Amine protonated

An example of enhanced ion production. The chemical equilibrium exists in a solution of an amine (RNH2). With little or no acid present, the equilibrium lies well to the left, and there are few preformed protonated amine molecules (ions, RNH3+) the FAB mass spectrum (a) is typical. With more or stronger acid, the equilibrium shifts to the right, producing more protonated amine molecules. Thus, addition of acid to a solution of an amine subjected to FAB usually causes a large increase in the number of protonated amine species recorded (spectrum b). 

Table 2. pA Values of Protonated Amines and Their A Oxides... 

In the presence of an anionic surfactant such as sodium dodecyl-benzenesulfonate [25155-30-0] any protonated amine salt present forms an insoluble salt (4). Salt formation results in an increase in the pH of the solution. 

In contradistinction to this, weak ferromagnetism has been observed in a number of chloro and bromo complexes of the type M2[CrX4] (M = a variety of protonated amines and alkali metal cations, X = Cl, Br), which are analogous to previously known copper(II) complexes (p. 1192). They have magnetic moments at room temperature in the region of 6BM (compared... 

Recently considerable attention has been directed at anion binding ligands. Macrobicyclic 27 29) and macrotricyclic amines 30,31) were topologically designed to host anions such as spherical Cl-, linear Nf 32). These anion substrates are incorporated into macrocyclic cavities lined with appropriate anion-binding sites capable of forming hydrogen bonds like those of protonated amines (see /, below). 

Neither the 2- nor 4-aminopyridine-l-oxides nor their substitution products can be protonated at the heterocyclic nitrogen. The findings regarding the diazotization kinetics of these compounds indicate that, under the reaction conditions studied by Kalatzis and Mastrokalos (1977), two simultaneous mechanisms take place. In the first of these, nitrosyl ions attack the free amine, whereas in the second they attack the protonated amine. 

Sodium dodecyl sulfate has been used as a pairing ion in reversed phase ion chromatography in the retention of several protonated amines [155]. 

The immediate product in any particular step is the protonated amine, but it rapidly loses a proton to another molecule of ammonia or amine in an equilibrium process, for example. 

When they are protonated, amines are compatible with water, a property critical in biochemical processes because it helps biological macromolecules dissolve in water. The N—H bond in an amine is fairly easy to break, so amines participate in the formation of several important classes of polymers, including nylon and proteins. 

Figure 2. Infrared spectra of a Na" and exchanged clays following the uptake of cyclohexylamine. Absorptions at 1585 and 1525 cnT are characteristic of the neutral and protonated amine species, respectively.

Replacement of the remaining ether oxygen by basic nitrogen leads to a compound that shows anti-malarial activity. Nitration of aniline derivative 38 leads to substitution para to the alkyl group. (Protonation of the amine under the reaction conditions leads to deactivation of the position para to that group relative to that para to alkyl. The position meta to the protonated amine is less deactivated.)... 

A Ni11 complex of a cyclam derivative with protonated amine pendant also catalyzes the electrochemical reduction of C02 to CO efficiently.1507... 

The plot of permeability coefficient versus molecular radius in Figure 10 shows the interdependence of molecular size and electric charge. The permeability of the solutes decreases with increasing size. The protonated amines permeate the pores faster than neutral solutes of comparable size, and the anions of weak acids permeate the pores at a slower rate. The transport behavior of the ionic permeants is consistent with a net negatively charged paracellular route. These results are phenomenologically identical to those found in the transport kinetics of... 

There is nothing unusual about the acidic behavior of ammonium salts. In fact, any protonated amine can function as a proton donor. Because of this, many amine salts have been used as acids in synthetic reactions. If the chlorides are used, the amine salts are known as amine hydrochlorides. One of the earliest amine hydrochlorides studied with regard to its behavior as an acid is pyridine hydrochloride (pyridinium chloride), C5H5NH+C1. In the molten state, this compound undergoes many reactions of the type just shown. 

These reactions have been known for almost 100 years and they have been extensively studied. The reactions are catalyzed by the corresponding ammonium salt in each case, although other protonated amines function as catalysts. It appears that the function of the catalyst is to supply ff+, which helps to force an end of the ethylenediamine molecule away from the metal. 

Many years ago, L. F. Audrieth studied numerous reactions of amine hydrochloride salts. These compounds contain a cation that is a protonated amine that can function as a proton donor. Consequently, the molten salts are acidic and they undergo many reactions in which they function as acids. This behavior is also characteristic of ammonium chloride as well as pyridine hydrochloride (or pyridinium... 

When titrating acids with a strong base, the acids titrate in order of increasing pKa. A carboxylic acid titrates before a protonated amine when strong base is added. 

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