Mercury, purification

Mercury purification processes can be summarized in four steps ... 

This reaction, preceded by the formation of Hg[Co(CO)4]2 from sodium amalgam and dicobalt octacarbonyl in a hydrocarbon solvent, is the basis of a recently proposed method for the purification of mercury 37). However, the cost of dicobalt octacarbonyl makes the widespread application of this mercury purification method unlikely. Treatment of Hg[Co(CO)4]2 with trimethylphosphite also liberates mercury, producing the nonionic derivative [Co(CO)3P(OCH3)3]2 rather than a salt 26)... 

Many mercury compounds are labile and easily decomposed by light, heat, and reducing agents. In the presence of organic compounds of weak reducing activity, such as amines (qv), aldehydes (qv), and ketones (qv), compounds of lower oxidation state and mercury metal are often formed. Only a few mercury compounds, eg, mercuric bromide/77< 5 7-/7, mercurous chloride, mercuric s A ide[1344-48-5] and mercurous iodide [15385-57-6] are volatile and capable of purification by sublimation. This innate lack of stabiUty in mercury compounds makes the recovery of mercury from various wastes that accumulate with the production of compounds of economic and commercial importance relatively easy (see Recycling). 

Natural gas contains both organic and inorganic sulfur compounds that must be removed to protect both the reforming and downstream methanol synthesis catalysts. Hydrodesulfurization across a cobalt or nickel molybdenum—zinc oxide fixed-bed sequence is the basis for an effective purification system. For high levels of sulfur, bulk removal in a Hquid absorption—stripping system followed by fixed-bed residual clean-up is more practical (see Sulfur REMOVAL AND RECOVERY). Chlorides and mercury may also be found in natural gas, particularly from offshore reservoirs. These poisons can be removed by activated alumina or carbon beds. 

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. 

An important use of a mercury cathode is in the purification of electrolyte solutions, for example the removal of traces of heavy metals from potassium chloride solutions.-All such impurities have much more positive deposition... 

A solution of 4.5 g (19.9 mmol) 4-(fm-butyldimethylsilyloxy)-2-cyclohexenone and 452 mg (1 mmol) of mercury(II) iodide is stirred at r.t. for 15 min and then cooled to — 78 °C. 5.03 g (24.8 mmol) of 1-ethoxy-1-(tm-bulyl(iimethylsilyloxy)ethene are added dropwise during 15 min. The mixture is stirred at — 78 °C for 2 h, quenched with 302 mg (3 mmol) of triethylamine and allowed to warm to r.t. The mixture is filtered through a short (3 cm) column of silica gel (deactivated with a 5% triethylamine solution in hexane/ethyl acetate, 10 1) eluting with hexane/ethyl acetate (10 1) and concentrated in vacuo. Purification of the crude material by flash chromatography (silica gel, hcxanc/cthyl acetate 30 1) gave the adduct as a colorless oil yield 7.98 g (18.7 mmol, 94%) d.r. (cisjtrans) 95.2 4.8. 

Zinc and mercury are found in the Earth s crust as suifide ores, the most common of which are sphaierite (ZnS) and cinnabar (HgS). See the previous section for descriptions of the extraction and purification of these metais. 

When an Alchemist Speaks of Mercury, Sulphur and Salt, He Speaks of His Spiritual, Astral and Physical Bodies, Not of the Elements. Alchemy Unveiled Describes the Tribulations That a Human Being Has to Pass Through in Order to Purify These Three Bodies. However, to Achieve the Level of an Alchemist Requires Daily Study and Strict Daily Mental, Astral and Physical Exercises for Many Lifetimes. Alchemy Unveiled Will Lead the Reader on a Journey of a Complete Purification of the Body, Soul and Spirit, and for the First Time the Mystery of the Philosopher s Stone Is Openly Explained... 

Purification processes are used to remove impurities such as sulfiirs, mercury, gums and waxes. The processes include absorption and stripping, solvent extraction and thermal diffusion... 

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