Palladous chloride

The catalyst is previously prepared in an apparatus for catalytic hydrogenation, in which are placed 0.5 g. of palladous chloride, 3.0 g. of Norite, and 20 ml. of distilled water. The bottle is swept out with hydrogen and then shaken with hydrogen for 2-3 hours at 2-3 atmospheres (40 lb.) pressure. The palladium on carbon is collected on a Biichner funnel, washed with five 50-ml. portions of distilled water, then with five 50-ml. portions of 95% ethanol, and finally twice with ether. Upon drying, about 3 g. of the catalyst is obtained. It is stored in a vacuum desiccator over solid sodium hydroxide. If the reduction of the chloro-lepidine does not proceed normally, the used catalyst should be removed by suction filtration and a fresh 3-g. portion of catalyst added. Failure of the reduction step is usually due to an inactive catalyst or to impurities in the acetic acid or chlorolepidine. The palladium catalysts, prepared as described elsewhere in this volume, are presumably also satisfactory for the reduction of 2-chlorolepidine (p. 77). 

A substitute may be prepared thus 0 05 gram palladous chloride is placed in a special shaking flask with 50 c.c, of 50 per cent, alcohol and 1 or 2 c c. of 1 per cent, aqueous solution of gum-arabic, the weight of gum being about one-fourth the weight of the palladous chloride. On shaking this mixture in an atmosphere of hydrogen the chloride is reduced with formation of a black solution of colloidal platinum, which is rendered stable by the small quantity of gum present. 

Pallado-. palladous, palladium (II). -chlorid, n. palladous chloride, palladium(II) chloride, -chlorwasserstoffsaure, /. chloropalladous acid, chloropalladic(II) acid, -hydro d, n. palladous hydroxide, palladium(II) hydroxide. 

The catalyst is prepared by suspending 5 kg of catalyst grade charcoal in 200 liters of water, in a pressure vessei, and adding thereto 25 liters of 4% (as Pd metal) aqueous palladous chloride. Air is displaced from the vessel and then hydrogen is passed into the aqueous mixture at a pressure of 3 to 5 psi, while stirring, until no further absorption is noted and the chloride is completely reduced to metal. 

Palladous chloride in preparation of hydrogenation catalyst, 46, 89 Paraformaldehyde, conversion to form aldoximc, 46,13 Pelargonyl fluoride 46, 6 1-Pentalenecaeboxylic acid, octa hydro-, 47,10... 

Palladous oxide,3/ PdO, may be prepared by the fusion of palladous chloride with sodium nitrate, and is an effective catalyst in hydrogenation, the most active form being produced when the fusion temperature is 600°,... 

The results on Pd complexes as catalyst for the 1 1 codimerization are very limited at this time (85-87). Schneider (85, 86) found that palladous chloride in conjunction with dibutylaluminum chloride catalyzes the formation of exclusively trans-1,4-hexadiene as the 1 1 codimerization product of ethylene and butadiene. A vyn-7r-crotylpalladium complex was postulated as the key intermediate. The criterion for selectivity toward... 

To a suspension of 50 g of purest precipitated calcium carbonate in 400 ml of distilled water is added 50 ml of a 5% solution of palladous chloride (PdClj) and the mixture is stirred for 5 minutes at room temperature and for 10 minutes at 80°. The hot suspension is shaken with hydrogen until no mofe absorption takes place, filtered with suction and the cake on the filter is washed thoroughly with distilled water. The cake is then stirred vigorously in 500 ml of distilled water the suspension is treated with a solution of 5 g of lead acetate in 100 ml of water, stirred for 10 minutes at 20° and finally for 40 minutes in a boiling water bath. The catalyst is filtered with suction, washed thoroughly with distilled water and dried at 40-50° in vacuo. 

Formula PdCb MW 177.33 forms a stable ddiydrate, PdCl2 2H20. Synonyms palladium(ll) chloride palladous chloride. 

My last comment concerns the reaction of palladium olefin complexes with carbon monoxide discovered by Tsuji. I agree that this is most likely to proceed by an insertion rather than an ionic mechanism. Chloride attack on coordinated olefin is rare however. Chloride ion is an inhibitor, for example in the palladous chloride catalyzed hydration of ethylene (0). I, therefore, wondered whether carbon monoxide was affecting the ease with which chloride attacks olefin. One can postulate that carbon monoxide participates in this insertion either as a gas phase reactant or by first forming a carbonyl olefin complex. Such complexes of the noble metals were unknown, but examining the reaction between carbon monoxide and the halogen bridged olefin complexes of platinum revealed that they are formed very readily... 

Dichloro-dihydroxylamino-palladium, [Pd(NH2QH)2Cl2], is one of the products isolated when hydroxylamine hydrochloride, sodium carbonate, and palladous chloride interact. It appears to exist in two forms, and separates in long, slender, yellow needles or as a yellow granular powder. Owing to its instability the investigation of the series to which it belongs is difficult.1... 

Dichloro-dipyridino-palladium, [Pd py2Cl2]. is produced by the addition of pyridine to an aqueous solution of palladous chloride or potassium chloropalladite. A red precipitate is first obtained, which dissolves on heating with excess of pyridine. From the liquid the substance is precipitated on the addition of concentrated hydrochloric acid as a bright yellow crystalline powder. If heated with ammonia, pyridine is eliminated and dichloro-diammino-palladium formed.2... 

Tetrammino-palladous Chloro-palladate, [Pd(NH3)4]PdCl3, is produced by the action of chlorine on cold aqueous diehloro-diammino-palladium, or by the action of aqua-regia on tetrammino-palladous chloride. The substance is a brownish-black crystalline body. It is precipitated and decomposed by hydrochloric acid, with liberation of nitrogen, the formation of ammonium chloride and porous palladium. Boiling water decomposes it into ammonium chloro-palladite. The corresponding bromo-palladite, [Pd(NH3)4]PdBr4, and nitrito-palladite, [Pd(NH3)4]Pd(N02)4, are also known. ... 

Diethylenediamino-palladous Chloride, [Pd en2]Cl2, is a light yellow crystalline substance. The corresponding bromide, [Pd en2]Br2, is dark yellow, and the iodide, [Pd en2]I2, is brownish yellow. The free base corresponding to the salts, [Pd en2](OH)2, has not been isolated, but in solution it is yellow in colour, strongly alkaline, and decomposes ammonium salts with evolution of ammonia.1... 

Dipyridino-palladic Chloride, [Pd py2]Cl4, is formed by the action of chlorine on dichloro-dipyridino-palladium suspended in chloroform. It crystallises in small orange-coloured prisms, and rapidly loses chlorine on exposure to moist air. If heated with potassium hydroxide a brown precipitate of palladic hydroxide separates, and if this is carefully neutralised with hydrochloric acid, potassium chloro-palladate crystallises out. Treatment with an aqueous solution of potassium iodide decomposes the salt, with formation of the palladous compound thus ... 

Copper and Iron. — Dissolve the palladium in nitrohydrochloric acid, and evaporate the excess of acid on the water-bath. Dissolve the residue in water, and add ammonia water until the flesh-colored precipitate of ammonium palladous chloride first formed redissolves. Then pass into the solution gaseous hydrochloric acid, whereby the palladium is precipitated as yellow palladosainine chloride, while iron and copper remain in solution. The precipitate is filtered off,... 

Palladous chloride (1 48 g, 0 0083 mole) (Note 1) is placed in a 10-ml. Erlenmeyer flask, and 3.6 ml. (0 043 mole) of 37% hydrochloric acid is added. The flask is shaken at about 30° until the palladous chloride is dissolved. The chloropalladous acid solution is transferred to a 150-ml. beaker with 45 ml of... 

The latter mechanism is of interest since the elimination is formerly a two-electron transfer and directly analogous to the mechanism of the formation of acetaldehyde in the oxidation of ethylene by palladous chloride (139). 

Addition of magnesium powder to ten times its own weight of cold water, followed by a little palladous chloride, causes the evolution of hydrogen, which spontaneously ignites. ... 

The finely divided metal is obtained for this purpose by reduction of palladous chloride with strips of metallic zinc, the palladium deposit being carefully washed and dried. After prolonged exposure to air it appears to lose its affinity for mercury, possibly on account of slow oxidation. 

Palladous Chloride, Palladium Dichloride, PdCl2, is obtained in the anhydrous condition as a sublimate on heating spongy palladium to dull redness in dry chlorine.4 The monosulphide, PdS, when heated in chlorine is converted into the anhydrous chloride, and the same salt is produced by dehydrating the dihydrate, PdCl2.2HsO, at a slightly elevated temperature. 

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