Tetraalkyl ammonium halides

Reaction of Na2Se and Na2Sc2 with Se in the presence of ethanolic solutions of tetraalkyl-ammonium halides and catalytic amounts of I2 yields dark green or black crystalline polyselenides (jc = 3,5-9) depending on the conditions used and the particular cation selected. Tetraphenylphosphonium salts and crown ether complexes of alkali or alkaline earth cations in dimethylformamide solution can also be used. " )... 

The osmotic coefficients calculated from Eq. (9) can be brought into good agreement with solution data up to about 1M for aqueous solutions of alkali (26) and alkaline earth halides, (30) tetraalkyl ammonium halides, T3l) mixed electrolytes, where the Harned coefficients are measured, (32) and electrolyte-non electrolyte mixtures, where Setchenow coefficients are measured. 

Oxidations with chromium trioxide.6 Secondary alcohols can be oxidized to ketones in good yields by Cr03 in the presence of catalytic amounts of tetraalkyl-ammonium halides. Yields from oxidation of primary alcohols are moderate. 

AIR3 (Aluminum trialkyls and their complexes with alkali metals or tetraalkyl-ammonium halides, especially fluorides in aromatics or as melts). 

The polarographic method is widely applicable to the analysis of inorganic substances. Most metallic cations, for example, are reduced at the DME. Even the alkali and alkaline-earth metals are reducible, provided that the supporting electrolyte does not react at the high potentials required here, the tetraalkyl ammonium halides are useful electrolytes because of their high reduction potentials. 

Phase-transfer agents are the most popular catalysts for the Halex reaction with alkaline fluorides. All types of transfer agents have been claimed tetraalkyl-ammonium halides (refs. 34, 48), Aliquat 336 (ref. 49), branched pyridinium halides (eventually supported on a polymer) (refs. 50 to 53), tetraalkylphosphonium chlorides (refs. 42, 54 - 57) or bromides (ref. 12), crown-ethers (refs. 58, 59) eventually associated with Ph4PBr (refs. 43, 60), tris-(dioxa-3,6-heptyl)amine (TDA-1) (ref. 61) or polyethyleneglycols (PEG) (ref. 62). 

M kosza et al. have confirmed the strong catalytic effect of trialkylamines in the generation of dichlorocarbene and also of dibromocarbene. Actually, di-bromocarbene generated by catalysis with trialkylamines adds to 1-alkenes, a reaction that is not observed with dibromocarbene generated with tetraalkyl-ammonium halide catalysts. The authors have presented indirect evidence that dichlorocarbene reacts with a trialkylamine to form a basic salt that abstracts a proton from chloroform ... 

Transition metal carbonyl derivatives are the catalysts of choice for these catalytic reactions. However, they are not particularly active when used as such and they must be activated by the appropriate co-catalysts. The co-catalysts most commonly used by us in the synthesis of carbamates are neutral ligands, especially chelating ones, tetraalkyl ammonium halides and alkali metal halides. Their role will be discussed in the following paragraphs. 

End points, at a molar ratio of 1 1 in conductometric titrations of the hydrogen halides against tetraalkyl ammonium halides in liquid hydrogen sulphide, provide evidence for the formation of [HBrCl]" and [HCII] , but not for [HBrI] (fig. 1). Similar conductomeuic titrations have demonsuated the formation of the species [HCy, [HBr ] and [Hy. ... 

SOS/TDDFT y calculations have been carried out for tetraalkyl-ammonium halide/carbon tetrabromide complexes and have revealed rather large third-order NLO responses as a result of charge transfer contributions from the haUde donor to the CBr4 acceptor. 

Lindenbaum S, Boyd GE. (1964) Osmotic and activity coefficients for the symmetrical tetraalkyl ammonium halides in aqueous solution at 25°C. J Phys Chem 68 911-917. 

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