Copper-ammonium salt process

The main advantages of the Cosorb process over the older copper ammonium salt process are low corrosion rate, abiHty to work in carbon dioxide atmospheres, and low energy consumption. The active CuAlCl C H CH complex is considerably more stable than the cuprous ammonium salt, and solvent toluene losses are much lower than the ammonia losses of the older process (94). 

Aqueous Copper Ammonium Salt Process, 1347 COSORB Process, 1357... 

Figure 16-22. Simplified fiow diagram of copper-ammonium-salt process for carbon monoxide removal from gases.

The COSORB process resembles the copper-ammonium salt process described in the preceding section in that it also uses a copper compound that forms a complex with absorbed CO. It is significantly different, however, in that the ab.sorbent is nonaqueous. The active component is cuprous aluminum chloride (CUAICI4) dissolved in an aromatic base, toluene (Haase, 1975). The absorption-desorption reaction can be represented by the following equation ... 

Principal operating problems of the copper-ammonium-salt CO-removal process may be listed as follows ... 

The metal-catalysed autoxidation of alkenes to produce ketones (Wacker reaction) is promoted by the presence of quaternary ammonium salts [14]. For example, using copper(II) chloride and palladium(II) chloride in benzene in the presence of cetyltrimethylammonium bromide, 1-decene is converted into 2-decanone (73%), 1,7-octadiene into 2,7-octadione (77%) and vinylcyclohexane into cyclo-hexylethanone (22%). Benzyltriethylammonium chloride and tetra-n-butylammo-nium hydrogen sulphate are ineffective catalysts. It has been suggested that the process is not micellar, although the catalysts have the characteristics of those which produce micelles. The Wacker reaction is also catalysed by rhodium and ruthenium salts in the presence of a quaternary ammonium salt. Generally, however, the yields are lower than those obtained using the palladium catalyst and, frequently, several oxidation products are obtained from each reaction [15]. 

Uranium minerals may be obtained in solution, in a suitable condition for estimation, by the following process. The ore is dissolved in aqua regia, or, if necessary, fused with alkali bisulphate and extracted mth hot hydrochloric acid. After evaporation to drjmess, the residue is taken up with dilute hydrochloric acid, and the solution saturated with hydrogeir sulphide in order to remove any copper, lead, bismuth, arsenic, antimony, or any other metal yielding an insoluble sulphide. The filtrate is concentrated and treated with ammonium carbonate, which precipitates the carbonates of the alkaline earths, iron, and most of the rare earths. The filtrate is neutralised by hydrochloric acid, evaporated to dryness, and the residue ignited to drive off ammonium salts, and then redissolved in dilute acid. The remaining rare earths, and particularly thorium, are next precipitated by the addition of oxalic acid. The filtrate, which contains the uranium in the uranyl condition, may now be precipitated by any of the methods described above. 

Didecyldimethylammonium chloride is used to prevent stain and mildew on freshly cut lumber81 If a quaternary ammonium salt monomer could be impregnated into wood, then graft polymerized to it, the process might displace some of the chromium copper arsenate treatments. Some antibacterial polymers (e.g., 4.9) work by gradual hydrolysis to release the active group.82... 

The COSORB solvent has a number of advantages over the aqueous solution of cuprous ammonium salts used in the early copper scrubbing process. It operates at low pressure, is unaffected by carbon dioxide and... 

Traditionally, antibacterial properties have been imparted to textile materials by chemically or physically incorporating chemical agents onto fabrics by means of coating processes. After World War II, the fungicides used on cotton fabrics were compounds such as 8-hydroxyquinoline salts, copper naphthenate, copper ammonium... 

Although adsorbed molecules of extractants are well oriented at the interface, the interfacial reactions occur more slowly, as recalculated for the same volume, than reactions in the aqueous phase. The extraction of palladium(II) from HCl solutions with dialkyl sulfides is a classic example of a very slow process. Modifying the extractant structure by adding a hydrophilic hydroxyl group and/or a phase transfer catalyst, e.g., trialkylamine or quaternary ammonium salt, increases the rate of extraction. The addition of sulfonic and phosphoric acids to hydroxyoximes may enhance the rate of copper extraction due to the formation of reverse micelles and the development of the microscopic interface. The a-acyloin oximes that form an intermediate complex that has a five-member ring with copper(II) increase the rate of extraction of aromatic hydroxyoximes. The addition of surfactants may cause both retardation and acceleration of extraction. If the interfacial tension is decreased, surfactants cause an increase in the interfacial surface area in dispersed systems. When they adsorb at the interface, they cause an additional... 

Alkaline etching solutions dissolve exposed field copper on printed boards by a chemical process of oxidation, solubilizing, and complexing. Aitunonium hydroxide and ammonium salts combine with copper ions to form cupric ammonium complex ions [Cu(NH3)4 ], which hold the etched and dissolved copper in solution at 18 to 30 oz/gal. 

Copper powders, having a variety of interesting particle shapes, can also be produced by the CQG method (9), a multi-step process involving gas/liquid and solid/liquid reactions. The process depends on the fact that copper can exist in two oxidation states. A copper (I) salt is fust produced by reducing an aqueous copper (n) ammonium sulphate solution with sulphur dioxide as... 

The salt process employs scrubbing of the gas with cuprous ammonium salt solution. Carbon monoxide forms a complex with the solution at high pressure and low temperature in the absorption column. The absorbed pure carbon monoxide is released from the solution at low pressure and high temperature. In the Cosorb process, cuprous tetrachloroaluminate (CuAlCl ) in a toluene medium is used as the absorbing liquid instead of the copper salt solution. A low corrosion rate and low energy consumption are the advantages of the Cosorb process over the previous one. 

The solvent process involves treating phthalonitrile with any one of a number of copper salts in the presence of a solvent at 120 to 220°C [10]. Copper(I)chloride is most important. The list of suitable solvents is headed by those with a boiling point above 180°C, such as trichlorobenzene, nitrobenzene, naphthalene, and kerosene. A metallic catalyst such as molybdenum oxide or ammonium molybdate may be added to enhance the yield, to shorten the reaction time, and to reduce the necessary temperature. Other suitable catalysts are carbonyl compounds of molybdenum, titanium, or iron. The process may be accelerated by adding ammonia, urea, or tertiary organic bases such as pyridine or quinoline. As a result of improved temperature maintenance and better reaction control, the solvent method affords yields of 95% and more, even on a commercial scale. There is a certain disadvantage to the fact that the solvent reaction requires considerably more time than dry methods. 

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