Magnesium chloride brine, solid

More commonly, salt is produced by the evaporation of natural brines which are formed by pumping water into salt wells and subsequently pumping the resulting brine to the surface. These brines usually contain sodium chloride as the main solute, together with relatively small quantities of other salts, such as sodium and calcium sulfates and potassium and magnesium chlorides. Upon evaporation of the water, the resulting solid therefore consists largely of sodium chloride, but if a purer product is desired, the brine must be suitably treated to remove at least the major portion of the impurities. 

The aqueous layers containing the silver(I) complex of methyl (lR,5R)-5-hydroxy-2-cyclopentene-l-acetate are then treated with an excess of saturated brine to precipitate silver chloride and free the desired product. After precipitation is complete, the water layer is decanted from the solid silver chloride. The solids are washed with ether (4 x 100 mL) and each ether layer is used to extract the water layer (Note 20). The combined ether layers are washed with 50 mL of brine and dried over anhydrous magnesium sulfate. Filtration and removal of solvent under reduced pressure yield 16-19 g of crude product. The product is distilled through a 4"-Vigreux column at 0.1 mm pressure to yield 12.8-14.7 g (27-31 ) of methyl (lR,5R)-5-hydroxy-2-cyclopentene-l-acetate, bp 74-78°C at 0,1 mm, [a]p5 -132° (CHjOH, a 1.06) (Notes 21, 22). 

The bittern (spent brine) from solar salt production contains 300 00 g/L dissolved solids relatively enriched in the less concentrated salt impurities. This may be either discarded or further worked to recover other elements of value. Brine from the Great Salt Lake, for instance, is processed for magnesium chloride hexahydrate recovery [10], which occurs at a density of 1.26g/cm. This is later converted to metallic magnesium [12]. The Dead Sea brines are processed primarily for potassium chloride (potash), but are also worked for sodium and magnesium chlorides and derived products such as bromine and hydrochloric acid [16] (Sections 6.2.2 and 8.8). 

In most production wells, chloride salts are found either dissolved in water that is emulsified in crude oU or as suspended solids. Salts also originate from brines injected for secondary recovery or from seawater ballast in marine tankers. Typically, the salts in crude oils consist of 75% sodium chloride, 15% magnesium chloride, and 10% calcium chloride. When crude oils are charged to crude distillation units and heated to temperatures above approximately 120 °C, hydrogen chloride is evolved from magnesium and calcium chloride, whUe sodium chloride is essentiaUy stable up to roughly 750 °C. 

The reaction mixture is cooled in a water-ice bath, and a saturated aqueous ammonium chloride solution is added at such a rate as to maintain the temperature below 35°C. Ammonium chloride solution is added in portions until addition produces no further exothermic reaction (Note 3). The supernatant solution is decanted through glass wool onto 400 g of ice in a 4-L separatory funnel. The residual solids are washed with three portions of hexane, approximately 1000 nt total, and the washes are decanted into the separatory funnel. After the phases are separated, the aqueous phase is washed with an additional 500-mL portion of hexane. The combined organic extracts are washed with 500 nl of saturated ammonium chloride, and then with 500 nl. of brine. The organic layer is dried over anhydrous magnesium sulfate and filtered. Most of the solvent is removed by a rotary evaporator and the residual oil is distilled at reduced pressure using an ice water-cooled fraction cutting head. After a small forerun, approximately 390-392 g (94% of theory) is collected as a colorless oil, bp 116°C/1.6 nm (lit. 155°C/17 rim). ... 

To a solution of N-methyl-4-nitrophenethylamine (1.5 g) (J.O.C., [1956], 21, 45) and 2-[4-nitrophenoxy]ethyl chloride (1.55 g) (C.A., [1955], 49, 3163e) in acetonitrile (50 ml) was added potassium carbonate (1.25 g) and sodium iodide (1.2 g) and the suspension was stirred at reflux for 72 hours. After evaporation to dryness, the residual oily solid was partitioned between a 2 N aqueous sodium bicarbonate solution and ethyl acetate. After two further extractions with ethyl acetate, the organic portions were combined, washed with a saturated aqueous brine solution, dried over magnesium sulfate, filtered and evaporated. The resultant orange solid (2.7 g) was crystallised from ethanol to give l-(4-nitrophenoxy)-2-[N-methyl-N-(4-nitrophenethyl)amino]ethane (1.9 g), m.p. 74°C. 

After cooling the reaction mixture in an ice-bath, the inorganic salts were removed by filtration and washed with acetone. The combined filtrates were concentrated in vacuo. The residual syrup was diluted with saturated brine and extracted with three portions of diethyl ether. The gathered extracts were dried over anhydrous magnesium sulfate, clarified with charcoal and treated with ethereal hydrogen chloride until precipitation was complete. The solid was slurried in diethyl ether and decanted several times, filtered and air-dried to give 3.8 g (86%) of tan 4-(2-di-n-propylaminoethyl)-7-(l-phenyl-lH-tetrazol-5-yloxy)-2(3H)-indolone hydrochloride. Recrystallization from 200 cc of hot acetonitrile gave 2.6 g (59%) of microcrystalline product, m.p. 245°C. 

The reaction mixture is poured into an ice-cold aqueous saturated ammonium chloride solution (700 mL). The aqueous phase is separated and extracted with ethyl acetate (2 x 500 mL). The organic phases are combined, washed with brine (500 mL), and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, crude 2 (115 g) is obtained as a white solid. 

Fig. 17. Relations of (a) sodium (b) potassium (c) calcium (d) magnesium (e) chloride and (f) sulfate vs. bromide, respectively, in the mine brine samples, compared to the trend (solid line of an evaporating seawater (after Carpenter, 1978).

To a solution of the ketone (20.4 g, 46.9 mmol) in THF (500 ml.) at 0 °C was added lithium tri-tert-butoxyaluminohydride I.iAIII(0/-Bu)3 (61.0 mL of a 1.0 M solution in THF, 61.0 mmol). The resulting reaction mixture was stirred for 30 min at 0 °C and then for 30 min at 25 °C. After the reaction was complete, as established by TLC analysis, it was quenched by the addition of saturated ammonium chloride (200 mL) followed by addition of EtOAc (300 mL). The mixture was stirred at 25 °C for 2 h, followed by extraction with EtOAc (3 x 300 mL). The combined extracts were washed with brine, dried over magnesium sulfate, and concentrated to give the crude product, which was purihed by flash chromatography (silica gel, 25% EtOAc in hexanes) to afford 19.4 g (95%) of the alcohol as a white solid. 

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