Tribasic acids

The mixed lanthanide (III) ions (Ln3+) can be absorbed from solution at the top of a column of a cation-exchange resin RSOsNa (Section 14.4) and then selectively eluted from it, that is, swept down the column in bands by a stream of a solution of a substance that competes with the Ln3+ for sites in the resin. An acidic tribasic chelating agent H3X (usually citric acid/sodium citrate buffer) is used so that, as in reaction 17.16, the tendency for a specific Ln3+ to form neutral LnX and so escape the electrostatic... 

Tribasic calcium phosphate occurs naturally as the minerals hydroxylapatite, voelicherite, and whitlockite. Commercially, it is prepared by treating phosphate-containing rock with sulfuric acid. Tribasic calcium phosphate powder is then precipitated by the addition of calcium hydroxide. Tribasic calcium phosphate is alternatively prepared by treating calcium hydroxide from limestone with purified phosphoric acid. It may also be obtained from calcined animal bones.Some tribasic calcium phosphate products may be prepared in coarser, directly compressible forms by granulating the powder using roller compaction or spray drying. 

Synonyms Citric acid, triammonium salt 1,2,3-Propanetricarboxylic acid, 2-hydroxy-, triammonium salt Triammonium citrate Triammonium salt of 2-hydroxypropan-1,2,3-tricarboxylic acid Tribasic ammonium citrate Empirical C6H17N3O7... 

Tetraoxophosphoric acid is a colourless solid, very soluble in water an 85% solution is often used ("syrupy phosphoric acid ). It is tribasic. giving the ions ... 

Arsenic(V) acid, H3ASO4 (strictly, tetraoxoarsenic(V) acid) is obtained when arsenic is oxidised with concentrated nitric acid or when arsenic(V) oxide is dissolved in water. It is a moderately strong acid which, like phosphoric V) acid, is tribasic arsenates V) in general resemble phosphates(V) and are often isomorphous with them. 

Dissolve (or suspend) 0-25 g. of the acid in 5 ml. of warm water, add a drop or two of phenolphthalein indicator and neutralise carefully with ca. N sodium hydroxide solution. Then add 2-3 drops of ca. O lN hydrochloric acid to ensure that the solution is almost neutral (pale pink colour). (Under alkaline conditions the reagent tends to decompose to produce the evil-smelling benzyl mercaptan.) If the sodium salt is available, dissolve 0-25 g. in 5 ml. of water, and add 2 drops of ca. 0 -hydrochloric acid. Introduce a solution of 1 g. of S-benzyl-iso-thiuro-nium chloride in 5 ml. of water, and cool in ice until precipitation is Dibasic and tribasic acids will require 0-01 and 0-015 mol respectively. 

Tetrabasic Lead Sulfate. Tetrabasic lead sulfate [12065-90-6] 4PbO PbSO, mol wt 1196.12, sp gr 8.15, is made by fusion of stoichiometric quantities of Htharge (PbO) and lead sulfate (PbSO heat of formation, Ai/ = — 1814 kJ/mol (—434.1 kcal/mol). Alternatively, tetrabasic lead sulfate may be prepared by boiling the components in aqueous suspensions. At about 70°C, tribasic hydrate reacts with lead oxide to form tetrabasic sulfate. At 80°C, this transformation is complete in - 20 hours. Tetrabasic lead sulfate is used in limited quantities in Europe as a PVC stabilizer. However, in the United States, lead-acid batteries have been developed by BeU Telephone Laboratories, which contain tetrabasic lead sulfate. Such batteries are used for emergency power at telephone switchboard stations and have an anticipated service life of over 50 years. 

Phosphorus. Eighty-five percent of the phosphoms, the second most abundant element in the human body, is located in bones and teeth (24,35). Whereas there is constant exchange of calcium and phosphoms between bones and blood, there is very Httle turnover in teeth (25). The Ca P ratio in bones is constant at about 2 1. Every tissue and cell contains phosphoms, generally as a salt or ester of mono-, di-, or tribasic phosphoric acid, as phosphoHpids, or as phosphorylated sugars (24). Phosphoms is involved in a large number and wide variety of metaboHc functions. Examples are carbohydrate metaboHsm (36,37), adenosine triphosphate (ATP) from fatty acid metaboHsm (38), and oxidative phosphorylation (36,39). Common food sources rich in phosphoms are Hsted in Table 5 (see also Phosphorus compounds). 

Properties. Phosphoric acid is a tribasic acid, in which the first hydrogen ion is strongly ionizing, the second moderately weak, and the third very weak. 

Maleic acid and fumaric acid can also be, and are often, incorporated in alkyd resins in the form of the Diels-Alder adduct of rosin. The adducts are tribasic acids which provide pendent carboxyl groups in the resin molecules, which can be saponified to give ionic, and, in turn, water-soluble characteristics to the resin. However, the resultant alkyds often have poorer color retention, toughness, gloss retention, and exterior durabiUty. 

Although cyanuric acid is a tribasic acid, only the first ionization is important at normal swimming pool pHs. The concentration of cyanurate is given by [H2Cy ] = Oc[, where is the total concentration of cyanuric acid and cyanurate ion and [Pg.299]

Paste Mixing. The active materials for both positive and negative plates are made from the identical base materials. Lead oxide, fibers, water, and a dilute solution of sulfuric acid are combined in an agitated batch mixer or reactor to form a pastelike mixture of lead sulfates, the normal, tribasic, and tetrabasic sulfates, plus PbO, water, and free lead. The positive and negative pastes differ only in additives to the base mixture. Organic expanders, barium sulfate [7727-43-7] BaSO carbon, and occasionally mineral oil are added to the negative paste. Red lead [1314-41 -6] or minium, Pb O, is sometimes added to the positive mix. The paste for both electrodes is characterized by cube weight or density, penetration, and raw plate density. 

Salt Formation. Citric acid forms mono-, di-, and tribasic salts with many cations such as alkahes, ammonia, and amines. Salts may be prepared by direct neutralization of a solution of citric acid in water using the appropriate base, or by double decomposition using a citrate salt and a soluble metal salt. 

There are four basic sulfates that can be identified by potentiometric titration using sodium carbonate (39,40) langite [1318-78-17, CuSO -3Cu(OH)2 H2 i brochantite [12068-81 -4] CuSO -3Cu(OH)2 antedite [12019-54-4] CuSO -2Cu(OH)2 and CuS0 -Cu0-2Cu(0H)2-xH20. The basic copper(II) sulfate that is available commercially is known as the tribasic copper sulfate [12068-81 ] CuS04-3Cu(0H)2, which occurs as the green monoclinic mineral brochantite. This material is essentially insoluble in water, but dissolves readily in cold dilute mineral acids, warm acetic acid, and ammonia solutions. 

Dicyclopentadienedicarboxyhc acid can undergo a Diels-Alder reaction in the presence of a stoichiometric amount of a dienophile at 140—190°C to give an adduct of the monomeric acid. The yield of adduct is usually 75—95%. A large number of polyfunctional compounds are easily prepared in this manner. The reaction with maleic anhydride gives a tribasic acid. 

Chemical Designations - Synonyms Sodium phosphate is generic term and includes the following (1) monosodium phosphate (MSP sodium phospWe, monobasic), (2) disodium phosphate (DSP sodium phosphate dibasic), (3) trisodium phosphate (TSP sodium phosphate, tribasic), (4) sodium acid pyrophosphate (ASPP SAPP disodium pyrophosphate (TSPP), (6) sodium metaphosphate (insoluble sodium metaphosphate), (7) sodium trimetaphosphate, and (9) sodium tripolyphosphate (STPP TPP) Chemical Formula (1) NaHjPO (2) Na HPO (3) NajPO (4) Na H P O, (5) Na P O, (6) (NaPOj) (7) (NaP03)3 (8) (NaP03) NaO (9) Na,P30,o. 

Rings (C) and (D) account for the production of quinoline, when the tribasic acid, Ci H OgN, m.p.>350°, obtained by the oxidation of ergotinine with nitric acid, is distilled with soda-lime. ... 

A consequence of the tribasic nature of phosphoric acid (three -OH groups attached to phosphorus) is the increased number of options available in the overall process of conversion of alcohol to protected phosphate. The conversion might be carried out by the sequence... 

Paste mixing means the addition of sulfuric acid and water. The result is a fairly stiff paste with a density between 1.1 and 1.4gcm 3 containing 8-12wt% of lead sulfate. The water content of thus mix determines the porosity of the active material achievable later (cf. "curing" below). In the paste, a mixture of lead sulfate and basic lead sulfate is formed (cf. Table 1). In the usual mixing process between room temperature and 50 °C, tribasic lead sulfate is formed. The generation of the tetrabasic... 

Orthophosphates are derived from the tribasic orthophosphoric acid (H3P04). 

Carboxylic acids with one acid group are known as monobasic acids while those with two acid groups are dibasic acids. All acids with more than one acid group are in the class of polybasic acids. The simplest organic acid, formic acid, is responsible for the irritation of bee and ant stings. Vinegar is a 5% solution of acetic acid in water. The acetic acid is responsible for the characteristic sour taste. Citric acid, found in citrus fruits and used in soft drinks, is a tribasic acid with three carboxylic acid groups. The dibasic acid, adipic acid, is a major component of nylon. 

Concentrated solutions of orthophosphoric acid, often containing metal salts, are used to form cements with metal oxides and aluminosilicate glasses. Orthophosphoric acid, often referred to simply as phosphoric acid, is a white crystalline solid (m.p. 42-35 °C) and there is a crystalline hemihydrate, 2H3PO4.H2O, which melts at 29-35 °C. The acid is tribasic and in aqueous solution has three ionization constants (pA J 2-15,7-1 and 12-4. 

Tribasic acids these are acids which have three replaceable hydrogen atoms in each molecule, such as, for example, H3P04. 

Analogously, a tribasic polyacid can be represented by the copolymer of maleic acid with acrylic acid ... 

E Nelson. Dissolution rate of mixtures of weak acids and tribasic sodium phosphate. J Am Pharm Assoc 47 300-302, 1958. 

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