Triethanolamine, reagent

H2 or O2 generation from water is a multielectron process. Optimization of photoredox-splitting of water necessitates the presence of a catalyst to mediate this complex multielectron transfer. In one such process, a sacrificial reagent triethanolamine (TEOA) is consumed irreversibly in the process, as denoted in Sch. 1 [9] ... 

The 5-nitrosallcylaldehyde reagent is prepared as follows. Add 0-5 g. of 5-nitrosalicylaldehyde (m.p. 124-125°) to 15 ml. of pure triethanolamine and 25 ml. of water shake until dissolved. Then introduce 0-5 g. of crystallised nickel chloride dissolved in a few ml. of water, and dilute to 100 ml. with water. If the triethanolamine contains some ethanolamine (thus causing a precipitate), it may be necessary to add a further 0 - 5 g. of the aldehyde and to filter off the resulting precipitate. The reagent is stable for long periods. 

Cu, Ni, Co, Cr, Fe, or Al, even in traces, must be absent when conducting a direct titration of the other metals listed above if the metal ion to be titrated does not react with the cyanide ion or with triethanolamine, these substances can be used as masking reagents. It has been stated that the addition of 0.5-1 mL of 0.001 M o-phenanthroline prior to the EDTA titration eliminates the blocking effect of these metals with solochrome black and also with xylenol orange (see below). 

The indicator solution is prepared by dissolving 0.2 g of the dyestuff in 15 mL of triethanolamine with the addition of 5 mL of absolute ethanol to reduce the viscosity the reagent is stable for several months. A 0.4 per cent solution of the pure dyestuff in methanol remains serviceable for at least a month. 

Discussion. Minute amounts of beryllium may be readily determined spectrophotometrically by reaction under alkaline conditions with 4-nitrobenzeneazo-orcinol. The reagent is yellow in a basic medium in the presence of beryllium the colour changes to reddish-brown. The zone of optimum alkalinity is rather critical and narrow buffering with boric acid increases the reproducibility. Aluminium, up to about 240 mg per 25 mL, has little influence provided an excess of 1 mole of sodium hydroxide is added for each mole of aluminium present. Other elements which might interfere are removed by preliminary treatment with sodium hydroxide solution, but the possible co-precipitation of beryllium must be considered. Zinc interferes very slightly but can be removed by precipitation as sulphide. Copper interferes seriously, even in such small amounts as are soluble in sodium hydroxide solution. The interference of small amounts of copper, nickel, iron and calcium can be prevented by complexing with EDTA and triethanolamine. 

When a photosynthetic organism is omitted, the addition of a photosensitizer is necessary. The methods use light energy to promote the transfer of an electron from a photosensitizer to NAD(P) via an electron transport reagent [6g]. Recently, carbon dioxide cvas reduced to formic acid with FDH from Saccharomyces cerevisiae in the presence of methylviologen (MV ) as a mediator, zinc tetrakis(4-methylpyridyl) porphyrin (ZnTMPyP) as a photosensitizer, and triethanolamine (TEOA) as a hydrogen source (Figure 8.8) [6h]. 

A. A. Perejma and L. V. Pertseva. Complex reagent for treating plugging solutions—comprises hydrolysed polyacrylonitrile, ferrochro-moUgnosulphonate Cr-containing additive, waste from lanolin production treated with triethanolamine and water. Patent RU 2013524-C, 1994. 

The reaction is carried out in 0.2M triethanolamine, pH 8.2. DMS should be the limiting reagent in the reaction to avoid blocking all amines on both molecules with only one end of the... 

The microspheres—synthesised via a two-step process (acid-catalysed hydrolysis and condensation of 3-mercaptopropyltrimethoxysilane (MPS) in aqueous solution, followed by condensation catalysed by triethanolamine)—have a narrow size distribution (Figure 5.16) and are considerably more stable than polystyrene divinylbenzene microspheres as shown in phosphoramidite oligonucleotide synthesis by the excellent retention of fluorescence intensity in each of the reagent steps involved in phosphoramidite DNA synthesis (Figure 5.17, in which the organo-silica microsphere free thiol groups are derivatized with ATTO 550 maleimide coupled to the entrapped dye). 

The addition of allylic boron reagents to carbonyl compounds first leads to homoallylic alcohol derivatives 36 or 37 that contain a covalent B-O bond (Eqs. 46 and 47). These adducts must be cleaved at the end of the reaction to isolate the free alcohol product from the reaction mixture. To cleave the covalent B-0 bond in these intermediates, a hydrolytic or oxidative work-up is required. For additions of allylic boranes, an oxidative work-up of the borinic ester intermediate 36 (R = alkyl) with basic hydrogen peroxide is preferred. For additions of allylic boronate derivatives, a simpler hydrolysis (acidic or basic) or triethanolamine exchange is generally performed as a means to cleave the borate intermediate 37 (Y = O-alkyl). The facility with which the borate ester is hydrolyzed depends primarily on the size of the substituents, but this operation is usually straightforward. For sensitive carbonyl substrates, the choice of allylic derivative, borane or boronate, may thus be dictated by the particular work-up conditions required. 

Traut s reagent is fully water-soluble and reacts with primary amines in the pH range 7—10. The cyclic imidothioester is stable to hydrolysis at acid pH values, but its half-life in solution decreases as the pH increases beyond neutrality. However, even at pH 8 in 25 mM triethanolamine the rate of sulfhydryl formation without added primary amine was found to be negligible. On addition of dipeptide amine, the reagent reacted quickly as evidenced by the production of Ellman s reagent color. The rate of reaction also can be followed by 2-iminothiolane s absorbance at 248 nm (Xmax e = 8 840 M 1 cm 1). As the cyclic imidate reacts with amines, its absorbance at... 

Girbotol process a continuous, regenerative process to separate hydrogen sulfide, carbon dioxide, and other acid impurities from natural gas, refinery gas, etc., using mono-, di-, or triethanolamine as the reagent. 

Air drawn through Palmes tube with three triethanolamine (TEA)-treated screens analyte converted into nitrite ion (NO, ) NO, treated with an aqueous solution of a reagent mixture containing sulfanilamide, H3P04, and V-1 -naphthy 1-ethylenediamine dihydrochloride color develops absorbance measured at 540 nm by a spectrophotometer, concentration determined from a standard calibration curve made from NaN02 (NIOSH Method 6700, 1984). 

Methyl-/V-fert(butyldimethylsilyl)trifluoroacetam-ide (MTBSTFA, CAS 77377-52-7) is another common silylation reagent used for CWC-related chemicals. BSTFA silylates aminoalcohols such as triethanolamine (CAS 102-71-6) give higher recoveries than MTBSTFA, but the te/T-butyldimethylsilyl ethers formed when MTBSTFA is used are more stable than the trimethylsilyl ethers formed with BSTFA. 

Creasy (68) investigated postcolumn derivatization of A-ethyldiethanolamine and triethanolamine with benzoyl chloride in combination with APCI. Derivatization of one hydroxyl group occurred after mixing the reagent with LC eluent, and sensitivity was not affected by derivatization. A possible advantage of this method is to increase the molecular mass to remove the analyte from interferences. 

Amines can also open epoxides. Ethylene oxide reacts with aqueous ammonia to give ethanolamine, an important industrial reagent. The nitrogen atom in ethanolamine is still nucleophilic, and ethanolamine can react further to give diethanolamine and triethanolamine. Good yields of ethanolamine are achieved by using excess ammonia. 

In order to determine S(IV) in rain water, it is necessary to prevent the oxidation of S(IV) between sampling and analysis. The suppressive effect on the oxidation of S(IV) was investigated by the addition of EDTA (Ethylenediaminetetraacetate) or TEA (Triethanolamine) as masking reagents for FeJ+ and Mn. Table III shows the suppressive effect of EDTA or TEA at various pH values. The suppressive effect was not observed between pH 3 and 5, because neither EDTA nor TEA chelate with Fe3+ and Mnz+ at these pH values. EDTA and TEA were found to be very effective for the suppression of the oxidation of S(IV) in solutions having neutral and basic pH values. 

Previous work on this reaction has included the use of triethanolamine as catalyst, as well as triethylamine as catalyst and solvent. [21-24] The use of elevated temperatures (>75°C) can lead to uncontrolled decarboxylation of malonic acid before condensation, giving acetic acid, which is then too weak a carbon acid to condense. This difficulty means that often up to 3 equivalents of the malonic acid need to be used to achieve good conversion. Our aim in this work was therefore to find a catalyst which would cause the condensation to occur efficiently, but at low enough temperatures to avoid decomposition of the malonic acid. Using THF as solvent and a 1 1 ratio of malonic acid to aldehyde, with 15g of catalyst per mole of reagent, we obtained high levels of conversion of aldehyde in a reasonable time (Table 3). 

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