Reid - Oil of Iron


THE PROCEDURE FOR MAKING THE OIL OF IRON

SINCE IT IS DIFFICULT, in fact almost impossible to obtain pure metallic Iron, it is preferable to commence the procedure by using C.P. (Chemically Pure) Ferrous Sulphate Crystals (Fe So4 7H2O), the Vitriol Salts of this metal. (Use Baker's Analyzed C.P. Ferrous Sulphate obtainable from any Chemical Reagent Supply House.) These Salts have already been purifled by several successive washings and recrystallization.

Using a Number 3 Porcelain Coors Crucible (glazed inside and outside) level full with the Ferrous Sulphate Crystals (five) calcine the Salts in the electric muffle furnace. Place the crucible containing the Salts in the cold furnace and then raise the temperature of the furnace to 1750 C. Continue the calcination until all fuming ceases and the iron is brought completely to a state of oxidation. This usually takes about two hours. A good supply of air should have access to the furnace. Remove the crucible and allow to cool to nearly room temperature. Transfer the oxide sponge to a glass mortar and triturate with a glass pestle to a fine powder.

Weigh out 14 grams (approximately one half ounce avoirdupois) of the powdered iron oxide and transfer to a Pyrex Beaker of about 800 ml. capacity and digest on the hot plate with 120 ml. of 6 normal Hydrochloric Acid until all the Iron oxide is in solution, adding more acid if neces sary to accomplish solution. Add 20 ml. of C.P. Nitric Acid (Specific Gravity 1.42) and boil for five minutes to bring all the Iron to the Ferric State. (Note: It cannot be assumed that the Iron Oxide product of the Calcination is in a uniform condition of oxidation.) Cool for a few minutes and filter the solution through a fast filter paper into a Pyrex Beaker of 2,000 ml. capacity, washing the filter paper with distilled water and allowing the washings to drain through this filter paper into the Beaker containing the main portion of the filtrate. Discard the filter paper and any residue remaining in it.

Make up the volume of the Solution in the Pyrex Beaker to 1,000 ml. Neutralize the Solution with 6 normal Sodium Hydroxide Solution (to make: Add to 250 gm. of Na OH, purified by alcohol, enough distilled water to make the volume 1,000 ml.) thus precipitative the Iron as Ferric Hydroxide, then add a slight excess of the 6 normal Sodium Hydroxide Solution. The solution containing the Iron should be stirred vigorously with a glass stirring rod during the preceeding operation. Still stirring vigorously, add 6. normal Hydrochloric Acid cautiously, using a dropper until the Solution is neutral or to the barest trace of acid reaction to litmus paper.

Make up the volume of the contents of the Pyrex Beaker to about 1,900 ml. with distilled water. Stir well and then allow the Ferric Hydroxide precipitate to settle for about an hour. Decant the clear Supernatant Solution. Again bring the volume of the contents of the Beaker to about 1,900 mi., stirring well as the distilled water is added, and allow to settle. Repeat this washing by decantation three or four times. (See Note 1.)

Heat the Solution, containing the washed Ferric Hydroxide precipitate, after the last decantation and without further addition of distilled water, to near boiling and filter through a hardened filter paper (Whatman No. 52 or No. 54) using vacuum with a Buechner Vacuum Filter Funnel and a Vacuum Filter Flask and finally washing any Ferric Hydroxide precipitate adhering to the wall of the Beaker into the Buechner Filter Funnel by means of a fine stream of distilled water from the wash bottle.

After the filtrate has been sucked through the Ferric Hydroxide cake into the Filter Flask, wash the Ferric Hydroxide cake in the Buechner with three consecutive 100 ml. portions of hot distilled water, taking great care to seal up with the end of a glass stirring rod all cracks which may develop in the Ferric Hydroxide cake, as they appear.

Maintain the vacuum in the Filter Flask after the last washing until the Ferric Hydroxide cake is free of excess water and is firm and solid. Remove the cake and filter paper by inserting the blade of a small spatula between the cake and the porcelain wall of the Buechner and running it around the periphery of the cake. Detach the Buechner Funnel from the Vacuum Filter Flask and invert the Buechner over a porcelain dish of sufficient diameter to receive the cake and filter paper and then jar these from the Buechner into the porcelain dish. Peal off and remove the hardened filter paper (this may be washed and used again) from the cake. Remove carefully any Ferric Hydroxide still adhering to the Buechner Funnel and add it to the main portion of the cake in the porcelain dish. Discard the filtrate and wash waters from the vacuum filtration.

Place the porcelain dish, containing the Ferric Hydroxide cake in the drying oven and dry at 225 deg. F. for about three hours. At intervals, as the drying proceeds, break up the cake in the dish with spatula or knife blade into smaller and smaller pieces until, finally, it has been chopped up into small pieces about the size of a match head. This will ensure proper drying. When the precipitate is finally quite dry, remove from the drying oven and allow to cool. Then transfer the dried material to a glass mortar and triturate it to a fine powder with the glass pestle.

Transfer the fine powder to a Pyrex Beaker of 400 ml. capacity. Add sufficient fuming C.P. Hydrochloric Acid (Specific gravity 1.18), to dissolve the powdered iron oxide (approximately 50 mi. should be sufficient).

Heat on the hot plate until all the solid material is in Solution. Pour the Hydrochloric Acid Solution, containing the Iron as Ferric Chloride, into a glazed porcelain evaporating dish (deep type) large enough to contain it and yet small enough to provide as small a surface area of the Solution as possible in the course of the evaporation to follow. (Use a Coors Slayed porcelain Dish 120 mm. Diameter. Height 50 mm.) No water may be used to wash any of the Ferric Chloride Solution adhering to the Beaker into the porcelain evaporating dish. Merely drain the contents of the Beaker into the dish. (See Note 4·) Evaporate the acid Ferric Chloride Solution slowly

NOTE 1·

The decantation is most easily performed by using the water vacuum pump with a

very slight degree of suction and by keeping the end of the rubber suction tube just below the surface of the clear supernatant solution. By watching the progrrss of the decantation through the wall of the Beaker, any suction of the precipitate through the tube when the solution level is approaching the top of the settled Fenic Hydmxide layer, may be avoided by raising the end of the suction tube and thus discontinuing the operation. This method is much easier and more effective than decantation by manipulation of the Beaker or "hand tilting."

NOTE 2· ETHER.

Use Ether Squibb (E R. Squibb & Sans, Nun York) for anesthesia in copper protected cans, holding 1 lb, net weight of Ether. This may be bought at a very low price from any wholesale Drug Company. I am sure it cannot be made on a small scale in the laboratory as cheaply as it may be bought wholesale.

Before using, rectify the Ether in a glass vessel (well stoppered) over anhydrous Potassium Carbonate, C.P. Ten or fifteen grams of Potassium Carbonate for each pound weight of Ether being rectified is sufficient. Let stand for 48 hours, shaking occasionally. Re-distill just before uaina.

NOTE 3. ETHYL ALCOHOL.

Use the U.S.P. 190 Proof Alcohol Distilled from Cane Ploducrs by th- Commercial

Solvents Corporaton, Agnen, California, if possible.

Redistill at 79" 80"C, to about 1/15th of original volume and rectify the distillate over Anhydmus Potassium Carbonate, C.P. using about 2'J gm. per litre of alcohol. Let

stand for 45 hours, shaking occasionally. Redistill at U40C before using.

NOTE 4· WATER.

All water used should be distilled water. It is absolutely essential that after the drying of the Ferric Hydroxide precipitate, no slightest trace of water should be allowed to enter into the procedure, and every precaution nmst be taken to prevent it so doing. Otherwise a proportion of the gross body of the Iron commensurate with the quantity of water present and with its solubility therein will be carried into the Ether Extract and will

not be thrown down in the subseguent procedures, for the reason that Ferric Chloride in solution with Hydrochlaric Acid in various degrees dilution with water, is soluble in Ether and subsequently in the alcohol added in the course of the distillations. Thus it will be present in the end product which will not be the true Oil of Iron.