Disodium hydrogen phosphate, effect

Commercially available 85% MCPBA is generally employed in chlorinated hydrocarbon solvents at room temperature. Reaction times are typically a few hours to several days. Buffers utilized include disodium hydrogen phosphate, sodium acetate and sodium bicarbonate, the catalytic effect of which has been occasionally noted. Acid catalysis with sulfuric acid or Nafion-H are alternatives. Oxidations have been performed at elevated temperature with the aid of radical scavengers. "... 

Tuchel et al. 238,2 39,240 have also examined the kinetics of the degradation of chloral hydrate in solutions containing sodium hydroxide, borax, disodium hydrogen phosphate and sodium phenobarbital. In addition, these authors examined the stabilizing effect of certain colloids (gum arable, agar-agar, and gelatin) on mixed solutions of chloral hydrate and sodium phenobarbital. ... 

The effect of phosphates on SCC susceptibifity ofa-brass was studied by Ashour and Ateya [239]. The results indicated that disodium hydrogen phosphate (DHP) inhibits the SCC in brass by the formation of zinc phosphate. SSRT and electrochemical tests were used to study the SCC properties of H62 brass in Mattsson s solution (MS) containing various concentrations of DHP by Du et al. [240]. MS was used as an accelerated SCC test environment for H62 brass. The susceptibifity of brass to SCC and film-induced stress decreased with increasing DHP concentrations. Electrochemical measurements confirmed that DHP inhibits SCC by forming a copper phosphate and zinc phosphate film on the brass surface. The film inhibits dezincification and decreases film-induced stress and reduces the susceptibility of brass to SCC. As shown in Fig. 9.62a, tarnishing... 

ZA2 Zafarani-Moattar, M.T. and Sadeghi, R., Effect of temperature on the phase equilibrium of aqueous two-phase systems containing polyvinylpyrrolidone and disodium hydrogen phosphate or trisodium phosphate, Fluid Phase Equil, 238, 129, 2005. 

The conditions for preparation of the arsenate are similar to those specified for the phosphate, except that a solution of 312 g. (1 mol) of disodium hydrogen arsenate 7-hydrate in 300 ml. of water (heated to 50° to effect solution) is substituted for the phosphoric acid. Hydroxylammonium arsenate may begin to crystallize before all of the arsenate has been added. An uncooled solution of 40 g. of sodium hydroxide (1 mol) in 100 ml. of water is added to effect neutralization. Three 150-ml. portions of water are used to wash the crude product. The yield is 200 to 210 g. of a product whose purity is approximately 95 per cent based on the hydroxylamine content. Purification can be effected by recrystallization of the arsenate from eight times its weight of water. Recovery amounts to about 145 g. (approximately 60 per cent) of a product with a purity of 98 per cent or better. 

Alcoholysis of the chloride on the plant scale was effected at 40°C (with brine cooling) by adding portions to the alcohol alternately with finely crystalline disodium phosphate to neutralise the hydrogen chloride produced. On one occasion, use of coarsely crystalline sodium phosphate (of low surface area) reduced the rate of neutralisation, the mixture became acid, and a runaway exotherm to 170°C developed leading to eruption of vessel contents. On another occasion, accidental addition of sodium sulfate instead of phosphate led to a similar situation beginning to develop, but an automatic pH alarm allowed remedial measures to be instituted successfully. See other neutralisation incidents... 

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