Saturated Aliphatic Amines

Oxidative attack on a carbon-hydrogen bond of an alkyl group a to a nitrogen atom is not restricted to saturated aliphatic amines. In fact X in an X-N-CH- structural subunit can be virtually any common atomic grouping that can be found in stable organic molecules. For example, w-carbon hydrogens of Aralkyl-substituted aromatic cyclic amines (119), aryl amines (120), amides (121), amidines (122), A-nitrosodialkylamines (123), etc. are all subject to oxidative attack, carbinolamine formation, and in most cases release of an aldehyde or ketone depending on the substitution pattern (1° or 2°)... 

In Tables 1-8 the first IP values of various amines are summarized. These values refer to the removal of an electron from the n orbital of the amines. The other ionizations of simple saturated aliphatic amines are of no particular interest. They are associated with the orbitals of the a framework of the molecules. More interesting are the effects of substituents and other structural factors on the energy of the n ionization or—in the limits of Koopmans theorem17, IP,- = —efCF—on the energy of the orbital. 

These conclusions are reinforced by measurement of natural abundance 15N chemical shifts in piperidines and decahydroquinolines (77JA8406,78JA3882,78JA3889). Lack of correlation between 13C shifts of cyclohexanes and 1SN shifts of piperidines bearing the same methyl substituents are attributed to, among other factors, solvent effects and the difference between H-lone pair and H-H interactions. Protonation served to cancel these stereoelec-tronic effects. Correspondence between 1SN shifts in N- and C- methyl substituted piperidines and decahydroquinoline hydrochlorides and the analogous 13C values were, however, generally much closer than for saturated aliphatic amines. 

A straightforward treatment of the base strength of aniline can be given. A saturated aliphatic amine such as methylamine has a base constant Kb of about 5 X 10 4, corresponding to the reaction H H... 

Duthaler, R.O. and Roberts, J.D., Steric and electronic effects on 15N chemical shifts of saturated aliphatic amines and their hydrochlorides, J. Am. Chem. Soc., 100, 3889, 1978. 

In conclusion, the use of amines for the characterization of adsorption and active sites raises the same problems as ammonia. The interaction of the amines, saturated aliphatic amines in particular, with oxide surfaces is certainly still less specific than that of ammonia because of their higher basicity and their larger molecular size. The influence of steric effects on amine adsorption has been discussed (172, 201b). Thus, Medema et al. (172) came to the conclusion that the adsorbed amount of an amine on 7-Al2 03 primarily depends on its molec-... 

Pyridines form crystalline, frequently hygroscopic, salts with most protic acids. Pyridine itself, with pATa 5.2 in water, is a much weaker base than saturated aliphatic amines which have pATa values mostly between 9 and 11. Since the gas-phase proton affinity of pyridine is actually very similar to those of aliphatic amines, the observed solution values reflect relatively strong solvation of aliphatic ammonium cations this difference may in turn be related to the mesomerically delocalised charge in pyridinium ions and the consequent reduced requirement for external stabilisation via solvation. 

Saturated aliphatic amines are similar to the alkanes, the main differences being the short C—N bond (C—C 1.523 A, C—N 1.450 A) and the replacement of one substituent by a lone pair of electrons (LP). The pyramidal structure of acyclic amines is quite labile, with barriers to inversion in the range 4-8 kcal mol (Rauk et al, 1971). The problem of the steric requirements of the lone pair has been much discussed in relation to conformational equilibria in saturated six-membered N-heterocycIes (Lambert and Feather-man, 1975 Blackburne et al, 1975). 

Synonyms 2-Aminopentane DEA DEN DETN Diethamine N,N-Diethy-lamine N-Ethylethanamine Classification Saturated aliphatic amine Empirical C4H11N Formula (C2Hs)2NH... 

CAS 109-73-9 EINECS/ELINCS 203-699-2 UN 1125 (DOT) FEMA 3130 Synonyms Amine C4 1-Aminobutane 1-Butanamine Butylamine MNBA Monobutylamine Mono-n-butylamine Classification Saturated aliphatic amine Empirical C4H11N Formula CH3(CH2)3NH2... 

Classification Saturated aliphatic amine Empirical C2H7N Formula CH3CH2NH2... 

Monobutylamine Mono-n-butylamine Classification Saturated aliphatic amine Empirical CjH-.N Formula CH3(CH2)3NH2... 

Synonyms Amlnoelhane 1-Aminoelhane EA Elhanamine Ethylamine anhydrous MEA Monoethylamine Classification Saturated aliphatic amine Empirical CjHjN Formula CHjCHjNHj... 

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