Tetramethylammonium Hydroxide Reagent

J.D.J. van den Berg and J.J. Boon, Unwanted alkylation during direct methylation of fatty (di)acids using tetramethylammonium hydroxide reagent in a Curie point pyrolysis unit, J. Anal. Appl. Pyrol., 61, 45 63 (2001). 

REAGENT PREPARATION. Phosphate buffer of pH 3.5, a saturated solution of NaH2P04 in distilled water, and tetramethylammonium hydroxide (TMAH) pentahydrate (Sigma) (48by weight in methanol)... 

Some mononitrocompds, such as o- p-Nirro-aniline, p-Nitrotoluene and some of their derivs produce orange or red color in dimethylformamide upon the addn of 0.1ml of 10% aqueous soln of tetramethylammonium hydroxide. Janovsky s reagent which is 10% aq NaOH soln may also be used) 22)G.H. Wetter, "Development of Instrumentation for Determining the Total Chromaticity and Chromaticity vs Time of... 

Several calorimetric methods were reported for spironolactone using different derivatization reagents, such as thiosemicarbazide at 440 nm [24], 4-dinitrobenzene at 400 nm [25], isoniazide at 375 nm [26], acetic acid-acetic anhydride then H2SO4 at 500 nm [27], 2,3,5-triphenyl-tetrazolium chloride and tetramethylammonium hydroxide at 480 nm [28] sodium nitroprusside at 700 nm, and phosphotungestic acid at 410 nm [29]. 

Bupivacaine (49a) and its phenolic metabolites (49b-c) were detected in urine after the samples underwent hydrolysis, LLE with ether, concentration by evaporation and derivatization with diazomethane, to obtain the methyl ethers (49d). End analysis was by GC-MS in the SIM mode". Another methylation reaction with this reagent was mentioned in Section III.A.2 . On-site methylation with tetramethylammonium hydroxide was proposed for the analysis of phenolic additives in polymeric materials, by the pyrolysis-GC method" . Pressurized LLE using phenytrimethylammonium hydroxide (50) or trimethylsulfonium hydroxide (51) for simultaneous methylation was applied to the... 

Study of the reusability of the catalyst shows a 10% decrease in the activity of the tetramethylammonium hydroxide/RuCl2(PPh3)3 reagent system in the oxidation of... 

In many cases the reaction of the tetrazolopyridinium salt (21) with nucleophiles is not regiospecific and takes place at C-5 and C-8a simultaneously. When the reagent attacks the tetrazolium salt (21) at position 8a, nitrogen elimination occurs <86T4827>. This was observed as the only reaction when 7-methyltetrazolo[l,5-a]pyridinium salt (26) was treated with tetramethylammonium hydroxide, and the iV-anilino-2-pyridone (27) was isolated in good yield (Equation (6)). 

Some bases, such as sodium hydroxide and tetramethylammonium hydroxide, are used for sample dissolution, as are some reagents that are not acids or bases, like hydrogen peroxide. The chemical literature contains sample dissolution procedures for virtually every type of material known and should be consulted. For elements and inorganic compounds, the CRC Handbook of Chemistry and Physics gives guidelines for dissolution in the tables of physical properties of inorganic compounds. 

Initially, tetramethylammonium hydroxide was used [121-124], but tetrabutylammonium hydroxide was better for very voiatile acids [125], and subsequently trimethylanilinium hydroxide (TMAH) was found to be preferable to the tetramethyl compound, and has been widely used as a methylating agent for a variety of different classes of compounds, particularly drugs, but also including acids [120, 126—129]. The w-trifluoro-methyl substituted analogue of TMAH has also been used for free fatty acids and lipid components in biological material, e.g. needle biopsies. This reagent, tri-methyl-(a,a,a-trifluoro-m-tolyl)ammonium hydroxide or TMTFTH, was chosen because it could be used at a... 

Separation of phenylthiohydantoin (PTH) amino acid derivatives, which are produced in the sequential analysis of proteins by the Edman degradation, is required. Ashraf-Khorassani etal. showed [21] how SFC on a cyanopropyl-modified silica column allowed the separation of more than twenty PTH-amino acids if an ion-pairing reagent (tetramethylammonium hydroxide) was present at low concentration in the methanol-modified CO2 mobile phase. 

Tetramethylammonium hydroxide (TMAH) is the most commonly used reagent for THM, and TMAH thermochemolysis has been extensively applied to the characterization of organic natural materials [98,103,104,107,108,124,127,134-138]. Py with TMAH involves the deprotonation of carboxylic acids and the hydrolysis of ester and ether bonds, followed by the formation of tetramethylammonium salts, which are subsequently subjected to thermal dissociation and leads to the formation of the corresponding methyl derivatives. 

The CFS hollow fiber suppressor (see Section 4.3.2) that was developed for cation-exchange chromatography could also be applied to cation analysis via ion-pair chromatography. It featured good solvent stability and sufficient permeability for the anionic ion-pair reagent This suppressor was regenerated with tetramethylammonium hydroxide at a concentration of c = 0.04 mol/L. 

Much higher amounts of organic solvents are required for the elution of tetra-alkylammonium compounds, which are used as reagents in ion-pair chromatography of anions. If the analysis times are kept constant, an amount of 60 mL/ L acetonitrile suffices to elute tetramethylammonium hydroxide at a hexanesulfonic acid concentration of c = 1 mmol/L (Fig. 6-29), 280 mL/L is needed for the elution of tetrapropylammonium ions, and 480 mL/L for the even more... 

Reagent 13.33 g (0.08 mol) of a-methoxyphenylacetic acid are dissolved in 27.8 ml of a 1.08 N aqueous solution of tetramethylammonium hydroxide (0.03 mol) and absolute alcohol added to give a final volume of 100 ml. The solution is allowed to stand at room temperature for at least 5 hours with occasional shaking and for a further 12 hours at 0° C. The cold solution is decanted from the precipitate of the sodium salt of the acid formed from impurities in the reagents and filtered by suction. 

III. Dilute tetramethylammonium hydroxide solution. Dilute 4 ml of an aqueous solution containing 25 0 to 26 0 per cent w/w of tetramethylammonium hydroxide to 100 ml with reagent I the solution should he freshly prepared. 

The addition sequence quat salt, caustic solution, pretreat-ment, then reagent is critical Addition of quat salts to caustic pretreated cellulose does not produce a significant enhancement of the extent of substitution. Similarly, addition of tertiary amines assuming that the corresponding quaternary salt of the reagent will be produced in situ is ineffective. Treatment of native cellulose with tetramethylammonium hydroxide alone did not produce an activated substrate. 

Reagents Nitration mixture nitric acid q = 1.5) and acetic acid 1 1 dimethylformamide 10% tetramethylammonium hydroxide in water. 

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