Water and ammonia

Parks E K, Welller B H, Bechthold P S, Hoffman W F, NIeman G C, Pobo L G and Riley S J 1988 Chemical probes of metal cluster structure reactions of Iron clusters with hydrogen, ammonia and water J. Chem. Rhys. 88 1622... 

Unsubstituted Amides. The most widely used synthetic route for primary amides is the reaction of fatty acid with anhydrous ammonia (11). Fatty acid and ammonia are allowed to react at approximately 200°C for 10 to 12 h under a constant vent of excess ammonia and water by-product. A pressure of 345—690 kPa (50—100 psi) is maintained by the addition of ammonia while the venting of water faciUtates the completion of the reaction. 

Manufacture, Shipment, and Analysis. In the United States, sodium and potassium thiocyanates are made by adding caustic soda or potash to ammonium thiocyanate, followed by evaporation of the ammonia and water. The products are sold either as 50—55 wt % aqueous solutions, in the case of sodium thiocyanate, or as the crystalline soHds with one grade containing 5 wt % water and a higher assay grade containing a maximum of 2 wt % water. In Europe, the thiocyanates may be made by direct sulfurization of the corresponding cyanide. The acute LD q (rat, oral) of sodium thiocyanate is 764 mg/kg, accompanied by convulsions and respiratory failure LD q (mouse, oral) is 362 mg/kg. The lowest pubhshed toxic dose for potassium thiocyanate is 80—428 mg/kg, with hallucinations, convulsions, or muscular weakness. The acute LD q (rat, oral) for potassium thiocyanate is 854 mg/kg, with convulsions and respiratory failure. 

Ammonium pentaborate tetrahydrate is very stable ia respect to ammonia loss. On heating from 100 to 230°C, it loses 75% of its water content but less than 1% of the ammonia. At 200°C, under reduced pressure, the water content drops to 1.15 mol, but only 2% of the ammonia is lost (61). At still higher temperatures all ammonia and water are expelled to give boric oxide (125). 

Ammonium sulfate fertilizer is made by reacting ammonia with sulfuric acid. In many parts of the world, calcium sulfate is in mineral form convertible to ammonium sulfate by combining it with ammonia and water - a virtually limitless source of sulfur. 

Although the code is based on well-recognized models referenced in the literature, some of the underlying models are based on "older" theory which has since been improved. The code does not treat complex terrain or chemical reactivity other than ammonia and water. The chemical database in the code is a subset of the AIChE s DIPPR database. The user may not modify or supplement the database and a fee is charged for each chemical added to the standard database distributed with the code. The code costs 20,000 and requires a vendor supplied security key in the parallel port before use. 

A stream of ethylene oxide is passed through a solution of 107 g of 2-(p-chlorophenoxy)-2-methylpropionic acid and 2 g of zinc chloride in 200 ml of toluene, previously heated to between 55°C and 60°C, until 24 g of the gas have been dissolved. The reaction is allowed to continue for five hours, with gentle stirring. After this time has elapsed, the solution is cooled and washed successively with water, dilute ammonia and water until its pH becomes neutral. It is dried over anhydrous sodium sulfate, the solvent Is separated off under vacuum, and the resulting liquid is the monoglycol ester of 2-(p-chlorophenoxv)-2-methylpropionlc acid. 

To a solution of 93.8 g of the monoglycol ester in 500 ml of benzene, there are added 55 g of nicotinic acid chloride and 25 g of trimethylemine dissolved in 200 ml of benzene. The solution is stirred gently at a temperature of 60°C for two hours. After this time, the solution is cooled and washed successively with water, dilute hydrochloric acid, dilute ammonia and water until neutrality, it is dried over anhydrous sodium sulfate, and the sol vent Is evaporated under vacuum In this wey llOg of glycol 2-(p-chlorophenoxy)-2-methylpropionate nico-tlnate Is prepared, which represents a yield of 84%. The product is a sllghly yellow oil having a refraction index of no = 1.5422 and which is distilled with decomposition et 214°C at a pressure of 0.3 mm. 

Water, 15% hydrochloric acid, 10% sodium bicarbonate and finally water. The solvent was stripped off. The residual oil was mixed with 300 ml of 28% aqueous ammonia for 1 hour. The ammonia and water were vacuum distilled at a temperature of 40°C or less. Then 300 cc of carbon tetrachloride was added and the solution dried with sodium sulfate. The solution was cooled at 0°C and then filtered. The crystals were washed with cold carbon tetrachloride and vacuum dried. The yield was 57 g of dried product having a melting point of 55°C to 56.5°C. 

The two most common industrial absorption-type refrigeration systems are (1) aqua ammonia and (2) lithium bromide-water, with ammonia and water respectively the refrigerant for each system. 

At medium temperatures of 400 °F/205 °C (equivalent to 250 psig, 17 bar, and typical of slightly larger industrial boilers), CHZ decomposes without the production of IDS to form nitrogen, ammonia, and water (see equation 2). 

Ammonium salts of the zeolites differ from most of the compounds containing this cation discussed above, in that the anion is a stable network of A104 and Si04 tetrahedra with acid groups situated within the regular channels and pore structure. The removal of ammonia (and water) from such structures has been of interest owing to the catalytic activity of the decomposition product. It is believed [1006] that the first step in deammination is proton transfer (as in the decomposition of many other ammonium salts) from NH4 to the (Al, Si)04 network with —OH production. This reaction is 90% complete by 673 K [1007] and water is lost by condensation of the —OH groups (773—1173 K). The rate of ammonia evolution and the nature of the residual product depend to some extent on reactant disposition [1006,1008]. 

It is due to the already significant surface atom-molecule interaction present in the case of ammonia and water before reaction, when the molecules adsorb strongly through their respective molecular lone-pair orbitals. 

Figure 9-16 shows the molecular shapes of methane, ammonia, and water, all of which have hydrogen ligands bonded to an inner atom. These molecules have different numbers of ligands, but they all have the same steric number. 

These profiles clearly show that in the gas phase the alkylations of both ammonia and water by o-QM are assisted by an additional water molecule H-bonded to o-QM (water-catalyzed mechanism), since S4 and S5 TSs are favored over their uncatalyzed counterparts (SI and S2) by 5.6 and4.0 kcal/mol [at the B3LYP/6-311 + G(d,p) level], respectively. In contrast, the reaction with hydrogen sulfide in the gas phase shows a slight preference for a direct alkylation without water assistance (by 0.8 kcal/mol). 

The variation of enthalpy for binary mixtures is conveniently represented on a diagram. An example is shown in Figure 3.3. The diagram shows the enthalpy of mixtures of ammonia and water versus concentration with pressure and temperature as parameters. It covers the phase changes from solid to liquid to vapour, and the enthalpy values given include the latent heats for the phase transitions. 

The reactor residence time is about 45 minutes, a 95 per cent approach to equilibrium being achieved in this time. The ammonia is fed directly to the reactor, but the carbon dioxide is fed to the reactor upwardly through a stripper, down which flows the product stream from the reactor. The carbon dioxide decomposes some of the carbamate in the product stream, and takes ammonia and water to a high-pressure condenser. The stripper is steam heated and operates at 180°C, whilst the high-pressure condenser is at 170°C and the heat released in it by recombination of ammonia and carbon dioxide to carbamate is used to raise steam. Additional recycled carbamate solution is added to the stream in the high-pressure condenser, and the combined flow goes to the reactor. 

A liquid absorption process for the removal of SO2 involves the absorption of the S02 into a solution of ammonia and water with resultant formation of ammonium sulfide. The liquid is then sent to an oxidizing unit to form ammonium sulfate, which can be sold as a by-product or reacted with milk of line to regenerate the ammonia and produce gypsum.28... 

Figure 1.10 The tetrahedral, trigonal pyramidal, and angular geometries of the methane, ammonia, and water molecules based on the tetrahedral arrangement of four electron pairs.

As the one of the main end products of protein metabolism in living organisms, urea is a primary source of organic nitrogen in soil (from animal urine, fertilizers, etc.). Monitoring the level of urea is important for medicine, as well as for environmental protection. Urease is an enzyme that breaks the carbon-nitrogen bond of amides to form carbon dioxide, ammonia and water. This enzyme is widely used for determination of urea in... 

The method used here was essentially that described by Stober et al. (4) which involves the room-temperature hydrolysis of tetra-ethylsilicate in ethanol containing varying amounts of ammonia and water, the latter two components control the final particle morphology and size. The method has been modified slightly by Bridger (2,5) and by van Helden and Vrij (3). 

Desorption with hot air and decontamination with air and mixture of evaporated ammonia and water was realized in special glass desorber (figure 2). 

Treatment with air and mixture of evaporated ammonia and water. 

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