Of phosphomolybdic acid

A solution of phosphomolybdic acid m nitric acid, which gives yellow precipitates of different shades. 

Phosphomolybdic acid oxidizes most organic compoimds nnder formation of a bine-grey dye. For reagent preparation, 250 mg of phosphomolybdic acid must be dissolved in 50 ml of methanol. The plate mnst be heated to 120°C until the predominantly blue spots are visible [17]. 

All reactions were monitored by TLC analysis on Merck silica gel 60 F254 plates, which were visualized by a 254-nm UV lamp and stained with an ethanolic solution of phosphomolybdic acid. TLC analysis showed clean formation of the 2-nitrobenzenesulfonamide (hexane ethyl acetate 3 2, R, = 0.33). 

The reaction is monitored by TLC (silica gel 1 9 EtOAc-hexane). The TLC plate is developed by dipping into a 0.02 M solution of phosphomolybdic acid in EtOH. The initially formed hydroxy stannane (R = 0.52) will stain blue without heating. The acyl stannane (R = 0.69) is observed by charring the plate. 

The reaction was monitored by TLC. The TLC plates (Si02, F254> mm), commercially available from Merck, Darmstadt, Germany, were eluted with ether and developed by dipping into a 10% ethanol ic solution of phosphomolybdic acid (Merck) and then heating. ... 

Impregnate drop-reaction paper with a solution of phosphomolybdic acid and then hold it for a short time over ammonia gas to form the yellow, sparingly soluble ammonium salt dry. Place a drop of the test solution on this paper a blue spot appears if tin(II) is present. 

The reagent consists of a 5 per cent aqueous solution of phosphomolybdic acid. It does not keep well. 

TLC analyses were performed on Macherey-Nagel Polygram SIL G UV/254 plates that were stained with a solution of phosphomolybdic acid in 95% ethanol. 

In our studies we synthesized surfactant salts of phosphomolybdic acid (PMA) and reacted them with tetraethyl orthosilicate (tetrabutyl titanate) in a salt-gel reaction in order to obtain a three-dimensional tunnel structure. It is based on the hydrothermal reaction using cetyltrimethylammonium bromide as a structuredirecting agent. Phosphomolybdic acid is unstable when the temperature is over 723 K. Calcination to decompose the template will make the inorganic portion of the structure to collapse invariably and to form dense M0O3.X phases. Therefore, we... 

We also used the surfactant salts of phosphomolybdic acid (PMA) to react with tetrabutyl titanate instead of TEOS in order to obtain a containing-titania mesoporous phosphomolybdic acid. However, after the solvent extraction, the titania-modified samples exhibited a BET surface area of only 7 13 mVg, which indicated that there are no inner pores in it. We think that it may be due to the difficulty in the formation of the Mo-O-Ti bonds. 

A convenient method of assay of phosphorylase activity is based on the rate of liberation of inorganic phosphate from glucose-1-phosphate, i.e., phosphorylase is measured in the direction of glycogen synthesis [6], After a 10-min incubation at 37°C followed by precipitation with trichloroacetic acid, the supernatant fraction is analysed for inorganic phosphate by the method of Fiske and SubbaRow [163]. This involves the formation of phosphomolybdic acid from the phosphate present and the reduction of the phosphomolybdic acid to produce a blue colour whose intensity is proportional to the amount of phosphate present. 

TLC analyses (Rf = 0.47, in EtOAc/hexane 7 3 the submitters observed Rf = 0.49 in EtOAc/hexane 4 1) were performed on 0.25-mm Merck 60 F254 silica gel plates (the submitters used 0.25-mm silica gel 60 plates supplied by EM Reagents) that were stained with a solution of phosphomolybdic acid in 95% ethanol. 

General Reactions of Alkaloids (Section 670).—Dissolve the amount of quinine sulphate that can be held on the point of a pen-knife in about 20 cc. of water. Observe the appearance of the solution. Add to 2 cc. of the solution drop by drop, a dilute (1 per cent) solution of tannic acid. Repeat using solutions of phosphomolybdic acid, picric acid, iodine in potassium iodide, and potassium mercuric iodide. The last-named solution can be prepared by adding an excess of a solution of potassium iodide to a solution of mercuric chloride. 

Geraniolene itself is 2,6-dimethyl-l,5-heptadiene (164), and has been made readily by reaction of isoprene with isobutylene in the presence of phosphomolybdic acid, this occurring with 69% selectivity and 56% conversion of Isoprene. 

W29. Wu, H., Contribution to the chemistry of phosphomolybdic acids, phosphotungstic acids and allied substances. J. Biol. Chem. 43, 189-220 (1920). 

To each beaker add 2.0 mL of phosphomolybdic acid and stir each solution to mix it thoroughly. 

The most important forms of phosphorus are inorganic orthophosphates which are determined photometrically with molybdenum. Orthophosphates react with ammonium molybdate in the presence of sulphuric acid and antimony ions to form heteropolyacids — phosphomolybdic acid. By reduction with ascorbic acid the yellow complex of phosphomolybdic acid changes into a solution of Phosphomolybdic Blue which can be determined photometrically ... 

General Scheme of Phosphorus Analysis. In the analysis of natural waters the measurement of all forms of phosphorus (P) can be divided into two parts (1) a preliminary treatment in which the P form of interest is separated and converted to orthophosphate, and (2) the colorimetric analysis of orthophosphate (usually by the formation of phosphomolybdic acid followed by its reduction with one of a variety of reducing agents to molybdenum blue). The forms of P in natural waters identified in this study are enumerated in Table IV. 

Bile acids can be also detected by dipping plates into 10% of phosphomolybdic acid in ethanol and then heating for 20 min at 120X" or by spraying the plates with a 1% solution of phosphomolybdic acid in 2-propanol and then heating at 120°C for 5-10 min. " Wardas and Jedrzejczak " separated selected free and conjugated... 

With respect to the adsorption isotherms of phosphomolybdic acid solutions. Figures lb, Ic and Id show the Mo adsorption isotherms in aqueous phase, ethanol-water and dimethylformamide, respectively. Unlike the isotherm already presented in this worit, the latter isotherms possess only one plateau, a fact that indicate the adsorption of only one species which would probably be the PMO(204o heteropolyanion. 

Ethanol-water (3 1) is used as TLC solvent and an ethanolic solution of phosphomolybdic acid used as spray reagent. The excellent cafibration curve obtained by this procedure for 2, 2"methylene bis (4-methyl-6-tert-butyl phenol) is illustrated in Figure 5.10. 

There are modifications of the above procedure which do not require the complete separation of phosphorus from silica, but depend on the preferential reduction of silicomolybdic acid to molybdenum blue in the presence of phosphomolybdic acid. In general, it is emphasized that dependable results rely on careful avoidance of contamination of the sample with silica from glassware, elimination of interference by phosphorus, and maximum sensitivity in making the colorimetric measurement (409-411). Baumann described a preferred technique for analysis of silica in blood and other biological materials (see Chapter 1, Ref. 320). 

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