Chloroplatinous acid

When platinum is dissolved in aqua regia it is first converted to platinic chloride, PtCl, and the latter at once unites with the excess of hydrochloric acid to give the stable soluble dibasic chloroplatinic acid, HjPtCle.f... 

When an amine, or a solution of its hydrochloride, is added to an aqueous solution of chloroplatinic acid, a salt of the base with the cliloroplatinic acid, of general formula BjiHiPtCle (where B is one molecule of the base) is formed and usually crystallises out, for these chloroplatinates hai e normally a rather low solubility in cold water. The chloroplatinate can be filtered off, dried, and then analysed by direct ignition, when only the metallic platinum ultimately remains. Knowing the percentage of platinum in the chloroplatinate, the molecular weight of the latter, and hence of the constituent base, can readily be calculated. 

Method 2. From chloroplatinic acid. Dissolve 3 - 5 g. of the purest commercial chloroplatinic acid (3) in 10 ml. of water contained in a 250 ml. P3rrex beaker or porcelain casserole, and add 35 g. of A.R. sodium nitrate (1), Evaporate the mixture to dryness by heating gently over a Bunsen flame whilst stirring with a glass rod. Then raise the temperature... 

It is insoluble in hydrochloric and nitric acid, but dissolves when they are mixed as aqua regia, forming chloroplatinic acid. 

Chloroplatinic acid, H2PtClg 6H2O—10% solution dissolve 1 g in 9 mL of water keep in a dropping bottle. 

At 165°C and in the presence of chloroplatinic acid as catalyst, isoprene reacts with trichlorosilane, metbyldicblorosilane, ethyldichlorosilane, ben2yldichlorosilane, and diben2ylchlorosilane (72). The addition is 1,4- with the substituted silane group attaching to the first carbon atom. 

Catalysis. Platinum-catalyzed hydrosilation is used for cross-linking siUcone polymers and for the preparation of functionally substituted silane monomers (250). The most widely used catalyst is chloroplatinic acid (Spier s catalyst), H2PtCl3. Other compounds that catalyze the reaction include Pt(Il)... 

Miscellaneous. Chloroplatinic acid is used in the production of automobile catalysts. Platino-type prints based on reduction of Pt(II) to Pt(0) by a photosensitive reducing agent such as iron(III) oxalate are used in art photography (261,262). Infrared imaging devices based on a platinum siLicide detector have been developed (263). 

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. 

There are two ways to produce acetaldehyde from ethanol oxidation and dehydrogenation. Oxidation of ethanol to acetaldehyde is carried out ia the vapor phase over a silver or copper catalyst (305). Conversion is slightly over 80% per pass at reaction temperatures of 450—500°C with air as an oxidant. Chloroplatinic acid selectively cataly2es the Uquid-phase oxidation of ethanol to acetaldehyde giving yields exceeding 95%. The reaction takes place ia the absence of free oxygen at 80°C and at atmospheric pressure (306). The kinetics of the vapor and Uquid-phase oxidation of ethanol have been described ia the Uterature (307,308). 

When a carrier is impregnated with a solution, where the catalyst deposits will depend on the rate of diffusion and the rate of adsorption on the carrier. Many studies have been made of Pt deposition from chloroplatinic acid (HgPtClg) with a variety of acids and salts as coim-pregnants. HCl results in uniform deposition of Pt. Citric or oxalic acid drive the Pt to the interior. HF coimpregnant produces an egg white profile. Photographs show such varied distributions in a single pellet. 

Ammonium chloroplatinate often can be used to advantage in place of chloroplatim c acid in the preparation of Adams catalyst. A mixture of 3 g. of ammonium chloroplatinate and 30 g. of sodium nitrate in a casserole or Pyrex beaker is heated gently at first until the rapid evolution of gas slackens and then more strongly until a temperature of 500° is reached. This operation requires about fifteen minutes and there is no spattering. The temperature is held at 500-520° for one-half hour and the mixture is then allowed to cool. The platinum oxide catalyst, collected in the usual way by extracting the soluble salts with water, weighs 1.5 g. and it is comparable in appearance and in activity to the material prepared from chloroplatinic acid. 

This procedure is particularly time-saving when scrap platinum or spent catalyst is used for the preparation of platinum oxide, for after conversion to chloroplatinic acid a purification is conveniently effected by precipitating the ammonium salt, and the direct fusion of this with sodium nitrate eliminates the tedious process of reconversion to chloroplatinic acid. Furthermore ammonium chloroplatinate is not hygroscopic and can he accurately weighed. The amount of catalyst obtained is almost exactly half the weight of the ammonium salt employed. 

Chloronaphthalene 40 Chloronitrobenzenes, 40 Chloropentafluoroethane, 40 Chlorophacinone, 40 4-Chloro-o-phenylenediamine, 40 Chlorophenols, 40 Chlorophenols, Mono, 40 Chloropicrin, 40 Chloroplatinic acid, 41 Chloroprene, 41... 

Chlor-oxyd, n. chlorine oxide, -phosphor, m. phosphorus chloride, -pikrin, n. chloropicrin. -platin, n. platinic chloride, -platinsiiure,. chloroplatinic acid, -quecksilber, n. mercury chloride (either one), -raucherung, /. chlorine fumigation. 

Platini-, platinic, platini-, platinum (IV). -chlorid, n. platinic chloride, platinum (IV) chloride, -chlorwasserstoff, m., -chlorwasserstoffsaure, /. chloroplatinic acid, chloroplatinic (IV) acid, -cyanwasserstoffsaure, /. cyanoplatinic acid, cyanoplatinic(IV) acid, platinicyanic acid. 

The hydrogen electrode consists of an electrode of platinum foil (approximately 1 X 1 X 0-002 cm) welded to a platinum wire which is fused into a glass tube. In order to increase its catalytic activity it is platinised by making it cathodic in a solution of chloroplatinic acid (2% chloroplatinic acid in 2 N HCl) frequently lead acetate is added to the solution (0-02%) and this appears to facilitate the deposition of an even and very finely divided layer... 

Commercial C.p. chloroplatinic acid varies somewhat in its purity. In this work that from the Mallinckrodt Chemical Works, St. Louis, was used and gave very satisfactory results. Since small amounts of impurities in the catalyst are important factors in the rate of reduction of certain types of compounds, this question of impurities in the chloroplatinic acid must be taken into account (Note 13). In a large proportion of the reductions studied, platinum oxide prepared from the chloroplatinic acid mentioned gave as good results as that from spectroscopically pure chloroplatinic acid made according to the directions of Wichers.1... 

Platinum black has been prepared chiefly by the reduction of chloroplatinic acid with formaldehyde 5 the details have been improved by Willstatter and Hatt 6 Willstatter and Waldschmidt-Leitz,7 and by Feulgen.8... 

A platinum on silica gel catalyst was prepared by impregnation of silica gel (BDH, for chromatographic adsorption) by a solution containing 0.5% (wt.) of sodium hydroxide and 0.5% (wt.) of chloroplatinic acid (both of analytical grade). The dried catalyst contained 1% (wt.) of platinum and a corresponding amount of the alkaline component. The BET surface area of the catalyst was 40 m2/g, the mean pore radius 150 A. The catalyst was always reduced directly in the reactor in a stream of hydrogen at 200°C for 2 hr. 

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... 

Chloronon-2-ene, 28 Chloroplatinic acid, 9 Chromium trioxide. 66. 79 Cinnamaldehyde, 73 Cleavage. 2-3,48-9... 

The addition of hydridosilanes across the triple bond of alkynes can be accomplished using a variety of catalysts, the best being chloroplatinic acid. cis-Addition, with terminal regioselectivity, is normally observed, with lower temperatures favouring a greater proportion of the terminal isomer (see also Chapter 17). 

Although the actual reaction mechanism of hydrosilation is not very clear, it is very well established that the important variables include the catalyst type and concentration, structure of the olefinic compound, reaction temperature and the solvent. used 1,4, J). Chloroplatinic acid (H2PtCl6 6 H20) is the most frequently used catalyst, usually in the form of a solution in isopropyl alcohol mixed with a polar solvent, such as diglyme or tetrahydrofuran S2). Other catalysts include rhodium, palladium, ruthenium, nickel and cobalt complexes as well as various organic peroxides, UV and y radiation. The efficiency of the catalyst used usually depends on many factors, including ligands on the platinum, the type and nature of the silane (or siloxane) and the olefinic compound used. For example in the chloroplatinic acid catalyzed hydrosilation of olefinic compounds, the reactivity is often observed to be proportional to the electron density on the alkene. Steric hindrance usually decreases the rate of... 

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