Perchlorate solutions

The most outstanding property of the perchlorates is their oxidising abiUty. On heating, these compounds decompose into chlorine, chlorides, and oxygen gas. Aqueous perchlorate solutions exhibit Httle or no oxidising power when dilute or cold. However, hot concentrated perchloric acid is a powerful oxidizer and whenever it contacts oxidizable matter extreme caution is required. The acidified concentrated solutions of perchlorate salts must also be handled with caution. Ammonium perchlorate [7790-98-9] (AP) is one of the most important perchlorates owing to its high (54.5%) O2 content and the... 

The ammonium perchlorate solution is spray-dried to the desired crystal size at air temperatures below 150°C and crystal temperatures of about 110°C. This procedure provides a pure product having a controlled grain size. Prior mechanical and thermal treatment affects the isothermal... 

Hydrolysis is very extensive in Pu(IV) solutions, less so in Pu(Ill) and Pu(VI), and least in Pu(V). The chemical properties of Pu(IV) are somewhat similar to those of Ce(IV) and U(IV) (see Cerium AND cerium compounds). The hydrolysis thermodynamics of Pu(IV) have been assessed in perchlorate solutions (105). The first hydrolysis equiUbrium is... 

Chemical Designations - Synonyms Dioxonium perchlorate solution Perchloric acid solution Chemical Formula HCIO4-H2O. 

Complete the following table fin aqueous perchlorate. solutions of barium... 

Lithium perchlorate solutions are thermally unstable and show explosion risks, especially in ethers [50, 51],... 

Aspects of the chemistry of cobalt(III) in aqueous perchlorate solution. G. Davies and B. Warn-quist, Coord. Chem. Rev., 1970, 5, 349-378 (85). 

Finally, in a recent study by Walling and El-Taliawi (216) it was shown that solvolytically generated vinyl cations may be reduced by Fe ions in solution to the corresponding vinyl radical. When 2-buten-2-yl triflate was solvolyzed in concentrated ferrous perchlorate solution in the presence of acrylonitrile monomer, polymerization of the acrylonitrile was observed. No such polymerization occurred under identical conditions in the absence of Fe ions. It seems that the polymerization of acrylonitrile was initiated by the vinyl radicals formed by reduction of the intermediate vinyl cation by Fe as follows (216) ... 

The effect of chloride ion on the exchange was found by these workers to be very small, whereas Plane and Taube had estimated a rate coefficient about five times larger in the presence of 10 M chloride ion than in perchlorate solution. Van der Straaten and Aten have studied the exchange in media 1 M with respect to HCl and have estimated a rate coefficient 3.0 x 10 l.mole". sec . The isotopic method ( Cr) and a separation procedure based on the precipitation of Cr(II) as the acetate complex was used. 

Oxidation potentials lead to a value of 7.9 x 10 for the equilibrium constant. Kinetic data for the reaction (from 0 to 55.6 °C) in acid perchlorate solutions (over the range 0.047-1.0 M) have been obtained spectrophotometrically by following the disappearance of V(V) (which absorbs strongly between 305 and 350 m/i) as a function of time. The second-order nature of the rate law... 

The stoichiometric equation for oxidation of vanadium(IV) by chromium(Vl) in acid perchlorate solutions is essentially... 

Although the oxidation of Cr(lII) by Ce(lV) is a rapid reaction in perchlorate solutions, the oxidation of Cr(III) by Co(III) in the same media occurs at a rate similar to or slower than that of the thermal decomposition of Co(lll) in perchloric acid (3 M). However, the Co(lII)- -Cr(III) reaction is subject to catalysis by Ag(I) ion and Kirwin et al have made a kinetic study of this system, viz. 

The reduction of Co(III) by Ag(I) in perchlorate solutions has been studied by Sutcliffe et al. Since the initial product of reaction is the very reactive Ag(Il) species, all solutions were subject to preliminary ozonolysis to remove traces of reducible impurities. The final products of reaction are Co(II) and Ag(l). Kinetic data were obtained spectrophotometrically by following the disappearance of Co(III) at 605 m/i, a small correction being applied for the absorbance of Co(ll). With Ag(I) in excess, the disappearance of Co(III) is second order, i.e., plots of the reciprocal of the corrected absorbance versus time are linear. The rate is directly proportional to the concentration of Ag(I), and inversely proportional to the square of the concentration of Co(II). These results can be understood in terms of the mechanism... 

U(VI) oxidises V(III) slowly in acid perchlorate solutions, the first step being... 

Heinje, G., Luck, W. A. P. Heinzinger, K. (1987). Molecular dynamics simulation of an aqueous sodium perchlorate solution. Journal of Physical Chemistry, 91, 331-8. 

The solvation property of the cations of this very polar aprotic solvent can make some salts more stable. Therefore, aluminium, sodium, mercury or silver perchlorate solutions are explosive. The same goes for iron (III) nitrate solutions. 

As in aqueous solution, the lanthanide contraction favors a change from nine-coordination for the light lanthanides to eight-coordination for the light lanthanides such that [Ln(DMF)8]3+ is the major species when Ln3+ = Ce3+-Nd3+, and that this becomes the only detected species when Ln3+ = Tb3+-Lu3+ in dimethylformamide perchlorate solution (11, 92, 93, 321-323). Thus, Nd3+ is characterized by AH° = -14.9 kJ mol-1, AS0 = -69.1 J K"1 mol-1, and AV° = - 9.8 cm3 mol-1 for the equilibrium shown in Eq. (25) (93). The molar volume of DMF is 72 cm3 mol- and it therefore appears that the substantially smaller magnitude of AV° is a consequence of significant... 

The hydrolysis of the zinc ion in varying anionic media has been investigated. In the pH range of 2.0 to 6.0 a dependence on the anion present is observed, with either sodium nitrate, sodium perchlorate, or sodium chloride at 0.5 M concentration. Only monomeric species were observed and [Zn(OH)]+(aq) was found in all three solutions while Zn(OH)2(aq) was only found in the perchlorate solution, demonstrating the effect of the anionic medium on the formation and stability of the hydrolytic species.339 ... 

Burkhart and Newton [J. Phys. Chem., 73 (1741), 1969] have studied the kinetics of the reaction between vanadium (II) and neptunium (IV) in aqueous perchlorate solutions... 

Schneider, 1984 Schneider and Schwyn, 1987 Schneider, 1988 Cornell et al., 1989). Perchlorate solutions that contain the dinuclear Fe2(OH)24+ to about 10 % of the total iron concentration can be kept unchanged for several weeks. This is by no means trivial, because it was recognized many years ago that solutions containing Fe2(OH)24+ to a significant degree are supersaturated with respect to solid phases such as FeO(OH) (Biedermann and Schindler, 1957). The low molecular species interact to produce species with a higher nuclearity (equation 7) ... 

Figure 1.5 The variation of precipitation times with molar ratios of a = HCO3 / Fe(III) for 0.6 M iron(III) perchlorate solutions, t is the somewhat arbitrarily defined time elapsed before a Tyndall effect is observed. (From Crichton, 1991.)...

Figure 2.J5 shows an image collected at —0.1 V in the perchlorate solution after the bulk deposition of several monolayers of Cu. 1 he Cu-Cu distance...

Figures 3.80(a) and (b) show the behaviour of n, k and the thickness L of a polypyrrole film during its growth on a Pt electrode in aqueous perchlorate solution obtained via in situ ellipsometry. A definite lag can be seen between the change in L and the changes in n and k. Up to c. 1.3 s the thickness of the film increases linearly with time while n and k remain constant. Between 1.3 and 2 s the growth almost tails off before increasing slowly up to 4 s and then more quickly until attaining a steady rate of increase at t > 4 s. Similarly at 1.3 s < t < 4 s both n and k increase, with n attaining a maximum value at 4 s before decreasing, while k increases at a lower rate at t > 4 s than at t < 4 s.

Aqueous perchlorate solutions, 18 274 Aqueous plugs, in microfluidics, 26 968 Aqueous polytetrafluoroethylene dispersions, 18 291 Aqueous potassium permanganate solutions, 15 597-600 Aqueous ring-opening metathesis polymerization (ROMP), 15 495... 

The acceptor properties of Ni2 + are weaker than those of Co2 + and under analogous conditions the extent of complex formation is smaller. When sodium azide is added to a 10 3 molar nickel (II) perchlorate solution in excess, the only azide-complex is monoazidonickel (II). The monochloro complex is present only in strong hydrochloric acid 81L Due to the low solvating properties of DMA even tetrachloronickelate (II) is found in such solutions. 

Figure 15. Cyclic voltammogratn on Pt(ll I) at 10 mV for various pH solutions of 0.8 - 4.6, when the respective anion concentration was kept at 0. M. (A) Sulfate solutions at [sulfate species] = O.IM. (B) Perchlorate solutions at [CIO4] = 0.1 A/. (C) Phosphate solutions at 0. M ionic strength of phosphate species. (From Ref. 62.)...

---