Ferrous chloride hydroxide

The importance of magnesium chloride has probably been exaggerated. There is little doubt that it can act as a catalyst in corrosion reactions by hydrolysing to form hydrochloric acid, being then regenerated by reaction between ferrous chloride and magnesium hydroxide. There is, however, little evidence that this reaction takes place in cold- or hot-water systems, and it is probably confined to steam boilers where it might be a cause of corrosive attack underneath scale deposits it does not constitute a problem in a properly conditioned boiler water. 

Schnepfe [83] has described yet another procedure for the determination of iodate and total iodine in seawater. To determine total iodine 1 ml of 1% aqueous sulfamic acid is added to 10 ml seawater which, if necessary, is filtered and then adjusted to a pH of less than 2.0. After 15 min, 1 ml sodium hydroxide (0.1 M) and 0.5 ml potassium permanganate (0.1M) are added and the mixture heated on a steam bath for one hour. The cooled solution is filtered and the residue washed. The filtrate and washings are diluted to 16 ml and 1ml of a phosphate solution (0.25 M) added (containing 0.3 xg iodine as iodate per ml) at 0 °C. Then 0.7 ml ferrous chloride (0.1 M) in 0.2% v/v sulfuric acid, 5 ml aqueous sulfuric acid (10%) - phosphoric acid (1 1) are added at 0 °C followed by 2 ml starch-cadmium iodide reagent. The solution is diluted to 25 ml and after 10-15 min the extinction of the starch-iodine complex is measured in a -5 cm cell. To determine iodate the same procedure is followed as is described previously except that the oxidation stage with sodium hydroxide - potassium permanganate is omitted and only 0.2 ml ferrous chloride solution is added. A potassium iodate standard was used in both methods. 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

Wastes containing complexing molecules such as EDTA can be treated by a coprecipitation with ferrous sulfate, ferrous chloride or dithiocarbamate, which is used in conjunction with the regular precipitant, such as sodium-hydroxide. The treatment scheme requires two reaction vessels. Sulfide precipitation can be also used for complexed metals treatment. 

Due to its symmetrical structure, pentaerythritol tetranitrate is characterized by high resistance to many reagents. Thus PETN, differing from the majority of nitric esters, is not readily decomposed by sodium sulphide at 50°C. On the other hand, it is decomposed quite quickly by boiling in a ferrous chloride solution. Boiling with a 2.5% solution of sodium hydroxide causes very slow decomposition, whereas nitrocellulose rapidly decomposes under these conditions. 

A variation of the above tests is that devised by Lenher.1Ms which depends on tho low solubility of certain metal ions in alkaline solution. Treatment of an epoxide with concentrator aqueous man ganoua chloride, for example, causes the gradual appearance of a manganous hydroxide precipitate as OH ions are liberated (Eq. SS i). Other halides examined by Lenher but found to he less effective wore nine chloride, ferrous chloride, and stannous chloride. 

Several theories have been advanced to explain this reaction. Ferrous chloride is formed at the outset, according to equation (1), while ferric hydroxide appears early in the reduction. At the end of the reduction the iron is almost completely in the form of Fe304. These two reactions may be explained by equations (2) and (3), and it is probable that the ferrous chloride catalyses both. 

A solution of 0.5 M ferrous chloride (FeCI2) and 0.25 M ferric chloride (FeCI3) (200 ml) was mixed with 5 M sodium hydroxide (200 ml) at 60°C by pouring both solutions to 100 ml of distilled water. The mixture was stirred for 2 min during which time a black, magnetic precipitate formed. After settling, the volume of the settled precipitate was approximately 175 ml. The concentration of iron oxide in the precipitate was about 60 mg/ml. The precipitate was then washed with water until a pH of 6-8 was reached. 

In the modern Hunt-Douglas process the ore is leached with dilute sulphuric acid, and the copper converted into cupric chloride by addition of ferrous chloride or calcium chloride. The use of the calcium salt entails removal of the calcium sulphate by filtration. The cupric salt is precipitated as cuprous chloride by reduction with sulphur dioxide, and the precipitate is converted into metallic copper by treatment with iron, or into cuprous oxide by the action of milk of lime. In this process the amount of iron needed is proportionately small, ferric hydroxide is not precipitated, and silver is not dissolved. 

The presence of gold in any of the precipitates described can be detected by solution in aqua regia, and reduction to metallic gold by various reagents, including ferrous chloride, ferrous sulphate, mercurous nitrate, stannous chloride, hypophosphorous acid, oxalic add,3 sulphurous acid, hydrogen peroxide and potassium hydroxide, formaldehyde, and hydroxylamine hydrochloride.4... 

Aqueous solutions of ferric chloride are conveniently prepared by dissolving iron in hydrochloric acid and subsequently saturating the solution with chlorine to oxidise the ferrous salt to the ferric condition. After standing, the solution should still smell of chlorine, otherwise sufficient of the gas has not been added. Excess may now be removed by bubbling carbon dioxide through the warm solution. Other methods of preparation consist in dissolving ferric hydroxide in aqueous hydrochloric acid and by oxidation of ferrous chloride in the presence of hydrochloric acid by some oxidiser such as nitric acid. 

On addition of a dilute solution of potassium permanganate to one of ferrous chloride, and subjecting to dialysis, the pure colloidal hydroxide is readily obtained.5 The sol is also obtained by oxidising a solution of ferrous chloride containing one gram equivalent of FeCl2 per litre with a 3 per cent, solution of hydrogen peroxide.6... 

A precipitate of ferric sulphide is also obtained when ammonium sulphide is added to a solution of a ferric salt, the alkali remaining in excess.4 If, however, the ferric salt is present in excess, the precipitate appears to consist of a mixture of ferrous sulphide and free sulphur. As obtained by either of the foregoing methods, the sulphide is hydrated and unstable in air. Dilute hydrochloric acid decomposes it completely into ferrous chloride, with evolution of hydrogen sulphide and a simultaneous deposition of sulphur. When boiled with water it yields ferric hydroxide and hydrogen sulphide. 

Another method 2 consists in passing the vapour of trimethylamine into a retort at red heat. The resulting products are passed into sulphuric acid, whereby ammonium cyanide is converted into hydrogen cyanide, which is now absorbed in potash to yield the corresponding cyanide. Ferrous hydroxide, prepared by addition of milk of lime to a solution of ferrous chloride, is added to the cyanide solution, and the liquid, after filtering, deposits a relatively pure crop of potassium ferrocyanide. 

Experiment 189. — (a) Put a few grams (3 to 5) of iron filings in a test tube, add about 10 cc. of dilute hydrochloric acid, and warm gently. Ferrous chloride is formed (in solution), (i) Pour a little into a test tube one-third full of sodium hydroxide solution. The precipitate is ferrous hydroxide. Watch the changes in color. To what are the changes due (2) Add a second portion to potassium ferricyanide solution. The precipitate is ferrous ferricyanide. Describe it. (3) Add a third portion to potassium thiocyanate solution. If ferric salts are absent, no change results. (4) Add a fourth portion to potassium ferrocyanide solution. The precipitate is ferrous ferrocyanide. Describe it. 

Chemical properties of iron. Passivity. Ferrous compounds ferrous sulfate, ferrous ammonium sulfate, ferrous chloride, ferrous hydroxide, ferrous sulfide, ferrous carbonate. Ferric compounds ferric nitrate, ferric, sulfate, iron alum, ferric chloride, ferric hydroxide, ferric oxide (rouge, Venetian red). Potassium ferro-cyanide, potassium ferricyanide, Prussian blue. 

To a solution of 24.4 g. (0.20 mole) of salicylaldehyde in 100 ml, of 95% ethanol are added 0.5 ml. of 2 If aqueous ferrous chloride solution and 0.1725 g. of platinum oxide catalyst [Org. Syntheses Coll. Vol. 1, 463 (1941)]. The mixture is shaken under a pressure of 3 atm, of hydrogen in a low-pressure hydrogenation apparatus [Org. Syntheses Coll. Vol. 1, 61 (1941)]. The absorption of hydrogen is complete in 1 hour. To the mixture is added 0.4 ml. of 1 iV aqueous sodium hydroxide solution, and the catalyst is recovered by filtration of the mixture. The solvent is removed from the filtrate by evaporation under vacuum, and the solid residue is recrystallized from 150 ml. of hot benzene. There is obtained a 92% yield of o-hydroxybenzyl alcohol as white crystals, m.p. 84.5-85°. 

Nitro-2-aminophenylarsinic acid (78 grams), in 900 c.c. of water and 480 c.c. of lOA sodium hydroxide solution, is well stirred and slowly treated with 20-6 per cent, ferrous chloride solution ( about 500 c.c.), the mixture being kept alkaline towards turmeric. After filtering and... 

The foregoing acids are crystalline solids, and in some cases may be crystallised from water. 5-Amino-2 4-dihydroxy-, 3 5-diamino-2-hydroxy-, and 4 5-diamino - 2 - hydroxyphenylarsinic acids reduce ammoniacal silver nitrate solution, the reaction being instantaneous with the latter two acids. 4-Acetylamino-8-hydroxy-2-nitrophenylarsinic acid, boiled with 2N sulphuric acid, yields 2 6-nitroaininophenol, but with potassium hydroxide the acetyl group is merely hydrolysed reduction of the acid with ferrous chloride produces the corresponding diamine. 3-Amino-4-hydroxyphenylarsinic acid tends to oxidise when recrystaUised from water, and when a cooled solution of the acid in 5 per cent, sodium hydroxide solution is treated with carbonyl chloride, it gives 1 2-dihydrobenzoxazolone-4-arsinic acid. 8-Amino-4-hydroxy-phenylarsinic acid also yields a number of N-acyl derivatives (see details on p. 296), the most important of which is the 8-acetylamino-compound,... 

In the presence of ferrous chloride, however, metallic iron reacts with water forming ferric hydroxide and liberating hydrogen which reduces the nitro benzene. The second stage of the reaction may then be written as follows ... 

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