Phosphorous special

Phosphorus compounds are very important as fertilizers (world use 1976/77 27-3 megatonnes as P2O5) but are widely used in matches, pesticides, special glasses and china ware, alloys (sleels. phosphor bronze), and metal treating (10%), detergents (40%), electrical components (e.g. GaP), foods and drinks (15%). Phosphates are an essential constituent of living organisms. U.S. production of phosphorus 1982 372 000 tonnes. 

In recent years, concentrated phosphoric acids, which may contain as much as 70% to 75% P2O5 content, have become of great importance to agriculture and farm production. World-wide demand for fertilizers has caused record phosphate production. Phosphates are used in the production of special glasses, such as those used for sodium lamps. 

Europium oxide is now widely used as a phospor activator and europium-activated yttrium vanadate is in commercial use as the red phosphor in color TV tubes. Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years. 

Extraction of Nonmetallic Inorganic Compounds. Phosphoric acid is usually formed from phosphate rock by treatment with sulfuric acid, which forms sparingly soluble calcium sulfate from which the phosphoric acid is readily separated. However, in special circumstances it may be necessary to use hydrochloric acid ... 

There are numerous variations of the wet process, but all involve an initial step in which the ore is solubilized in sulfuric acid, or, in a few special instances, in some other acid. Because of this requirement for sulfuric acid, it is obvious that sulfur is a raw material of considerable importance to the fertilizer industry. The acid—rock reaction results in formation of phosphoric acid and the precipitation of calcium sulfate. The second principal step in the wet processes is filtration to separate the phosphoric acid from the precipitated calcium sulfate. Wet-process phosphoric acid (WPA) is much less pure than electric furnace acid, but for most fertilizer production the impurities, such as iron, aluminum, and magnesium, are not objectionable and actually contribute to improved physical condition of the finished fertilizer (35). Impurities also furnish some micronutrient fertilizer elements. 

The vapor-phase conversion of aniline to DPA over a soHd catalyst has been extensively studied (18,22). In general, the catalyst used is pure aluminum oxide or titanium oxide, prepared under special conditions (18). Promoters, such as copper chromite, nickel chloride, phosphoric acid, and ammonium fluoride, have also been recommended. Reaction temperatures are usually from 400 to 500°C. Coke formed on the catalyst is removed occasionally by burning. In this way, conversions of about 35% and yields of 95% have been reported. Carba2ole is frequently a by-product. 

The radioactive isotopes available for use as precursors for radioactive tracer manufacturing include barium [ C]-carbonate [1882-53-7], tritium gas, p2p] phosphoric acid or pP]-phosphoric acid [15364-02-0], p S]-sulfuric acid [13770-01 -9], and sodium [ I]-iodide [24359-64-6]. It is from these chemical forms that the corresponding radioactive tracer chemicals are synthesized. [ C]-Carbon dioxide, [ C]-benzene, and [ C]-methyl iodide require vacuum-line handling in weU-ventilated fume hoods. Tritium gas, pH]-methyl iodide, sodium borotritide, and [ I]-iodine, which are the most difficult forms of these isotopes to contain, must be handled in specialized closed systems. Sodium p S]-sulfate and sodium [ I]-iodide must be handled similarly in closed systems to avoid the Uberation of volatile p S]-sulfur oxides and [ I]-iodine. Adequate shielding must be provided when handling P P]-phosphoric acid to minimize exposure to external radiation. 

A method suitable for analysis of sulfur dioxide in ambient air and sensitive to 0.003—5 ppm involves aspirating a measured air sample through a solution of potassium or sodium tetrachloromercurate, with the resultant formation of a dichlorosulfitomercurate. Ethylenediaminetetraacetic acid (EDTA) disodium salt is added to this solution to complex heavy metals which can interfere by oxidation of the sulfur dioxide. The sample is also treated with 0.6 wt % sulfamic acid to destroy any nitrite anions. Then the sample is treated with formaldehyde and specially purified acid-bleached rosaniline containing phosphoric acid to control pH. This reacts with the dichlorosulfitomercurate to form an intensely colored rosaniline—methanesulfonic acid. The pH of the solution is adjusted to 1.6 0.1 with phosphoric acid, and the absorbance is read spectrophotometricaHy at 548 nm (273). 

Esters of phosphorous acid derived from aUphatic alcohols and unhindered phenols, eg, tris(nonylphenyl)phosphate (24), hydrolyze readily and special care must be taken to minimize decomposition by exposure to water or high humidity. The phosphorous acid formed by hydrolysis is corrosive to processing equipment, particularly at high temperatures. 

Strong dehydrating agents such as phosphorous pentoxide or sulfur trioxide convert chlorosulfuric acid to its anhydride, pyrosulfuryl chloride [7791-27-7] S20 Cl2. Analogous trisulfuryl compounds have been identified in mixtures with sulfur trioxide (3,19). When boiled in the presence of mercury salts or other catalysts, chlorosulfuric acid decomposes quantitatively to sulfuryl chloride and sulfuric acid. The reverse reaction has been claimed as a preparative method (20), but it appears to proceed only under special conditions. Noncatalytic decomposition at temperatures at and above the boiling point also generates sulfuryl chloride, chlorine, sulfur dioxide, and other compounds. 

The wash primer is a special type of vinyl coating. This material contains a poly(vinyl butyral) resin, zinc chromate, and phosphoric acid in an alcohol-water solvent. The coating is so thin it is HteraUy washed onto a freshly blasted steel surface, where it passivates the metal surface by converting it to a thin iron phosphate-chromate coating. The alcohol solvent makes it possible to apply the coating over damp surfaces. The coating forms the first coat of... 

Phosphoric Acid Fuel Cell This type of fuel cell was developed in response to the industiy s desire to expand the natural-gas market. The electrolyte is 93 to 98 percent phosphoric acid contained in a matrix of silicon carbide. The electrodes consist of finely divided platinum or platinum alloys supported on carbon black and bonded with PTFE latex. The latter provides enough hydrophobicity to the electrodes to prevent flooding of the structure by the electrolyte. The carbon support of the air elec trode is specially formulated for oxidation resistance at 473 K (392°F) in air and positive potentials. 

Good Good 100 7.3 Special alloy with good resistance to sulfuric, phosphoric, and fatty acids resistant to clilorides in some environments... 

The term novolac refers to the early use of phenolic to replace expensive shellac-based coatings. Novolacs are now those resins made at formaldehyde-to-phenol molar ratios of less than one-to-one. They are generally, though not always, manufactured under acidic conditions. Sulfuric or oxalic acids are most often chosen as catalyst though aromatic sulfonic acids and phosphoric acid are also quite common. Many other acids are used for special purposes. The finished novolac resin is incapable of further polymerization or crosslinking and therefore... 

Fire Hazards - Flash Point Not flammable Flammable Limits in Air (%) Not flammable Fire Extinguishing AgerUs Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Oxides of sulfur and phosphorous may be formed when exposed to a fire situation Behavior in Fire Data not available Ignition Temperature Not pertinent Electrical Hazard Not pertinent Bunting Rate Not pertinent. 

A considerable number of examples will be found in the text in which halo-genated and other substituted olefins are produced. Their modes of fonnation do not usually differ in principle from the corresponding unsubstituted case. However, some special methods have been used, for example, the direct preparation of halo olefins from ketones with phosphorous hahdes, or via hydrazones. 

The production of maleic anhydride from n-butenes is a catalyzed reaction occurring at approximately 400-440°C and 2-4 atmospheres. A special catalyst, constituted of an oxide mixture of molybdenum, vanadium, and phosphorous, may be used. Approximately 45% yield of maleic anhydride could be obtained from this route ... 

It is not possible to plate rhodium directly on to reactive metals of the type mentioned above, in view of the acid nature of the electrolyte, but copper and its alloys, e.g. nickel-silver, brass, phosphor-bronze, beryllium-copper, which are of special importance in the electrical contact field, may be plated directly. Even in this case, however, an undercoat is generally desirable. 

Of special biochemical importance are the esters of monosaccharides with phosphoric acid. They are generally termed phosphates (e.g. glucose 6-phosphate). In biochemical use, the term phosphate indicates the phosphate residue regardless of the state of ionization or the counter ions. 

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