Ammonia system

The alkali amides are stable, crystalline salts the heavy metal amides are often explosive. The amides are the bases of the ammonia system. 

Ammonia has low miscibility in mineral oils, alkylbenzenes, and polyol ester lubricants, particularly at low temperatures. A typical ammonia system uses a coalescing separator that removes all oil in droplet or aerosol form and drains it back to the compressor. Sometimes separators are equipped with some means of cooling the discharge gas to condense any oil that is discharged as a vapor. 

One concern in conventional processing is the achievement of uniform reagent appUcation and uniform cross-linking (18). An area in which adequate treatment of aU fibers is necessary is in flame-retardant finishing. One means of obtaining thorough treatment has been the use of vacuum impregnation, in which the fabric is first passed over a vacuum slot to remove air from the fabric interstices, foUowed by exposure to the phosphoms flame-retardant solution in the precondensate ammonia system (19). 

Toluene is a useful co-solvent in metal-ammonia reductions as first reported by Chapman and his colleagues. The author has found that a toluene-tetrahydrofuran-ammonia mixture (1 1 2) is a particularly useful medium for various metal-ammonia reductions. Procedure 8a (section V) describes the reduction of 17-ethyl-19-nortestosterone in such a system. Ethylene dibromide is used to quench excess lithium. Trituration of the total crude reduction product with methanol affords an 85% yield of 4,5a-dihydro-17-ethyl-19-nortestosterone, mp 207-213° (after sintering at 198°), reported mp 212-213°. For the same reduction using Procedure 5 (section V), Bowers et al obtained a 60% yield of crude product, mp, 196-199°, after column chromatography of the total reduction product. A similar reduction of 17-ethynyl-19-nortestosterone is described in Procedure 8b (section V). The steroid concentration in the toluene-tetrahydrofuran-ammonia system is 0.05 M whereas in the ether-dioxane-ammonia system it is 0.029 M. 

The lithium (or calcium) ammonia system apparently does not have severe conformational requirements, since a 17 -acetoxy-20-ketone reacts to give the... 

A typical pictorial flow diagram for the ammonia system is given in Figure 11-14 for a single-stage system and in Figure 11-15 for a two-stage ammonia system. 

Oil is not a real problem in centrifugal machines, except that its carry-through affects condensation in the condenser. In an ammonia system, the oil will setde out and can be purged from low points of the system, as receiver, evaporator, etc. 

Condensers for ammonia systems may have an oil trap, usually in the form of a drain pot, and the liquid outlet will be above this. 

Similar studies have been carried out (43) on the ammonia system in an attempt to detect the reaction ... 

In several systems studied the secondary ion is formed by more than one ion-molecule reaction. For example, we have found (43) that the NH4 + ion is formed in the ammonia system by the concurrent reactions ... 

A mercury manometer used with ammonia became blocked by deposition of a grey-brown solid, which exploded dining attempts to remove it mechanically or on heating. The solid appeared to be a dehydration product of Millon s base and was freely soluble in sodium thiosulfate solution. This method of cleaning is probably safer than others, but the use of mercury manometers with ammonia should be avoided as intrinsically unsafe [1,2]. Although pure dry ammonia and mercury do not react even under pressure at 340 kbar and 200° C, the presence of traces of water leads to the formation of an explosive compound, which may explode during depressurisation of the system [3], Explosions in mercury-ammonia systems had been reported previously [4,5],... 

Figure 15. Three pairing schemes for the ammonia system.

This example of the copper ion-hydroxide-ammonia system clearly demonstrates how complexation effects can either increase or decrease the solubility of a species of interest, and how such effects can be manipulated at the whim of the formulator. 

Melting Mechanisms of Crystals (Ubbelohde). Metal-Ammonia Systems, Structure and Properties of... 

Structure and Properties of Metal-Ammonia Systems (Das) Studies in the Kinematics of Isothermal Diffusion. A Macrodynamical Theory of Multicomponent Fluid Diffusion (Lamm). ... 

Are ammonia systems protected from possible damage by moving vehicles ... 

Here Va and are the true velocities at the entrance, of gas and liquid, respectively, and do is the critical droplet diameter. The value of the Wee depends on the degree of shock at the entrance section e.g., for smooth liquid injection, 22 was used, and for tee entrances, 13 to 16. Collier and Hewitt (C6) also measured entrainment in air-water mixtures, and have extended the same correlation to much wider ranges, using We — 13 in the case of jet injection with the results shown in Fig. 9. Anderson et al. (A5), during mass-transfer studies in a water-air-ammonia system, found en-... 

Pure Silica Ncinoparticles. Based on experiments conducted with the TEOS/ AOT/isooctane/water/ammonia system, and water-to-surfactant molar ratios in the range 5.7-15.8, Yamauchi et al. (20) prepared silica particles with diameters of 14-71 nm. Also using AOT, but with a different oil, i.e toluene, Espiard et al. 

The experimental data of Espiard et al. (21,22), based on the AOT/ toluene/water/ammonia system, showed an increase in particle size with increase in R. This observation led the authors to conclude that the droplet size of the microemulsion water pool was a key determinant of particle size. The effect of R on particle size was also investigated for silica nanoparticles synthesized in AOT/ decane/water/ammonia microemulsions (31). No particles were observed below about R = 4. However, as R increased from 5 to 9.5, the particle size also increased, in agreement with the observations of Espiard et al. (21,22). As noted previously (see Figure 2.2.3), in this microemulsion system, free water pools do not become... 

Fig. 2.2.16 Time evolution of the mean diameter of Si02 particles produced in the NP-5/cyclohexane/water/ammonia system at different R values. (From Ref. 29.)...

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