Magnesium sulfate solution preparation

In the laboratory, magnesium hydroxide may be prepared by double decomposition reactions by adding a soluble hydroxide to solutions of magnesium salts i.e., adding caustic soda solution to magnesium sulfate solution ... 

Dodecyl tosylate was prepared from 1-dodecanol by the procedure of Marvel and Sekera.5 Crystallization from a dried (magnesium sulfate) solution in light petroleum ether afforded white needles, m.p. 27.5-28.5°. 

MgO-supported carbon catalyst was also prepared by impregnating an aqueous magnesium sulfate solution. The dried impregnated carbon was washed with concentrated ammonium hydroxide solution to convert the sulfate into magnesium hydroxide. This washed carbon was dried and heated in a tubular reactor as just described to convert the hydroxide to oxide. 

Final Preparation Pipet 50.0 mL of Magnesium Sulfate Solution into the flask, add exactly the volume, / , in milliliters, of Standard EDTA Solution, determined as directed under Titer Determination (below), then dilute to volume with water, and mix. 

In some preparations, NaOH solutions were introduced into the magnesium sulfate solution and the solution of sodium metasilicate in the course of the precipitation process. 

Procedure Mix several pinches of calcium sulfate with water leave the mixture to stand overnight the solution becomes clear, a big solid residue can be observed at the bottom. Dip the conductivity tester into distilled water, then into the saturated solution. Prepare a 0.1 molar magnesium sulfate solution and dilute it with the help of the graduated cylinder once at 1 2 and once at 1 10. Measure the conductivity of these solutions and compare with the conductivity of saturated calcium sulfate solution. 

To a mixture of 50 ml of dry THF and 0.050 mol of l-tert.-butoxy-2-pentyne (prepared by ethylation of HC-CCH O-tert.-Ci,H9 in liquid ammonia was added 0.055 mol of butyilithium in about 35 ml of hexane in 10 min at -30°C. After stirring for 20 min at -25°C the solution was cooled to -50°C and 0.06 mol of methyl iodide was added in one portion, followed 10 min later by 50 ml of water. The aqueous layer was separated and extracted twice with diethyl ether. The solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum. 

Ojj 1.5323, prepared from phenol, KOH in ethanol and propargyl bromide) was added and the mixture was heated at 60°C for 15 min. It was then poured into 200 ml of ice-water and the reaction products were extracted with diethyl ether. The ethereal extracts were washed with saturated NH Cl solution, dried over magnesium sulfate and then concentrated in a water-pump vacuum. There remained 9.5 g of 3 1 mixture... 

To a mixture of 100 ml of THF and 0.10 mol of the epoxide (note 1) was added 0.5 g Of copper(I) bromide. A solution of phenylmagnesium bromide (prepared from 0.18 mol of bromobenzene, see Chapter II, Exp. 5) in 130 ml of THF was added drop-wise in 20 min at 20-30°C. After an additional 30 min the black reaction mixture was hydrolysed with a solution of 2 g of NaCN or KCN and 20 g of ammonium chloride in 150 ml of water. The aqueous layer was extracted three times with diethyl ether. The combined organic solutions were washed with water and dried over magnesium sulfate. The residue obtained after concentration of the solution in a water-pump vacuum was distilled through a short column, giving the allenic alcohol, b.p. 100°C/0.2 mmHg, n. 1.5705, in 75% yield. 

A mixture of 0.10 mol of the acetylenic alcohol, 0.12 mol of triethylamine and 200 ml of dichloromethane (note 1) was cooled to -50°C. Methanesulfinyl chloride (0.12 mol) (for its preparation from CH3SSCH3, (08300)30 and chlorine, see Ref. 73) was added in 10 min at -40 to -50°0. A white precipitate was formed immediately. After the addition the cooling bath was removed and the temperature was allowed to rise to -20°0, then the mixture was vigorously shaken or stirred with 100 ml of water. The lower layer was separated off and the aqueous layer was extracted twice with 10-ml portions of CH2CI2. The combined solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum (note 2). The yields of the products, which are pure enough (usually 96%) for further conversions, are normally almost quantitative. 

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