ITQ‐69: A Germanium‐Containing Zeolite and its Synthesis, Structure Determination, and Adsorption Properties

Abstract

In this work, a new zeolite named as ITQ‐69, has been synthesized, characterized and its application as selective adsorbent for industrially relevant light olefins/paraffins separations has been assessed. This material has been obtained as pure germania as well as silica‐germania zeolites with different Si/Ge ratios using a diquaternary ammonium cation as organic structure directing agent. Its structure was determined by single‐crystal X‐Ray diffraction showing a triclinic unit cell forming a tridirectional small pore channel system (8×8×8R). Also, it has been found that Si preferentially occupies some special T sites of the structure as deduced from Rietveld analysis of the powder X‐ray diffraction patterns. In addition, the new zeolite ITQ‐69 has been found to be stable upon calcination and thus, its adsorption properties were evaluated, showing a promising kinetic selectivity for light olefin separations in the C3 fraction.

Structural Motifs in Aryl Organogermanium Ge-O Derivatives for Material Design

“…The presence of organic substituents at peripheral Ge atoms in compound 4 enables the formation of chiral monocrystals that are suitable to undergo XRD analysis. It is known that germanium zeolites [66] and molecular Ge compounds [67] of similar structures may be used for the sorption of hydrocarbons. Special interest will be paid to the organogermanium compounds, including these and other (absorption/emission optical [68] and semiconducting [69]) properties caused by the different types of conjugation (σ-, π-, and d-) [70] between the structural blocks, which stimulates in future novel research on germanium-heteroatom derivatives.…”

Understanding the mechanism and kinetics of the formation and breaking of ring structures during silica polymerization: a computational study

“…For example, recently synthesized lowdensity zeolite ITQ-69 has interconnected channels of 8 member rings (MRs) and exhibits great promise in the molecular separation of olefins from paraffins. 29 The ZSM-5 zeolite containing 5MR and 10MRs is used in refineries for residual hydrocracking and octane enhancement by catalytic cracking. In a recent study, 30 the structure of silica nanoparticles was altered to have a smaller ring size distribution, which reduces water retention in the nanoparticles.…”