Monohydrogen phosphate

The gels precipitated as described above are not useful in ion-exchange systems because their fine size impedes fluid flow and allows particulate entrainment. Controlled larger-sized particles of zirconium phosphate are obtained by first producing the desired particle size zirconium hydrous oxide by sol—gel techniques or by controlled precipitation of zirconium basic sulfate. These active, very slightly soluble compounds are then slurried in phosphoric acid to produce zirconium bis (monohydrogen phosphate) and subsequently sodium zirconium hydrogen phosphate pentahydrate with the desired hydrauhc characteristics (213,214). 

In Eq. (6-35), A/Z is the molar heat of ionization of the buffer acid at the conditions (temperature, solvent composition) of the kinetic studies. It happens that for many commonly used acidic buffers this quantity is small. Hamed and Owen give A//2 = —0.09 kcal/mol for acetic acid at 25°C, for example. The very important buffer of dihydrogen phosphate-monohydrogen phosphate is controlled by pK2 of phosphoric acid at 25°C its heat of ionization is —0.82 kcal/mol. 

Variable results have been reported with this pigment and an examination of its inhibitive action has led to the conclusion that under rural and marine conditions, where the pH of the rain-water is above 5, it behaves as an inert pigment owing to its limited solubility. However, in industrial and urban areas, where the pH of the rain-water may be in the region of 4 or lower, it is converted into the more soluble monohydrogen phosphate. This reacts in the presence of oxygen, with the steel surface to form a mixture of tribasic zinc and ferric phosphates, which being insoluble protects the steel from further attack. 

When a solution of 4(5)-aminoimidazole (64) (Scheme 6) in dipotassium monohydrogen phosphate solution was treated with 1,1,3,3,-tetramethoxypropane, imidazo[l,5-a] pyrimidine (63) was obtained as a yellow hygroscopic solid (40%) [71 BSF(2) 1031 ]. 

Disodium laurimino dipropionate, cosmetic surfactant, 7 834t Disodium monohydrogen phosphate, 18 831 Disodium octaborate tetrahydrate, 4 242t, 266-267... 

Similarly, the number of milliequivalents of potassium phosphate in 10 mL of potassium monohydrogen phosphate can be calculated as follows ... 

A potassium phosphate solution contains 3.5 g of potassium dihydrogen phosphate (MW = 136) and 6.5 g of potassium monohydrogen phosphate (MW = 174) in 40 mL. If 5 mL of this solution are added to a liter of D5W, how many milliequivalents of potassium phosphate will be represented in the infusion ... 

Pyro- and di-phosphates, the simplest members of the group of condensed phosphates, are so well known that only the results of recent investigations will be described here, and only in so far as they bear on the chemistry of condensed phosphates. Thus, ever since Clark s investigations 52), it has been common knowledge among chemists that diphosphates arc obtained by heating monohydrogen phosphates, or by double decomposition of other diphosphates. It was unexpected, however, to find that an equilibrium... 

B. o-Phthalaldehyde. The a,a,a, a -tetrabromo-0-xylene (344-370 g.) obtained as described above, part A, is placed in a 5-1. round-bottomed flask with 4 1. of 50% (by volume) ethanol and 275 g. of potassium oxalate. The mixture is heated under reflux for 50 hours (a clear yellow solution is formed after 25-30 hours). About 1750 ml. of the ethanol is then removed by distillation (which is stopped before the product begins to steam-distil), and 700 g. of disodium monohydrogen phosphate dodecahydrate (Na2HP04-12H20) is added to the aqueous residue. The mixture is steam-distilled rapidly (Note 4), using an efficient condenser, until 10-12 1. of distillate is collected and the distillate no longer gives a black color test for o-phthalaldehyde 8 when a portion is treated with concentrated ammonium hydroxide fol-... 

Pharmacopeial compendia establish a couple of tests that should be carried out with raw material batches to determine their level of impurities. Concomitants usually detected are heavy metals, chloride, or sulfated ash. The presence of byproducts varies from raw material to raw material. Examples can be both innocuous substances such as monohydrogen phosphate, which is an impurity in dihydrogen phosphate salts and glycine, which is an impurity in alanine, and toxic substances, such as the classical enantiomer S of thalidomide. 

Dissolve in the following order azelastine hydrochloride, edetic acid, sodium chloride, benzalkonium chloride, citric acid, and sodium monohydrogen-phosphate, and mix well. 

Verlinde CLMJ, Noble MEM, Kalk KH, Groendijk H, Wierenga RK, Hoi WGJ. Anion binding at the active site of trypanosomal triosephosphate isomerase monohydrogen phosphate does not mimic sulphate. Eur J Biochem 1991 198 53- 57. 

The furosemide extraction procedure was later examined for potential application in the analysis of thiazide diuretics in milk. Since this procedure could not provide sufficiently clean extracts for thiazides, additional acidic and basic extraction procedures were evaluated (557). Thus, milk was deproteinized with trichloroacetic acid, phosphoric acid, or potassium dihydrogen phosphate and centrifuged. The supernatants were extracted with ethyl acetate, evaporated to dryness, reconstituted in mobile phase, and analyzed by liquid chromatography. The recoveries in most cases were low and widely variable. Basic extraction, on the other hand, with sodium bicarbonate/potassium carbonate mixture or potassium monohydrogen phosphate followed by extraction with ethyl acetate also gave poor recoveries in most cases. It appears that a significant degradation of chlorothiazide occurred under the basic conditions. 

Disodium 1,2 ethanedithiol, 39, 23 Disodium monohydrogen phosphate dodecahydrate, 34, 83, 37, 74 Distillation, steam, of p dithiane,... 

Sulfato complexes of chromium(II) are known, and the insolubility of the monohydrogen phosphate Cr(HP04) 4H20 suggests anion coordination (Section 35.3.5.1). 

Equilibrium constants for ionization reactions are usually called ionization or dissociation constants, often designated Ka. The dissociation constants of some acids are given in Figure 2-16. Stronger acids, such as phosphoric and carbonic acids, have larger dissociation constants weaker acids, such as monohydrogen phosphate (Ill Of ), have smaller dissociation constants. 

Additional base reacts with the monohydrogen phosphate ion to produce phosphate ion, P043-. When this reaction is complete, the primary species in solution are the phosphate ion and sodium ion, which form a solution of Na3P04(aq). To reach this stoichiometric point, we have to add another mole of base for each mole of acid present (F in the plot). At this point, a total of 3 mol OH has been added for each mole of H3P04. Notice that the third stoichiometric point is not as distinct as the first two, largely because fCa3 is comparable to Kw. 

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