Alkylammonium nitrates

Similar to the imidazolium ILs, very low solubility of the ammonium ILs was observed in alkanes. Eor example, the solubility of butyl(2-hydroxyethyl) dimethylammonium bromide, [(Ci)2C4HOC2N]Br, exhibited a simple eutectic system with immiscibility in the liquid phase in the IL mole fraction range from XjL = 0.02 to 0.70 [53] the other ammonium salt, (benzyl)dimethyl-alkylammonium nitrate, [Be(Ci)2C N] [NOJ showed very small solubility in the liquid phase in hexadecane and it was slightly better in hexane (immiscibility from XjL = 10 to 0.90) [99] for the ammonium salt with an alkane substituent only, didecyldimethylammonium nitrate, [(Cio)2(Q)2N][N03], the solubility in the liquid phase was better in hexane (immiscibility from XjL = 10 to 0.50) than in hexadecane, where the immiscibility was observed in the whole IL mole frachon [100]. In all systems with imidazolium and ammonium salts, an increase in the alkyl chain length of the alkane (solvent) resulted in a decrease of solubility. 

The Diels-Alder reaction is an important and widely used reaction in organic synthesis (Sauer and Sustmann, 1980), and in the chemical industry (Griffiths and Previdoli, 1993). Rate enhancement of this reaction has been achieved by the use of solvents such as water, surfactants, very high pressure, lithium amides, alkylammonium nitrate salts, and macrocyclic hosts (Sherman et ak, 1998). Diels-Alder reactions can be ran in neutral ionic liquids (such as 1-butyl-3-methylimidazolium trifluoromethanesulfo-nate, l-butyl-3-methylimidazolium hexafluorophophate, l-butyl-3-methylimidazolium tetrafluoroborate, and l-butyl-3-methylimidazolium lactate). Rate enhancements and selectivities are similar to those of reactions performed in lithium perchlorate-diethyl ether mixtures. 

Ammonium nitrate is insoluble in N2O4 but alkylammonium nitrates dissolve readily [1]. 

Ionic liquids (IL) are organic salts that can be stored in a liquid state at room temperature, a breakthrough achieved only recently when imidazolium and pyridinium derivatives were introdnced [1 ]. In early 1900s, alkylammonium nitrates were found to have a melting temperature of 12°C [5]. However, till 1980, there was no... 

The alkylammonium nitrate salts and salts containing the l-alkyl-2-alkylimidazolium cation with chloride or bromide anions were mostly molten salts, in that their melting points were >100 °C. In contrast, the PILs that contained alkylammonium cations with small carboxylic acids and most of the salts with an imidazolium cation were predominately RT-PILs, or had low melting points. 

Backbone Substitution of Alkylammonium Nitrate Salts Journal of... 

Relatively extensive studies of the fast thermolysis of related classes of alkylammonium nitrate salts have been conducted that permit the gas products from fast thermolysis to be correlated with the composition of the parent salt. Classes of compounds for which data have been gathered are [(CH3)nNH4. ]N03, n= 1-3 [70], [ (CH3CH2)nNH4 n]W03, n= 1-4 [70], [CH3(CH2)nNH3]N03, n= 0-3 [70], [H3. N(CH2CH2)NH3.y ]N03, n= 0-2 [71], [H2N(CH2)nNH3]N03, n= 1-4,6 [72] and a series of five N-methyl substituted ethanediammonium dinitrate salts [73]. 

There is no evidence that alkylammonium nitrate salts convert to nitrosamines via the nitramine intermediate [70,72]. Studies of authentic samples of the respective nitramines indicate that they would volatilize and be detected by infrared spectroscopy if they had formed. No nitramines were detected from any salt studied. 

Methylammonium nitrate salts undergo a-carbon oxidation leading to amides, such as formamide and W,N-dimethylformamide [70]. On the other hand, the longer chain alkylammonium nitrates release alkylnitrates. This reaction for n-butylammonium nitrate is straightforwardly represented by equation (6) based on the gas products evolved [70]. 

The temperature at which the higher temperature exotherm occurs with many of these compounds is quite sensitive to the applied pressure in the cell [77]. Because the fast thermolysis/FTIR spectroscopy experiment largely involves the condensed phase, the only way the static pressure in the cell can affect the temperature of the exotherm is by influencing the heterogeneous condensed phase/gas phase chemistry. Thus, we conclude from the pressure sensitivity that the thermal decomposition of alkylammonium nitrate salts involves an extensive amount of heterogeneous gas phase/condensed phase chemistry. This notion is consistent with many of the comments in this section, especially with regard to the participation of HNOo in the degradation chemistry. 

Nitrosamine (RpNNO) Containing Compounds. Nitrosamines are receiving attention in the explosives and propellants field, not so much for their value as primary materials, but from the fact they have been identified among the slow and fast thermal decomposition products of nitramines [42-44] and alkylammonium nitrate salts [70,72,73]. 

Oyumi, Y. and Brill, T.B. (1987) Thermal Decomposition of Energetic Materials 25. Shifting of the Dominant Decomposition Site by Backbone Substitution of Alkylammonium Nitrate Salts Journal of Physical Chemistry 91, 3657-3661. 

Notable novelties concerning the structure of ionic liquids came from the contribution of Atkin and co-workers, who showed the existence of pre-peaks in the X-ray structure factors of protic ionic liquids (alkylammonium nitrates) with small side chains [73]. This intermediate-range ordering is likely to be due to different kinds of structural features than those observed in ionic liquids with longer side chains, but demonstrates once more how ionic liquids are full of surprises. Strong pre-peaks in other protic ionic liquids were also described in a number of contributions by Umebayashi and co-workers [60]. 

The history of ionic liquids (and the closely related molten salts) has a rather ill-defined beginning, although it is most commonly dated back to 1914 and the work of Walden on the use of alkylammonium nitrates. - The next burst of interest occurred with the discovery of chloroaluminates formed by combining quaternary heterocyclic cations with aluminum chloride. These materials exhibited a great deal of potential for use in a variety of areas, but all suffered from extreme sensitivity to moisture. 

Quaternary alkylammonium nitrate salts were shown by Horwitz et al. [54] to extract Am considerably more efficiently from low-acid, highly salted aqueous nitrate solutions than do tertiary alkylamines. The extraction sequence for trivalent actinides into either Aliquat 336 (a mixture of trioctylmethylammonium and tridecylmethylammonium salts made by General Mills, Inc.) nitrate or trilaurylmethylammonium nitrate is Cm < Cf < Am < Es. 

High purity separation of Pr and Nd (99.9%) was carried out by Hsu et al. (1980) using quaternary alkylammonium nitrate R3CH3N N03 (0.65 M) in xylene as diluent. The extraction reaction was determined to be... 

About the earliest study of molten organic salts was the measurement of surface tensions by Walden of a number of alkylammonium nitrates, thiocyanates, and halides. Most recently the chlorides have been studied by Kisza and Hawranek. The surface tensions of these salts are similar to those for organic liquids and they range from 20 to 50 dyn/cm. These... 

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