Sulfuric acid hydrates

Rate-determining protonation to give a vinyl cation rather than 1,4 addition of water has been proposed as the most consistent mechanism (25) for the acid-catalyzed hydration of arylpropiolic acids in aqueous sulfuric acid. Hydration of arylpropiolic acid closely resembles the acid-catalyzed isomeriza-... 

As may be seen from Table 21.8, the sulfuric acid hydrates are highly polar that implies [34-38] their active involvement in the strong dipole-charge interaction with atmospheric ions and substantial enhancement in nucleation rates due to the dipole-charge interaction. Further work is needed in order to quantify the effect of other atmospheric molecules and molecular clusters on ion nucleation rates. 

Combination of several molecules accompanied by relocation of a polyatomic radical The formation of sulfuric acid hydrate from-S -3 and H, of Nordhauser s oil of vitriol [H2S2O7] from anhydrous sulfuric acid and sulfuric acid hydrate, the production of hydrates of dibasic acids when water reacts with the anhydride, the formation of amino acids from the action of water on imiiies, and of amides when NH3 acts on imides, etc., belong here. For instance ... 

Several molecules are held together to become an indivisible molecule because the diatomic radical of sulfuric acid rearranges itself in such a way that one half of it takes the place of the typical hydrogen. This is by far the most common case it is exactly the same process which causes the formation of sulfuric acid hydrate from sulfuric acid anhydride and water, and the formation of Nordhauser s oil of vitriol from sulfuric acid anhydride and hydrate. For instance ... 

Naturally, aU metal chlorides elute before hydrochloric acid. When judging by the values of BtVo.os under similar conditions, the separation selectivity of FICl from metal chlorides increases slightly on all tested sorbents in the series K" " < Na < Li < Ca, along with the increase of the radius of the hydrated cations. In combination with the larger anion S04 - (Vdr = 3.79A), only polyvalent cations have a chance to significantly contribute to the separation. Indeed, Cu(II), Fe(II), and Al(III) sulfetes readily separate from sulfuric acid. Hydrated radii of these cations are estimated as 4.19, 4.28, and 4.75 A, respectively, according to which aluminum has the smallest breakthrough volume. 

IR studies of the H20+.Ne open-shell complex were consistent with a planar, translinear proton-bound H-O-H-Ne geometry. Vibrational spectra were calculated ab initio methods) for the potential energy minima of the H30 (H20)4 cluster. FTIR data were used to follow low-temperature interconversions of sulfuric acid hydrates, H3O+HSO4 and [H502+]2S04 " at a variety of water partial pressures. ... 

Infrared spectra from NASA s Galileo mission show distinct absorptions on Jupiter s moon Europa that have been attributed to one or more sulfuric acid hydrates. Sulfuric acid in solution with water causes significant freezing-point depression of water s melting point, down to 210 K, and this would make more likely the existence of liquid solutions beneath Europa s icy crust.The interpretation of the spectra is somewhat controversial. Some planetary scientists prefer to assign the spectral features to the sulfate ion, perhaps as part of one or more minerals on Europa s surface. 

Couling et al, 2003] S. B. Couling, K. J. Sully, and A. B. Horn. Experimental study of the heterogeneous interaction of SO3 and H2O Formation of condensed phase molecular sulfuric acid hydrates. Journal of the American Chemical Society 125 1994-2003. 

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 ). 

---