Ammonium applications

In general, the first step in virtual screening is the filtering by the application of Lipinski s Rule of Five [20]. Lipinski s work was based on the results of profiling the calculated physical property data in a set of 2245 compounds chosen from the World Drug Index. Polymers, peptides, quaternary ammonium, and phosphates were removed from this data set. Statistical analysis of this data set showed that approximately 90% of the remaining compounds had ... 

Aldehydes and ketones may be converted into the corresponding primary amines by reduction of their oximes or hydrazones (p. 93). A method of more limited application, known as the Leuckart Reaction, consists of heating the carbonyl compound with ammonium formate, whereby the formyLamino derivative is formed, and can be readily hydrolysed by acids to the amine. Thus acetophenone gives the i-phenylethylformamide, which without isolation can be hydrolysed to i-phenylethylamine. 

Dilute hydrochloric or sulphuric acid finds application in the extraction of basic substances from mixtures or in the removal of basic impurities. The dilute acid converts the base e.g., ammonia, amines, etc.) into a water-soluble salt e.g., ammonium chloride, amine hydrochloride). Thus traces of aniline may be separated from impure acetanilide by shaking with dilute hydrochloric acid the aniline is converted into the soluble salt (aniline hydrochloride) whilst the acetanilide remains unaffected. 

The method is generally applicable when other modes of esterification are either slow, inefficient, or likely to cause isomerisation it is, however, time-consuming and expensive. Small quantities of acid impurities are sometimes produced, hence it is advisable to wash the ester with saturated sodium bicarbonate solution. The silver salt can usually be prepared by dissolving the acid in the calculated quantity of standard ammonium hydroxide solution and... 

This reaction is applicable to many aliphatic acids and their ammonium salts. 

Quaternary ammonium salts as we have seen are useful m synthetic organic chem istry as phase transfer catalysts In another more direct application quaternary ammo mum hydroxides are used as substrates m an elimination reaction to form alkenes... 

Quaternary ammonium salts compounds of the type R4N" X find application m a technique called phase transfer catalysis A small amount of a quaternary ammonium salt promotes the transfer of an anion from aqueous solution where it is highly solvated to an organic solvent where it is much less solvated and much more reactive... 

Other Applications. Alkylhenzyl dim ethyl ammonium salts are made from alcohols in the find use as biocides and... 

Applications. Ammonium bifluoride solubilizes sihca and sihcates by forming ammonium fluorosilicate [16919-19-0] (NH 2 ip6 ... 

Ammonium Ion Removal. A fixed-bed molecular-sieve ion-exchange process has been commercialized for the removal of ammonium ions from secondary wastewater treatment effluents. This application takes advantage of the superior selectivity of molecular-sieve ion exchangers for ammonium ions. The first plants employed clinoptilolite as a potentially low cost material because of its availability in natural deposits. The bed is regenerated with a lime-salt solution that can be reused after the ammonia is removed by pH adjustment and air stripping. The ammonia is subsequentiy removed from the air stream by acid scmbbing. 

Table 1. Selected Quaternary Ammonium Compounds and Their Applications...

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Cerium(IV) ammonium nitrate in methanol has been used to oxidize phenazine to the mono-N-oxide (41) in good yield (75JCS(P1)1398), but no other reports on the application of this reagent to the pyrazine or quinoxaline series have appeared. 

An important extension of these reactions is the Mannich reaction, in which aminomethyl-ation is achieved by the combination of formaldehyde, a secondary amine and acetic acid (Scheme 24). The intermediate immonium ion generated from formaldehyde, dimethyl-amine and acetic acid is not sufficiently reactive to aminomethylate furan, but it will form substitution products with alkylfurans. The Mannich reaction appears to be still more limited in its application to thiophene chemistry, although 2-aminomethylthiophene has been prepared by reaction of thiophene with formaldehyde and ammonium chloride. The use of A,iV-dimethyf (methylene) ammonium chloride (Me2N=CH2 CF) has been recommended for the iV,iV-dimethylaminomethylation of thiophenes (83S73). 

Ammonium ion, JV-(2-thenyl)-N-benzyldimethyl-Stevens and Sommelet rearrangement, 4, 800 Ammonium salts, diallyldialkyl-polymerization, 1, 293 Ammonium salts, 2-pyrrolylmethyl-nucleophilic substitution abnormal, 4, 244 Sommelet rearrangement, 4, 244 Ammonium salts, trimethyl(l,3,5-triazinyl)-applications, 3, 525 Amobarbital, 3, 150 Amodiaquine, 1, 145 Amolanone applications, 4, 708... 

The application of ammonium molybdophosphate and other unsoluble in water salts of heteropolyacids for preconcentration of heavy metals of first group elements Cs(I), Ag(I), Cu(I) and also T1(I), Hg(I) (M(I)) is described. The shortcomings of ammonium molybdophosphate as ionexchanger are ... 

For some applications it is necessary that static charge should not accumulate on the product. This is important in such diverse applications as mine belting and gramophone records. The use of antistatic agents such as quaternary ammonium compounds has been of some limited value in solving this problem. 

Evaporators have performed successfully in a number of industrial applications. Typical materials that are processed in evaporators include Caustic Soda, Caustic Potash, Sodium Carbonate, Sodium Dichromate, Sodium Nitrate, Ammonium Nitrate, Phosphoric Acid Superacid, Potash, Urea, Glue, Glycerine,... 

Although the clam structures are of interest as ammonium ion binders, they are by no means the only azacrown compounds of interest in this application. Sutherland and coworkers have examined a number of azacrowns as primary ammonium ion bind-ers - . In addition, Metcalfe and Stoddart have utilized bis-azacrowns to bind secondary ammonium cations. 

The mono salt tends to produce needles while the di-basic salt results in crystals that are more granular. Ammonium phosphate finds application as a fertilizer. 

Benzyl and alkyl tnalkylsilyl ethers undergo clean fluonnation to give good yields of benzyl and alkyl fluorides, respectively, when reacted with a combination of d quaternary ammonium fluoride and methanesulfonyl orp- toluenesulfonyl fluoride. The reactions are applicable strictly to a primary carbon-oxygen bond, secondary and tertiary alkyl silyl ethers remain intact or, under forcing conditions, aie dehydrated to olefins [29] (equation 22)... 

Quaternaiy ammonium salts, as we have seen, aie useful in synthetic organic chemistry as phase-transfer catalysts. In another, more direct application, quaternaiy ammonium hydroxides aie used as substrates in an elimination reaction to fonn alkenes. 

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