Phosphorus tetroxide

Phosphorus tetroxide , P2O4, which can be made by thermal decomposition of the triiodide as in (4.67), forms white crystals which sublime at about 180°C. At about 350°C, oxidation to the pentox-ide takes place in air. The oxide dissolves in water with considerable evolution of heat to give a mixture of phosphorous and phosphoric acids. 

---

Phosphorus sulfochloride, 79 42 Phosphorus sulfohalides, physical properties of, 79 43t Phosphorus-sulfur bonds, 79 26-27 Phosphorus tetroxide, 79 52 Phosphorus tribromide, physical properties of, 4 325... 

The molecular formulae of the tri- and pent-oxides are respectively P406 and P4O10 as shown respectively by T. E. Thorpe and A. E. H. Tutton, and by W. A. Tilden and R. E. Barnett. It is assumed that the phosphorus in the trioxide is tervalent because hydrogen chloride converts the oxide into phosphorous chloride, Pd3, and phosphorous acid, P(OH)3 while phosphorus in the pentoxide is assumed to be quinquevalent because water converts the oxide into phosphoric acid, 0 P(0H)3. Since water converts phosphorus tetroxide, P204, into a mixture of phosphorous and phosphoric acids, it has been argued that one phosphorus atom is tervalent, and the other quinquevalent. In the alleged phosphorus tetritoxide, P40, of A. Michaelis, the phosphorus is assumed to be tervalent ... 

Phosphorus tetroxide, P204 Phosphoric oxide, P2Oj... 

The fact that phosphorus tetroxide, P204, furnishes phosphoric and phosphorous acids when treated with water is expressed by the structural formula 0=P=03=P. If phosphorus tetroxide be the anhydride of hypophosphoric acid—vide supra—it might be anticipated that 0=P 03=P- -2H20->0(0H)2P—0— P(0H)2. If the last formula really represented the structure of hypophosphoric acid, it would follow that (i) this acid would be a reducing agent like phosphorous acid, but it is not and that (ii) it ought to be possible to prepare at least two isomers by the action of sodium hydroxide on dipotassium hypophosphate, and of potassium hydroxide on disodium hypophosphate, say ... 

Phosphorus tribromide Potassium, ruthenium tetroxide, sodium, water... 

Sulfuryl dichloride Alkalis, diethyl ether, dimethylsulfoxide, dinitrogen tetroxide, lead dioxide, phosphorus... 

Thus, Mathis et al. [1, 2] investigated oxidation reactions with 4-nitroperbenzoic acid, sodium hypobromite, osmium tetroxide and ruthenium tetroxide. Hamann et al. [3] employed phosphorus oxychloride in pyridine for dehydration. However, this method is accompanied by the disadvantages that the volume applied is increased because reagent has been added and that water is sometimes produced in the reaction and has to be removed before the chromatographic separation. 

Fortunately, the oxidation of l,2 5,6-di-0-isopropylidene-a-D-glucofura-nose to l,2 5,6-di-0-isopropylidene-a-D-nfoo-hexofuranos-3-ulose (1) can be accomplished using either phosphorus pentoxide (10, 44) or acetic anhydride (10, 52) in methyl sulfoxide although this oxidation is effected with ruthenium tetroxide (6,7, 46), it is exceeding difficult with other oxidizing agents (53). Keto-sugar 1 is reduced stereospecifically... 

C. By Oxidation.—This year s literature has been notable for attempts to study the details of certain phosphine oxidation reactions. In one such investigation nitric acid was found to oxidize phosphines, or phosphine sulphides, to phosphine oxides with inversion of configuration at phosphorus, whereas dinitrogen tetroxide, in the absence of acid, was found to oxidize the same compounds with predominant retention. The partial racemization observed with the latter reagent was probably due to the racemization of the oxides, since methylphenyl-n-propylphosphine oxide... 

It also reacts with nitrogen oxides. It combusts if it is heated in nitrogen oxide, it detonates in nitrogen tetroxide at ambient temperature. The same happens with phosphorus pentoxide. 

A large number of reagents are available for the preparation of nitro PAHs. These include fuming nitric acid in acetic acid (20) or acetic anhydride (13), sodium nitrate in trifluoroacetic acid (21) or trifluoroacetic acid and acetic anhydride (17), dinitrogen tetroxide in carbon tetrachloride (22), sodium nitrate in trimethyl phosphate and phosphorus pentoxide (23), and nitronium tetrafluoroborate in anhydrous acetonitrile (24). Alternative approaches must be used to synthesize nitro PAHs substituted at positions other than the most reactive carbon. For instance,... 

Phosphorus pentafluoride Phosphorus pentasulfide Phosphorus pentoxide Phosphorus, red Phosphorus tribromide Phosphorus bichloride Water or steam Air, alcohols, water Formic acid, HF, inorganic bases, metals, oxidants, water Organic materials Potassium, ruthenium tetroxide, sodium, water Acetic acid, aluminum, chromyl dichloride, dimethylsulfoxide, hydroxylamine, lead dioxide, nitric acid, nitrous acid, organic matter, potassium, sodium water... 

Sulfides Sulfur Sulfur dioxide Sulfuric acid Sulfuryl dichloride Acids, powerful oxidizers, moisture Oxidizing materials, halogens Halogens, metal oxides, polymeric tubing, potassium chlorate, sodium hydride Chlorates, metals, HC1, organic materials, perchlorates, permanganates, water Alkalis, diethyl ether, dimethylsulfoxide, dinitrogen tetroxide, lead dioxide, phosphorus... 

OSMIUM TETROXIDE - WHITE PHOSPHORUS - WHITE PHOSPHORUS TRICHLORIDE PHOSPHORUS PENTACHLORIDE PHOSPHINE... 

---