Phosphorus equivalent weights

The usual method of preparing phosphorous acid from phosphorus (III) chloride and water is complicated by the necessity of avoiding any rise in temperature which might lead to the formation of phosphoric acid by disproportionation. This tendency to disproportionate makes direct reaction between equivalent weights of pure phosphorus-(III) chloride and water, or concentration of dilute solutions of phosphorous acid by evaporation on a steam bath, impossible. 

Analysis of Phosphonium Ion Polymers. The equivalent weight of a reagent must be known for synthetic use. That is not necessarily easy with polymer-bound reagents. Polymer-bound phosphonium ions, however, can be analyzed well. The halide counterions at the phosphonium sites can be determined titrimetrically after they have been displaced from a small sample of the reagent by another anion such as nitrate (13). The solvent swollen reagent can be analyzed qualitatively by C-13 and P-31 NMR, and P-31 NMR can even be used quantitatively (although with less accuracy than the titrimetric analysis for halide) by peak area comparison with an internal standard (391. Elemental analyses for phosphorus and halide should be used periodically to confirm the results of analyses performed in the chemist s own laboratory. 

The legal basis for the sale of fertilizers throughout the world is laboratory evaluation of content as available nitrogen, phosphorus, and potassium. By convention, numerical expression of the available nutrient content of a fertilizer is by three successive numbers that represent the percent available of N, P20, and K O, respectively. Thus, for example, a 20—10—5 fertilizer contains available nitrogen in the amount of 20% by weight of N, available phosphoms in amount equivalent to 10% of P2O5, and available potassium in amount equivalent to 5% K O. The numerical expression of these three numbers is commonly referred to as the analysis or grade of the fertilizer. Accepted procedures for laboratory analysis are fixed by laws that vary somewhat from country to country. 

In the Brown et al. (1980, 1981) and Starke et al. (1982) studies, the air concentrations of white phosphorus smoke were expressed in terms of orthophosphoric acid equivalents. In reviewing the methods used to estimate the concentration of orthophosphoric acid, ATSDR detected a calculation mistake. According to the authors equation for determining the orthophosphoric acid concentration of the sample, the molecular weight was divided by 3 milliequivalents. At pH 9.6, the molecular weight should be divided by 2 milliequivalents. A correction was made to exposure levels for the three studies. White... 

White Phosphorus Smoke. No data on developmental effects in humans exposed to white phosphorus smoke were located. No developmental effects were observed in rats exposed in utero to concentrations of white phosphorus smoke as high as 1,742 mg orthophosphoric acid equivalents/m3 for 15 minutes/day (Brown et al. 1981 Starke et al. 1982). However, exposure of the dams and pups to white phosphorus smoke in utero and during lactation resulted in an 8% decrease in pup body weight, a 68% decrease in pup survival, and a 35% decrease in viability (Brown et al. 1981 Starke et al. 1982). These results may be due to interference with the pups suckling, decreased milk production, decreased suckling due to respiratory tract irritation in the pups, or another compound-related effect. No dermal exposure developmental studies were located. 

Phosphorus Diiodide, P2I4, was first prepared by fusing the constituents in equivalent proportions.6 50 grams of iodine and 4 grams of red phosphorus are melted in a flask and, after partial cooling, 2-5 grams of white phosphorus are added in small pieces.7 Or, equal parts by weight of iodine and phosphorus are dissolved in carbon disulphide and the solution is cooled to 0° C., when the com-... 

P0(0H)2, may be prepared in three ways (1) Phosphorus trichloride (1 gram-molecule) is carefully added to four molecular equivalents of f ovaleraldehyde and the unstable oil which results is decomposed with twenty times its weight of water. Two layers are obtained, the upper one containing two-tliirds of the aldehyde employed, the lower one containing a solution of the hydroxyphosphiiiic acid (2) By heating... 

Eutrophication potential (EP). Eutrophication is referred to as the pollution state of aquatic ecosystems where the overfertilisation of water and soil has turned into an increased growth of biomass. EP is calculated in kg based on a weighted sum of the emission of nitrogen and phosphorus derivatives such as N2, NOx, NH, P04, P and chemical oxygen demand (COD). The classification factors for EP are expressed as phosphates equivalents. 

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