Tetraalkylammonium Subject

In zeolite synthesis (ref. 2) an aqueous mixture containing a silicon source, an aluminum source, an alkali source (usually NaOH) is autoclaved and subjected to hydrothermal treatment. Hydrated Na-ions are then filling the pore system in the as-synthesized zeolite. In the case of relatively high Si/Al zeolites an organic template is required which is usually a tetraalkylammonium compound, applied as the bromide or the hydroxide. 

Bisphosphonates (bone resorption inhibitor drugs) were subject to many investigations. They can chelate to metal surfaces, producing chromatographic peak tailing. Different tetraalkylammonium salts, commonly selected as IPRs in separation of bisphosphonates [85], were replaced by volatile organic amines when ELSD was used [86]. 

In an earlier publication (6) we considered the basic assumptions of the models. This chapter briefly reviews this subject and extends the tests by adding new results of the AH° of tetrabutylammonium bromide (Bu4NBr) in mixtures of water with acetonitrile (ACN) and with ethylene carbonate (EC) and preliminary results of some substituted and unsymmetrical tetraalkylammonium salts in mixtures of water with DMF. 

The transfer of an inorganic ion such as OH from one phase to another is called phase transfer, and the tetraalkylammonium salt is referred t as a phase-transfer catalyst. Many different kinds of organic reactions, includ ing oxidations, reductions, carbonyl-group alkylations, and 8 2 reaction an subject to phase-transfer catalysis, often with considerable improvements ii yield. 8 2 reactions are particularly good candidates for phase-transfi-catalysis because inorganic nucleophiles can be transferred from an aqut ous (protic) phase to an organic (aprotic) phase, where they are much mort reactive. For example ... 

The SPPO composite membranes in hydrogen form were subjected to exchange with tetraalkylammonium ions before being tested for their reverse osmosis performance. The purpose of this experiment is to investigate the effect of the sulfonic anion and that of the alkyl chain in the tetraalkylammonium ion on the reverse osmosis performance, when these two effects are superimposed. 

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