Tetramethylammonium hydroxide TMAOH

In the case of an acid HX titrated with a quarternary ammonium base R4NOH there are a few complications as a consequence of some additional equilibrium constants and of a certain degree of instability of the titrant tetramethylammonium hydroxide (TMAOH) in pyridine for this reason the titrant solution was standardized against benzoic acid and used only on the day of preparation. Now, in addition to KHX and ifHX > we had to deal with... 

Basic silicate solutions were prepared by using silicic acid (ex Baker, dried at 350 °C) and a solution of the organic bases [25 wt % tetramethylammonium hydroxide (TMAOH), 40 wt % tetra-ethylammonium hydroxide (TEAOH), 20 wt % tetrapropylammonium hydroxide (TPAOH) ex Fluka] and, optionally, dimethyl sulfoxide (DMSO). A solution of hexamethonium hydroxide [ (MejNCgH NM ) (OH) 2] was prepared from the bromide salt (ex Sigma) and A O. 

Even cationic species such as the (hydrated) hydrogen ion (H ) can be lured into the hydrophobic silicone films from water medium as long as they contain appropriate additives to allow penetration of the analyte. For instance, Nivens et al. [140,141] have reported fabrication of silicone/ sol-gel films using a hydroxy-terminated poly(dimethyl siloxane (PDMS-OH), tetraethoxysilane (TEOS) and 3-ami-nopropyltriethoxysilane (APTES) mixture in ethanol-water. Tetramethylammonium hydroxide (TMAOH) is added to the mixture to entrap the fluorescent pH indicator dye 8-hydroxypyrene-l,3,6-trisulfonic acid trisodium salt (HPTS) [102], after base-catalyzed polycondensation of the silanes and the PDMS-OH. Silica optical fibers are stripped from their jacket at the distal end and dip-coated with the indicator gel before the end of gelation (24 h). The optical fluorosensor is able to measure between pH 6.0 and 8.5 for 6 months if stored in buffer medium. 

Strong evidence of ionic association was found by Stilbs and Lindman 69) in their PGSE study of aqueous polyelectrolyte solutions, polyacrylic acid and poly-methacrylic acid, neutralized by tetramethylammonium hydroxide, with or without sodium counterions. While polymer diffusion could not be detected since its T2 was too short, TMAOH and water diffusion was measured as function of degree of neutralization a, or Na+ content. A pronounced minimum of D(TMAOH) near a = 1 was interpreted in terms of a two-site model, leading to the determination that at a = 1, approximately half of the counterions are bound in both systems. Fourier transform techniques permitted the simultaneous measurement of diffusion of water and TMAOH. 

Si02 0.0015 Ti(OEt)4 0.12 CTABr 0.26 TMAOH 24.3 H20 were CTABr is cetyltrimethylammonium bromide (from Aldrich), TMAOH is tetramethylammonium hydroxide (from Aldrich). The silica source was Aerosil-200 from Degussa and Ti(OEt)4 was supplied by Alpha Products. The crystallization was performed at 100°C for 48 hours in Teflon lined stainsteel autoclaves. The solid was recovered by filtration and exhaustive washing with distilled water until neutral pH in the filtrate was obtained. Then, the Ti-MCM-41 was dried at 60°C for 24 hours. The occluded surfactant was removed by calcination at 540°C in nitrogen for 1 hour and subsequently, for 5 hours in air. 

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