Ferric perchlorate

Ferric perchlorate (9H2O) [13537-24-1] M 516.3, pK -2.4 to -3.1 (for HCIO4). Crystd twice from cone HCIO4, the first time in the presence of a small amount of H2O2 to ensure that the iron is fully oxidised [Sullivan J Am Chem SocS4 4256 7962]. Extreme care should be taken with this preparation because it is potentially DANGEROUS. 

Heravi MM, Behbahani FK, Oskooie HA, Shoar RH (2005) Catalytic aromatization of Hantzsch 1,4-dihydropyridines by ferric perchlorate in acetic acid. Tetrahedron Lett 46 2775-2777... 

Loeppert, R.H. Hossner, L.R. Amin, P.K. (1984) Formation of ferric oxyhydroxides from ferrous and ferric perchlorate in stirred calcareous systems. Soil Sd. Soc. Am. J. 48 ... 

Metastability of Hydrolyzed Iron (III) Solutions The low solubility of ferric hydroxide has been alluded to in the Introduction. Feitknecht and Michaelis (29) have observed that aU ferric perchlorate solutions to which base has been added are unstable with respect to eventual precipitation of various forms of hydrated ferric oxides. In 3 M NaC104 at 25° C the two phase system reaches an apparent equilibrium after 200 hours, according to Biedermann and Schindler (6), who obtained a reproducible solubility product constant for ferric hydroxide at varying degrees of hydrolysis. It appears that many of the solutions used in the equilibrium studies of Hedstrom (9) and Biedermann (22) were metastable, and should eventually have produced precipitates. Nevertheless, since the measured potentials were reversible, the conclusions reached about the species present in solution remain valid. 

Diffusion control constant flux mode. Table P.3 contains the potential transient data obtained on a platinum working electrode (against SHE) immersed in an aqueous solution of 0.1 M ferric perchlorate and 1.0 M ammonium perchlorate. The experiment was carried out at a constant current of 10 mA/cm2, and the diffusion coefficient of both reactant and product is assumed to be 10 5 cm2/s. 

H. E. Roscoe s cupric salt is supposed to be cupric hexammino-diaquo-perchlorate, [Cu(NH3)4(H20)2](C104)2. Hydrated ferric perchlorate is likewise regarded as [Fe(H2O)0](ClO4.H2O)3. A number of organic perchlorates have been prepared by K. K. A. Hobold,27 R. Roth, and A. G. von Zedtwitz. 

When irradiated with UV light in aqueous solution, hydrated ferric ions are photoreduced to ferrous ions with the production of hydroxyl radicals. Thus, the photolysis (>290nm) of aqueous solutions of atrazine, ametryn, prometryn, and prometon in the presence of ferric perchlorate or ferric sulfate was greatly enhanced in comparison to direct photolysis (Larson et al., 1991). In the absence of oxygen or in stream water, photoreaction rates were... 

Table 2. Spectral properties of various simple hydroxamic acids in the presence of ferric perchlorate reagent (Gallup, P. M S. Seifter, M. Lukin and E. Meilman J. Biol. Chem. 235, 2619, I960).

Reaction of ferrous and ferric perchlorates with pyzNO (L) in EtOH-teof yields complexes of the formulas FeL3(ClC>4)2 (red) and FeL ClO (straw yellow), respectively (48,49). The ferrous complex, on exposure to moisture, adds on a molecule of water, turning orange. The resulting aquo complex shows IR bands characteristic of coordinated perchlorate (Table III). A number of Fe(II) and Fe(IH) complexes, containing donor molecules like mmpp, puHNO, phzNO, phzNC>2, quxNO, quxNC>2, and adH, have been proposed to involve unidentately or bidentately coordinated perchlorates (21, 35, 39-41, 53). 

Ferric perchlorate, Fe(C104)3, results on dissolving hydrated ferric oxide in perchloric acid. It has not been obtained in crystalline form. 

A solution of ferric perchlorate, containing free perchloric acid in order to repress hydrolysis, was shaken with finely divided silver until equilibrium of the system... 

Iron Perchlorate. The ferrous perchlorate and ferric perchlorate solutions were prepared as described by Kury (15). 

Salehi, P., Motlagh, A. R. Silica gel supported ferric perchlorate a new and efficient reagent for one pot synthesis of amides from benzylic alcohols. Synth. Common. 2000, 30, 671-675. 

Another application of the Debye-HQckel equations, involving an equilibrium between polyvalent ions, is worthy of mention because of its interast in another connection ( 45h). If a solution of ferric perchlorate, containing... 

Ferric perchlorate reagent. Stock 8.5 g of ferric perchlorate is dissolved in 20 ml of water and then made up to 250 ml with 72-73% perchloric acid. Working 45 ml of stock solution is added to 755 ml of absolute methanol prepare just before use... 

Distillation ofhydrazoic acid from strong acid solutions is the most common method of separation [12, 17], For small quantities of azide ion in relatively large volumes of solvent, evaporation in alkaline media or carrier precipitation is necessary for the preliminary concentration of azide ions prior to distillation. The distillations are usually made from perchloric acid solutions. A 50-ml round-bottom flask, with a side-arm attached (so that a stream of inert gas passes through the solution) and an air condenser is preferable for distilling hydrazoic acid. The addition of a diluent carrier gas provides added safety. Absorbing solutions for the hydrazoic acid include known, excess quantities of ceric ion. standard base, or a known quantity of ferric perchlorate for colorimetric determination of small quantities of azide ion. The distillation separation is complex and lengthy, but the method is reliable and has universal applicability. 

A 25-ml aliquot of 0.11 M ferric perchlorate solution is pipetted into a 250-ml beaker marked to indicate the 100-ml level, and 25 ml of distilled water is added. The pH is adjusted to 2.2 with 0.1 N perchloric acid or 0.1 N sodium hydroxide (carbonate-free), using a pH meter. A sample containing no more than 10 mg of azide is distilled into the ferric perchlorate. The solution is mixed and diluted to 90 ml with distilled water, the pH is checked, and the solution is transferred to a 100 ml volumetric flask and diluted to volume. The absorbance is measured at 460 nm against a ferric perchlorate blank. The amount of azide in the sample is calculated from a calibration curve made from standard sodium azide solutions ranging from 0.5 to 10.0 mg az.ide per 100 ml. 

Table 4J. Complex formation of inorganic anions with ferric perchlorate color-forming reagcntt [36].

Imanari et al. has reported a spectrophotometric detection of many inorganic anions using a post-column reactor [42]. A stream of ferric perchlorate, which is essentially colorless, is mixed with the column effluent. The ferric perchlorate is colorless because perchlorate is a poor complexing anion, but most anions will complex the iron and form colored species that can be detected at 330-340 nm (Table 4.3). A similar detection method works for ions such as orthophosphate, pyrophosphate, nitrilo-triacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA) [46]. 

Hydrous iron(in) oxide is readily soluble in acids but also to a slight extent also in strong bases. When concentrated solutions of strontium or barium hydroxide are boiled with ferric perchlorate, the hexahydroxo-ferrates(in), M3[Fe(OH)6]2, are obtained as white crystalline powders. With alkali-metal hydroxides, substances of composition IV FeOz can be obtained these can also be made by fusion of Fe203 with the alkali-metal hydroxide or carbonate in the proper stoichiometric proportion. Moderate concentrations of what is presumably the [Fe(OH)6]3 ion can be maintained in strongly basic solutions. 

The determination of formation constants may involve the photometric measurement of the complex formed in the presence of a large excess of one of the reagents, so that the formation of the complex may be considered to be essentially complete this is known as the method of mixtures of nonequimolar solutions. This method is based on Job s general equation [27, 28] for systems involving mixtures. The method has been applied to the determination of the dissociation constant of Fe(III)-sulfo-salicyclic acid mixtures in a pH 5.3 buffer, using sulfosalicyclic acid solutions 3, 5, and 8 times as concentrated as the ferric perchlorate. The best results were obtained by assuming that a 1 1 complex is formed, and was calculated to be 2 x 10" . 

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