Magnesium without

Another process by Siemens is to electrolyse a solution of the double salt formed by treating antimony sulphide with sulph-hydrate of calcium, barium, strontium, or magnesium. Without the use of diaphragms, the hydrogen liberated at the cathode end combines with the sulphur of antimony sulphide, and the antimony is deposited, while at the same moment the sulph-hydrates of other metals are formed, to be in turn converted into disulphides by the oxygen developed in the reaction. 

P. Alenfelt, Corrosion Protection of Magnesium without the Use of Chromates , Py-ratechnica XVI, 1995. 

As the reaction beings to subside, run in from the dropping-funnel without delay a mixture of 25 ml. of acetone and 20 ml. of benzene, in order to maintain a brisk and continuous reaction. When the reaction finally subsides, heat the mixture on a boiling water-bath for 45 minutes with occasional shaking. If the shaking does not break up the spongy mass of magnesium pinacolate,... 

Pour the reaction mixture into a 1-litre round-bottomed flaak, add 250 ml. of water, fit a still head and a condenser for downward distillation (Fig. II, 13, 3, but without the thermometer). Distil the mixture until about 125 ml. of distillate (two layers) have been collected. Saturate with salt (about 30 g. are required), and separate the upper layer of cj/cZohexanone extract the aqueous layer with 25-30 ml. of ether and combine the ether extract with the cycZohexanone layer. Dry with about 6 g. of anhydrous sodium or magnesium sulphate, filter the solution into a distilling flask of suitable size to which a condenser has previously been attached. Distil oflF the ether from a water bath—a beaker containing warm water is satisfactory. Distil the residual liquid from an air bath or a wire gauze, and collect the cyclohexanone at 153-156°. The yield is 16 g. 

Commercial p-toluenesulphonyl chloride may be purified by dissolving it in benzene, washing with 6 per cent, sodium hydroxide solution, drying by shaking with anhydrous potassium carbonate or magnesium sulphate, and distilling under reduced pressure b.p. Hd /lS mm. m.p. 69°. The distillation should be completed without interruption. 

To a solution of 0.40 mol of butyllithium in about 280 ml of hexane were added 280 ml of dry THF with cooling below -10°C. Subsequently 0.40 mol of 1,1-diethoxy--2-propyne (see Chapter V, Exp. 28) was introduced in 15 min at -30 to -10°C. To the solution obtained was then added in 15 min with cooling at about -15°C 0.40 mol of chloromethyl ethyl ether (note 2). After the addition stirring was continued for 1 h without cooling. The mixture was then shaken with concentrated ammonium chloride solution and the ethereal layer was separated off. The aqueous layer was extracted twice with diethyl ether. After drying the ethereal solutions over magnesium sulfate the diethyl ether was evaporated in a water-pump vacuum. 

The extracts were dried (without washing) over magnesium sulfate and after removing the solvents in a water-pump vacuum the ketone was distilled (b.p. 35-40°C/ 2 0... 

The layers were separated and four extractions with the light petroleum fraction (50-ml portions) were carried out without delay (note 1). The combined extracts were washed with ice-water and subsequently dried over magnesium sulfate. The solution was warmed in a water-pumpvacuum and the ethoxyacetylene condensed in a receiver cooled at -80°C (see Chapter I for the description of this procedure). Redistillation of the contents of the receiver at normal pressure (760 nmHg) through a 40-cm Vigreux column gave ethoxyacetylene, b.p. 52°C, n ° 1.3820 in 62-702 yield. 

To a solution of 8 g of lithiim alanate in 250 ml of diethyl ether was added in 15 min 24 g (0.3 mol) of 2-penten-4-yn-l-ol (III, Exp. 57). The diethyl ether began to reflux and a rubber-like greyish precipitate was formed. After heating for 1 h under reflux the flask was placed in an ice + ice-water bath and water (150 ml) was added dropwise with vigorous stirring. After this hydrolysis procedure the ethereal solution was decanted and the aqueous jelly layer was extracted ten times with diethyl ether. The ethereal extracts were dried (without washing) over magnesium sulfate and subsequently concentrated in a water-pump vacuum. 

A mixture of 100 ml of water and 0.10 mol of methylthioallene (see Chapter IV, Exp. 23) was placed in the flask and 24 g of sodium periodate were added in five portions at intervals of 4 min. The mixture was agitated vigorously and the temperature was kept between 25 and 30°C by occasional cooling. After 1 h twenty extractions with 10-ml portions of chloroform were carried out. The combined extracts were dried (without previous washing) over magnesium sulfate. Removal of the chloroform by evaporation in a water-pump vacuum gave the reasonably pure (> 9i%) le... 

A mixture of 0.10 mol of 1-ethylthio-l-propyne (see IV, Exp. 23 and Ref. 1) and 100 ml of glacial acetic acid was heated at 95°C, then 35 ml of 33% hydrogen peroxide were added in 15 min with occasional cooling. After this addition the mixture was kept for 1 h at 100°C, then cooled to 20°C and 200 ml of water were added. Ten extractions with 20-ml portions of chloroform were carried out and the combined extracts were dried over magnesium sulfate (without previous washing)... 

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