Subject metal chlorides

Materials of Construction. GeneraHy, carbon steel is satisfactory as a material of construction when handling propylene, chlorine, HCl, and chlorinated hydrocarbons at low temperatures (below 100°C) in the absence of water. Nickel-based aHoys are chiefly used in the reaction area where resistance to chlorine and HCl at elevated temperatures is required (39). Elastomer-lined equipment, usuaHy PTFE or Kynar, is typicaHy used when water and HCl or chlorine are present together, such as adsorption of HCl in water, since corrosion of most metals is excessive. Stainless steels are to be avoided in locations exposed to inorganic chlorides, as stainless steels can be subject to chloride stress-corrosion cracking. Contact with aluminum should be avoided under aH circumstances because of potential undesirable reactivity problems. 

In analogous reactions arylmetal compounds of thallium (ArTICl, addition of Tl-Na alloy, Nesmeyanov and Makarova, 1952), of tin (Ar2SnCl2, addition of Sn, Nesmeyanov et al., 1936), of lead (Ar4Pb, Pb-Na alloy, Nesmeyanov and Makarova, 1954 Nesmeyanov et al., 1954) were obtained (yields up to 80% with Hg, 10-40% with the other metals). Tetravalent metal salts often react to give a mixture of partially arylated metal chlorides (ArwMCl4 , n = 1 to 3). Waters (1939) was one of the few chemists outside Nesmeyanov s school who worked on that subject (arylation of lead). 

Good electrical conductance is one of the characteristics of many though not all molten salts. This characteristic has often been employed industrially. Various models have been proposed for the mechanism of electrical conductance. Electrolytic conductivity is related to the structure, although structure and thermodynamic properties are not the main subjects of this chapter. Electrolytic conductivities of various metal chlorides at the melting points are given in Table 4 together with some other related properties. "... 

During the period 1965-1975 the chemistry of the 1,2-dithiolene complexes of the transition metals was the subject of considerable study.86,87,91-98 However, during this period of great activity few complexes of the early transition metals were reported aside from those of vanadium. The problem had much to do with synthetic procedures, since reaction of, say, the anhydrous metal chlorides with the dithiolene or its sodium salt did not prove successful. However, the use of metal dialkylamides99 did result in clean reactions (e.g. equation 21). 

Of all these processes only flame hydrolysis is used to produce oxides with high surface areas on a large industrial scale Therefore, the emphasis of this article lies on this subject In general, this process is suitable for any volatile compound that can be decomposed at a high temperature to form an oxide Possible precursor compounds that can be used are metal chlorides carbonyls such as Ni(CO)4 or Fe(CO)s, and volatile alcoholates Reactions that have been studied are, for example, the manufacture of AUOj from A1CU [3]... 

Ethylene oxide vapor is extremely flammable at concentrations ranging from 3% to 100% and subject to explosive decomposition. Although liquid ethylene oxide is relatively stable, contact with acids, bases, or heat, particularly in the presence of metal chlorides and oxides, can lead to a violent polymerization. 

The subject of Sect. 5.2.1 to 5.2.4 was the electrochemical production of chlorine and of caustic alkali. It shall be noted in addition, that chlorine is obtained as a by product if metal chlorides like NaCl, MgCh, or others are electrolyzed in their molten form to produce the metals (see Chapter 4). From aqueous NaCl, caustic alkali and hydrochloric acid can be produced without generation of chlorine, using an electrodialytic separation process [35],... 

This is further illustrated by Fig. 2-45 for several metal chlorides at a temperature of 727 °C. If volatile metal chlorides are the only compounds that are formed by the corrosion process, evaporation will take place, and in mass change measurements during a corrosion test, a linear rate law is observed for the decrease in mass. If the metals are subjected to atmospheres consisting of chlorine and oxygen, thus allowing the formation of metal chlorides and metal oxides at the same time, the situation is characterized by the following equation... 

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

Electrolytic Preparation of Chlorine and Caustic Soda. The preparation of chlorine [7782-50-5] and caustic soda [1310-73-2] is an important use for mercury metal. Since 1989, chlor—alkali production has been responsible for the largest use for mercury in the United States. In this process, mercury is used as a flowing cathode in an electrolytic cell into which a sodium chloride [7647-14-5] solution (brine) is introduced. This brine is then subjected to an electric current, and the aqueous solution of sodium chloride flows between the anode and the mercury, releasing chlorine gas at the anode. The sodium ions form an amalgam with the mercury cathode. Water is added to the amalgam to remove the sodium [7440-23-5] forming hydrogen [1333-74-0] and sodium hydroxide and relatively pure mercury metal, which is recycled into the cell (see Alkali and chlorine products). 

Because of the presence of an extended polyene chain, the chemical and physical properties of the retinoids and carotenoids are dominated by this feature. Vitamin A and related substances are yellow compounds which are unstable in the presence of oxygen and light. This decay can be accelerated by heat and trace metals. Retinol is stable to base but is subject to acid-cataly2ed dehydration in the presence of dilute acids to yield anhydrovitamin A [1224-18-8] (16). Retro-vitamin A [16729-22-9] (17) is obtained by treatment of retinol in the presence of concentrated hydrobromic acid. In the case of retinoic acid and retinal, reisomerization is possible after conversion to appropriate derivatives such as the acid chloride or the hydroquinone adduct. Table 1 Hsts the physical properties of -carotene [7235-40-7] and vitamin A. 

Aluminium chloride (anhydrous) [7446-70-0] M 133.3, m 192.6°. Sublimed several times in an all glass system under nitrogen at 30-50mm pressure. Has also been sublimed in a stream of dry HCl and has been subjected to a preliminary sublimation through a section of granular aluminium metal [for manipulative details see Jensen J Am Chem Soc 79 1226 1957]. Fumes in moist air. 

The subject is also closely related to fuel-ash corrosion which in most cases is caused by a layer of fused salts such as sulphates and chlorides Attention has been focused on the electrochemistry of this type of corrosion and the relevant thermodynamic data summarised in the form of diagrams . Fluxing and descaling reactions also resemble in some respects reactions occurring during the corrosion of metals in fused salts. A review of some of the more basic concepts underlying corrosion by fused salts (such as acid-base concepts and corrosion diagrams) has appeared. ... 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

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