Alkylammonium alkylation

Figure 4. Arrhenius plot of log(viscosity) against TJT, where (a) shows the strong and fragile regions and (b) shows a close-up of the region occupied by the PILs. The PILs are categorized by their cation as either alkylammonium (Alkyl), imidazolium (Im), or heterocyclic (Het) and by their anion as either carboxylate (Garb), fluorinated (Fluor), or inorganic (Inorg). The legend in (b) is for both plots.

The addition of potassium, caesium, or tetra-alkylammonium (alkyl = methyl, ethyl, or n-butyl) salts has a marked effect on the rate of aquation of the tris-(5-nitro-l,10-phenanthroline)iron(n) cation. For a given concentration of added salt,... 

Symmetrical catanionic surfactants consist of anionic and cationic surfactants of the same chain length. Alkylammonium alkyl sulfates [such as decylammonium decyl sulfate (DeADeS), dodecylammonium dodecyl sulfate (DDADDS), and tetradecylammonium tetradecyl sulfate (TDATDS)] are prepared by mixing equimolar solutions of alkylammonium chloride and the corresponding alkyl sulfate. The reaction can be represented as... 

FIG. 2 Plots of ( ) the solid ctystaUine-soM crystalline and (O) solid crystalline-liquid crystalline transition temperatures and ( ) the temperature of isotropization as a function of the total number of C atoms, 2n, in molecules of symmetrical alkylammonium alkyl sulfate. 

Room temperature ionic liquids arc currently receiving considerable attention as environmentally friendly alternatives to conventional organic solvents in a variety of contexts.144 The ionic liquids have this reputation because of their high stability, inertness and, most importantly, extremely low vapor pressures. Because they are ionic and non-conducting they also possess other unique properties that can influence the yield and outcome of organic transformations. Polymerization in ionic liquids has been reviewed by Kubisa.145 Commonly used ionic liquids are tetra-alkylammonium, tetra-alkylphosphonium, 3-alkyl-l-methylimidazolium (16) or alkyl pyridinium salts (17). Counter-ions are typically PF6 and BF4 though many others are known. 

In this study, tetra-n-alkylammonium bromides ((n-Alkyl)4NBr, QBr) were used as the phase-transfer catalysts. The reaction will proceed in the catalyst-rich liquid phase in a way... 

Recently, the abilities of primary to tertiary alkylammonium ions with Me, Et, and -Bu groups to transport water to NB have been studied [48]. As the result of careful consideration of the ion-pair formation, it has been shown that the hydration numbers (w ) of the ammonium ions in NB, being little affected by the alkyl chain length, are simply dependent on the class of the ammonium ion % = 1.64, 1.04, 0.66, respectively, for the primary, secondary, and tertiary ammonium ions. 

The derivative-forming process in pyrolytic alkylation involves two sequential reactions deprotonation of the acidic substrate in aqueous solution by the strongly basic tetra-alkylammonium ion and the thermal decomposition of the quaternary M-alkylammonium salt formed to give a tertiary amine and alkyl derivative. For some weak acids both processes may occur virtually simultaneously in the injector oven of the gas chromatograph. 

Rao and Singh32 calculated relative solvation free energies for alkyl- and tetra-alkylammonium ions using same conditions as described before for neutral molecules (except, atomic partial charges were not scaled for ions). The values obtained with coordinate coupling were in better agreement with... 

Alkylation of P-dicarbonyl compounds and p-keto esters occurs preferentially on the carbon atom, whereas acylation produces the 0-acyl derivatives (see Chapter 3). There are indications that C- and 0-alkylated products are produced with simple haloalkanes and benzyl halides, but only C-alkylated derivatives are formed with propargyl and allyl halides [e.g. 90]. Di-C-alkylation frequently occurs and it has been reported that the use of tetra-alkylammonium 2-oxopyrrolidinyl salts are more effective catalysts (in place of aqueous sodium hydroxide and quaternary ammonium salt) for selective (-90%) mono-C-alkylation of p-dicarbonyl compounds [91]. 

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. 

ILs based on the l-alkyl-3-methyIimidazoIium cation, [C CiIm] , or tetra-alkylammonium cation, [(C )4N]l are among the most popular and commonly studied or used in technological improvements. As for the anions, l7is(trifluoromethylsulfonyl)imide, [Tf2N], and alkylsulfate, [C S04] (n = 1, ll 8), are much superior compared to the more commonly investigated hexafluorophosphate, [PFg] , and tetrafluoroborate, [BF4], being hydrolytically stable and less viscous. Comparing the results of the solubility of ILs in typical solvents from different publications, it can be concluded that the miscibility gap in the liquid phase increases in the order alcohol < aromatic hydrocarbon < cycloalkane < n-alkane [50-54,66,78,79,95-100,127-136]. 

The dichalcogenides of group VI do not readily form intercalates with organic molecules. But n-alkylammonium compounds can be prepared by ion-exchange reactions of the hydrated sodium intercalation compounds such as Na j(H20)o g M0S2. Alkylammonium compounds prepared by this route show lattice expansions that depend on the alkyl chain length, very similar to the MX2-n-alkylamine systems described above. This raises the fundamental question whether protonated amines are the actual intercalated species in both the cases, involving reduction of the host. In fact, this constitutes the basis of the new model for the intercalation reaction in MX2 proposed by Schollhorn (1980). 

The availability of formation constants for a large number of structurally diverse alkylammonium ions also encourages attempts to identify quantitatively those chemical features of a resident ligand species that are responsible for stability and selectivity within complexes of cucurbituril. In order to secure interpretable results, a subset of data was compiled, restricted to mono-substituted ammonium ions carrying exclusively alkyl or thioether residues [9]. Only included were moieties for which internal complexation with cucurbituril was established (NMR evidence) and for which substrate-specific overcrowding (such as with the arenes) was unlikely. A short list consisting of the first 24 guests in Table 1 was... 

Long-chain quaternary alkyl-ammonium phosphates (27) Quaternary alkylammonium and alkylpyridinium mercury amido-sulfonates (28)... 

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