains 2-dimensional intersecting 8-ring pores, from both powder and single crystal data.

Synthesis and catalytic activity of UZM-12

Abstract UZM-12 is a microporous crystalline aluminosilicate with ERI topology synthesized via the Charge Density Mismatch approach. The Charge Density Mismatch approach features synthesis from clear aluminosilicate solutions with high organic template content that are subsequently treated with crystallization inducing solutions. The solution containing low amounts of alkali and a higher charge density organic “crystallization” template, yields UZM-12 with Si/Al > 5.5 and nano- to micron-sized crystallites of spherical, plate or rod morphology depending on crystallization template, K + /Al ratio and synthesis conditions. Crystallization templates include the diquat-6, diquat-4, and benzyltrimethylammonium cations. The thermal, steam stability, and acid properties of H-UZM-12 were determined using the combinatorial heptane microreactor.

05-P-16 - Synthesis, characterization and structural aspects of novel microporous indium

Publisher Summary This chapter discusses the synthesis, characterization, and structural aspects of a novel family of indium silicate microporous materials, designated InSi-n. The InSi-n phases have been synthesized with 11 novel framework topologies and contain In/Si ratios of 0.25–1. Most InSi-n phases are stable to calcination to at least 500°C and show adsorption behavior that is zeolitic in character. Ion-exchange behavior similar to zeolites has also been observed in InSi-n materials. Preliminary structural details include a crystal structure determination of a new topology with 8-ring channels and high-resolution electron microscopy (HREM) evidence for large pores in the members of the InSi-n family.