Disodium dihydrogen orthophosphate

Materials Required Plasma protein solution 2.0 ml mixed phosphate buffer pH 7.0 with azide [To 1000 ml of a solution containing 1.8% w/v of disodium hydrogen orthophosphate and 2.3% w/v of sodium chloride and sufficient of a solution containing 0.78% w/v of sodium dihydrogen orthophosphate and 2.3% w/v of sodium chloride (about 280 ml) to produce a pH of 7.0 Dissolve sufficient sodium azide in the resulting solution to give a 0.02% w/v solution] 1000 ml ... 

Of the various methods for preparing disodium dihydrogen hypophosphate, the one depending upon the oxidation of red phosphorus with sodium chlorite seems to be the best, considering both the yield and the simplicity of the procedure. In this reaction, phosphites and orthophosphates... 

Disodium hydrogen phthalate-sodium dihydrogen orthophosphate... 

Disodium hydrogen phthalate-sodium dihydrogen orthophosphate Dipotassium hydrogen phthalate-potassium dihydrogen orthophosphate Potassium dihydrogen orthophosphate-sodium hydroxide Borate buffer, phosphate buffer... 

Phosphate buffered saline (PBS) 8.5 g of sodium chloride, 1.07 g of disodium hydrogen orthophosphate (or 2.7 g of NagHP04 2H20), 0.39 g of sodium dihydrogen orthophosphate (or 0.51 g of NaH2P04 2H20). Make up to 1 L with disdlled water. 

Leininger and Chulski have demonstrated that disodium dihydrogen hypophosphate Is produced in the oxidation of red P with NaClOs in a yield of about 42%. In addition, 19% orthophosphate, 35% phosphite, and 2% hypophosphite are formed. The procedure, somewhat cumbersome because of the large cooling apparatus required, has been Improved and simplified by Baudler and, later, by Remy and Falius. According to the latter authors, special apparatus is unnecessary. Sufficient phosphorus must be available, however, and the heat of reaction must be rapidly removed. The yield Is better than that achieved by Leininger and Chulski. 

Disodium dihydrogen pyrophosphate dissolves slowly in cold water, a 1 per cent solution having a pH of 4.1 to 4.3. One hydrate, Na2H2P207 6Ha0, can be crystallized from aqueous solutions at slightly below room temperature. The hydrated crystals are biaxial negative with a = 1.456, jS = 1.464, and 7 = 1.465( .002). When heated they lose their water of crystallization around 36°. In aqueous solution the disodium pyrophosphate hydrolyzes to orthophosphate, the rate of hydrolysis depending on the temperature. At 70° a 1 per cent solution is hydrolyzed approximately 10 per cent in 6 hours at 100° the hydrolysis is complete in less than 6 hours. ... 

Sodium triphosphate I, the stable phase, is produced when an intimate mixture of 1 mol of sodium dihydrogen orthophosphate with 2 mols of disodium hydrogen orthophosphate is heated to 540 to 580 for 2 hours in a platinum dish. ... 

Orthophosphoric acid Monosodium dihydrogen orthophosphate Disodium monohydrogen orthophosphate Trisodium orthophosphate... 

Disodium hydrogen orthophosphate + potassium dihydrogen orthophosphate Disodium hydrogen orthophosphate + potassium dihydrogen orthophosphate Disodium tetraborate decahydrate Disodium tetraborate decahydrate Sodium hydrogen carbonate + sodium carbonate... 

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