Molybdic acid reaction with

Low molecular weight silicic acids were separated by Baumann (82) with paper chromatography using a mixture of isopropyl alcohol, water, and acetic acid as the moving liquid and the molybdic acid reaction to locate the separate species. 

The relative rate of reaction with molybdic acid varied with the calculated particle size. A log-log plot of the data showed the same slope as found by Her (Figure 1.15) for the rate of dissolution of particles in this size range in 0.1 N NaOH solution. This shows that the rate of depolymerization or dissolution in both systems depends... 

The total phosphoms content of the sample is determined by method AOCS Ja 5-55. Analysis of phosphoUpid in lecithin concentrates (AOCS Ja 7-86) is performed by fractionation with two-dimensional thin-layer chromatography (tic) followed by acid digestion and reaction with molybdate to measure total phosphorous for each fraction at 310 nm. It is a semiquantitative method for PC, PE, PI, PA, LPC, and LPE. Method AOCS Ja 7b-91 is for the direct deterrnination of single phosphoHpids PE, PA, PI, PC in lecithin by high performance Hquid chromatography (hplc). The method is appHcable to oil-containing lecithins, deoiled lecithins, lecithin fractions, but not appHcable to lyso-PC and lyso-PE. 

Oxidation. Maleic and fumaric acids are oxidized in aqueous solution by ozone [10028-15-6] (qv) (85). Products of the reaction include glyoxyhc acid [298-12-4], oxalic acid [144-62-7], and formic acid [64-18-6], Catalytic oxidation of aqueous maleic acid occurs with hydrogen peroxide [7722-84-1] in the presence of sodium tungstate(VI) [13472-45-2] (86) and sodium molybdate(VI) [7631-95-0] (87). Both catalyst systems avoid formation of tartaric acid [133-37-9] and produce i j -epoxysuccinic acid [16533-72-5] at pH values above 5. The reaction of maleic anhydride and hydrogen peroxide in an inert solvent (methylene chloride [75-09-2]) gives permaleic acid [4565-24-6], HOOC—CH=CH—CO H (88) which is useful in Baeyer-ViUiger reactions. Both maleate and fumarate [142-42-7] are hydroxylated to tartaric acid using an osmium tetroxide [20816-12-0]/io 2LX.e [15454-31 -6] catalyst system (89). 

The pigments are obtained by preparing an aqueous solution of disodium hydrogenphosphate and adding a sodium molybdate solution (containing molybdenum trioxide and aqueous sodium hydroxide). Acidified with hydrochloric acid or with sulfuric acid, the reaction mixture is then added to an aqueous solution of the... 

The limit test for phosphate is based upon the formation of ayellow colour reaction with molybdovanadic reagent (combination of ammonium vanadate and ammonium molybdate) in an acidic medium. However, the exact composition of the molybdovanadophosphoric acid complex is yet to be established. 

In aqueous solutions, calcium chloride undergoes double decomposition reactions with a number of soluble salts of other metals to form precipitates of insoluble calcium salts. For example, mixing solutions of calcium chloride with sodium carbonate, sodium tungstate and sodium molybdate solutions precipitates the carbonates, tungstates, and molybdates of calcium, respectively. Similar precipitation reactions occur with carboxylic acids or their soluble salt solutions. CaCb forms calcium sulfide when H2S is passed through its solution. Reaction with sodium borohydride produces calcium borohydride, Ca(BH4)2. It forms several complexes with ammonia. The products may have compositions CaCl2 2NH3, CaCb dNHs, and CaCb SNHs. 

According to C. F. Barwald and A. Monheim (1835), the decomposition is accelerated by the presence of organic substances. J. Milbauer tried the effect of thirty-two metal chlorides of sodium tungstate and molybdate of uranyl sulphate and of sulphuric, selenic, arsenic, and boric acids on the photo-decomposition of chlorine water, and found. that none accelerated but that most retarded the action. Chlorine catalyzes the decomposition of bromine water and bromine, chlorine water while iodine does not accelerate, but rather retards the reaction, probably by forming relatively stable iodine compounds. A. Bcnrath and H. Tuchel found the temp, coeff. of the velocity of the reaction with chlorine water between 5° and 30° increases in the ratio 1 1 395 per 10°. 

Molybdenum(VI) dioxyacetylacetonate (molybdenyl acetylacetonate) was first prepared by Gach1 by the action of acetylacetone upon molybdenum(VI) oxide at room temperature. Since he also isolated a small quantity of the same compound by the reaction between molybdenum (II) hydroxide and acetylacetone, he believed the compound to be Mo(C5H702)2. Rosenheim and Bertheim2 later prepared the compound by refluxing an ethanolic solution of acetylacetone with molybdic acid. They correctly identified the product as molybdenyl acetylacetonate. Morgan and Castell3 later duplicated the preparation of Rosenheim and Bertheim and verified their formula. 

The reaction progress was monitored by TLC analysis (silica gel) using hexane-ethyl acetate (4 1, v/v) with 3.5% methanolic phospho-molybdic acid as indicator bromoketal, Rr0.37, bromoketone, Rf0. 5. 

Assays of bromate and perbromate concentrations are required during the procedure. Bromate concentrations that are at least comparable to the perbromate may be determined iodometrically by reaction with sodium iodide in acid solution containing molybdate, followed by titration with standardized thiosulfate. After reduction of the bromate the solution should be ca. 0.1 M each in H+ and in free iodide ion. Perchloric, hydrochloric, or sulfuric acids may be used. The molybdenum(VI) concentration should be ca. 10 3 M. 

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