Acidity ammonia

A new dimension to acid-base systems has been developed with the use of zeolites. As illustrated in Fig. XVIII-21, the alumino-silicate faujasite has an open structure of interconnected cavities. By exchanging for alkali metal (or NH4 and then driving off ammonia), acid zeolites can be obtained whose acidity is comparable to that of sulfuric acid and having excellent catalytic properties (see Section XVIII-9D). Using spectral shifts, zeolites can be put on a relative acidity scale [195]. An important added feature is that the size of the channels and cavities, which can be controlled, gives selectivity in that only... 

We selected liquid ammonia because of its pronounced solubilizing characteristics and powerful ionizing properties. At -33°C and atmospheric pressure, the pKa-value for auto-ionization of liquid ammonia [2NH3 = NH2 + NH4 ] is 34 and since the equivalent value for water is only 14, many substances (with pKa-values between 14 and 34) which are neutral in water should be capable of splitting off protons in liquid ammonia. Acidic... 

Because of the base strength of liquid ammonia, acids that are weak in water ionize completely in liquid ammonia. 

Use of a Pipe Reactor (Melt Granulation). A more recent development that has been adopted in most U.S. granulation plants involves the substitution of a pipe reactor or a pipe-cross reactor for the preneutralizer vessel as the locale for the ammonia-acid... 

The post-ammonia acidic conjugate fraction from rice is similarly complex by RP-TLC and further analyses are pending. The relatively lower abundance of polar, water-soluble metabolites from rice may be offset by formation of a methanol-insoluble... 

Acidity and acid strength distribution were evaluated by temperature-programmed desorption (TPD) of ammonia. Acid sites were classified as weak (W) Tj s < 300 °C, medium (M) 300 < Tjes < 450 °C, and strong (S) 450 < Tjes < 550 °C. ... 

Arylamines can undergo hydrolysis in acid or basic media to afford phenol and ammonia. Acid hydrolysis can be achieved under treatment with ZnCh, HCl, BF3, H2SO4 or H3PO4 at very high temperatures (equations 9-11). Arylamines with ortho or para electron-withdrawing groups can also undergo hydrolysis in basic media by treatment... 

Although the evolution of hydrogen from liquid ammonia acid solutions even on a metal with high overvoltage such as lead obviously demands a higher overvoltage than in water (approximate values of overvoltage 1.1-1.2 V for a current density of W -IO" A/cm in a 0.1 M ammonium chloride solution it nonetheless... 

The methyl 4,6-0-benzylidene-2, S-dideoxy-S-C-nitro-iS-D-er /i/iro- and -threo-hex-2-enosides can be prepared by a facile elimination of acetic acid from the appropriate 2-0-acetyl-3-deoxy-3-C-nitro compounds they add hydrogen, ammonia, acids, and alcohols to give pyranoside products having deoxy, aminodeoxy, acyloxy, and alkoxy groupings at C-2 A wide variety of 3-amino-3-deoxy sugar derivatives may therefore be synthesized from these unsaturated compounds. 

A 5 -P-borane-substituted thymidine monophosphate (68) and triphosphate (see Section 2) have been prepared from the boranophosphoramidate (69) which was obtained by reacting the thymidine 5 -(J-cyanoethylphosphoramidite with borane-diisopropylethylamine complex followed by treatment with ammonia. Acid hydrolysis of (69) gave the thymidine monophosphate derivative (68).The compound shows similar stability to normal nucleoside monophosphates, hydrolysis proceeding by P-0 rather than P-B cleavage. Acid phosphatase hydrolysed (68) to thymidine whilst the analogue was not a substrate for alkaline phosphatase. 

Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals (Ammonia, Acids and Fertilisers) LVIC-AAF... 

Properties Nondusting free-flowing beads sol. in lower alcohols, esters, ketones, alkalis dens. 9.3 Ib/gal vise. 65 cps (25% in water/ammonia) acid no. 59 flash pt. (PMCC) > 200 F... 

Ammonia is added to dust free, hot flue gas on the pressurized side of the blower. After passing through a regenerative heat exchanger (W4) the flue gas/ammonia mixture is treated in the first wash tower (B4) with a wash solution, formed by the ammonia, acidic components of the flue gas and water fed into the tower. Here the following reactions proceed simultaneously ... 

Since the proton affinity of hydrazine is similar to that of ammonia, acid-base reactions are similar to those in this solvent system. Many compounds are known to act as moderately strong acids, but only a few substances (notably the hydra-zides of the alkali metals) behave as bases. NaN2H3 may be obtained by drop wise addition of hydrazine to a suspension of finely divided sodium in dry ether. Electrolysis in liquid hydrazine gives nitrogen at the anode and hydrogen at the cathode . 

Just as in water, substances which produce ions (HjO ions in water) are acids and substances which produces NH ions are bases (OH ions in water). Thus all ammonium salts are acids and amides are bases in liquid ammonia. Acid-base neutralization reaction occur as in aqueous media. 

When treated with ammonia, acid chlorides are converted into amides. 

When treated with ammonia, acid chlorides are converted into amides. Two equivalents of ammonia are required one to serve as a nucleophile and the other to serve as a base. 

Plant solutions are normally prepared by dissolving metallic copper in a mixture of ammonia, acid, and water. The use of distilled water is desirable since chlorides or sulfates, which may be introduced with less-pure water sources, can result in corrosion. It is necessary to blow air into the dissolver to oxidize the copper to the cupric state, and the cupric copper that is formed is capable of dissolving additional elemental copper by oxidizing it to the soluble cuprous form. The reaction is also of value as a means of controlling the cupric/cuprous ion ratio in the solution as it is made. Careful control of ammonia and acid concentrations is also required. An excess of acid relative to aimnonia can cause the solution to become corrosive, while insufficient ammonia or acid can result in the precipitation of copper compounds. 

As sulfonic acids are strong acids, they present no difficulties during chromatography on paper, even when neutral solvents are used. Hence, they can be successfully chromatographed in basic ( -propanol-ammonia 2 1 /z-buta-nol saturated with ammonia), acid ( -butanol-acetic acid-water 4 1 5), and neutral solvent systems (tert-butanol-ethanol-water 4 3 3). 

European Commission, 2007. Integrated pollution prevention and control reference document on best available techniques for the manufacture of large volume inorganic chemicals— ammonia, acids and fertilisers. Retrieved from http //eippcb.jrc.es/reference/BREF/lvic bref 0907.pdf (accessed 05.10.12). 

---