Liquid ammonia reactions

A number of synthetically useful reactions use this as solvent, and usually involve either the use of, or generation of strongly basic species. The usual quench for this type of reaction is to add carefully) an excess solid ammonium chloride, and then allow the ammonia to evaporate fume cupboard). 

In conclusion, the correct quench for a reaction is usually simple to determine, given that adequate consideration is given to the reagents used 

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In order for a metathesis reaction to occur in water, some product must be removed from the reaction. Generally, this involves the formation of a precipitate, the evolution of a gas, or the formation of an unionized product. Because solubilities are different in liquid ammonia, reactions are often unlike those in water. Although silver halides are insoluble in water, they are soluble in liquid ammonia as a result of forming stable complexes with ammonia. Therefore, the reaction... 

Liquid, determination of density and refractive index of, 1029-1034 Liquid ammonia, reactions in, 895-902 Liquids, partially miscible, 17-19 Liquids, supercooled, 22, 23 Liquidus, 26, 33... 

In contrast to the liquid ammonia reaction trisodiumphosphide, Na3P, is the major product resulting from the reaction of white phosphorus (red phosphorus, proved less satisfactory) with sodium potassium alloy or with sodium dispersions in inert organic media (e.g. toluene) at temperatures varying from 80 to 145 °C The phosphide Na3P reacts readily with methyl halides in glyme solvents to afford methylphosphorus compounds in ca. 60% overall yields under optimum... 

Formaldehyde diethyl dithioacetal can also be metalated by sodamide in liquid ammonia. Reaction of butyl bromide leads to an 84% yield of pentanal diethyl bisthioacetal 398,399... 

Final proof of the structure of tetrandrine came when the alkaloid was subjected to the sodium in liquid ammonia reaction (127, 133). The two products d-l-(4 -methoxybenzyl)-V-methyl-6,7-dimethoxy-l, 2,3,4-tetra-hydroisoquinoline (XXXIX) and d-l-(4 -hydroxybenzyl)-iV-methyl-6-methoxy-7-hydroxy-l,2,3,4-tetrahydroisoquinoline (XL) were isolated. It is thus evident that the structure of tetrandrine must be represented by XXX. However it was also proved (126) that isotetrandrine is represented by the same structure (XXX) and that its cleavage products are... 

Reaction of sodium with yttrium in liquid ammonia in the molar ratios 3 1 and 1 1 under pressure and at moderate temperatures gave Na3[Y(NH2) ] and Na[Y(NH2)4 ]. Y(NH2)3 was obtained from Na[Y(NH2)4,] and NH I, or from YI3 and KNH2 in liquid ammonia. Reaction of Y metal with ammonia under conditions different to those above gave YN. 

Inhibition of the reaction is also abserved for large concentrations of the complex, apparently due to ion pairing. The importance of considering ion-pairing in liquid ammonia reactions is evident since the conductivity of the solutions pass through a maximum and actually decrease during the two-step reaction... 

In order to study a bis[8]annulene compound with a divalent central metal atom we have synthesized and characterized the divalent ytterbium complex K2[Yb(CgHg)2]F K2[Yb(CgHg)2]r and its calcium analogue, K2[Ca(CgHg)2].51 These compounds were prepared by a reaction which utilizes the solubility of ytterbium and calcium metals in liquid ammonia. Reaction of cyclooctatetraene, potassium and either ytterbium or calcium, in liquid ammonia solution, gives the desired potassium salt of the complex dianion. 

Inorganic amides contain the ion NH2". They are formed by the action of ammonia on metals or by the ammonolysis of nitrides. The heavy metal amides are prepared by meta-thetical reactions in liquid ammonia, e.g. 

CH2C1 CH2C1. Colourless liquid with an odour like that of chloroform b.p. 84 C. It is an excellent solvent for fats and waxes. Was first known as oil of Dutch chemists . Manufactured by the vapour- or liquid-phase reaction of ethene and chlorine in the presence of a catalyst. It reacts with anhydrous ethano-ales to give ethylene glycol diethanoate and with ammonia to give elhylenediamine, these reactions being employed for the manufacture of these chemicals. It burns only with difficulty and is not decomposed by boiling water. 

In organic chemistry the term refers to compounds containing the NH2 ion or the > NH group. These are prepared by the action of heat on amides or by metathetica reactions in liquid ammonia. The heavy metal imides are explosive. 

By analogy, ammonium salts should behave as acids in liquid ammonia, since they produce the cation NH4 (the solvo-cation ), and soluble inorganic amides (for example KNHj, ionic) should act as bases. This idea is borne out by experiment ammonium salts in liquid ammonia react with certain metals and hydrogen is given off. The neutralisation of an ionic amide solution by a solution of an ammonium salt in liquid ammonia can be carried out and followed by an indicator or by the change in the potential of an electrode, just like the reaction of sodium hydroxide with hydrochloric acid in water. The only notable difference is that the salt formed in liquid ammonia is usually insoluble and therefore precipitates. 

This reaction also occurs slowly when sodium is dissolved in liquid ammonia initially a deep blue solution is formed which then decomposes giving hydrogen and sodium amide. 

Liquid ammonia, like water, is only a poor conductor of electricity. Ammonium salts dissolved in water behave as acids giving the ion NH4, whilst amides which give the ion NHj behave as bases. Thus the reaction ... 

Evidence for the solvated electron e (aq) can be obtained reaction of sodium vapour with ice in the complete absence of air at 273 K gives a blue colour (cf. the reaction of sodium with liquid ammonia, p. 126). Magnesium, zinc and iron react with steam at elevated temperatures to yield hydrogen, and a few metals, in the presence of air, form a surface layer of oxide or hydroxide, for example iron, lead and aluminium. These reactions are more fully considered under the respective metals. Water is not easily oxidised but fluorine and chlorine are both capable of liberating oxygen ... 

Cobalt has an odd number of electrons, and does not form a simple carbonyl in oxidation state 0. However, carbonyls of formulae Co2(CO)g, Co4(CO)i2 and CoJCO),6 are known reduction of these by an alkali metal dissolved in liquid ammonia (p. 126) gives the ion [Co(CO)4] ". Both Co2(CO)g and [Co(CO)4]" are important as catalysts for organic syntheses. In the so-called oxo reaction, where an alkene reacts with carbon monoxide and hydrogen, under pressure, to give an aldehyde, dicobalt octacarbonyl is used as catalyst ... 

VI,16. REACTIONS IN LIQUID AMMONIA. SOME ACETYLENIC COMPOUNDS ... 

The catalyst is finely-divided iron and is produced by adding a little crystallised ferric nitrate and a slight excess of sodium to liquid ammonia the reaction is probably ... 

The reaction between sodium acetylide in liquid ammonia solution and carbonyl compounds gives a-acetylenyl carbinols (compare Section 111,148), for example ... 

Monosodium acetylide may also be prepared by the reaction of acetylene with sodium In liquid ammonia ... 

Ccasionally the reaction mixture does not become completely black nor free from suspended solid here the acetylide is in an insoluble (or sparingly soluble) form, but it gives satisfactory results in the preparation of hex-l-yne. The saturated solution of the soluble form of mono-sodium acetylide in liquid ammonia at — 34° is about i- M. 

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