Chloride salt baths

Several other useful modifications of calciothermic reduction have been successfully developed for the preparation of this neodymium-bearing magnetic alloy. One of these is reduction-extraction which involves the reduction of neodymium sesquioxide (Nd203) with calcium in a molten calcium chloride-sodium chloride salt bath at 750 °C and the simultaneous extraction of the reduced metal into a molten neodymium-zinc or neodymium-iron alloy pool. The neodymium-zinc alloy product is treated in vacuum to remove zinc and produce neodymium metal, while the neodymium-iron alloy is itself the end product of... 

The most common fused salt baths are complex mixtures of alkah chlorides, rigorously purified and dried. Fused salt plating must be done under an inert atmosphere. Often argon is used because nitrogen can react with some metals. Inert anodes, eg, Pt-coated titanium or graphite, are used and the plating metal is suppHed by additions of an appropriate metal salt. 

Pt—Q—Salt, [Pt(NH3)2(HP04)] and [Pt(OH)3] (259,260). Chloride-based baths have been superseded by P-Salt-based baths, which are more stable and relatively easily prepared. Q-Salt baths offer even greater stabiUty and produce hard, bright films of low porosity. Plating under alkaline conditions employs salts of [Pt(OH3)] . These baths are easily regenerated but have low stabiUty. Platinum films have uses in the electronics industry for circuit repair, mask repair, platinum siUcide production, and interconnection fabrication (94). Vapor deposition of volatile platinum compounds such as [Pt(hfacac)2] and... 

The cell bath in early Downs cells (8,14) consisted of approximately 58 wt % calcium chloride and 42 wt % sodium chloride. This composition is a compromise between melting point and sodium content. Additional calcium chloride would further lower the melting point at the expense of depletion of sodium in the electrolysis 2one, with the resulting compHcations. With the above composition, the cells operate at 580—600°C, well below the temperature of highest sodium solubiUty in the salt bath. Calcium chloride causes problems because of the following equiUbrium reaction (56) ... 

The reaction temperature of 500—600°C is much lower than that required for the reductive chlorination. The volatile chlorides evolve from the molten salt bath. The boiling points of NbCl, TaCl, and WOCl He between 228 and 248°C. These compounds must therefore be separated by means of a distillation column. The chlorination of ferroalloys produces very pure tantalum pentachloride in toimage quantities. The TaCl contains less than 5 )J.g Nb/g Ta, and other metallic impurities are only amount to 1—2 lg/g Ta. 

Electrolytic Processes. The electrolytic procedures for both electrowinning and electrorefining beryUium have primarily involved electrolysis of the beryUium chloride [7787-47-5], BeCl2, in a variety of fused-salt baths. The chloride readUy hydrolyzes making the use of dry methods mandatory for its preparation (see Beryllium compounds). For both ecological and economic reasons there is no electrolyticaUy derived beryUium avaUable in the market-place. 

Nickel sulfamate is more soluble than the sulfate salt, and baths can be operated using higher nickel concentrations and higher currents. Sulfamate baths have been found to have superior microthrowing power, the abiUty to deposit in small cracks or crevices. Using one nickel salt, only a hydrometer and pH paper are needed to control the bath. A small amount of chloride salt was added as a proprietary. Highly purified nickel sulfamate concentrates are commercially available that can be used to make up new plating baths without further purification. 

Desyl chloride (a-cbloro-desoxybenzoin, m-chloro-co-phenyl acetophenone) [447-31-4] M 230.7, m 62-64 , 66-67 ,67.5 , 68 . For the purification of small quantities recrystallise from pet ether (b 40-60°), but use MeOH or EtOH for larger quantities. For the latter solvent, dissolve 12.5g of chloride in 45mL of boiling EtOH (95%), filter and the filtrate yields colourless crystals (7.5g) on cooling. A further crop (0.9g) can be obtained by cooling in an ice-salt bath. It turns brown on exposure to sunlight but it is... 

B. cis-1,2-Gyclohexanedimethanol Dimethanesulfonate. In a 5-1., three-necked, round-bottomed flask, immersed in an ice-salt bath and fitted with a mechanical stirrer and an addition funnel, is plaeed a solution of 111 g. (0.97 mole) of methanesulfonyl chloride in 1.21. of pyridine. While cooling and stirring, a solution of 46.4 g. (0.322 mole) of m-l,2-cyclohexanedimethanol in 250 ml. of pyridine is added dropwise at a rate such that the temperature does not exceed 0° (Note 5). Upon completion of the addition, the mixture is stirred at — 5° to 0° for an additional 2 hours. Two liters of cold 10% hydrochloric acid is introduced at a rate which maintains the reaction mixture below 20° (Note 5). The solid which separates is isolated by suction filtration, washed sequentially with 11. of dilute hydrochloric acid and 21. of water, and air-dried. There is isolated 93-95 g. (96-98%) of the dimethanesulfonate having m.p. 66-67.5°. Reorystallization from methanol gives needles melting at 75-76° (Note 6). 

B. (l-Azido-3,3-dimethoxy-l-propenyl)benzene. In a 2-1., one-necked, round-bottomed flask equipped with a magnetic stirrer and powder funnel are placed 156 g. (0.45 mole) of the iodoazide from Part A and 1500 ml. of anhydrous ether. The solution is stirred and cooled in an ice-salt bath (— 5° to 0°), and 62 g. (0.55 mole) of potassium <-butoxide (Note 6) is added. The powder funnel is then replaced by a calcium chloride drying tube and the mixture is stirred for 4 5 hours at 0°. At the end of this time 350 ml. of water is added while the mixture is still cold. The ethereal layer is then separated and washed with three 350-ml. portions of water and dried over magnesium sulfate. The solvent is removed with a rotary evaporator without heating, leaving 67-75 g. (68-76%) of (l-azido-3,3-dimethoxy-l-propenyl)-benzene as a dark oily liquid (Note 7). This material can be used without further purification for Part C (Note 8). 

Kochsalz, n. common salt (sodium chloride), -bad, n. (common) salt bath brine bath, -flamme, /. sodium chloride flame. 

Salz-ather, m. muriatic ether (old name for ethyl chloride), -ausbluhung,/. efflorescence of salt, -bad, n. salt bath. -base,/, salifiable base (old term), -bedarf, m. salt requirement. -beize, /. (Leather) salt dressing, -bergwerk, n. salt mine, salzbildend, p.a. salt-forming. 

Nickel thermocouple sheaths have been used satisfactorily in salt baths, e.g. in barium chloride at 1 000-1 100°C and in sodium and potassium chlorides at up to 980°C. If the salt is contaminated with sulphur then an Inconel sheath is preferred to one of nickel. The latter type is also satisfactory in cyanide baths used for case-hardening. 

B. 2-Cyclohexyloxyethanol. A well-dried, 3-1. three-necked, round-bottomed flask is equipped with a stirrer, a pressureequalizing dropping funnel, and a condenser to whose top is attached a calcium chloride drying tube. The flask is charged with 242 g. (1.81 moles) of anhydrous aluminum chloride powder and is immersed in an ice-salt bath. Anhydrous ether (25-50... 

In a tared Erlenmeyer flask surrounded by an ice-salt bath is placed 100 g. (1.78 moles) of acrolein (Org. Syn. 6,1) (Note 1). When the temperature has dropped to —10 to —15° a current of dry hydrogen chloride (Org. Syn. 6, 64) is passed into the acrolein until it shows a gain in weight of 65 g. (1.78 moles). This requires about two hours. The product thus obtained is a clear, viscous, slightly yellow liquid which becomes very turbid and dark colored on standing one or two days (Note 2). 

A. 2,3-Dibromopropionaldehyde diethyl acetal. A 500-ml., three-necked, round-bottomed flask is equipped with a mechanical stirrer, a pressure-equalizing dropping funnel fitted with a calcium chloride drying tube, and a thermometer. The flask and dropping funnel are charged with 28.0 g. (0.5 mole) of freshly distilled acrolein and 80.0 g. (0.5 mole) of bromine, respectively. The acrolein is stirred rapidly and cooled to 0° in an ice-salt bath, then bromine is added at a rate such that the temperature is kept at... 

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