Ferric hydroxide, preparation

Unless all the excess of ammonia has been driven off in the preparation of the neutral salt, the result obtained on adding ferric chloride will be misleading owing to the precipitation of ferric hydroxide. If this is suspected, the tests should be repeated using an aqueous solution of the pure sodium salts of these acids for comparison. 

Prepare the neutral ferric chloride solution (i.e., free from hydrochloric acid) by adding dilute sodium hydroxide solution dropwise to the bench reagent until a slight precipitate of ferric hydroxide is formed. Filter off the precipitate and use the clear filtrate for the test. 

Ferric ammonium citrate [1185-57-5]—A mixture of complex chelates prepared by the iateraction of ferric hydroxide with citric acid ia the presence of ammonia. The chelates occur ia brown and green forms, are dehquescent ia air, and are reducible by light. 

As described in U,S. Patent 2,575,611, 107 parts of freshly prepared ferric hydroxide are added to 295 parts of choline dihydrogen citrate dissolved in 200 parts of distilled water and heated to approximately 80°C until a homogeneous solution occurs. The resulting reddish brown solution may be used as such or it may be dried by evaporating the water,... 

The average adult body contains approximately 4 g of iron, of which roughly two-thirds exists in the form of hemoglobin. Treatment of certain types of anemias usually consists of dietary supplementation or the administration of therapeutic iron preparations by oral and parenteral routes. Iron is often administered by i.m. as iron-dextran complex which is ferric hydroxide and dextran containing 50 mg of iron per milliliter. 

Sugimoto, T. Sakata, K.(1992) Preparation of monodispersed pseudocubic a-Fe203 parti-des from condensed ferric hydroxide gel. 

If ferric hydroxide be prepared by the hydrolysis of ferric chloride the resulting colloid contains chlorine ions which can be replaced by more readily adsorbable picrate or eosinate ions leaving hydrochloric acid in solution. 

One of the earliest known chemical properties of ferric salts was their ready conversion to ferric hydroxide colloids in solutions. These solutions were intensively studied in the classic period of colloid chemistry, and their properties have been discussed in detail by Weiser (8). Since the focus of these studies was on colloid properties per se, precautions were taken to prepare pure colloids. Generally hydrolyzed solutions would be dialyzed extensively against distilled water to remove foreign ions. Even the purest preparations retained detectable concentrations of anions, consistent with a positive surface charge on the colloidal particles. 

In 1900 Sir William Crookes prepared a solution containing a uranium salt and a small amount of a ferric salt. When he added to this an excess of a solution containing ammonium hydroxide and ammonium carbonate, he found that the resulting ferric hydroxide precipitate was intensely radioactive. After studying the radioactive properties of the substance which precipitates with the iron, he said, For the sake of lucidity the new body must have a name. Until it is more tractable I will call it provisionally UrX—the unknown substance in uranium (30). It is now known as uranium Xi. H. N. McCoy and W. H. Ross, B. B. Boltwood, and R. B. Moore and H. Schlundt found independently that there are two uraniums, uranium 1 and uranium 2 (12, 48, 81, 108, 109, 110). 

Precipitation of ferric hydroxide gel was also observed in the preparation of spindlelike hematite (a-Fe203) particles in a dilute ferric chloride solution in the presence of phosphate (9). In this case, however, the positive role of the gel was not definite since similar uniform hematite paricles were obtained as well in homogeneous systems in the presence of the same anions (9). Also, Hamada and Matijevic (10) prepared uniform particles of pseudocubic hematite by hydrolysis of ferric chloride in aqueous solutions of alcohol (10-50%) at I00°C for several days. In this reaction, it was observed that acicular crystals of (3-FeOOH precipitated first, and then they dissolved with formation of the pseudocubic particles of hematite. The intermediate P-FeOOH appears to work as a reservoir of the solute to maintain an ideal supersaturation for the nucleation and growth of the hematite. Since the (3-FeOOH as an intermediate and the pseudocubic shape tire not peculiar to the alcohol/water medium... 

An impure sample of potassium ferrate, K2Fe04, may be prepared as follows Dissolve sufficient ferric chloride, FeCl3,6H20, to correspond to 40 g. Fe(OH)3 in 2 1. of hot water and precipitate the hydroxide with potassium hydroxide. Wash the precipitate repeatedly with hot water by decantation until nearly all chlorides have been removed and evaporate the suspended hydroxide to a volume of about 65 cc., bringing it into a porcelain dish that will hold about 250 cc. Break up 25 g. of solid potassium hydroxide into small pieces and add it to the ferric hydroxide, warming the mixture to insure solution. 

Ferric acetylacetonate was prepared in the usual way from freshly precipitated ferric hydroxide (m.p., 183.5°C. (d.) (corr). Found C, 50.8 H, 5.98 Fe, 15.48. Calculated for C15H21OeFe C, 50.9 H, 5.95 Fe, 15.8 weight %). N,N -Di-sec-butyl-p-phenylenediamine (DSBPD) was commercially available material (ICI Topanol M) redistilled (b.p., 105°C./0.05 mm.). Examination by infrared failed to detect any impurities. The first fraction obtained from the distillation contained p-phenyl-enediamine (2 weight % on total DSBPD). 

Colloidal saccharated iron is sometimes used in place of ferric hydroxide as an antidote in arsenical poisoning, but its adsorptive capacity depends on the alkalinity of the medium.4 Thus a commercial preparation containing 0-75 per cent, of sodium hydroxide was found to adsorb 12-57 per cent, of arsenious oxide (reckoned on the amount of iron present) addition of alkali increased the adsorption until, with 1-28 per cent, of sodium hydroxide present, there was a maximum adsorption of 27 per cent. The addition of acid correspondingly diminished the adsorption. A gel of ferric magnesium hydroxide, if prepared without boiling, also adsorbs arsenic from sodium arsenite solutions.5... 

Ferric orthoarsenite cannot be prepared directly from ferric hydroxide and arsenious oxide.4 The brown product obtained by shaking freshly precipitated ferric hydroxide with an aqueous solution of arsenious oxide has been described 5 as a basic ferric arsenite of composition 4Fe203.As203.5H20. A similar substance is obtained by adding aqueous arsenious oxide or sodium arsenite to ferric acetate solution. If ferric chloride, sulphate or nitrate is used, the ferric salt is not completely precipitated. The product is oxidised in moist air, and decomposes when heated. It is very doubtful whether this is a chemical individual, however, for it has been shown that the removal of arsenious oxide from the solution by the ferric hydroxide is due to adsorption, the amount removed depending upon the conditions and the age of the adsorbent. This subject is discussed more fully on p. 154. 

The potassium salt is best prepared by the action of chlorine on ferric hydroxide in basic medium. 

Daniel and Keulks (104) investigated Bi-Fe-Mo oxide catalysts prepared by reacting the a-bismuth molybdate with ferric hydroxide. Comparison of these catalysts with bismuth molybdate and ferric oxide indicated that mechanistically the Bi-Fe-Mo oxide catalysts resembled bismuth molybdate in their ability to form an allyl species. Under the same reaction conditions, the composition with Bi-Fe-Mo atomic ratio equal to 6 9 10 exhibited higher conversion than and the same selectivity as the bismuth molybdate catalysts. In contrast to bismuth molybdate, the Bi-Fe-Mo oxide catalysts were found to maintain their activity and se-... 

P roblem 3 How will you prepare the colloidal solutions of the following Arsenic sulphide, ferric hydroxide, gold, sulphur, silicic acid, carbon, iodine, mastic. (Meerut 2000)... 

Ferric hydroxide sol A colloidal solution of ferric hydroxide is obtained by adding a freshly prepared saturated solution of ferric chloride (2 or 3 ml) drop by drop to 500 ml of boiling distilled water. Ferric chloride hydrolyses to give a brown sol of ferric hydroxide sol. 

The isonitrile gold(I) nitrate ([AuI(N03)(CN-But)]) has been used to prepare Au/Fe203 89 the complex was added to a slurry of freshly precipitated ferric hydroxide in acetone. After removal of solvent and calcination (673 K), small gold particles (<4nm) were obtained with a loading of 3wt.% Au. 

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