Distillation of mercury

Fig. 3J0 Plot of cumulative pore volume against logarithm of r the effective pore radius, (o) For charcoal AY4 A by mercury intrusion O by capillary condensation of benzene, (b) For zinc chloride carbon AYS A by mercury intrusion O by capillary condensation of benzene x by capillary condensation of benzene, after mercury intrusion followed by distillation of mercury under vacuum at temperature rising to 350°C. (Courtesy...

Silver is usually extracted from high-grade ores by three common processes that have been known for many years. These are amalgamation, leaching, and cyanidation. In one amalgamation process, ore is crushed and mixed with sodium chloride, copper sulfate, sulfuric acid, and mercury, and roasted in cast iron pots. The amalgam is separated and washed. Silver is separated from its amalgam by distillation of mercury. 

Cognate preparation. 1-Phenylethanol. Use 10.4g (11.5ml, 0.1 mol) of styrene, and carry out the oxymercuration and reduction as described above. The yield of recovered mercury is 17.5 g (87%), and traces continue to separate during the work-up procedure. Distil the final crude product under reduced pressure and collect the 1-phenylethanol at 110-115 °C/25mmHg. Towards the end of the distillation the decomposition of residual organo-mercurial compounds ensues, and co-distillation of mercury contaminates the product collect the contaminated fraction separately. The first fraction, yield 6.2 g (51%), is 92 per cent pure by g.l.c. (retention time 5.33 minutes) the impurity is mainly styrene (tR 2.16 minutes). The mercury-contaminated fraction (3.0 g, 25%) is 85 per cent pure by g.l.c. 

An easy way to perform the distillations of mercury amalgam is to construct a small retort using iron pipe fittings from the hardware store, pack charcoal briquettes around it and start the fire outside. Again the outlet is submerged in a container of water and the distillation of metallic mercury proceeds. When the distillation stops, be sure to remove the retort outlet from the water or the vacuum created by the cooling retort will draw the water into the apparatus with possible dire consequences, i.e. explosion. 

The apparatus in Figure 119b has a built-in efficiency of two collection vessels. This double alembic or distilling head can be made of iron if vegetables are distilled or steam-distilled. However, the distillation of oil of vitriol and other acidic substances (Figure 120) requires tin or tin-lined vessels. Distillation of mercury, Le Fevre notes, can never employ metallic vessels since amalgamation will occur. The diarist Samuel Pepys visited Le Fevre s laboratory on January 15,... 

Fig. 5. Automatic distillation of mercury. (Length of distillation vessel 180 mm.,diameter 35mm. the vessel is insulated with a thick layer of asbestos.)...

As stated above for the TBP distillation, petroleum cannot be heated above 340°C without its molecules starting to crack. Because of this, analytical distillation of heavy fractions is done according to the ASTM D 1160 method for petroleum materials that can be partially or completely vaporized at a maximum temperature of 400°C at pressures from 50 to 1 mm of mercury (6.55 to 0.133 kPa). 

The distillation of crudes chosen for their yield in heavy fractions is the most common means. Bitumen is extracted from the residue from a vacuum distillation column (a few dozen mm of mercury), the latter being fed by atmospheric distillation residue. Unlike the practice of a decade ago, it is now possible to obtain all categories of bitumen, including the hard grades. 

The distillation heads Fig. 22(F) and Fig. 22(G) can be fitted with thermometers having a ground-glass cone just above the bulb (Fig. 22(M)). These are expensive, and it is usually more convenient to fit a thermometer pocket (Fig. 22(N)) which consists of a small well , fitting as shown into the neck of the flask. A small volume of mercury is placed in the well just to cover the bulb of a conventional thermometer, and thus provides excellent thermal contact between the thermometer and the sides of the pocket. 

In molecular distillation, the permanent gas pressure is so low (less than 0 001 mm. of mercury) that it has very little influence upon the speed of the distillation. The distillation velocity at such low pressures is determined by the speed at which the vapour from the liquid being distilled can flow through the enclosed space connecting the still and condenser under the driving force of its own saturation pressure. If the distance from the surface of the evaporating liquid to the condenser is less than (or of the order of) the mean free path of a molecule of distillate vapour in the residual gas at the same density and pressure, most of the molecules which leave the surface will not return. The mean free path of air at various pressures is as follows —... 

The word calcium is derived from calx, the Latin word for lime. The Romans used large quantities of calcium oxide or lime as mortar in constmction (see Lime and limestone). Because calcium compounds are very stable, elemental calcium was not produced until 1808 when a mercury amalgam resulted from electrolysis of calcium chloride in the presence of a mercury cathode. However, attempts to isolate the pure metal by distilling the mercury were only marginally successful. 

The formylation product is too sensitive to purify by distillation even at pressures of 1-2 mm. of mercury. 

Potassium (metal) [7440-09-7] M 39.1, m 62.3 , d 0.89. Oil was removed from the surface of the metal by immersion in n-hexane and pure Et20 for long periods. The surface oxide was next removed by scraping under ether, and the potassium was melted under vacuum. It was then allowed to flow through metal constrictions into tubes that could be sealed, followed by distillation under vacuum in the absence of mercury vapour (see Sodium). EXPLOSIVE IN WATER. 

Blowing air through the hot, crude, liquid metal oxidizes traces of metals such as Fe, Cu, Zn and Pb which form an easily removable scum. Further purification is by distillation under reduced pressure. About 4000 tonnes of mercury are used annually but only half is from primary, mine production the other half being secondary production and sales from stockpiles. The main primary producer is now Spain, but several other countries, including the former Soviet Union, China and Algeria, have capacity for production. 

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