Polyphosphate, , Preparation

Since the safety history of calcium phosphates is well known, it was chosen as a material of first choice. Raw materials were lime, CaO, and phosphoric acid, H3PO4, both of which have been used in foods throughout the civilized world for hundreds of years. It was decided to attempt the following reaction for a start  

To make life simpler, what one actually does in the laboratory is to heat monocalcium orthophosphate to drive out water contained in the melt and then slowly cool the system to crystallize [Ca(P03)2]Ai. 

A first try was nothing more than heating about 200 g of monocalcium orthophosphate, contained in a platinum dish, to a melt near 1000 °C. This system was then slowly cooled and crystals formed, as expected. These crystals were removed from the dish as a dense cake about 2 cm thick. The cake was crushed and milled in various ways to determine if these crystals could in any way be considered fibers. 

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Aqui et al. investigated the cyclization of diethyl A-(3-substituted phe-nyl)aminomethylenemalonates (251) under different cyclization conditions (75JHC557). For cyclization, they applied a 4 7 mixture of concentrated sulfuric acid and acetic anhydride, polyphosphoric acid, polyphosphate (prepared from phosphorus pentoxide and diethyl ether in chloroform), phosphoryl chloride, and Dowtherm A (see Table VI). They found the most effective cyclization conditions were thermal cyclization (heating in Dowtherm A) and polyphosphate. 

The ring closure of (V-[4-ethyl-3-(2-chlorophenoxy)methylphenyl]ami-nomethylenemalonate (757, R = 2-ClPhOCH2, R1 = Et) in polyphosphate (prepared from phosphorus pentoxide and ethanol in xylene at 100°C) at 150°C for 30 min afforded quinoline-3-carboxylate (759, R = 2-ClPhOCH2, R1 = Et) in 74% yield (79EGP136742). 

Figure 3.12 Absorption and luminescence spectra of CdS sols ( polyphosphate preparation ) with varying starting pH. From Ref. [28].

The complex preparative interrelationships occurring in the sodium polyphosphate system are summarized in Fig. 12.21 (p. 531). Thus anhydrous NaH2p04, when heated to 170" under conditions which allow the escap>e of water vapour, forms the diphosphate Na2H2p207, and further dehydration at 250" yields either Maddrell s salt (closed system) or the cyclic trimetaphosphate (water vapour pressure kept low). Maddrell s salt converts from the low-temperature to the high-lemperaturc form above 300", and above 400" reverts to the cyclic... 

Polyphosphates are also an important class of organophosphorus polymers. In addition to their flame-retardant characteristics, they possess attractive plasticizing properties and can be used as polymeric additives to other polymers [123-128]. In general, polyphosphates can be prepared by interfacial [119,129], melt [130], or solution polycondensation [131,132a,b]. Kricheldorf and Koziel [133] prepared polyphosphates from silylated bisphenols. 

Diarylimidazohnes 119 that act as potential P2X receptor antagonists have been prepared by microwave-assisted cyclization of amino amides in the presence of TMS-polyphosphate at 140 °C for 8 min [78]. This reaction seems quite general (for variations on R) as more than 35 compounds have been prepared with this method (Scheme 41). 

The luminescence of macrocrystalline cadmium and zinc sulfides has been studied very thoroughly The colloidal solutions of these compounds also fluoresce, the intensity and wavelengths of emission depending on how the colloids were prepared. We will divide the description of the fluorescence phenomena into two parts. In this section we will discuss the fluorescence of larger colloidal particles, i.e. of CdS particles which are yellow as the macrocrystalline material, and of ZnS particles whose absorption spectrum also resembles that of the macrocrystals. These colloids are obtained by precipitating CdS or ZnS in the presence of the silicon dioxide stabilizer mentioned in Sect. 3.2, or in the presence of 10 M sodium polyphosphate , or surfactants such as sodium dodecyl sulfate and cetyldimethylbenzyl-ammonium... 

A gel of diesel or crude oil can be produced using a phosphate diester or an aluminum compound with phosphate diester [740]. The metal phosphate diester may be prepared by reacting a triester with phosphorous pentoxide to produce a polyphosphate, which is then reacted with an alcohol (usually hexanol) to produce a phosphate diester [870]. The latter diester is then added to the organic liquid along with a nonaqueous source of aluminum, such as aluminum isopropoxide (aluminum-triisopropylate) in diesel oil, to produce the metal phosphate diester. The conditions in the previous reaction steps are controlled to provide a gel with good viscosity versus temperature and time characteristics. All the reagents are substantially free of water and will not affect the pH. 

The experimental weight loss in the first and second step (4.0 and 4.5% respectively) is in agreement with that corresponding to condensation to pyrophosphate (4.0%) and polyphosphate (4.2X, n 1). Furthermore, the IR spectra of melamine phosphate and of the residues at 300 and 330 C (Figure 14 spectra A, B and C respectively) show that besides the typical bands of phosphate salts (950-1300 cm-1) which are present in the three spectra, a new absorption due to P-O-P bonds (ca. 890 cm-1) appears in the spectra of the residues. The absorptions due to melamine salt structures (e.g. 780-790 and 1450-1750 cm ) are closely similar in the three spectra of Figure 14. Fire retardants based on melamine pyrophosphate and polyphosphate are reported in the literature 51 as well as methods for preparation of these salts (25-... 

Calculation of Brine Components. In order to satisfy U.S.D.A. regulations, care must be taken during brine preparation so that finished product protein meets or exceeds 17 percent. The following formula can be used to determine brine composition (Isolated soy protein, salt, dextrose, polyphosphate, etc.) (6). 

Nakagome and co-workers effected the successful cyclization of N-ethyl-N-arylaminomethylenemalonates (749) in poly phosphoric acid, prepared from orthophosphoric acid and phosphorus pentoxide in polyphosphate ester (PPE), prepared from phosphorus pentoxide and anhydrous diethyl ether in chloroform in phosphoryl chloride on the action of boron trifluoride etherate on the action of acetic anhydride and concentrated sulfuric acid or on the action of phosphorus pentoxide in benzene [71GEP2033971, 71JHC357 76JAP(K) 18440]. Depending on the work-up process, l-ethyl-4-oxoquinoline-3-carboxylates (750, R1 = Et), l-ethyl-4-oxoquinoline-3-carboxylic acids (750, R2 = H) and 3-ethoxycarbonyl-4-chloroquinolinium iodides (751) were obtained. Only the cyclization of... 

Flumequine was prepared when 6-fluoro-2-methyl-1,2,3,4-tertrahydro-quinoline was first reacted with alkylidene malonates and trimethyl orthoformate in THF in the presence of p-toluenesulfonic acid, and then the products, alkylidene (6-fluoro-2-methyl-1,2,3,4-tetrahydroquinolin-1 -yl) methylenemalonates, were cyclized in xylene on the action of polyphos-phoric acid or ethyl polyphosphate at 110-115°C for 1 hr (89EUP310849). 

An evaluation of numerous clays, including kaolins and bentonites of comparable particle size and distribution, revealed a wide variation in the properties of LDEE-clay composites prepared under identical conditions with similar loadings. This may be attributed to the interference with the radical reactions involved in the coupling sequence. This is confirmed, in part, by the finding that the most effective clays were those which were reported to have been treated with sodium polyphosphate to improve their dispersibility in water during papermaking processes. Solomon reported (1) that treatment of the clays which inhibited radical reactions with sodium polyphosphate reduced the inhibition. 

A. Analysis of Wastewater and Natural Waters. The presence of certain anions in wastewater effluents can cause deterioration of natural water systems. Phosphorous and nitrogen can be present in several chemical forms in wastewaters. Phosphorous is usually present as phosphate, polyphosphate and organically-bound phosphorus. The nitrogen compounds of interest in wastewater characterization are ammonia, nitrite, nitrate and organic nitrogen. Analyses are often based on titrimetric, and colorimetric methods (3). These methods are time consuming and subject to a number of interferences. Ion Chromatography can be used to determine low ppm concentrations of these ions in less than thirty minutes with no sample preparation. 

Calcium polyphosphate, dissociation and chain length, 4 48 Calcyclin, 46 454-456 Californium, 20 111 availability and price, 31 2 isotopes, 2 201 melting point, 31 6 oxidation state, 2 197 physical properties, 31 36 preparation and purification, 31 5, 7, 12, 33 apparatus, 31 34, 35 purity, 31 3 radioactivity, 31 33 vapor pressure, 31 6 Califomium-252, a-decay, 31 28 Californium oxide, metallothermic reduction, 31 7, 33... 

Previous methods for the preparation of salts of geranyl diphosphate and other allylic isoprenoid diphosphates are based on condensation between the alcohol and inorganic phosphate by trichloroacetonitrile as originally reported by Cramer and modified by Popjak The reaction generates a complex mixture of organic and inorganic polyphosphates which must be separated by chromatography. The desired diphosphate ester has been prepared on small... 

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