Ferrous acid

Until recent years the only syntheses of 3-hydroxy quinoline involved multistep processes, the last step of which consisted of the conversion of 3-aminoquinoline to 3-hydroxyquinoline via the diazonium salt. " Small quantities of quinoline have been oxidized to 3-hydroxyquinoline in low yields by using oxygen in the presence of ascorbic acid, ethylenediaminetetraacetic acid, ferrous sulfate, and i)hosi)halc buffer. The decarboxylation of 3-hydroxycinchoninic, acid in boiling nitrobenzene has been re-... 

Chemical Designations - Synonyms Ferrous oxalate dihydrate, Ferrox, Iron protoxalate. Oxalic acid (ferrous salt) Chemical Eormula FeC204 2H20. 

Besides Fe-, other reducing agents that may be used in conjunction with H2O2 are aliphatic amines, Na2S203 thiourea, ascorbic acid, glyoxal, sulfuric acid, NaHSOs, sodium nitrite, ferric nitrate, peroxidase, AgNOs, tartaric acid, hydroxylamine, ethylene sulfate, sodium phosphite, formic acid, ferrous ammonium sulphate, acetic acid, ferrous sulphate, and HNO2, etc,... 

The liberated iodine may be titrated using std thiosulfate soln, or, in trace analysis, detd by spectrophotometric methods. Other reducing agents commonly used in peroxide analysis are hydriodic acid, ferrous, titanous, stannous, and arsenious ions. Also (recently), triphenylphos-phine, which is oxidized to triphenyl phosphine oxide. The excess triphenyl phosphine may be detd gravimetric ally, tit rime trically, or spectro-photometrically... 

Flydrochloric acid regeneration. This process is used to treat the spent pickle liquor containing free hydrochloric acid, ferrous chloride, and water that is obtained from steel finishing operations. The liquor is concentrated by heating to remove some of the water, followed by thermal decomposition in a roaster at temperatures (925 to 1050°C) sufficient for complete evaporation of water and decomposition of ferrous chloride into iron oxide (ferric oxide, Fe203) and hydrogen chloride (HC1) gas.19 The iron oxide is separated for offsite recovery or... 

When iron oxides dissolve in hydrochloric acid, ferrous chloride is formed according to the following reactions ... 

Synthesis of the 1,2-dihydrodiol of BcP by conventional methods was blocked by the failure of attempts to synthesize its potential synthetic precursors 1-keto-l,2,3,4-tetrahydro-BcP and 1,2-dihydro-BcP (66). However, BcP 1,2-dihydrodiol was obtained in low yield ( 1%) by oxidation of BcP with ascorbic acid-ferrous sulfate (66). 

The 10,11-dihydrodiol of MBA was synthesized from MBA by Method III (12). Hydrogenation of MBA over a platinum catalyst took place regiospecifically in the terminal ring to provide 8,9,10,11-tetra-hydro-MBA (75). Treatment of the latter with DDQ furnished 8,9-dihydro-MBA which underwent conversion to the 10,11-dihydrodiol by the usual procedures. Oxidation of MBA with ascorbic acid-ferrous sulfate to afford low yields ( <0.2%) of the five possible di-hydrodiols has also been described (76). 

Chen, E.C. McGuire, G. Lu, H.Y., "Vapor-Liquid Equilibria of the Hydroclhoric Acid Ferrous Chloride-Water System", J. Chem. Eng. Data, 1974, L5, 233... 

Blesa MA, Marinovich HA, Baumgartner EC, Maroto AJG. 1987. Mechanism of dissolution of magnetite by oxalic acid ferrous iron solutions. Inorganic Chemistry 26 3713-3717. 

Homogenization with NaOAc solution at 100°C for lOmin Enzymatic digestion with acid phosphatase, papain, amylase, glucosidase with addition of glyoxylic acid, ferrous sulfate solution and Gh at 37°C for 18h centrifugation ... 

E) Acid ferrous sulfate solution, 0.5N. Dilute 8g of ACS reagent grade ferrous sulfate hepta-hydrate (FeS04.7H30) to the mark in a 1000-ml volumetric flask with distd water. Add... 

Oxalic Acid, Diammonium Salt Oxalic Acid Dinitrile Oxalic Acid, Ferrous Salt Oxalonitrile Oxammonium Sulfate 3-Oxa-1,5-Pentanediol 2-Oxetanone Oxides of Nitrogen Oxirane... 

Breslin DT, Schuster GB (1996) Anthraquinone photonucleases mechanisms for GG-selective and nonselective cleavage of double-stranded DNA. J Am Chem Soc 118 2311-2319 BrodieBB, Axelrod J, Shore PA, Udenfriend S (1954) Ascorbic acid in aromatic hydroxylation. II. Products formed by reaction of substrates with ascorbic acid, ferrous ion, and oxygen. J Biol Chem 208 741-750... 

The HA polymer can be degraded nonenzymatically by a free radical mechanism,226 particularly in the presence of reducing agents such as thiols, ascorbic acid, ferrous, or cuprous ions. This mechanism of depolymerization requires the participation of molecular oxygen. The use... 

Pyrites occurs in rocks of all ages, both eruptive and sedimentary. In some cases it is evidently an original mineral, whilst in others it has been formed as a secondary product. Large quantities are found in Spain and are used in the manufacture of sulphuric acid, ferrous sulphate, and ferric oxide. 

With more dilute acid ferrous nitrate is apt to be formedL. See p. 175. 

Bromine attacks it at red heat with incandescence chlorine is less vigorous in its action, whilst iodine and hydrogen iodide have no action, even at 1100° C. The chlorate and nitrate of potassium do not affect it at their melting-points, but at higher temperatures decompose it with incandescence. Fused alkali hydroxides and carbonates decompose it rapidly. Concentrated sulphuric acid is without action in the cold, but with the boiling acid ferrous sulphate is produced. Dilute nitric acid dissolves it when hot, and the concentrated acid acts vigorously. Dilute hydrochloric acid is without action, and the hot concentrated acid acts only slowly. 

Figure 4 Change in pH as a function of the amount of pyrite oxidized under four scenarios (i) pyrite oxidizes to an acid ferrous sulfate solution without any further oxidation (solid line) (ii) pyrite oxidizes and the resultant ferrous sulfate solution is allowed to oxidize, hut no precipitation is allowed (upper dashed line) (iii) pyrite oxidizes, the ferrous sulfate solution oxidizes and precipitates ferrihydrite (p-Ksp = 4.89, lower dashed line) and (iv) pyrite oxidizes, ferrous sulfate solution oxidizes, and goethite precipitates (dotted line). Computed with PHREEQCI at 25 °C and 1 har, thermodynamic data from Nordstrom et al. (1990).

The following descriptive material concerns the solubility of iron in the reduced form (ferrous iron, Fe ) and the oxidized form ferric iron, Fc ). In a solution of strong acid, ferrous iron exists as a complex with water, Fe(M2D)h The complex contains six molecules of water. At higher pH, some of the protons of the complex are released, generating Fe(OH)2. Fe(OH)2 is pale green and, if present at sufficiently high concentrations, can form a gelatinous precipitate. Its maximal solubility at pH 7 is about 0.1 M. Hence, this form of iron is fairly soluble at neutral pH. 

Lacey, D.T. and Lawson, F., 1970. Kinetics of the liquid-phase oxidation of acid ferrous sulfate by the bacterium Thiobacillus ferrooxidans. Biotechnol. Bioeng., 12 29—50. 

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