Tris methylammonium salts

At this point the hygroscopic potassium salt may be isolated and dried, or, more conveniently, the potassium salt may be dissolved in water and the carborane anion precipitated with one of a variety of large cations, such as the rubidium, cesium, tetramethylammonium, or trimethylammonium ions. The tri-methylammonium salt of the carborane anion is useful because it is readily purified by recrystallization from water and may be easily converted in solution to salts containing other counterions. ... 

Many of the salts which have been prepared are explosive and sensitive to heat or impact. These include chlorites of copper (violent on impact), hydrazine (monochlorite, inflames when dry), nickel (explodes at 100°C but not on impact), silver (at 105° or on impact), sodium, tetramethylammonium, mercury, thallium and lead (which shows detonator properties). Several other chlorites not isolated and unstable in solution include mono-, di- and tri-methylammonium chlorites. The metal salts are powerful oxidants [1], Chlorites are much less stable than the corresponding chlorates, and most will explode under shock or on heating to around 100°C [2], Individually indexed compounds are ... 

The corresponding amine, (N3CH2)3CNH2, has been synthesized independently by two groups,and was converted into the tris(azidomethyl)methylammonium salts (Scheme 13.3). 

The medium impact-sensitivity of this solid propellant component is greatly increased by co-crystallisation of certain impurities, notably nitryl perchlorate, potassium periodate and potassium permanganate [1]. The presence of certain minimum amounts of mono-, di, tri- or tetra-methylammonium perchlorates in the salt leads to a single step decomposition, at around 290°C for the monoderivative [2],... 

As for solvents, liquid ammonia or dimethylsulfoxide are most often used. There are some cases when tert-butanol is used as a solvent. In principle, ion-radical reactions need aprotic solvents of expressed polarity. This facilitates the formation of such polar forms as ion-radicals are. Meanwhile, the polarity of the solvent assists ion-pair dissociation. This enhances reactivity of organic ions and sometimes enhances it to an unnecessary degree. Certainly, a decrease in the permissible limit of the solvent s polarity widens the possibilities for ion-radical synthesis. Interphase catalysis is a useful method to circumvent the solvent restriction. Thus, 18-crown-6-ether assists anion-radical formation in the reaction between benzoquinone and potassium triethylgermyl in benzene (Bravo-Zhivotovskii et al. 1980). In the presence of tri(dodecyl)methylammonium chloride, fluorenylpi-nacoline forms the anion-radical on the action of calcium hydroxide octahydrate in benzene. The cation of the onium salts stabilizes the anion-radical (Cazianis and Screttas 1983). Surprisingly, the fluorenylpinacoline anion-radicals are stable even in the presence of water. 

A quantitative assessment of the effects of head group bulk on, S k2 and E2 reactions in cationic micelles has been made.148 The kinetics of the acid-catalysed hydrolysis of methyl acetate in the presence of cationic, anionic, and non-ionic surfactants has been reported on.149 The alkaline hydrolysis of -butyl acetate with cetyltrimethylammonium bromide has also been investigated.150 The alkaline hydrolysis of aromatic and aliphatic ethyl esters in anionic and non-ionic surfactants has been studied.151 Specific salting-in effects that lead to striking substrate selectivity were observed for the hydrolysis of /j-nitrophenyl alkanoates (185 n = 2-16) catalysed by the 4-(dialkylamino)pyridine-fimctionalized polymer (186) in aqueous Tris buffer solution at pH 8 and 30 °C. The formation of a reactive catalyst-substrate complex, (185)-(186), seems to be promoted by the presence of tris(hydroxymethyl)methylammonium ion.152... 

Tris-(hydroxymethyl)methylammonium hydrochloride (TRIS-HCl) [1185-53-1] M 157.6, m 149-150 (dec). Crystallise the salt from 50% EtOH, then from 70% EtOH. TRIS-hydrochloride is also available commercially in a highly pure state. Otherwise, recrystallise it from 50% EtOH, then 70% EtOH, and dry it below 40° to avoid risk of decomposition. [Beilstein 4 H 304.]... 

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