Orthophosphate derivatives

The prefix is also used in orthophosphates, orthocarbonates, orthoformates and ortho-silicates, which are derivatives of POCOH), the hypothetical C(OH)4, HC(OH)3 and Si(OH)4 respectively in these the word ortho is always written in full. 

Phosphoric acids and the phosphates maybe defined as derivatives of phosphoms oxides where the phosphoms atom is in the +5 oxidation state. These are compounds formed in the M2O—P20 system, where M represents one cation equivalent, eg, H", Na", 0.5 Ca ", etc. The molecular formula of the phosphoms(V) oxide [1314-56-3] is actually P O q, but this oxide is commonly referred to in terms of its empirical formula, P2O5. StmcturaHy, four phosphoms—oxygen (P—O) linkages are arranged in an approximate tetrahedral configuration about the phosphoms atom in the phosphate anion. Compounds containing discrete, monomeric PO ions are known as orthophosphates or simply as phosphates. 

Condensed phosphates are derived by dehydration of acid orthophosphates. The resulting polymeric stmctures are based on a backbone of P—O—P linkages where PO tetrahedra are joined by shared oxygen atoms. The range of materials within this classification is extremely broad, extending from the simple diphosphate, also known as pyrophosphate, to indefinitely long-chain polyphosphates and ultraphosphates (see Table 1). Both weU-defined crystalline and amorphous materials occur among the condensed phosphates. 

Na[Sb(OH)g], respectively. The latter compound is one of the least soluble sodium salts known and is useful in sodium analysis. Numerous polyantimonate(V) derivatives are prepared by heat treatment of mixtures of antimony trioxide and other metal oxides or carbonates. Of these, K Sb O [12056-59-6] and K Sb O [52015-49-3] have been characterized by x-ray. These consist of three-dimensional networks of SbO in which corners and edges are shared with K" ions located in tunnels through the network (23). Simple species such as SbO and Sb20 2, analogous to orthophosphate and pyrophosphate, apparendy do not exist. 

Phosphates. Insoluble orthophosphates may be precipitated with phosphate ion derived from trimethyl or triethyl phosphate by stepwise hydrolysis. Thus 1.8M sulphuric acid containing zirconyl ions and trimethyl phosphate on... 

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

Phosphorus forms a wide variety of oxoanions, which outnumber those formed by any other element except silicon [ 1 ]. Many of these anionic hgands are of industrial importance and their derivatives are essential components of numerous biological processes. Some of the more common examples include orthophosphate PO " (1), phosphite HPO " (2) and metaphosphate PO3 (3). 

The most general method for the simultaneous analysis of oxyanions by gas chromatography is the formation of trimethylsilyl derivatives. Trimethylsilyl derivatives of silicate, carbonate, oxalate, borate, phosphite, phosphate, orthophosphate, arsenite, arsenate, sulfate and vanadate, usually as their ammonium salts, are readily prepared by reaction with BSTFA-TMCS (99 1). Fluoride can be derivatized in aqueous solution with triethylchlorosilane and the triethylfluorosilane formed extracted into an immiscible organic solvent for analysis by gas chromatography [685). 

In 1970, Monroe and Rooker(28) claimed the use of aluminum salts of acid orthophosphate esters as viscosity builders for use in fracturing fluids. The application of these materials began a new era of hydrocarbon gelling agents. Monroe(29) later claimed the use of Fe30it as a metal activator of phosphate esters and in 1971 described several other metals(30) that could be used with amine neutralization agents. Numerous metallic ionic derivatives can be used as effective "activators" or crosslinkers to prepare a gel. 

Some coupled systems allow measurement of the main N and P forms (nitrate, ammonia and orthophosphates) [22,27,29], among which is a system based on membrane technology in combination with semi-micro continuous-flow analysis (pCFA) with classical colorimetry. With the same principle (classical colorimetry), another system [30] proposes the measurement of phosphate, iron and sulphate by flow-injection analysis (FIA). These systems are derived from laboratory procedures, as in a recent work [31] where capillary electrophoresis (CE) was used for the separation of inorganic and organic ions from waters in a pulp and paper process. Chloride, thiosulphate, sulphate, oxalate,... 

When oxygen is excluded from the polymerization system, the initiating species is derived from ascorbic acid directly (50,51). Santappa (50) showed that a complex obtained from ascorbic acid and sodium hydrogen orthophosphate was a more effective initiator than ascorbic acid alone, and that the increased efficiency is due to reduction of the reactivity of the oxidized species toward semireduced dye when it is complexed to orthophosphate. 

The calcium salt of 2-amino-2-deoxy-D-glucosyl phosphate has been synthesized37 by the interaction of 2-acetamido-3,4,6-tri-0-acetyI-2-deoxy-a-D-glucosyl chloride with silver orthophosphate, with subsequent partial saponification. On the basis of optical rotation, the derivative has been assigned to the a-n series. 2-Amino-2-deoxy-D-glucosyl phosphate is much less stable than the 6-phosphate toward acidic hydrolysis, but it is markedly more... 

XPS, AES, RAIR The tribofilms were amorphous phosphates which are mainly orthophosphate (P043 ) and pyrophosphate (PjQ,4") associated with Zn and Ca derived from carbonate-detergent RMs (Willermet etal., 1991,1992, 1995a). 

However, most nucleophiles attack 5-oxazolones at the carbonyl group and the products are derivatives of a-amino acids formed by acyl-oxygen fission. Thus the action of alcohols, thiols, ammonia and amines leads, respectively, to esters, thioesters and amides orthophosphate anion gives acyl phosphates (Scheme 18). The use of a-amino acids in this reaction results in the establishment of a peptide link. Cysteine is acylated at the nitrogen atom in preference to the sulfur atom. Enzymes, e.g. a-chymotrypsin and papain, also readily combine with both saturated and unsaturated azlactones. A useful reagent for the introduction of an a-methylalanine residue is compound (202). Both the trifluoroacetamido and ester groups in the product are hydrolyzed by alkali to give a dipeptide. The alkaline hydrolyzate may be converted into the benzyloxycarbonyl derivative, which forms a new oxazolone on dehydration. Reaction with an ester of an amino acid then yields a protected tripeptide (equation 45). 

Just recently, Stauffer and Steinbeiser [96] have presented an intermole-cular consecutive aryl amination-Suzuki coupling sequence where, in the presence of potassium orthophosphate as a weak base and Pd[P(ferf.-Bu)3]2 as a catalyst system, the morpholino-biaryl derivative 111 was obtained in moderate yield (Scheme 40). 

IV.28 ORTHOPHOSPHATES, P04 Three phosphoric acids are known orthophosphoric, H3P04 pyrophosphoric, H4P207 and metaphosphoric acid, HP03. Salts of the three acids exist the orthophosphates are the most stable and the most important solutions of pyro- and metaphosphates pass into orthophosphates slowly at the ordinary temperature, and more rapidly on boiling. Metaphosphates, unless prepared by special methods, are usually polymeric, i.e. are derived from (HP03) . 

The first report of orthophosphate-bridged species described a complex (NH4)2 (H)4[Pt2(P04)4(H20)2 and several derivatives thereof152). Further preparative and structural investigations have provided a detailed picture of the chemistry of these compounds. The sodium analog of the above compound was obtained in crystalline form... 

Derivation Controlled calcination of sodium orthophosphate mixture from sodium carbonate and phosphoric acid. May contain up to 10% pyrophosphate and up to 5% tri-metaphosphate. 

The retention model developed by Eon and Guiochon [7,8] to describe the adsorption effects at both gas-liquid and liquid-solid interfaces, which was later modified by Mdckel et al. [6] to account for the retention at chemically bonded reversed-phase materials in HPLC, is not applicable to ion chromatography. But if the dependence of the capacity factors of various inorganic anions on the column temperature is studied, certain parallels with HPLC are observed. The linear dependences shown in Fig. 3-2 are obtained for the ions bromide and nitrate when the In k values are plotted versus the reciprocal temperature (van t Hoff plot). However, in the case of fluoride, chloride, nitrite, orthophosphate, and sulfate, the k values were found to be constant within experimental error limits in the temperature range investigated. Upon linear regression of the values in Table 3-1, the following relations are derived for bromide and nitrate ... 

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