Tetrabutylammonium hydroxide TBAH

Determination by oxidation of ascorbic acid (spec A = 548 nm) Diaminetetraacetic acid (DCTA)ZCHjCN used as eluent Tetrabutylammonium hydroxide (TBAH)/aq. CH CN used as eluent KHjPO buffer (pH = 7) lodometric titration... 

The most simple cycle is the 2,2,5,5-tetramethyl-l-oxa-2,5-disilacyclopentane (1 in Scheme 3.3). This and equivalent monomers (structures 2,3 and 4 in Scheme 3.3) have been polymerized using different catalytic means. The team of Loy and Rahimian [187, 188] carried out the polymerization of all these monomers using a basic catalyst (i.e. tetrabutylammonium hydroxide TBAH) and Bronsted adds, namely formic and triflic adds or cationic photoinitiators. Monomer 3, a soUd, was either polymerized in THF or copolymerized with 1. The polymerization was very fast (<30 min), and resulted in a material that could resist temperatures of up to 500 °C. The authors were confident that these dicydic monomers, produced via crossUnked materials, would in time replace the conventional sol-gel technique, as the polymerization is straightforward, solvent-free, has less than 5wt% shrinkage, and generates no porosity in the final material. 

TBAH Tetrabutylammonium hydroxide TMTD Tetramethylthiuram disulfide... 

The mesogenic units with methylenic spacers were prepared by reacting the sodium salt of either 4-methoxy-4 -hydroxybiphenyl or 4-phenylphenol with a bromoester in DMF at 82° C for at least 4 hours in the presence of tetrabutylammonium hydrogen sulfate (TBAH) as phase transfer catalyst. In this way, ethyl 4-(4-oxybi-phenyl)butyrate, ethyl 4-(4-methoxy-4 -oxybiphenyl)butyrate, ethyl 4-(4-oxybiphenyl)valerate, ethyl 4-(4-methoxy-4 -oxybiphenyl)-valerate, n-propyl 4-(4-oxybiphenyl)undecanoate and n-propyl 4-(4-methoxy-4 -oxybiphenyl)undecanoate were obtained. These esters were hydrolyzed with base and acidified to obtain the carboxylic acids. The corresponding potassium carboxylates were obtained by reaction with approximately stoichiometric amounts of potassium hydroxide. Experimental details of these syntheses were described elsewhere (27). 

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