Anhydrous ferric oxide

To test this approach, 5 g samples -300 mesh Tyler, of a low-rank vitrinite, were stirred for 6 hrs in liquid ammonia (150 ml -33°C) containing 5 gms of potassium amide and 5 g of sodium amide. (The amides were formed in the medium, before introducing the coal, by action of anhydrous ferric oxide (1 g) or ferric chloride (1.5 g) on alkali metals.) Thereafter, 100 ml of anhydrous ethyl ether was added, the suspended coal material ethylated with C2H5Br (32 ml), and the reaction mixture stirred until all ammonia and ether had evaporated. Following... 

English red consists essentially of anhydrous ferric oxide in very fine powder, more or less deep red in colour. It usually contains small quantities of silica and silicates, alumina, lime and magnesia, and often sulphates, chlorides and free sulphuric acid it may also contain manganese and copper. It is often sold mixed with considerable proportions of gypsum (Venetian red), barium sulphate and chalk sometimes its colour is heightened or modified by addition of artificial organic colours. 

Immense deposits of a variety known as red fossil ore occur in the United States, containing from 30 to 50 per cent, of iron and from 0-4 to 0 7 of phosphorus. Red ochre is another form of anhydrous ferric oxide, but the term is also used for a variety of turgite. 

Red haematite has been found at Torquay, apparently pseudo-morphic with pyrites, which is remarkable, for, although pyrites is frequently oxidised to limonite, it is indeed rarely that it is converted into anhydrous haematite. It is suggested that pyrites was converted into ferric chloride by the action of sea water, and that this reacted with limestone to yield anhydrous ferric oxide 4 in some such manner as that indicated above. 

The heats of formation of anhydrous ferric oxide below 400° C. are given as follow —... 

Polymorphism of Ferric oxide.—The yellow colour in certain bricks is stated to be due to a yellow modification of anhydrous ferric oxide rendered stable by alumina.6... 

When iron is attacked by fused sodium peroxide, dark red, tabular crystals of a monohydrate, Fe203.H20, are obtained, of density 3 8 at 27° C. The hydrate is magnetic, and when heated to low redness a magnetic form of anhydrous ferric oxide is obtained.3... 

Gravimetric Methods.—If the iron is already in solution, it is first oxidised to the ferric condition and precipitated as ferric hydroxide by addition of ammonia to the boiling solution. The precipitate is well washed, dried in an oven, ignited in a crucible, and weighed as anhydrous ferric oxide, Fe203. 

The formation of diphenyl on oxidation of phenyl magnesium bromide by anhydrous ferric chloride has been known for some... 

The homopolymerization ofl consists of a room-temperature reaction of the monomer dissolved in nitrobenzene in the presence of anhydrous ferric chloride. Polymerizations were carried out under a stream of dry nitrogen. As depicted in Scheme 2, the homopolymerization of 1 to form 6FNE takes place by means of the Scholl reaction. The mechanism of the Scholl reaction was assumed to proceed through a radical-cation intermediate derived from the single-electron oxidation of the monomer and its subsequent electrophilic addition to the nucleophilic monomer. The reaction releases two hydrogens, both as protons, to form the... 

Towards metallic oxides the behaviour of thionyl chloride is similar to that of sulphur monochloride, which is perhaps hardly surprising in view of the course of its thermal decomposition. The reaction is fairly general, the oxide being converted into the corresponding anhydrous chloride. From the action of the chloride on zinc oxide (at 150° C.), cadmium oxide (at 200° C.), arsenious oxide (up to 200° C.), antimony trioxide (at room temperature), bismuth trioxide (at 150° to 200° C.), ferric oxide (at 150° C.), magnesium oxide (at 150° to 200° C.), cupric oxide (at 200° C.) and cuprous oxide (at 200° C.), it may be concluded that the main reaction, assuming a bivalent metal, M, is as follows ... 

Red ochres, which occur naturally but are more often obtained by calcining the yellow forms, are analogous in composition, excepting that the ferric oxide is wholly or partially anhydrous. 

The oxidation of 90 was effected with anhydrous ferric chloride in ethanol, affording the neutral d7 nickelacarborane [ctoso-3-(ic2-PhBp)-3,l,2-C2B9HH] (90), which was found to be isostructural with its anionic congener. 

Oxidative dimerization of A,A-dialkyl-<9-(8-lithio-7-quinolyl)carbamates with anhydrous ferric chloride has been shown to be efficient for the preparation 1,1 -dioxygenated 8,8 -biquinolyls (Scheme 61) and it is anticipated that this tandem halogen-dance oxidative dimerization reaction will find further applications for the synthesis of other highly substituted biaryl molecules.96... 

The haematites consist essentially of ferric oxide, Fe203, and may be divided into two groups according as they are anhydrous or contain... 

When ferric acetate solution is exposed to hydrogen gas at 850° C. and under 230 atmospheres5 pressure, ferric oxide is precipitated as an anhydrous red mass, insoluble in water but soluble in hydrochloric acid. At 400° C. and under a pressure of 420 atmospheres, metallic iron is obtained.1... 

Ferric oxide is also prepared from liquors containing ferric salts in solution, and which are otherwise waste products in many manufacturing processes. If ferrous salts are present, they are first oxidised by addition of nitric acid or bleaching powder. The acid is neutralised by addition of soda or lime, ferric hydroxide being precipitated. The washed product is finally dehydrated by heat, becoming perfectly anhydrous at 500° C. upwards.5... 

The anhydrous salt, FeS04, is extremely difficult to prepare in a state of purity. It results, more or less contaminated with a basic salt,6 when any hydrate is heated in vacuo to a temperature somewhat above 140° C. It is stated also to result when the heptahydrate is dissolved in concentrated sulphuric acid.8 It then separates as microscopic prisms. It is white in appearance, insoluble both in alcohol and in concentrated sulphuric acid- Its heat of solution 6 m water is 14,901 calories at 13-5° C. Density 2-841. At dull red heat it decomposes, yielding first a basic sulphate and finally ferric oxide. Thus —... 

Iron diselenide, FeSe2, is prepared by heating anhydrous ferric chloride to dull red heat in hydrogen selenide.3 When ignited in oxygen, it yields ferric oxide and selenium dioxide. 

It may also be prepared by addition of ferric oxide, phosphate,3 or of anhydrous ferrous sulphate 4 to metaphosphoric acid until no more of the salt will dissolve. The whole is then heated until the sulphuric acid has been expelled and crystallisation sets in. 

The heat of combustion of carbonyl ferrocyanic acid is 809,800 calories, the products being nitrogen, carbon dioxide, water, and ferric oxide.4 The heat of formation of the anhydrous acid is —48,600 calories 5 the acid is thus less strongly endothermic than ferrocyanic acid (—122,000 calories). 

Ferric chloride, FeClg fiHoO, is obtained as yellow deliquescent crystals by evaporation of a solution made by oxidation of ferrous chloride with chlorine. Solutions of ferric ion containing chloride ion are more intensely colored, yellow or brown, than nitrate or sulfate solutions because of the formation of ferric chloride < omplexes. Anhydrous ferric chloride, FCoClg, can be made by passing chlorine over heated iron. 

Esters of carboxylic acids undergo oxidative coupling in the a positions with respect to ester groups when treated in the enolate form with ferric chloride. Thus ethyl acetate stirred with lithium diisopropylamide in tet-rahydrofuran at -78 °C for 10 min and subsequently with anhydrous ferric chloride in dimethylformamide yields 69% of diethyl succinate [911]. 

Laberty and Navrotsky (1998) determined the enthalpies of formation of a number of iron oxide and oxyhydroxide polymorphs. Data are listed in Table 2 which also compares the enthalpy relations among aluminum, iron, and manganese. It is evident that the Fe oxyhydroxide phases are much less stable relative to the anhydrous ferric phase (hematite) than are the aluminum oxyhydroxides relative to corundum. This is consistent with the much more frequent observation of hematite than of corundum in the field. It is also evident that the iron phases are as rich in polymorphism as the aluminum phases. It is clear that the enthalpy differences for both anhydrous (AI2O3, Fe203, Mn02) and hydrous (AlOOH, FeOOH, MnOOH) polymorphs are small, setting the stage for nanoscale stability crossovers. 

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