Phosphorus, in organic compounds

Ion Chromatography. - Organic phosphorus-containing acids and their thio- and dithio- analogues have been analysed by ion chromatography 2 and the microdetermination of phosphorus in organic compounds has been accomplished. ... 

Nagashima H and Kuboyama K (1996) Microdetermination of phosphorus in organic compounds by ion chromatography. Bunseki Kagaku 45 941-946. 

C. Phosphorus in Organic Compounds Test by ignition with lime (conversion to phosphate)... 

Other elements which occur in organic compounds, such as phosphorus, arsenic, other non-metals, and metals in organic combination, are detected by destroying the organic material by oxidation (with nitric acid in a sealed tube or by fusion with potassium nitrate or sodium peroxide) and then applying the usual tests. 

The OH radical reactions with a number of nitrogen-, sulfur- and phosphorus-containing organic compounds appear to proceed, at least in part, by an initial addition reaction (Atkinson, 1989,1994 Kwok et al., 1996), although the products observed may in some cases be those expected from H-atom abstraction. Note that the recent study of Talukdar et al. (1997) indicates that the reactions of the OH radical with alkyl nitrates proceed only by H-atom abstraction, and Table 14.1 gives the applicable substituent group factors for alkyl nitrates. 

Many attempts have been made to synthesise organophosphorus compounds directly from the element with varying degrees of success.i In general mixtures of products are obtained, and the yields are frequently low and variable. The main difficulty is the insolubility of phosphorus in organic liquids and consequently the reactions are heterogeneous with the attendant problems of diffusion and local concentration differences. 

Phosphorus in the form of phosphate is the principal source of P for plants. Phosphorus is commonly applied in fertilisers although its uptake by plants is much less than that of N and K and its availability is one of the most common nutritional limitations to crop yield (Bould etal., 1983). Some of the P in soils and soil solutions may be present in organic compounds. However, it is unlikely to be available to plants in its organic form and decomposition of organic matter releases P in its available... 

Phosphorus combined in organic compounds, or as phosphide in metals, is also estimated after oxidation by precipitation as ammonium phosphomolybdate or magnesium ammonium phosphate, with the subsequent treatment which is described on pp. 181—183. The methods by which the phosphorus is brought into solution vary with the nature of the material which is being analysed. Organic compounds are oxidised in a sealed tube with fuming nitric acid or in a flask by a mixture of concentrated sulphuric and nitric acids. 

Most of the common elements in organic compounds—C, N, O, and the halogens— follow the octet rule. Hydrogen is a notable exception, because it accommodates only two electrons in bonding. Additional exceptions include boron and beryllium (second-row elements in groups 3A and 2A, respectively), and elements in the third row (particularly phosphorus and sulfur). 

Most of the elements found in organic compounds, such as carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, fluorine, and iodine, have one major isotope. Chlorine and bromine, on the other hand, have two, giving characteristic patterns to the mass spectra of their compounds. 

Phosphorus [137], sulfur [138-140,143], selenium [141,143], and tellurium [142,143] electrodes may be used for incorporation of these elements in organic compounds. Sulfur and selenium are used in a mixture with graphite, whereas white phosphorus may be used melted or in contact with carbon or mercury tellurium has sufficient conductivity to be used directly or applied on a platinum electrode. 

From the knowledge of the extractant characteristics of both neutral and mono-acidic phosphorus-based organic compounds now available, it is possible to tailor-make extractants for a specifically desired separation of two metals. The present study is concerned with neutral mono-nuclear, phosphorus-based extractants for use in affecting the mutual separation of U(VI) and Th(IV). 

Liquid-liquid extraction (LLE) systems using neutral phosphorus-based organic compounds have been the subject of extensive study since Warf (1) first reported the use of tributyl phosphate, TBP, as a useful extractant for cerium(IV), uranyl and thorium nitrates. After more than twenty years, liquid-liquid extraction systems (such as the Purex and Thorex processes) employing TBP dissolved in a suitable diluent versus an aqueous HNO3 phase remain the most widely accepted systems for reactor fuel reprocessing. 

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