Addition ammonia

Sodium acetyllde. Replace the ammonia - addition tube by a wide tube reaching almost to the bottom of the flask (or use the device depicted in Fig. II, 7, 12, b) and pass acetylene (Fig. VI, 16, 1, c) into the suspension of sodamide in liquid ammonia maintain the bath temperature at about — 35° so that little ammonia is lost. Continue the passage of acetylene until a uniformly black liquid is formed (usually 4r-5 hours) (7). Carefully watch the wide gas entry tube if much solid collects inside this tube, remove it before the tube is completely blocked. Add liquid ammonia, if necessary, to restore the original volume (ca. 3 5 litres). 

The enyne system in the amines 828=88-8 8-882 can be reversed by potassium amide in liquid ammonia. Addition of the enyne amines to an equivalent amount of this reagent gives the potassium acetylides, K-8e8-88=88-8R2, from which the ynene" amines can be obtained in excellent yields by addition of solid ammonium chloride. 

Van der Plas et al. (86JOC1147) demonstrated that the formation of identical tautomeric 1,2-dihydropyrimidines 46a and 46a on amination of 5-nitropyrimidine is favored at a low temperature, while ammonia addition at room temperature produces the thermodynamically more stable 1,4-dihydro adduct 46b (Scheme 15). 

Alternative conditions for reductive decyanations can be used. The allylic ether in compound 26, an intermediate in a total synthesis of (-)-roxaticin, was prone to reduction when treated with lithium in liquid ammonia. Addition of the substrate to an excess of lithium di-ferf-butylbiphenylide in THF at -78°C, and protonation of the alkyllithium intermediate provided the reduced product 27 in 63% yield, as a single diastereomer (Eq. 7). a-Alkoxylithium intermediates generated in this manner are configurationally stable at low temperature, and can serve as versatile synthons for carbon-carbon bond forming processes (see Sect. 4). 

Ferrum purissimum (Merck) yielded, under the same working conditions, initially, 0.4% ammonia, but after a relatively short time this yield decreased to zero. An addition of 1.7% of sodium hydroxide to this pure iron resulted in yields up to 1.8% ammonia, additions of 0.6%... 

The lyases comprise enzyme class 4. They are enzymes cleaving C-C, C-0, C-N and other bonds by elimination, not by hydrolysis or oxidation. Lyases also catalyse addition to donble bonds. The types of reactions catalysed by lyases are decarboxylation (decarboxylase), hydration/dehydration (hydratase/dehydratase), ammonia addition/deamination (ammonia-lyase), cyanohydrin formation/cleavage (oxynitrilase),... 

L-aspartic acid by ammonia addition to fumaric acid by aspartase (from E. coli)... 

Cadmium salts form with ammonia addition compounds which correspond, for the most part, to those of zinc. 

The ammonia additive compounds of arsenic trihalides all react energetically on addition of cold concentrated sulphuric acid with formation of arsenic trilialides, a fact which Besson regards as evidence that the ammonia derivatives are true additive compounds. 

The first well-eharacterised ammonia additive derivative of chromium was prepared by Fremy in 185S.2 Shortly after, in 1802, the compound was examined by Cleve,3 who prepared a number of compounds of chromic salts and ammonia. He proved the composition of these substances and endeavoured, in so far as the knowledge of that time allowed, to explain their constitution. 

No ammonia additive compounds of chromous salts arc known, but certain salts unite with hydrazine, forming complex salts of the same type as the ammines. 

The ammonia addition compounds of cobaltous salts are unstable, and on that account there is no long series of these salts as in the ease of the ammino-cobaltie salts, where ammonia groups may be partially replaced by acidic groups, water, and other molecules, and where the complex is sufficiently stable to allow of different salts being prepared by double decomposition. 

Ammonium Azide Ammonates, Ammonium azide forms with ammonia addition products a)Monoammonate, NH4N3-NHa, its existence was established from a study of the system ammonium azide-ammonia (Refs 7 8) b) Diammonate, NH4Na 2NH3, clear, col elongated plates stable at -33°, but incapable of existence at 0° (Ref 7) c)Tetrammonate,... 

In a shallow aquifer, the oxidation of TCE and other chloroalkenes was compared under conditions of phenol or methane amendments (Hopkins, Semprini McCarty, 1993). The objective was to stimulate the growth and metabolism of bacteria comparable to P. cepacia G4 and M. trichosporium OB3b, respectively. It is possible, however, that the methane-stimulated bacteria expressed particulate (membrane-bound) methane monoxygenase, which is known to oxidize TCE much more slowly than sMMO (DiSpirito et al., 1992). Under the conditions used, the phenol stimulation led to greater removal of TCE and dichloroethylenes. Ammonia addition, thought to stimulate ammonia-oxidizing bacteria that oxidize TCE (Vanelli et al., 1990), showed the lowest extent of TCE oxidation in groundwater microcosm tests (Hopkins et al., 1993). 

The Htereoohemic Uy specific character of the reaction of amimv. with simple alkyl-substituted epoxides was established by Dickey and co-workers in an investigation of ammonia addition to ci - ami fraiw-2,3- poxybutane. Products of this condensation were found to tv threo- and eryiW3-amino-2-butanol respectively (Eq. 618). 

Various methods for lowering the concentrations of NO in combustion products have been proposed lowering the temperature,13 which decreases NO output from both sources introduction of ammonia additives,1, 15 which reacts readily with NO and use of a plasma jet of nitrogen atoms.16 In coal combustion the nitrogen oxide is removed in a heterogeneous reaction on the surface of the coal particles.17... 

Pure activated aluminas are also capable of catalyzing the skeletal isomerization of olefins (104, 105), but at considerably higher temperatures (350°-400°C) than those required for double-bond isomerization. The results obtained by Pines and Haag (105,106) leave little doubt that this type of isomerization is acid catalyzed. They found that (a) skeletal isomerization of cyclohexane or 3,3-dimethylbutene-l over pure alumina was poisoned upon ammonia addition and (b) the order of appearance of products from 3,3-dimethylbutene-l isomerization as contact time is increased was that predicted from carbonium ion theory. They also used indicator tests to show that the seat of acid activity in -y-alumina consists of Lewis, not Br0nsted, acidity. Independent infrared studies of pyridine chemisorbed on pure alumina have verified the existence of Lewis acidity and the absence of Brpnsted acidity in pure alumina (23, 107). 

Calorimetric data were consistent with the chemisorbed water being in a dissociated state before exposure to ammonia. Additional support for this view comes from NMR studies (244, 245), which showed that water adsorbed by montmorillonite is more highly dissociated than in the normal state. The average lifetime of a proton in a particular molecule is sufficiently short to suggest that the adsorbed water is 1000 times more highly dissociated than in the liquid state. 

Ammonia. Addition of concentrated ammonia may cause an explosion.2... 

The results of these calculations are summarized in Table II. Formal charges predict that all nitroquinolines should have their highest reactivity at C-2. This is not confirmed by the experimental results. By comparing the experimental results with the FMO calculations it became evident that the order of reactivity of the ammonia addition is in good agreement. Thus, the addition reaction is orbital-controlled (87JOC5643). 

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