Mercury iodide preparation

Preparation of Mercury(II) Iodide. Prepare a 0.02 N solution of mercury(II) nitrate. Boil 2-3 ml of the solution, add an equal volume of a 0.02 N potassium iodide solution, and let the mixture stand to your next lesson. Filter off the precipitate (what is its composition ) through a paper filter, wash it with water, and dry it in a drying cabinet at 70 °C. What happens to the salt when it is kept in the air ... 

Although prepared in a similar manner to the lead compound, the product formed with mercury iodide contains one atom less of sulphur per molecule, thus, mercury thiodi-imide, HgN2S.NH3. 

Ethyltripropylarsonium iodide, (CH8.CHs.CIt2)3(C2ll5.)AsI, is prepared in a similar manner to the preceding compound. It sinters at 230° C., and melts with deeomiKisition at 287° C. The mercuri-iodide is a pale yellow substance. 

With the exception of arylmercury compounds (like thiomersal) as a stabilizing addition to some eyedrops and the application of one drop of a mercury chloride solution in the eyes of newborns for syphilis prophylaxis, mercury-containing pharmaceutical preparations are obsolete today. But in many countries with dark-skinned people, skin-lightening creams and soaps are sold containing up to 3% mercury iodide or 10% mercury amidochloride. Despite a prohibition of the distribution of these products in the European Community, in Northern America, and in many African states, they are still exported from several European countries as germicides to the third world and reimported illegally to European cities with a substantial black population like London, etc. [8]. 

According to Salter (1869), There may be obtained from iodine and mercury a very pretty pink colour, analogous in composition to pure scarlet. He includes no further details regarding preparation, though states that it alters to the scarlet form (mercury iodide, q.v.). 

Scarlet lake may refer to either a cochineal lake or, according to Field (1835), a crimson lake and vermilion or iodine scarlet (mercury iodide qq.v). Salter (1869) states that scarlet lake is prepared in the form of drops from cochineal, and is of a fine transparent red colour and excellent body... It is generally tinted with vermihon. Heaton (1928) indicates that this was still a term of current use, listing two meanings, one a pigment based on cochineal and vermilion and another a scarlet from artificial dyes . 

Standard methods which convert alkylmercury iodides into bis(alkyl)-mercurials fail to convert perfluoroalkylmercury iodides into bis(perfluoro-alkyl)mercurials. The preparation of primary bis(perfluoroalkyl)mercurials can be accomplished by treating perfluoroalkylmercury iodides with silver, copper, or cadmium amalgams. Alternatively, the parent perfluoroalkyl iodide will react directly with the amalgam. By either method yields are from 40 to 90%. 

Hydrogen iodide is prepared in a similar way to hydrogen bromide, by the action of water on a mixture of iodine and violet phosphorus. TTie hydrogen iodide evolved may be collected by downward delivery or may be condensed (b.p. 238 K) it reacts with mercury and so cannot be collected over the latter. 

Ethyl phenylethylmalonate. In a dry 500 ml. round-bottomed flask, fitted with a reflux condenser and guard tube, prepare a solution of sodium ethoxide from 7 0 g. of clean sodium and 150 ml. of super dry ethyl alcohol in the usual manner add 1 5 ml. of pure ethyl acetate (dried over anhydrous calcium sulphate) to the solution at 60° and maintain this temperature for 30 minutes. Meanwhile equip a 1 litre threenecked flask with a dropping funnel, a mercury-sealed mechanical stirrer and a double surface reflux condenser the apparatus must be perfectly dry and guard tubes should be inserted in the funnel and condenser respectively. Place a mixture of 74 g. of ethyl phenylmalonate and 60 g. of ethyl iodide in the flask. Heat the apparatus in a bath at 80° and add the sodium ethoxide solution, with stirring, at such a rate that a drop of the reaction mixture when mixed with a drop of phenolphthalein indieator is never more than faintly pink. The addition occupies 2-2 -5 hoius continue the stirring for a fiuther 1 hour at 80°. Allow the flask to cool, equip it for distillation under reduced pressure (water pump) and distil off the alcohol. Add 100 ml. of water to the residue in the flask and extract the ester with three 100 ml. portions of benzene. Dry the combined extracts with anhydrous magnesium sulphate, distil off the benzene at atmospheric pressure and the residue under diminished pressure. C ollect the ethyl phenylethylmalonate at 159-160°/8 mm. The yield is 72 g. 

Mercuric chloride is widely used for the preparation of red and yellow mercuric oxide, ammoniated mercury/7(9/USP, mercuric iodide, and as an intermediate in organic synthesis. It has been used as a component of agricultural fungicides. It is used in conjunction with sodium chloride in photography (qv) and in batteries (qv), and has some medicinal uses as an antiseptic. 

Titanium diiodide may be prepared by direct combination of the elements, the reaction mixture being heated to 440°C to remove the tri- and tetraiodides (145). It can also be made by either reaction of soHd potassium iodide with titanium tetrachloride or reduction of Til with silver or mercury. 

Boujlel and Simonet used an electrochemical method to prepare a group of similar compounds, including compound ]5, shown in Eq. (3.41). In a typical case, benzil was reduced in DMF solution at the dropping mercury electrode in the presence of tetrabutylammonium iodide, used in this case as a supporting electrolyte rather than phase transfer catalyst. In the presence of diethylene glycol ditosylate, compound 15 (mp 77— 78°) was isolated in 10% yield. Using the same approach, acenaphthenedione was reduc-tively cyclized with triethylene glycol ditosylate to afford the product (mp 84—85°, 42% yield) shown in Eq. (3.42). 

The photochemical or thermal reaction between petfluoroalkyl iodides and mercury-cadmium amalgams has been used for the synthesis of perfluoro-alkylmercury compounds [150] Functionalized analogues have been prepared similarly via this route [151, 152] (equation 117), and the preparation of bis(tri-fluoromethyl)mercury has been described [153]... 

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

Further routes of cyclizations have been studied in parallel in the case of cis- and rra/J5-2-hydroxymethyl-l-cyclohexylamine (106) (880PP73). The preparation of thiourea or urea adducts 107 and 108 with phenyl isothiocyanate or phenyl isocyanate proceeds smoothly. The reaction of 107 with methyl iodide and subsequent alkali treatment, by elimination of methyl mercaptan, resulted in the iminooxazine 109 in high yields. The ring closures of both cis and trans thiourea adducts to 1,3-oxazines proceed with retention. Cyclodesulfuration of the adduct 107 by mercury(II) oxide or N,N -dicyclohexylcarbodiimide resulted in the iminooxazine 109, but the yield was low and the purification of the product was cumbersome. The ring closure of 108 with thionyl chloride led to the iminooxazine 109 in only moderate yield. 

Some aryl iodides are known to generate the diaryImercury at a mercury cathode. In the case of 4-iodoaniso e, reduction at more negative potentials in dimeth-ylfonnamide leads to the formation of less di(4-methoxyphenyl)mercury. At glassy carbon, anisole is the only reduction product. 4-Bromoanisole gives only anisole at either mercury or carbon [143]. Mercur> has been used as cathode material for many preparative experiments with aryl halides but glassy carbon and also stainless steel are very satisfactory alternatives. 

The reaction with mercury gave as the initial product trifluoromethyl mercuric iodide, CFsHgl, a white crystalline solid very similar to methyl mercuric iodide. From it, the free base, CFjHgOH, and a number of salts were prepared. 

Alternatively, the compound can be prepared by the reaction of mercury with methyl iodide in the presence of sunlight or by mercuration reaction of organics. 

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