Tertiary amines aliphatic, determination

Refaat et al. [24] used a spectrophotometric method for the determination of primaquine, and 16 other tertiary amine drugs, in bulk or in pharmaceuticals. The method involved the condensation of malonic acid with acetic anhydride in the presence of a tertiary amine in an aliphatic or a heterocyclic system. The condensation product is highly fluorescent and allows the spectrofluorimetric determination of the drug in the ng/mL ranges (Xcx = 415 nm and >.em = 455 nm). 

Aliphatic amines have been determined by a number of methods. Batley et al. [290] extracted the amines into chloroform as ion-association complexes with chromate, then determined the chromium in the complex colorimetri-cally with diphenylcarbazide. The chromium might also be determined, with fewer steps, by atomic absorption. With the colorimetric method, the limit of detection of a commercial tertiary amine mixture was 15ppb. The sensitivity was extended to 0.2 ppb by extracting into organic solvent the complex formed by the amine and Eosin Yellow. The concentration of the complex was measured fluorometrically. Gas chromatography, with the separations taking place on a modified carbon black column, was used by Di Corcia and Samperi [291] to measure aliphatic amines. 

The flow-cell design was introduced by Stieg and Nieman [166] in 1978 for analytical uses of CL. Burguera and Townshend [167] used the CL emission produced by the oxidation of alkylamines by benzoyl peroxide to determine aliphatic secondary and tertiary amines in chloroform or acetone. They tested various coiled flow cells for monitoring the CL emission produced by the cobalt-catalyzed oxidation of luminol by hydrogen peroxide and the fluorescein-sensitized oxidation of sulfide by sodium hypochlorite [168], Rule and Seitz [169] reported one of the first applications of flow injection analysis (FTA) in the CL detection of peroxide with luminol in the presence of a copper ion catalyst. They... 

In general, EC reactions are typically observed according to the following general rank order (by relative ease of oxidation) o,p-quinol and o,p-aminophenol > tertiary amine > m-quinol rv phenol rv arylamine > secondary amine thiol > thioether primary amines, aliphatic alcohols. (HDVs) each redox active metabolite are obtained from the response across adjacent EC-Array sensors. These data are a reflection of the kinetic and thermodynamic components of electron transfer reactions. Since chemical structure is a critical determinant of an analyte s redox behavior, the intrinsic generation of an HDV with EC-Array provides qualitative information for each species. 

In aliphatic compounds the normal compound has usually the highest b.p.7 Menschutkin considered that, with alcohols, it is not the primary, secondary, or tertiary character that determines the b.p. (primary > secondary >tertiary), but the position of the side-chain relative to hydroxyl. With alcohols, alkyl halides, amines, carboxylic acids, and esters, the b.p. is lower the nearer the side chain is to the substituent. This holds especially for higher homologues, e.g. amyl, hexyl, and heptyl alcohols and derivatives. 

The authors studied the polymerization of formaldehyde with amines including tertiary amines at —78°C in various solvents (Table 1), and determined the conversion after 15 min reaction time. Tertiary amines are highly reactive initiators for formaldehyde polymerizations even at the level of 10 mole T per mole 1 of formaldehyde. The reactivity of the amine is related to its pXg value but also to the branching of the aliphatic side chains of the substituents on the nitrogen atom. Branched amines, especially when the branching is on the a-carbon atom as in the case of a tertiary butyl group, are less effective initiators than tertiary amines with n-alkyl chains. The pX a of the amine is not the essential feature for an efficient tertiary amine initiator, because pyridine was almost as effective as tri-n-butylamine but quinoline, with a similar pK g as pyridine, is almost inactive (Table 1). 

Tsukioka, T., Ozawa, H., and Murakami, T., Gas chromatographic-mass spectrometric determination of lower aliphatic tertiary amines in environmental samples, J. Chromatogr., 642, 395-400, 1993. 

The class to which an amine belongs can be determined by treating it with acetyl chloride or acetic anhydride. The reactions which take place with these substances are analogous to those described under the aliphatic amines. Benzenesulphonyl chloride is of particular value in distinguishing primary, secondary, and tertiary amines from one another. The reactions have already been described (473). 

High-molecular-weight aliphatic amines are used extensively in many industries. The total primary- and secondary-amine content of aliphatic amines can be determined easily and rapidly by functional-group analysis in the near infrared [9], using chloroform solvent and 5-cm fused-silica cells. Primary amines have characteristic absorption maxima at 2.02 /um and 1.55 m, whereas secondary amines absorb only at 1.55 fim. Quantitation is achieved by the calibration-curve method using a series of standard solutions of primary and of secondary amines. Most other methods for the determination of total primary, secondary, or tertiary amine in a mixture are lengthy or inaccurate, or are unsuitable for small samples. 

Purely aromatic or purely aliphatic tertiary amines and quaternary ammonium salts do not react with nitrous acid, but mixed aromatic-aliphatic amines of the dimethylaniline type form green or yellow p-nitroso derivatives (Figure 3.5.4) when treated with nitrous acid. This reaction has also been used for the determination of nitrites. 

Tertiary aliphatic amines are rather difficult to detect, but they can be detected at 254 run after quatemization with p-NBBr [66]. Pilocarpine and isopilocarpine were derivatized in a sealed ampoule for 24 h at 40 °C, then separated by ion-pair HPLC. Tertiary amines can also be determined by post-chromatographic derivatization. Kudoh et al. described a method [67] involving derivatization with 1% dtric acid in acetic anhydride at 120 C, separation on a chemically bonded silica gel Nucleosil 5N(CH3)2, column, and detection at 550 nm. 

Organic residual components are the most worrying because of their toxicity. Some of these compounds are formed as by-products. Volatile organic compounds are determined by headspace GC, GC-MS. Intermediate products, such as sultones and sulfones, from sulfonation of olefin and alkyl-benzene, respectively, can be detected by LC. Unreacted products, like ethylene oxide from the synthesis of ethoxylated nonionic and anionic surfactants, are studied by GC benzyl chloride from the quaternization of tertiary amines and aliphatic amines from amidation reaction are determined by LC (Figure 5). 

In addition to the determination of total base, it is also possible to titrate mixtures. This can be done in two ways. One is to titrate mixtures based on the type of amines present. For example, one can distinguish between primary, secondary, and tertiary amines. This is done simply. Acetylate the primary and secondary amines in the mixture with acetic anhydride. They are converted to amides which are only weakly basic. Tertiary amines are not affected and titrate very well. A further differentiation can be made, however. The primary amine can be reacted with salicyl aldehyde to form a Schiff base. The secondary and tertiary amines are unaffected as far as basic strength is concerned, so that one can titrate the sum of secondary and tertiary amines. By these two titrations plus a determination of total amine, one can resolve the mixture. This approach works well for aliphatic amines, but not for aromatic amines. 

Quantum-chemical ab initio calculations have been conducted to determine the proton affinities of tripyrrolidinyl-and l,4,7-trimethyl-l,4,7-triazacyclononane (8 and 9, respectively). Their proton affinities have been found to be up to 20 kcal mol-1 higher than the values of noncyclic tertiary aliphatic amines due to an effective stabilization of the ammonium cations <2005T12371>. 

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