The Role of Silver Nitrate Ion Pairs in the Alkyl Halide—Silver Nitrate Reaction

1965 ◽  
Vol 69 (2) ◽  
pp. 661-664 ◽  
Author(s):  
G. D. Parfitt ◽  
A. L. Smith ◽  
A. G. Walton
1975 ◽  
Vol 28 (4) ◽  
pp. 693 ◽  
Author(s):  
SD Hamann

Measurements have been made of the influence of hydrostatic pressure on the rates of three kinds of bimolecular substitution reactions of alkyl halides in solution. They are reactions with (a) halide ions in acetone solution (Finkelstein reactions), (b) silver nitrate in aqueous ethanol and (c) mercuric nitrate in aqueous dioxan. ��� The Finkelstein reactions were unsymmetrical with respect to the halogen atoms, for instance I- + PrCl → PrI+Cl-. They were all accelerated by an increase of pressure, in contrast to the sym- metrical exchange I*- + PrI → PrI* + I-, which is known to be retarded by an increase of pressure. This fact supports Gonikberg's view of the role of partial desolvation in the symmetrical reactions. Reactions involving LiCl as the source of halide ions were accelerated much more than those involving KI, simply because an increase of pressure enhances the dissociation of unreactive LiCl ion pairs. ��� Reactions of the types (6) and (c) were also accelerated by an increase of pressure, a fact which argues against a suggestion that the attacking species might be ion pairs.


2021 ◽  
Author(s):  
Maria A. Kokh ◽  
Clement Laskar ◽  
Gleb S. Pokrovski

<p>Knowledge of molybdenum (Mo) speciation under hydrothermal conditions is a key for understanding the formation of porphyry deposits which are the primary source of Mo. Existing experimental and theoretical studies have revealed a complex speciation, solubility and partitioning behavior of Mo in fluid-vapor-melt systems, depending on conditions, with the (hydrogen)molybdate (HMoO<sub>4</sub><sup>-</sup>, MoO<sub>4</sub><sup>2-</sup>) ions and their ion pairs with alkalis in S and Cl-poor fluids [1-3], mixed oxy-chloride species in strongly acidic saline fluids [4, 5], and (hydrogen)sulfide complexes (especially, MoS<sub>4</sub><sup>2-</sup>) in reduced H<sub>2</sub>S-bearing fluids and vapors [6-8]. However, these available data yet remain discrepant and are unable to account for the observed massive transport of Mo in porphyry-related fluids revealed by fluid inclusion analyses demonstrating 100s ppm of Mo (e.g., [9]). A potential missing ligand for Mo may be the recently discovered trisulfur radical ion (S<sub>3</sub><sup>•-</sup>), which is predicted to be abundant in sulfate-sulfide rich acidic-to-neutral porphyry-like fluids [10]. We performed exploratory experiments of MoS<sub>2</sub> solubility in model sulfate-sulfide-S<sub>3</sub><sup>•-</sup>-bearing aqueous solutions at 300°C and 450 bar. We demonstrate that Mo can be efficiently transported by S<sub>3</sub><sup>•-</sup>-bearing fluids at concentrations ranging from several 10s ppm to 100s ppm, depending on the fluid pH and redox, whereas the available data on OH-Cl-S complexes cited above predict negligibly small (<100 ppb) Mo concentrations at our conditions. Work is in progress to extend the experiments to wider T-P-composition range of porphyry fluids and to quantitatively assess the role of S<sub>3</sub><sup>•-</sup> in Mo transport by geological fluids.</p><ul><li>1. Kudrin A.V. (1989) <em>Geochem. Int. </em><strong>26</strong>, 87–99.</li> <li>2. Minubayeva Z. and Seward T.M. (2010) <em>Geochim. Cosmochim. Acta</em> <strong>74</strong>, 4365–4374.</li> <li>3. Shang L.B. et al. (2020) <em>Econ. Geol. </em><strong>115</strong>, 661–669.</li> <li>4. Ulrich T. and Mavrogenes J. (2008) <em>Geochim. Cosmochim. Acta </em><strong>72</strong>, 2316-2330.</li> <li>5. Borg S. et al. (2012) <em>Geochim. Cosmochim. Acta</em> <strong>92</strong>, 292–307.</li> <li>6. Zhang L. et al. (2012) <em>Geochim. Cosmochim. Acta</em> <strong>77</strong>, 175–185.</li> <li>7. Kokh M.A. et al. (2016) <em>Geochim. Cosmochim. Acta </em><strong>187</strong>, 311–333.</li> <li>8. Liu W. et al. (2020) <em>Geochim. Cosmochim. Acta</em> <strong>290</strong>, 162–179.</li> <li>9. Kouzmanov K. and Pokrovski G.S. (2012) <em>Soc. Econ. Geol. Spec. Pub.</em> <strong>16</strong>, 573–618.</li> <li>10. Pokrovski G.S. and Dubessy J. (2015) <em>Earth Planet. Sci. Lett. </em><strong>411</strong>, 298–309.</li> </ul>


2015 ◽  
Vol 17 (22) ◽  
pp. 5718-5721 ◽  
Author(s):  
Chengliang Li ◽  
Hongmei Deng ◽  
Chunju Li ◽  
Xueshun Jia ◽  
Jian Li

2016 ◽  
Vol 27 (4) ◽  
pp. 615-621 ◽  
Author(s):  
Caterina Fraschetti ◽  
Antonello Filippi ◽  
Maria Elisa Crestoni ◽  
Enrico Marcantoni ◽  
Marco Glucini ◽  
...  
Keyword(s):  

2013 ◽  
Vol 16 (special) ◽  
pp. 177-188
Author(s):  
Akram. O. Esmail ◽  
◽  
Hemn.O. Salih ◽  
Keyword(s):  

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