Platinum acidic sulfate solution

Figure 5. Typical cyclic voltammogram of smooth platinum obtained in a deaerated acidic sulfate solution.

A platinum-iron on silica gel catalyst was prepared by impregnating silica gel (BDH, for chromatographic adsorption) with an aqueous solution of chloroplatinic acid (analytical grade) and sodium hydroxide (analytical grade). The dry product was then impregnated by a ferrous sulfate solution (C.P. grade) and the water was removed in a rotating evaporator. The prepared catalyst contained 1% Pt, 0.7% Fe, and 2% NaOH (by... 

The fact that the decomposition of ozonides is catalyzed by finely divided metals (silver, platinum, palladium) and metal salts such as ferrous sulfate suggests a free-radical mechanism.23 2-Butene ozonide is broken down with dilute ferrous sulfate solution into acetic acid and acetaldehyde.23... 

Metallic copper is sometimes obtained by leaching a copper ore with sulfuric acid and then depositing the metal by electrolysis of the copper sulfate solution. Most copper ores, however, are converted into crude copper by chemical reduction. This crude copper is cast into anode plates about 2 cm thick, and is then refined electrolytically. In this process the anodes of crude copper alternate with cathodes of thin sheets of pure copper coated with graphite, which makes it possible to strip off the deposit. The electrolyte is copper sulfate. As the current passes through, the crude copper dissolves from the anodes and a purer copper deposits on the cathodes. Metals below copper in the EMF series, such as gold, silver, and platinum, remain undissolved, and fall to the bottom of the tank as sludge, from which they can be recovered. More active metals, such as iron, remain in the solution. 

Fig. 7. Dependence of electrode surface charge on potential expressed, relative to the zero-charge point, on mercury (1) in 0.1 N sodium fluoride solution, on platinum (2) in 0.01 N sulfuric acid+ 0.01 N cesium sulfate solution, and on rhodium (3) in 0.01 N sulfuric acid + 1 N sodium sulfate.

Fig. 8. Dependence of benzene adsorption on potential at platinum electrode in solutions of sulfuric acid + sodium sulfate and sodium hydroxide + sodium sulfate with various pH values [120] ...

A nonstationary potentiostatic method was used to determine the mutual effects of adsorbed cations and hydrogen on platinum. Figure 9 shows the potentiostatic I, cp curves for a platinized platinum electrode in solutions of sulfuric acid and with additions of zinc sulfate at 20 C. The curve for 1 N sulfuric acid has characteristic form with two maxima in the hydrogen region and clearly defined double-layer and oxygen regions [15]. 

Pla.tinum, Platinum plating has found appHcation in the production of platinised titanium, niobium, or tantalum anodes which are used as insoluble anodes in many other plating solutions (see Metalanodes). Plating solutions were often based on platinum "P" salt, which is diamminedinitroplatiniim (IT). A dinitroplatinite sulfate—sulfuric acid bath has been used to plate direcdy onto titanium (129). This bath contains 5 g/L of the platinum salt, pH adjusted to 2.0 with sulfuric acid. The bath is operated at 40°C at 10—100 A/m. Other baths based on chloroplatinic acid have been used in both acid and alkaline formulations the acid bath uses 20 g/L of the platinum salt and 300 g/L hydrochloric acid at 65° C and 10—200 A/m. The alkaline bath uses 10 g/L of the platinum salt, 60 g/L of ammonium phosphate and ammonium hydroxide to give a pH of 2.5—9.0. The alkaline bath can be plated directly onto nickel-base alloys acid baths require a gold strike on most metals. 

A weighed amount of sample is dissolved in a mixture of propanone and ethanoic acid and titrated potentiometrically with standard lead nitrate solution, using glass and platinum electrodes in combination with a ferro-ferricyanide redox indicator system consisting of 1 mg lead ferrocyanide and 0.5 ml 10% potassium ferricyanide solution. The endpoint of the titration is located by graphical extrapolation of two branches of the titration plot. A standard solution of sodium sulfate is titrated in the same way and the sodium sulfate content is calculated from the amounts of titrant used for sample and standard. (d) Water. Two methods are currently available for the determination of water. 

In order to increase the contact of a catalyst with hydrogen and the compounds to be hydrogenated platinum (or other metals) is (are) precipitated on materials having large surface areas such as activated charcoal, silica gel, alumina, calcium carbonate, barium sulfate and others. Such supported catalysts are prepared by hydrogenation of solutions of the metal salts, e.g. chloroplatinic acid, in aqueous suspensions of activated charcoal or other solid substrates [28. Supported catalysts which usually contain 5, 10 or 30 weight percent of platinum are very active, and frequently pyrophoric. 

Acetylenic aromatic acids having the triple bond Hanked by carboxyl and an aromatic ring were partially reduced to olefinic aromatic acids by chromous sulfate in aqueous dimethylformamide at room temperature in high yields. Phenylpropiolic acid afforded irani -cinnamic acid in 91% yield [195]. Its sodium salt in aqueous solution gave on catalytic hydrogenation over colloidal platinum at room temperature and atmospheric pressure 80% yield of cis-cinnamic acid if the reaction was stopped after absorption of 1 mol of hydrogen. Otherwise phenylpropanoic acid was obtained in 75-80% yield [992]. 

I. 4-methoxyacetophenone (30 //moles) was added as an internal standard. The reaction was stopped after 2 hours by partitioning the mixture between methylene chloride and saturated sodium bicarbonate solution. The aqueous layer was twice extracted with methylene chloride and the extracts combined. The products were analyzed by GC after acetylation with excess 1 1 acetic anhydride/pyridine for 24 hours at room temperature. The oxidations of anisyl alcohol, in the presence of veratryl alcohol or 1,4-dimethoxybenzene, were performed as indicated in Table III and IV in 6 ml of phosphate buffer (pH 3.0). Other conditions were the same as for the oxidation of veratryl alcohol described above. TDCSPPFeCl remaining after the reaction was estimated from its Soret band absorption before and after the reaction. For the decolorization of Poly B-411 (IV) by TDCSPPFeCl and mCPBA, 25 //moles of mCPBA were added to 25 ml 0.05% Poly B-411 containing 0.01 //moles TDCSPPFeCl, 25 //moles of manganese sulfate and 1.5 mmoles of lactic acid buffered at pH 4.5. The decolorization of Poly B-411 was followed by the decrease in absorption at 596 nm. For the electrochemical decolorization of Poly B-411 in the presence of veratryl alcohol, a two-compartment cell was used. A glassy carbon plate was used as the anode, a platinum plate as the auxiliary electrode, and a silver wire as the reference electrode. The potential was controlled at 0.900 V. Poly B-411 (50 ml, 0.005%) in pH 3 buffer was added to the anode compartment and pH 3 buffer was added to the cathode compartment to the same level. The decolorization of Poly B-411 was followed by the change in absorbance at 596 nm and the simultaneous oxidation of veratryl alcohol was followed at 310 nm. The same electrochemical apparatus was used for the decolorization of Poly B-411 adsorbed onto filter paper. Tetrabutylammonium perchlorate (TBAP) was used as supporting electrolyte when methylene chloride was the solvent. 

But [said he] it was still necessary to learn the base of the salt. Its solution could not be precipitated either by tartaric acid in excess or by platinum chloride. Consequently it could not be potassium. I mixed another portion of a solution of the same salt with a few drops of pure potash, but without its becoming cloudy. Therefore it contained no more magnesia hence it must be a salt with soda for a base. I calculated the quantity of soda which would be necessary to form it but it always resulted in an excess of about 5 parts in 100 of the mineral analyzed. Therefore, since it seemed probable to me that the different substances might not have been well washed, Or that the analysis might not have been made with sufficient precision in other respects, I repeated it twice more with all the care possible, but always with results very little different. I obtained. Silica. 78 45, 79.85, Alumina 17 20, 17.30 Sulfate 19.50, 17.75. At last, having studied this sulfate more closely, I soon found that it contained a definite fixed alkali, whose nature had not previously been known (21). 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

The process for electrowinning of copper is schematically shown in Fig. 12.9. If copper(I) sulfate in AN-H20-H2S04 solution is electrolyzed using a platinum electrode as anode and a copper electrode as cathode, one-electron processes occur at the two electrodes (Cu1 —> Cu2 at the anode and Cu1 —> Cu° at the cathode). Compared with the conventional electrowinning from the aqueous acidic solution of copper(II) sulfate (water oxidation at the anode and Cu2+ —> Cu° at the cathode), the electric power consumed is only about 10% and high-quality copper can be obtained. It is of coruse necessary to return Cu2+, generated at the anode, to Cu+. But various methods are applicable to it, e.g., by the contact with coarse copper. 

Powder very finely 20 g. of antimony oxide, Sb2C>3 (or metallic antimony), and add this in small portions at a time to 250 cc. of hot concentrated sulfuric acid contained in an evaporating dish. Maintain the heat until all of the powder has been dissolved, if necessary adding a little more acid to keep the white sulfate in solution. Allow the solution to cool and filter off the fine crystals on a platinum cone or a Witte plate with very small holes, pumping them as dry as possible. Spread the pasty mass on pieces of unglazed dishes, putting one such piece on top of another, to make a pile that consists of alternate layers of plate and sulfate. Put the entire pile in a desiccator so as to prevent absorption of moisture from the air. If the sulfate is rather wet, it may be necessary to scrape it off the plates and repeat the operation with fresh ones. Finally, spread... 

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