Phosphorus requirements/recommendations

Several considerations recommended their employment (a) aromatic amines readily displace the more strongly basic aliphatic amines from phosphoramidic monoesters54 (b) the transition state for displacement would require the accommodation of phosphorus and the entering and leaving groups in a five-... 

The recommended ratio of phosphorus to calcium is 1 1, except in infants it is 2 1. For older infants, the recommended intake of phosphorus is increased to 80% of the calcium requirement, so that the ratio is similar to cow s milk (Harper 1969). Both phosphorus and calcium are distributed similarly in foods, hence a sufficient intake of calcium ensures a sufficient intake of phosphorus. The exception is cows milk, which contains more phosphorus than calcium (Harper 1969). The adult daily requirement for phosphorus is about 700 mg. A balanced diet provides sufficient amounts of phosphorus because it is commonly found in foods (phosphoproteins and phospholipids, inorganic phosphate), especially milk and milk products, wheat, meats and fish (Latner 1975). In the body, normal serum (inorganic) phosphorus levels are 4-7 mg/100 mL in children and 3-4.5 mg/100 mL in adults and the elderly. In body fluids and tissues, normal serum phosphorus levels found are 40, 170-250, 360, and 22,600 mg/100 mL in blood, muscle, nerve, and both bones and teeth, respectively (Harper 1969 Tietz 1970). 

About 10 g. of pure sulfur(VI) oxide is prepared in the apparatus shown in Fig. 13. Concentrated oleum is placed in flask A which is cooled, evacuated, and sealed at point 1. Tube B is cooled in liquid air until the required amount of sulfur(VI) oxide has distilled over it is then sealed at point 2. Further purification of the trioxide by vacuum distillation is usually unnecessary. The procedure for reaction of the oxide with the required amount of heavy water (2.5018 g./lO g. SOs) is similar to that described in the preparation of deuterophosphoric acid except that sulfur(VI) oxide, being more volatile than phosphorus (V) oxide, should be cooled to —78° before being placed in the side arm of Fig. 14. An inert Fluorlube tap grease is recommended. Limb E is cooled and the apparatus evacuated slowly to prevent volatilization and entrainment of sulfur (VI) oxide in the vacuum line. When the oxide has been completely... 

Isocyanates also can react with each other to produce carbodiimides with the loss of carbon dioxide. This reaction requires high temperatures unless catalyzed by specific phosphorus compounds. Formation of carbodiimides normally is not an important cross-linking mechanism in polyurethane adhesives. However, carbodiimides are sold by Dow Chemicals (Ucarlnk ), Nisshinbo Industries (Carbodilite ), and Stahl USA (XR-2569). They have been recommended as water scavengers, crosslinkers, and stabilizers for carboxyl functional polyurethanes. The carbodiimide can react with water to give a urea, which still can react with additional isocyanate to produce a biuret. 

Phosphate requirements have not been determined for humans. The Food and Nutrition Board recommends a 1/1 ratio of calcium to phosphorus, by weight, in the diet and states that the precise ratio of Ca/P is not important in human... 

In order to stabilize the ammonium salts, the presence of free amine in the system is recommended. With respect to this additional requirement, an ideal system must have the same good retention for amines as well as for phosphorus and rhodium. Therefore the choice of distearylamine could only be regarded as a good compromise of hydroformylation requirements and membrane separation properties. 

Calcium carbonate is the salt of choice because it contains the highest amount of elemental calcium and is the least expensive (see Table 88-5). The fraction of calcium absorbed is dose-limited, so maximum single doses of 600 mg or less of elemental calcium are recommended. Calcium carbonate tablets should be taken with meals to enhance absorption. Calcium citrate absorption is acid-independent and need not be administered with meals. Although tricalcium phosphate contains 39% calcium, nonabsorbable calcium-phosphorus complexes may limit overall calcium absorption compared to other products. This product may be required for up to 10% of seniors with hypophosphatemia that cannot be resolved with increased dietary intake. Disintegration and dissolution rates vary significantly between products and lots. Products with good disintegration and dissolution rates and lead contents of less than 1 mcg/day should be recommended. 

While broad agreement existed on the forms and limits of detectability required for the adequate biological interpretation of nitrogen analyses there was less meeting of the biological minds on the required attributes of phosphorus form differentiation. It was pointed out that the present ability to make interpretive judgments from phosphorus data was limited so that differentiation beyond total P, soluble P, and soluble orthophosphate was probably not justifiable. The detectable limits recommended for the analysis of P forms ranged between 3 to 10 fig, P/hter. 

Under normal conditions, sisal does not require commercial fertilizers. But sisal responds very well to nitrogen, phosphorus, and potassium. In general, an application of 60-100 kg nitrogen, 30-35 kg phosphorus, and 60-100 kg potassium per ha per year is recommended. 

Preliminary sample treatment often involves filtration, which helps to "arbitrarily" separate the particulate and the dissolved phases. Filtration is required to obtain filterable reactive and total filterable reactive phosphorus and is highly recommended at site just... 

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