Acidity phosphates

The lanthanum phosphate phosphor is usually prepared by starting with a highly purified coprecipitated oxide of lanthanum, cerium, and terbium blended with a slight excess of the stoichiometric amount of diammonium acid phosphate. Unlike the case of the aluminate phosphor, firing is carried out in an only slightly reducing or a neutral atmosphere of nitrogen at a temperature 1000° C. Also this phosphor is typically made with the addition of a flux,... 

Mixed mono- and dialkyl are used as catalysts for resin curing and as intermediates for fire retardants, oil additives, antistatic agents (qv), and extraction solvents. An equimolar mixture of mono- and dialkyl acid phosphates are formed at a 1 6 mole ratio of oxide to alcohol. 

A number of acidic phosphates which vary in their rate of reaction are available for use in a wide variety of bakery appHcations. These acids, which include monocalcium phosphate, sodium aluminum phosphate, and sodium acid pyrophosphate, release carbon dioxide at a controlled rate to give a certain fraction prior to baking the remaining fraction is released at a specific time during baking. Controlled releasing of carbon dioxide at the time it is needed can also be achieved by a mixture of different types of leavening acids. 

Naphthyl phosphate disodium salt [2183-17-7] M 268.1, pK 0.97, pK 5.85 (for free acid). The free acid has m 157-158° (from Me2CO/ C6H6). The free acid is crystd several times by adding 20 parts of boiling CgHg to a hot solution of 1 part of free acid and 1.2 parts of Mc2CO. It has m 157-158°. [J Am Chem Soc 77 4002 1 955.] The monosodium salt was ppted from a soln of the acid phosphate in MeOH by addition of an equivalent of MeONa in MeOH. [J Am Chem Soc 72 624 1950.] See entry on p.550 in Chapter 6. 

ACID BUTYL PHOSPHATE see BUTYL ACID PHOSPHATE ... 

Chemical Designations - Synonyms Bis-(2-ethylhexyl) Hydrogen Phosphate Di-(2-ethylhexyl) Phosphate Di-(2-ethylhexyl) Acid Phosphate Chemical Formula [CH3CH2CHiCH2CH(CiH3)CHiO]2POOH. 

Butter Yellow, 29 Butyl acetates, 29 Butyl acid phosphate, 29 Butyl acrylate, 29 Butyl alcohols, 29 Butyl amines, 29 Butylate, 30... 

Figure 1. Separation of isomeric S-deoxy D-erythro-hexulosonic acid phosphates.

A suspension of lithium methoxide (prepared from 1.00 g (31.2 mmol) of methanol in 50 mL of THF and 17.7 mL (27.2 mmol) of 1.54 M butyllithium in hexane) is transferred via a cannula into a — 78 C sol ution of 5.86 g (27.1 mmol) of 2-[(/ )-(/T)-1-chloro-2-butenyl]-4,4,5,5-tctramethyl-l,3,2-dioxaborolane in 100 mL of THF. The solution is warmed, becoming homogeneous at 0 JC, and stirred for 1 h. Solvents arc removed in vacuo and the residue dissolved in 150 mL of petroleum ether (bp 40 -60 °C). This solution is washed with a citric acid/boric acid/phosphate buffer (pH 3) until the aqueous phase shows a pH of 4. The aqueous phase is extracted with 50 mL of petroleum ether (bp 40 - 60 rC). The combined organic extracts are dried over MgS04 and concentrated in vacuo to give a slightly tan oil yield 5.34 g (90%) ca. 90% ee. 

The 2-keto-3-deoxy-aldonic acid (phosphate) aldolases from Pseudomonas strains - 3-deoxy-2-keto-L-arabonate (F.C 4.1.2.18), 3-deoxy-2-keto-D-xylonate (EC 4.1.2.28), 3-deoxy-2-keto-6-phospho-D-gluconate (EC 4.1.2.14) and 3-deoxy-2-keto-6-phospho-D-galactonate aldolase (EC 4.1.2.21) - appear to be specific even for the acceptor components, but allow stereoselective syntheses of the respective natural substrates29. 

Histones are small, basic proteins required to condense DNA into chromatin. They have been first described and named in 1884 by Albrecht Kossel. There are five main histones HI, H2A, H2B, H3 andH4. An octamer of core histones H2A, H2B, H3 andH4 is located inside a nucleosome, the central building block of chromatin, with about 150 base pairs of DNA wrapped around. The basic nature of histones, mediated by the high content of lysine and arginine residues, allows a direct interaction with the acidic phosphate back bone of DNA. The fifth histone HI is located outside at the junction between nucleosomes and is referred to as the linker histone. Besides the main histones, so-called histone variants are known, which replace core histones in certain locations like centromers. 

Acid phosphates (e.g., orthophosphates) such as phosphoric acid or sodium dihydrogen phosphate)... 

NOTE Acid phosphates and SHMP may attack chemical tanks and associated equipment, so acid-resistant equipment should be specified. Alternatively, the addition of caustic up to a pH level of 8.2 to 8.3 (the production of a pink color when tested with phenolphthalein) provides adequate protection. A further alternative is to add neutralizing amine to the tank. 

Low pH localized corrosion resulting from acid phosphates. 

Coordinated phosphate control charts assume either that all contribution to pH level is derived from phosphate or that the buffering action of phosphate is sufficient to overcome the presence of other alkaline species, such as amines. Neither assumption is true. This may lead operators to conclude perhaps that a higher than anticipated bulk water pH level (caused by the presence of amine) should be rectified by the addition of MSP. This action may lower localized Na P04 ratios below 2.2 1.0, producing acid phosphate corrosion (phosphate wastage) and resulting in tube thinning and ultimately tube failure. 

Additionally, the combination of high temperatures (over 600 to 610 °F/320 °C, 1,550 psia/107 bar) and acid phosphates has given rise to more pronounced acid phosphate attack of both magnetite and base metal, which in modem tube steel alloy compositions may produce esoteric corrosion products such as maricite (NaFeP04). Secondary corrosion by caustic gouging (as similarly evidenced by hydrogen evolution) also occurs. 

Figure 10.5 Coordinated, congruent, precision control, equilibrium and non-acid phosphate programs for higher-pressure WT boilers...

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