Aliphatic amines, determination

Abate, determination of 261, 262 Acetate, determination of 60-62 Aliphatic amines, determination of 287-289... 

It is worth noting, however, that the prototropic equilibrium between the N-nitrosoamine (3.7) and the diazohydroxide (3.9) has been determined semiquan-titatively for the analogous diazotization of an aliphatic amine. Fishbein and coworkers (Hovinen et al., 1992) determined an upper limit for the nitrosoamine equilibrium concentration (<1.5% see also Zollinger, 1995, Sec. 7.2). 

Relative rates of alkylation of toluene and benzene using a mixture of nitro-sonium hexafluorophosphate, nitromethane (or acetonitrile) and aliphatic amine as the alkylations agent have been determined at 25 °C as follows360 1.5 (ethyl-amine), 2.5 (i-propylamine) and 3.5 (benzylamine) nothing more as yet is known about the kinetics of alkylation with these new alkylating reagents. 

Possanzini, M. and Di Palo, V., Improved HPLC determination of aliphatic amines in air by diffusion and derivatization techniques, Chromatographia, 29,151, 1990. 

Generally, the results of the measurements indicated that, where dissociation constants were determined by conductometry and also potentiometric titration, they were in agreement with each other further, KHX is low, e.g., about 10 4-10 6moll 1 for aromatic sulphonic acids and 10 13-10 16 moll-1 for carboxylic acids, Xhx2 is high, e.g., 102-104, and KBis low again, e.g., 10 5-10 6 for aliphatic amines and 10 10 for aromatic amines. 

The use of an extended arene (tetrahydroanthracene) in [OsCl(en)(ri6-tha)]+ (29) gave rise to a similar potency (112). This is in contrast with the data for ruthenium-arenes, where the same substitution gave rise to a 10-fold increase in activity. Further work therefore needs to determine if the extended Os-arenes can intercalate into DNA in a manner similar to Ru-arenes. Replacement of the iV /V-chelating ligand en for other AyV-bidentates with pyridine, aliphatic amine, or azopyridine donor atoms leads to loss of activity, probably because of slower hydrolysis and higher acidity of the coordinated water (112). 

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. 

Florence and Farmer [295] determined parts per million of aliphatic amines in sea water using spectrophotometric procedures. 

A comparative study of the analysis of aliphatic amines by GC-FID, GC-TSD and HPLC with refractive index detector (RID), using isopropylamine as internal standard, gave good results in all cases. Determination of trimethylamine oxide by HPLC with a pulsed amperometric detector was problematic136. 

A determination of traces of low (Ci to C4) aliphatic amines in the atmosphere consists of passing air through an absorber containing phosphorous acid, derivatizing with m-toluyl chloride and end analysis by HPLC-UVD LOD 1-5 pmol of amine, corresponding to concentrations lower than 0.1 pg/m3 of air, in a 300 L sample232. 

The fate of dissolved amines during disinfection of water by chlorination was determined by membrane injection MS. Aliphatic amines undergo TV-chlorination to exhaustion of the N-H atoms by one of the tentatively proposed paths shown in reaction 28. Aromatic amines undergo mainly ring substitution however, the possible intervention of N-C1 intermediates is not excluded. At pH 10.6 aniline chlorination is much slower than that of n-butylamine383. 

The action of nitrous acid on a primary, aliphatic amine is still a complex process, inasmuch as it is necessary to postulate certain steps that are imperfectly understood, but it can nevertheless be considered that the process leads ultimately to a carbonium ion.26,27 The carbonium ion thus formed is termed hot, that is to say, it is non-solvated and chemically activated the nature of the products resulting from its decay is essentially determined by the conformation of the initial state the electronic factors in effect at the time of the transition state exert little influence.27... 

Zhang AQ, Mitchell SC, Ayesh R, Smith RL (1992) Determination of trimethylamine and related aliphatic amines in human urine by head space gas chromatography. J Chromatogr 584 141-145... 

It was suggested8 in 1932 that carbonium ions are intermediates in the conversion of a primary aliphatic amine into nitrogen-free products by the action of nitrous acid. In the weakly acidic solutions normally used for deamination of aliphatic amines, the rate-determining... 

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