the acid h2po4- and po43- could best be referred to as what compounds

Phosphoric Acid

C.B. Spainhour , in Encyclopedia of Toxicology (Third Edition), 2014

Abstruse

Phosphoric acid, likewise known as orthophosphoric acrid, is a triprotic acrid that exists as a dumbo liquid. It is an irritant or corrosive to the skin, optics, and other mucous membranes of both humans and laboratory animals. Its salts, though, exhibit a significantly lower irritancy potential. Moderate toxicity has been observed in mice when exposed via the inhalation route. Phosphoric acid is non genotoxic nor carcinogenic, only phosphate salts accept been reported to promote the activity of known carcinogens. Exposures are treated typically past irrigation or flushing with water. Phosphoric acid has enjoyed pregnant interest equally a food additive to various cola drinks, causing great controversy with regard to the potential for harmful effects. The major consideration in the pollution of the aquatic environment is the pH of the h2o as regards effects on ethnic flora and fauna. There is no bioamplification or bioaccumulation reported.

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Phosphoric Acid*

Samantha East. Gad , Russell Barbare , in Encyclopedia of Toxicology (2nd Edition), 2005

Uses

Phosphoric acid is a component of fertilizers (lxxx% of total employ), detergents, and many household cleaning products. Dilute solutions have a pleasing acid taste; thus, information technology'southward too used as a nutrient condiment, lending acidic properties to soft drinks and other prepared foods, and in water treatment products. It is also used in rust proofing, engraving, and metal coating and is an intermediate or reagent in many manufacturing processes. Phosphoric acid also occurs naturally in many fruits and their juices. Apart from use of phosphoric acid itself, the greatest consumption of phosphoric acrid is in the manufacture of phosphate salts. Taking reward of its power to lower blood pH, phosphoric acid has been used therapeutically to treat lead poisoning.

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Nontraditional Acid-Base Analysis

Kate Hopper BVSc, PhD, DACVECC , in Small Animal Critical Care Medicine (Second Edition), 2015

Phosphate Issue

Phosphoric and sulfuric acids are products of protein metabolism and are normally excreted by the kidneys. Patients with acute kidney injury or failure retain these acids, resulting in a metabolic acidosis. The phosphoric acid contribution toward BE, from a given inorganic phosphorus concentration, is adamant by use of the equation in Table 55-ane. Elevated phosphorus will cause a negative effect and indicates an acidotic influence on BE. Considering serum phosphorus concentration is normally low, hypophosphatemia does not cause a clinically significant alkalosis. Sulfate is not unremarkably measured and is therefore i of the unmeasured anions.

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PRESERVATIVES | Traditional Preservatives – Organic Acids

J.B. Gurtler , T.L. Mai , in Encyclopedia of Nutrient Microbiology (2d Edition), 2014

Phosphoric Acid (Inorganic Acid)

Phosphoric acid, although an inorganic acid, is worthy of mention in this chapter. It is used predominantly as an acidulant, almost exclusively in the production of carbonated beverages, although its use in foods bears controversy due to its furnishings on health. Insufficiently, phosphoric acid is extremely inexpensive, possessing a characteristic flat sour gustation that is reminiscent of citric acid. It is a relatively strong, dissociated acrid, enabling it to easily acidify colas to the depression desired pH (2.five) needed to establish proper carbonation, although its antimicrobial efficacy is far junior to most organic acids, principally due to its dissociated state, which precludes ease of transport across the bacterial membrane.

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Polymers for a Sustainable Environment and Green Energy

T. Heinze , T. Liebert , in Polymer Science: A Comprehensive Reference, 2012

x.05.6.2.ii Phosphates

Phosphoric acid is trifunctional and possesses the ability to cross-link cellulose, leading to insoluble products with undefined structure. Cross-link cellulose phosphates may be used as weak cation exchangers. ^444,445 Phosphorylation is too carried out to increase the flame retardancy of textile fibers. ⁴⁴⁶

Typical phosphorylating agents are polyphosphoric acrid, POCl₃, P_twoO₅, phosphoric acid salts, and h2o-gratuitous H₃PO₄ in combination with P_iiO_v. ⁴⁴⁷ The conversion of cellulose with H₃PO_four and urea unremarkably yields highly swellable products. ^448,449 An interesting phosphorylation mixture is H₃PO₄ in combination with P₂O_v and (C₂H_fiveO)₃PO. In hexanol, a cellulose phosphate gel is obtained that is expected to promote calcium phosphate formation during bone regeneration. ⁴⁵⁰

The effective reagent POCl_three tin can be exploited in unlike reaction media (due east.g., DMF and Py), but the reaction yields but partly soluble products (cross-linking). Moreover, if the reaction is carried out in DMF, remarkable chlorination occurs due to the formation of iminium compounds. ⁴⁵¹ Therefore, formamide is the recommended reaction medium for conversions of cellulose with PCl₃, PCl₅, and POCl₃. ⁴⁵² The reaction of cellulose dissolved in nonderivatizing solvents (e.g., DMAc/LiCl) does not yield soluble products. Spontaneous gelation occurs resulting in inhomogeneous products. ⁴⁵³ North₂O₄/DMF is an appropriate medium for the preparation of cellulose phosphates applying POCl₃ and TEA. ⁴⁵⁴ POCl_three tin be partially hydrolyzed with h2o or treated with N_twoO₄ in order to reduce the reactivity of the reagent. ⁴⁵⁵ H2o-soluble cellulose phosphates tin can as well be prepared starting from CAs with polytetraphosphoric acid and subsequent deacetylation. ⁴⁵⁶

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Cements and Liners

B.W. Darvell DSc CChem CSci FRSC FIM FSS FADM , in Materials Scientific discipline for Dentistry (Tenth Edition), 2018

•7.4 Setting reactions

Phosphoric acid was again used for the liquid in these now all-just obsolete silicate cements, although the concentration and additives were unlike from those used with zinc phosphate cement. The reason for this selection may be based on a combination of factors. Phosphoric acid is a relatively weak acid, so that dissolution of the glass would be relatively slow. Notwithstanding, the particular chemical science of the aluminium ions released may boss the resultant properties. Information technology would tend to give a stronger product due to the stronger ionic interactions between the tribasic phosphoric acid and a trivalent cation. At that place would also be improve water binding as well considering of the high charge and opportunities for hydrogen bonding.

Aluminium ions besides readily class polymeric species in solution, with polyvalent anions forming bridges betwixt the similarly highly-charged aluminium cations (Fig. 7.iv); phosphate thus performs this role well. These bridged structures (Fig. 7.v) extend as the concentration of aluminium rises during the hydrolysis and dissolution of the glass, and somewhen result in the coprecipitation of highly hydrated aluminium phosphate and silica gels. In that location may even exist some covalent bonding between these two making, in effect, a unmarried network. These inter-penetrating insoluble gels thus form the matrix of the cement in which are embedded the unreacted glass particles, which again must exist in excess to form the strong core of the blended structure. In that location are likewise small crystallites of the only very slightly soluble calcium fluoride formed at the same time. The reactions may exist summarized as follows:

Fig. vii.4. Aluminium phosphate complex bridge construction found in solution.

Fig. seven.5. Possible construction of a fragment of the aluminium phosphate gel polymer. The rings probably prefer the 'chair' conformation, as in cyclohexane (see Fig. 17§2.14).

(vii.ii) $\begin{array}{ccc}\mathit{glass}+{\text{H}}^{+}& \Rightarrow & {\text{Al}}^{\mathrm{iii}+}+{\text{Ca}}^{2+}+{\text{Na}}^{+}+{\text{SiO}}_{\mathrm{iv}}^{4-}+{\text{F}}^{-}\\ n{\text{SiO}}_{\mathrm{iv}}^{\mathrm{iv}-}+4n{\text{H}}^{+}& \Rightarrow & {\left({\text{SiO}}_2\right)}_n\cdot 2\mathrm{northward}{\text{H}}_{\mathrm{two}}\text{O}\left(\mathit{silica}\mathit{gel}\right)\\ x{\text{Al}}^{3+}+\mathrm{ten}{\text{PO}}_{\mathrm{four}}^{3-}& \Rightarrow & {\left({\text{AlPO}}_{\mathrm{iv}}\right)}_x\left(\mathit{phosphate}\mathit{gel}\right)\\ {\text{Ca}}^{2+}+\mathrm{two}{\text{F}}^{-}& \Rightarrow & {\text{CaF}}_2\\ {\text{Na}}^{+}+2{\text{H}}^{+}+{\text{PO}}_{\mathrm{four}}^{3-}& \Rightarrow & {\text{NaH}}_2{\text{PO}}_{\mathrm{four}}\end{array}$

(No try has been made to remainder these reactions, equally the glass is not a stoichiometric chemical compound and the exact chemistry of well-nigh of the reaction products is uncertain. For example, silica gel is a very indefinite entity. They must instead be treated as purely symbolic tokens rather than rigorous statements.) These reactions lead to the full general kind of structure shown in Fig. 7.6.

Fig. 7.6. General structural alter on setting for a silicate drinking glass - acid cement.

Setting is accompanied by shrinkage. Given that fact and that these materials are non-adhesive, in that location was therefore a trend to marginal leakage. A farther problem is that a sure proportion of the reaction products are very soluble, in particular the sodium phosphate (Fig. seven.7), although this dissolution is near complete very chop-chop (Fig. vii.8).

Fig. 7.7. Leaching from silicate cements of aluminium and phosphorus, expressed as their oxides, as a function of pH.

Fig. seven.eight. Comparative dissolution rates of silicate and zinc phosphate cements.

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Heteroatom Manipulation

Yoshihiro Hayakawa , in Comprehensive Organic Synthesis, 1991

An organic phosphoric acid is a well recognized structural unit appearing in a number of biologically important substances such as nucleic acids, phospholipids, and inositol phosphates, and, accordingly, efforts to construct the structure have extensively been made so far, providing many means to the organic phosphoric acrid derivatives. ^ane Among the existing methods, the most straightforward and synthetically useful one is phosphorylation of protic substances. In phosphorylation, of swell importance is discovery of constructive phosphorylating agents. In addition, invention of the protecting groups for a phosphoric acid moiety is sometimes an essential trouble, because the many important classes of biochemical substances discussed in a higher place are phosphomonoesters or phosphodiesters, which generally are derived past deprotection of the corresponding phosphotriester precursors. This chapter describes methods of phosphorylation, which are classified by the blazon of phosphorylating agents employed, and makes brief discussion on the protecting groups.

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Enzymatic Polymerizations

Jun-ichi Kadokawa , in Methods in Enzymology, 2019

2.half dozen Activeness assay of GP

GP activities are evaluated for polymerization and phosphorolysis every bit follows (Bhuiyan et al., 2003; Takaha et al., 2001).

Grooming of phosphoric acid scale bend: 0.i, 0.ii, 0.three, 0.4, 0.5, 0.6   mmol/L potassium dihydrogen phosphate aqueous solutions were prepared. 800   μL of molybdate reagent (15   mmol/L ammonium molybdate and 100   mmol/Fifty zinc acetate aqueous solution) and 200   μL of 0.57   mol/L sodium ascorbate aqueous solution were added to a mixture of 200   μL of distilled water and 200   μL of each phosphate solution. The mixtures were incubated at xxx   °C for 20   min. Absorbance of the mixture was measured at 850   nm. A phosphoric acrid scale bend was prepared past plotting the concentration of phosphoric acid at Y-centrality and the absorbance at 850   nm at 10-axis.

Assay for polymerization: The product of phosphate (P_i) from Glc-ane-P is measured according to the literature method (Bhuiyan et al., 2003; Takaha et al., 2001). Briefly, a reaction solution (200   μL) of Glc-1-P (monomer, 45   mmol/50), soluble starch (primer, 1% (w/v)) in acetate buffer (0.2   mol/L, pH 6.0), and thermostable GP (from Aquifex aeolicus VF5, 0.323   U) was incubated at temperature range from 22   °C to 100   °C for 30   min. The reaction was stopped by adding twenty% (westward/5) sodium dodecyl sulfate aqueous solution (x   μL). The amount of P_i released was measured past the method according to the literature (Saheki, Takeda, & Shimazu, 1985) with small modification as follows. 800   μL of molybdate reagent (15   mmol/L ammonium molybdate and 100   mmol/L zinc acetate aqueous solution) and 200   μL of 0.57   mol/L sodium ascorbate aqueous solution were added to the reaction mixture. The mixture was incubated at 30   °C for fifteen   min. Absorbance of the mixture was measured at 850   nm. The amount of inorganic phosphate produced in the reaction was determined by using the abovementioned phosphoric acrid calibration curve.

Assay for phosphorolysis: Activity was assayed by evaluating the corporeality of Glc-1-P produced from soluble starch and P_i by the ⁱH NMR analysis. A reaction mixture (600   μL) containing sodium phosphate buffer (0.1   mol/L, pH 7.0), ane% (due west/five) soluble starch, and thermostable GP (from Aquifex aeolicus VF5, 0.323   U) was incubated at range from 22   °C to 100   °C for fifteen   min. The reaction was stopped by adding twenty% (w/v) sodium dodecyl sulfate aqueous solution (10   μL). The mixture was dissolved in 0.5   mol/50 NaOD/D_twoO for ¹H NMR measurement to determine the corporeality of Glc-1-P produced in the reaction.

The relative activities of the enzyme for polymerization and phosphorolysis are shown in Fig. half dozen.

Fig. 6. Effect of temperature on the activeness of thermostable GP (Aquifex aeolicus VF5) for polymerization (●) and phosphorolysis (▪).

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ANTIOXIDANTS | Synthetic Antioxidants

G. Ramis-Ramos , in Encyclopedia of Nutrient Sciences and Nutrition (Second Edition), 2003

Orthophosphoric Acrid and Orthophosphates

The antioxidant synergism of orthophosphoric acid and its salts is a result of their power to complex metallic ions. The redox potential of the Fe₃₊/Fe_ii+ pair is especially lowered in the presence of phosphates, even in acid medium. Orthophosphoric acid can be used to assist in caramelization (FDA 73.85), equally a neutralizing agent in cacao (FDA 163.110), and every bit an acidifying agent in cheese manufacture (FDA 133.123, 124). Several sodium and potassium orthophosphates and pyrophosphates can also be used as emulsifying agents to process cheese (FDA 133.169, 173). The acid is likewise added to soft drinks and has miscellaneous industrial applications.

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Chiral heteroatom-containing compounds

Piotr Kiełbasński , Marian Mikołajczyk , in Hereafter Directions in Biocatalysis, 2007

three.6 Stereocontrolled transformations of organophosphorus acid esters

A variety of phosphoric acid triesters and their derivatives are used as pesticides. Although in that location are no natural phosphorotriesters, those bogus ones undergo decomposition in the soil, implying that some microorganisms be which are capable of hydrolysing them. The first written report on a stereoselective enzymatic phosphotriester hydrolysis was published in 1973, when Dudman and Zerner succeeded in the enzymatic preparation of optically active northward-butyl methyl p-nitrophenyl phosphate starting from the racemic substrate. The enzyme involved in this reaction was an ingredient of the horse or beef serum. ¹⁰¹ Afterwards on, phosphotriesterase, an enzyme establish in sure native soil bacteria (Pseudomonas diminuta and Flavobacterium sp.), was shown to degrade organophosphates. ¹⁰² Raushel et al. used this enzyme for hydrolysis of the phosphonothionate 92 and institute out that information technology hydrolysed exclusively the (Due south)-enantiomer of the substrate. The reaction proceeded with inversion of configuration at phosphorus and gave the (Due south)-enantiomer of the thioacid 93 (Equation 44). ¹⁰³

(44)

Phosphotriesterase from P. diminuta (PTE) was found to exhibit high hydrolytic activeness towards various types of tetracoordinated phosphorus acid esters. Apart from the phosphonothionate 92, phosphoric acrid triesters 94 (Equation 45), ¹⁰⁴ benzenephosphonic acid diester 95 (Equation 46) ¹⁰⁵ and methylphenylphosphinic acid ester 96 (Equation 47) ¹⁰⁶ were as well stereoselectively hydrolysed nether kinetic resolution weather condition. Of class, in the case of the latter iii kinds of substrates, half of the reacting ester was irreversibly lost due to the germination of achiral phosphorus acids.

(45)

In the case of the phosphotriesters 94, the use of engineered mutants of phosphotriesterase allowed not only to enhance but even to reverse the stereoselectivity of the native enzyme. The ees of the recovered esters exceeded 95%. ¹⁰⁴

(46)

In turn, for the phosphonic acrid diester 95, stereoselectivity of the native phosphodiesterase was enhanced by over three orders of magnitude by alteration of the pKa values of the leaving group phenol. For example, for Ten = CO₂Me, Y = H the stereoselectivity was 5000 higher than for X = NO₂, Y = ii-F. ¹⁰⁵

(47)

Both types of manipulation were applied to attain the required enantiomer and the highest enantioselectivity in the hydrolysis of the phosphinic acid diester 96. ¹⁰⁶

Finally, non-racemic phosphorothioic and phosphonothioic acids 98 were obtained via a PTE-catalysed stereoselective hydrolysis of the prochiral substrates 97 (Equation 48). ¹⁰⁷ The absolute configurations of the thioacids 98 depended on whether native PTE or its mutants were used.

(48)

In addition to phosphotriesterase from P. diminuta (PTE) discussed above, 2 other types of enzymes were found to exhibit phosphotriesterase action. Interestingly, both are peptidases – the enzymes which in nature hydrolyse a peptide bond. The first i – organophosphorus acrid anhydrolase (OPAA) from Alteromonas sp. JD6.5 – is a proline dipeptidase; its original activity is to cleave a dipeptide bond with a prolyl residue at the carboxy terminus. ^108,109 The 2nd one – aminopeptidase P (AMPP) from Escherichia coli – is a proline-specific peptidase that catalyses hydrolysis of North-terminal peptide bonds containing a proline residue. ^110,111

OPAA was found to exhibit stereoselectivity towards phosphorotriester substrates 94, with a preference for the (Due south)-enantiomer. Surprisingly, the selectivity was most apparent for the substrates in which the non-hydrolysing substituents did not differ too much. For example, for 94 (R¹ = Me, R² = Et) the chiral preference was 112-fold, while for 94 (R¹ = Me, R² = i-Pr) it was 100-fold. ¹⁰⁸ Similarly, p-nitrophenyl analogues of sarin 99 and soman 100 (fluorine replaced by the p-nitrophenoxy group) were stereoselectively hydrolysed by OPAA with a 2- to 4-fold preference for the (R)-enantiomer. In the instance of the soman analogue 100, the enzyme also exhibited an additional preference for the configuration of the stereogenic carbon atom, which depended on the configuration at phosphorus. ¹⁰⁹

In turn, AMPP was found to stereoselectively hydrolyse the phosphonothionate 101, exhibiting preference towards the (S)-enantiomer. The hydrolysis proceeded with inversion of configuration at phosphorus, similar to that shown in Equation 44. ¹¹¹

All the enzymes discussed in a higher place belong to the class of dimetalloenzymes. ¹¹² In this context, it should exist mentioned that serine-blazon hydrolases are irreversibly inhibited by organophosphorus esters, among them highly toxic chemical warfare agents. Still, in some cases, for instance of man butyrylcholinoesterase, the inhibited enzyme could be reactivated by proper mutations. ¹¹³ Moreover, such mutations were constitute to confer phosphotriesterase action in this enzyme! ¹¹⁴

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