Double-decomposition

The method of hydrolysis depends on the nature of the product. It is usually sufficient to add dilute sulphuric acid to the ethereal solution and to shake thoroughly, when the magnesium enters the aqueous solution, whilst the organic compound remains in the ether. Alternatively, however, the ethereal solution may be poured on to ice and water, and then treated with dilute sulphuric acid. Should the product be affected by this acid, the hydrolysis can be carried out with an aqueous solution of ammonium chloride. In the following examples the hydrolysis is usually shown as a simple double decomposition... 

Potassium Nitrate. Potassium nitrate, known but Httle used as a fertilizer for many years, may be reclaimed as a by-product of the production of sodium nitrate from natural deposits of caflche in Chile. KNO also has been produced by the double decomposition reaction between sodium nitrate and potassium chloride ... 

Calcium carbonate can be prepared by the double decomposition of calcium chloride and sodium carbonate in aqueous solution. Its density and... 

Ca.ustlciZa.tlon, Time, particularly the high calcium type, reacts with carbonates such as Na2C02 and Li2C02 to form other hydroxides and carbonates through double decomposition or metathesis reactions as foUow ... 

Heating metallic lithium in a stream of gaseous ammonia gives lithium amide [7782-89-0] LiNH2, which may also be prepared from Hquid ammonia and lithium in the presence of platinum black. Amides of the alkaH metals can be prepared by double-decomposition reactions in Hquid ammonia. For example... 

Manufacture. The history of ammonium chloride manufacture is linked to the birth of the soda and synthetic ammonia iadustries. Consequendy this haUde has always been a by-product ia great supply. Production by direct reaction of ammonia and hydrochloric acid is simple but usually economically unattractive a process based on metathesis or double decomposition is generally preferred. 

Several commercial grades are available fine crystals of 99 to 100% purity, large crystals, pressed lumps, rods, and granular material. Double-Decomposition Methods. Double-decomposition processes all iavolve the reaction of sodium chloride, the cheapest chlorine source, with an ammonium salt. The latter may be suppHed directiy, or generated in situ by the reaction of ammonia and a supplementary iagredient. Ammonium chloride and a sodium salt are formed. The sodium salt is typically less soluble and is separated at higher temperatures ammonium chloride is recovered from the filtrate by cooling. 

A.mmonium Sulfate—Sodium Chloride Process. Ammonium sulfate, a readily available by-product, has been much used to make ammonium chloride by a double decomposition reaction with sodium chloride. 

Direct Meutra.liza.tion, Because of the avadabiHty of by-product ammonium salts, the double decomposition routes are usually more favorable economically for ammonium chloride manufacture. However, where surplus hydrogen chloride is available, the direct neutralisation process has been used (15)... 

Manufacture. Historically, ammonium nitrate was manufactured by a double decomposition method using sodium nitrate and either ammonium sulfate or ammonium chloride. Modem commercial processes, however, rely almost exclusively on the neutralization of nitric acid (qv), produced from ammonia through catalyzed oxidation, with ammonia. Manufacturers commonly use onsite ammonia although some ammonium nitrate is made from purchased ammonia. SoHd product used as fertilizer has been the predominant form produced. However, sale of ammonium nitrate as a component in urea—ammonium nitrate Hquid fertilizer has grown to where about half the ammonium nitrate produced is actually marketed as a solution. 

Bina Selenides. Most biaary selenides are formed by beating selenium ia the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts ia aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH 2S [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the teUurides. Selenides of the alkah, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are iasoluble ia water. Polyselenides form when selenium reacts with alkah metals dissolved ia hquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

Stannic and stannous chloride are best prepared by the reaction of chlorine with tin metal. Stannous salts are generally prepared by double decomposition reactions of stannous chloride, stannous oxide, or stannous hydroxide with the appropriate reagents. MetaUic stannates are prepared either by direct double decomposition or by fusion of stannic oxide with the desired metal hydroxide or carbonate. Approximately 80% of inorganic tin chemicals consumption is accounted for by tin chlorides and tin oxides. 

Meta.1 Sa.lt Forma.tion. At least three methods are commonly used to prepare metals salts. The fkst of these is known as the double decomposition method. 

Garboxylates. Cerium carboxylates, water-insoluble, can be made (11) by double decomposition and precipitation using water-soluble precursors, or by reaction of an insoluble precursor directly with the organic acid. Cerous oxalate [139-42-4] 2-ethyIhexanoate (octanoate),... 

Salt Formation. Citric acid forms mono-, di-, and tribasic salts with many cations such as alkahes, ammonia, and amines. Salts may be prepared by direct neutralization of a solution of citric acid in water using the appropriate base, or by double decomposition using a citrate salt and a soluble metal salt. 

MetaUic soaps are manufactured by one of three processes a fusion process, a double decomposition or precipitate process, or a direct metal reaction (DMR). The choices of process and solvent depend on the metal, the desired form of the product, the desired purity, raw material avadabihty, and cost. 

Double Decomposition. In the double decomposition reaction, an inorganic metal salt such as a sulfate, chloride, acetate, or nitrate reacts with the sodium salt of the carboxyUc acid ia a hot aqueous solution. The metal soap precipitate is filtered, washed, dried, and milled. 

Hydrolysis. The general process definition for hydrolysis embraces all double-decomposition reactions between water (usually ia the form of acid or alkah solutions of a wide range of strengths) and an organic molecule. 

This double decomposition route was developed in Germany and has been used in the UK since 1971. 

Doppel-wirkung, /. double action, -wurzel, /. Math.) double root, -zentner, m. double centner. lOO kilograms. -zersetzung, /. double decomposition, -zunder, m. combination fuse. 

Umsetzung, /. transposition double decomposition conversion, change transformation reversal reaction transplantation exchange, sale, business. Umsetzungsgeschwindigkeit, /. velocity of transformation, reaction rate. 

Any decomposition involving the addition of water. Specifically, a double decomposition reaction between water and another substance. 

Can be specified as substitution or as double decomposition reactions, discussed in Sect. 4.3.) A short account of other and more complicated reactions is given in Sect. 4.4. 

This solid state double decomposition may be schematically represented by... 

Fig. 22. Schematic representation of the solid phase double decomposition reactions...

Hydrolysis is a special type of double decomposition in water which in addition to its function as a solvent splits up a normal salt partially to form the acid and the base from which the salt is derived. In short, hydrolysis is a partial reversal of neutralization. 

Double-substitution or double-replacement reactions, also called double-decomposition reactions or metathesis reactions, involve two ionic compounds, most often in aqueous solution. In this type of reaction, the cations simply swap anions. The reaction proceeds if a solid or a covalent compound is formed from ions in solutions. All gases at room temperature are covalent. Some reactions of ionic solids plus ions in solution also occur. Otherwise, no reaction takes place. For example,... 

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