Nitric stability diagram

The thermodynamics of nitric acid production based on ammonia can be represented well by the stability diagram shown in Eigure 6.4.3. If we recall Eq. (4.2.13), we know that the standard reaction Gibbs function ArG corresponds to the... 

Figure 6.4.3 Stability diagram of main reactions of nitric acid production based on ammonia.

It is convenient to use phase diagrams [46] to represent the thermodynamic properties that determine the stability and equilibrium composition of water-containing aerosols. The properties of interest are the temperature, the vapour pressure and composition of the various components in the condensed phases. This is particularly important with respect to the composition and stability of the various hydrates formed at low temperature in the nitric acid-water [47] and sulfuric acid-water binary systems [48], and the ternary systems HjSO/HNOj/HjO and HjSO/HCl/HjO [49],... 

Fig. 12.14. Flow diagram for the manufacture of nylon 66 yarn (1) air (2) cyclohexane from petroleum (3) reactor (4) recycle cyclohexane (5) still (6) cyclohexanol-cyclohexanone (7) nitric acid (8) converter (9) adipic acid solution (10) still (11) impurities (12) crystallizer (13) centrifuge (14) impurities (15) adipic acid crystals (16) dryer (17) vaporizer (18) ammonia (19) converter (20) crude adiponitrile (21) still (22) impurities (23) hydrogen (24) converter (25) crude diamine (26) still (27) impurities (28) nylon salt solution (29) reactor (30) stabilizer (31) calandria (32) evaporator (33) excess water (34) autoclave (35) delustrant (36) water sprays (37) casting wheel (38) polymer ribbon (39) grinder (40) polymer flake (41) spinning machine (42) heating cells (43) spinnerette (44) air (45) draw twisting (46) inspection (47) nylon bobbin. (Note Whenever the demand for liquid polymer at a spinnerette is large, as, for example, in the spinning of tire yarn, it is pumped directly from the autoclave.)...

Oxidized nitrogen forms anions nitrous and nitric acids, i.e., nitrates NOj and nitrites NO2. As diagram Eh vs. pH shows, the nitrate form of nitrogen is positioned along the upper limit of H O stability. The equilibrium between aquaphilic NOj and may be evaluated from a reaction ... 

Figure 4 shows the stratospheric particle zoo with all currently known or speculated transitions between diflTerent particles . Phases shown are either marked as liquid (1) or as a sulfuric acid hydrate (SAX, with X = M, T, H, etc., including the mixed hydrate MIX) or nitric acid hydrate (NAX, with X = T, D, P etc.). On the left hand side the diagram shows the stability regions of the solid phases under typical stratospheric conditions at 50 mbar (5 ppmv H2O, 10 ppbv HNO3). The right hand side of Fig. 4 shows transitions relating these phases. Thermodynamically allowed transitions that are also kinetically feasible are marked by an arrow (-+), while transitions which are thermodynamically allowed but kinetically so slow that they will not occur in the stratosphere are marked by crossed arrows ). 

---