Neutral ammonium acetate

Both normal or neutral ammonium acetate [631-61-8], NH4C2H2O2, and the acid salt are known. The normal salt results from exact neutralization of acetic acid using ammonia the acid salt is composed of the neutral salt and acetic acid. 

The normal salt, CH COONH, is a white, deUquescent, crystalline soHd, formula wt 77.08, having a specific gravity of 1.073. It is quite soluble in water or ethanol 148 g dissolve in 100 g of water at 4°C. The salt s solubiUty in water increases only slightly as temperature increases up to about 25 °C. The specific gravity of aqueous neutral ammonium acetate ranges from 1.022 to 1.092 as solution concentration increases from 10 to 50 wt % (4). The normal salt melts at 114°C, but decomposes before reaching its boiling point. 

The artifacts possible with an ethanol-neutral ammonium acetate system are described by K. C. Towey and R. M. Roberts,/. Chromatogr., 47, 287 (1970). 

The use of brine as a solvent in the hydrometallurgical separation of lead from its ores was extensively studied by Lyon and Ralston (H8). Saturated sodium chloride solution and neutral ammonium acetate solutions were found to be good solvents for lead chloride and lead sulfate. Lead oxide and lead carbonate became soluble if the brine was first acidified with either sulfuric or hydrochloric acid. The dissolved lead was recovered electrolytically (S18). Marsden (M13) used this method in a process to recover lead from zinc plant residues. About 80% recovery of the lead was obtained by leaching at ambient temperature and the recovery of lead was increased to 98% when hydrochloric acid was added to the brine. 

In contaminated soils and sediments, thallium is largely mobile. Thallium is readily adsorbed by freshwater sediments, but quantitatively remobilized again with neutral ammonium acetate or neutral ammonium chloride (Sager. 1991). In the stream sediment of the Lenne near a smelter, Tl at a total of 2 mg/kg was found to be very immobile. Only 15% was dissolved by 1M HNO3, and less than 1% at pH > 2 (Gunther et al., 1987), thus indicating the input of non-processed ore material. 

Surprisingly, this effect is also occasioned by nearly neutral ammonium acetate. The yellow suspensions of the water-insoluble ammonium or potassium salts of phosphomolybdic acid are also affected in this way by OH donors. 

Ammonium acetate solutions formed by neutralizing acetic acid using ammonium hydroxide are essentially neutral. Thus, these solutions are suitable for standardization of electrodes, and for use as titration standards. Solutions must be used while fresh, however, as they become acidic on standing. 

Isolation of dry, normal ammonium acetate, prepared by neutralizing acetic acid with anhydrous ammonia or ammonium carbonate, is difficult because of ammonia loss during evaporation of water. Consequendy, commercial grades of ammonium acetate are often mixtures of the neutral and acid salts, or are suppHed as ammonium acetate solution [8013-61-4]. 

The acidic double salt of ammonium acetate and acetic acid [25007-86-7], CH COONH CH COOH, is made by dissolving the neutral salt in hot acetic acid or by distilling the neutral salt. During distillation the acid salt is formed as a heavy oil that solidifies on cooling. It crystallizes as long, dehquescent needles that melt at 66 °C. Acid ammonium acetate is readily soluble in both water and alcohol. 

The 1 2 metal complex dyes are dyed either at neutral pH or with ammonium acetate, and the exhaustion achieved by the effect of van der Waals forces. The pH is then aUowed to go slightly acidic to form salt linkages between the dye anion and the protonated primary amine groups in the wool (NH3 ). AU the dyes have similar dyeing properties and the conditions of appHcation do not damage the wool. 

Substituents in the 6-position (cf. 267) show appreciable reactivity. 6-Bromo-as-triazine-3,5(2j, 4j )-dione (316) undergoes 6-substitution with secondary amines or hydrazine, with mercaptide anions or thiourea (78°, 16 hr), with molten ammonium acetate (170°, 24 hr, 53% yield), and with chloride ion during phosphorous oxychloride treatment to form 3,5,6-trichloro-as-triazine. The latter was characterized as the chloro analog of 316 by treatment with methanol (20°, heat evolution) and hydrolysis (neutral or acid) to the dioxo compound. The mercapto substituent in 6-mercapto-as-triazine-3,5(2iI,4if)-dione is displaced by secondary... 

Reactions with aqueous solutions. Uniform dissolution or corrosion of metals in acid, alkaline or neutral solutions (e.g. dissolution of zinc in hydrochloric acid or in caustic soda solution general corrosion of zinc in water or during atmospheric exposure). Reactions with non-aqueous solution (e.g. dissolution of copper in a solution of ammonium acetate and bromine in alcohol). 

Either the Mohr titration or the adsorption indicator method may be used for the determination of chlorides in neutral solution by titration with standard 0.1M silver nitrate. If the solution is acid, neutralisation may be effected with chloride-free calcium carbonate, sodium tetraborate, or sodium hydrogencarbonate. Mineral acid may also be removed by neutralising most ofthe acid with ammonia solution and then adding an excess of ammonium acetate. Titration of the neutral solution, prepared with calcium carbonate, by the adsorption indicator method is rendered easier by the addition of 5 mL of 2 per cent dextrin solution this offsets the coagulating effect of the calcium ion. If the solution is basic, it may be neutralised with chloride-free nitric acid, using phenolphthalein as indicator. 

The precipitate is soluble in free mineral acids (even as little as is liberated by reaction in neutral solution), in solutions containing more than 50 per cent of ethanol by volume, in hot water (0.6 mg per 100 mL), and in concentrated ammoniacal solutions of cobalt salts, but is insoluble in dilute ammonia solution, in solutions of ammonium salts, and in dilute acetic (ethanoic) acid-sodium acetate solutions. Large amounts of aqueous ammonia and of cobalt, zinc, or copper retard the precipitation extra reagent must be added, for these elements consume dimethylglyoxime to form various soluble compounds. Better results are obtained in the presence of cobalt, manganese, or zinc by adding sodium or ammonium acetate to precipitate the complex iron(III), aluminium, and chromium(III) must, however, be absent. 

Ammonium acetates, 2 711-712 Ammonium alum calcination, 2 395 neutralization, 2 430 Ammonium benzoate, 3 634 Ammonium bicarbonate, 2 712-713 Ammonium bifluoride, 2 717-718 Ammonium bisulfate formation, 10 98 Ammonium bromide, 2 714... 

When chromatographic resolution of species based on modifications located at the protein surface is desired, it may be advisable to use conditions that favor retention of native conformation.17 Here, the standard acidic conditions described in the preceding text may be inappropriate, and mobile phases buffered near neutrality may be required. Buffers based on ammonium acetate, ammonium bicarbonate, and triethylammonium phosphate may prove more useful in resolving polypeptide variants with differing posttranslational modifications, amino acid substitutions, or oxidation and deamidation products. The addition of more hydro-phobic ion-pairing agents may be needed to obtain polypeptide retention, and a variety of alkyl sulfonates and alkyl amines have been described for specific applications.17... 

Thermospray (TSP) [29-31] unites three modes of operation. In pure TSP, a solution of the analyte and a volatile buffer, usually 0.1 M ammonium acetate, is evaporated from a heated capillary at a flow rate of 1-2 ml min into a heated chamber, hence the term thermospray. As the solvent evaporates, the analyte is forming adducts with ions from the buffer salt. While most of the neutrals are removed by a vacuum pump, the ions are extracted orthogonally from their main axis of motion by use of an electrostatic potential. The ions are transferred into a quadrupole mass analyzer through a pinhole of about 25 pm in diameter (Fig. 11.2). The quadrupole was employed according to its tolerance to poor vac-... 

Ammonium acetate is made by exact neutralization of acetic acid with ammonia to neutral pH (pH 7) ... 

Preparative, paper-chromatography is frequently used for further fractionation of the resulting mixtures. The high lability of glycosyl esters of nucleoside pyrophosphates seriously limits the choice of solvent systems. Systems used most commonly are neutral or slighdy acidic mixtures of ethanol with ammonium acetate,24,25 or weakly acidic solvents based on 2-methylpropionic acid.26 A solvent system containing morpholinium borate has also been found extremely useful.27... 

Synonym Neatsfoot Oil Necatorina Nechexane Neutral Ahhonium Pluoride Neutral Anhydrous Calcium Hypochlorite Neutral Lead Acetate Neutral Nicotine Sulfate Neutral Potassium Chromate Neutral Sodium Chromatetanhydrous Neutral Verdigris Nickel Acetate Nickel Acetate Tetrahyorate Nickel Ammonium Sulfate Nickel Ammonium Sulfate Hexahydrate Nickel Bromide Nickel Bromide Trihydrate Nickel Carbonyl Nickel Chloride Nickel Chloride Nickel Cyanide Nickel Iiu Fluoborate Nickel Fluoroborate Solution Nickel Fluoroborate Nickel Formate Nickel Formate Dihyorate Nickel Nitrate Nickel Nitrate Hexahydrate Nickel Sulfate Nickel Tetracarbokyl Nickelous Acetate Nickelous Sulfate Nicotine Nicotine Sulfate Nifos Nitralin Nitram O-Nitraniline P-Nitraniline Nitric Acid Nitric Acid, Aluminum Salt Nitric Acid, Iron (111) Salt Compound Name Oil Neatsfoot Carbon Tetrachloride Neohexane Ammonium Fluoride Calcium Hypochlorite Lead Acetate Nicotine Sulfate Potassium Chromate Sodium Chromate Copper Acetate Nickel Acetate Nickel Acetate Nickel Ammonium Sulfate Nickel Ammonium Sulfate Nickel Bromide Nickel Bromide Nickel Carbonyl Nickel Chloride Nickel Chloride Nickel Cyanide Nickel Fluoroborate Nickel Fluoroborate Nickel Fluoroborate Nickel Formate Nickel Formate Nickel Nitrate Nickel Nitrate Nickel Sulfate Nickel Carbonyl Nickel Acetate Nickel Sulfate Nicotine Nicotine Sulfate Tetraethyl Pyrophosphate Nitralin Ammonium Nitrate 2-Nitroaniline 4-Nitroaniline Nitric Acid Aluminum Nitrate Ferric Nitrate... 

With TSP, ammonium acetate has emerged as the best general-purpose electrolyte for ionizing neutral samples. Improved ionization can be obtained by the use of a filament or discharge electrode to generate reactive ions for CI (87, 88). The processes involved in filament or discharge-assisted ionization must be used when operating in the absence of a buffer with nonaqueous eluents. With ionic analytes, the mechanism of ion evaporation is supposed to be primarily operative since ions are produced spontaneously from the mobile phase (89). Ion evaporation often yields mass spectra with little structural information in order to overcome this problem, other ionization modes or tandem MS have been applied (90). 

Ammonium Acetate(Normal), CHsCOO.NH4, mw77-08 Wh deliq crysts, mp 114°, bp decomp, d 1.171 at 25°/4° (see Note). Sol in w ale, si sol in acet. Can be prepd by neutralizing acetic acid with ammonia or Amm carbonate. The commercial salt contains some acid salt (see below ). The pure salt is used as a lab reagent, etc... 

Alkylthio groups are sometimes replaced in nucleophilic substitutions, but such reactions are difficult in most neutral azoles. Thus, 3-alkylthio-l,2,4-thiadiazoles resist the action of aniline at 100°C, ammonia at 120°C, molten urea and ammonium acetate. However, hydrazine attacks... 

---