Mercuric chloride, reaction with

This method is especially suited to the trithionates and tetrathionates, and is applicable even in the presence of thiosulphate or sulphite by first titrating the neutral solution with iodine, which indicates the total quantity of sulphite and thiosulphate, and then determining the acidity developed during the iodine titration, from which the amount of sulphite can be calculated. Finally the mercuric chloride reaction is applied to another portion of the original solution and by determination... 

Diiodobenzo[6 jthiophene is prepared by treating the bis(mercuric chloride) derivative with iodine. Benzo[ > jthiophenes having an iodine atom at the 4-, 5-, 6- and 7-positions are obtained in high yield from the appropriate diazonium salt by the usual replacement reactions. 

The inorganic products of the ozonolysis reactions were determined for three different organomercurials. Ozonolysis of two dialykylmer-curials produced a mixture of mercuric chloride, mercurous chloride, and mercuric oxide (Reactions 3 and 14, Table I) while one alkylmercuric halide gave only mercuric and mercurous chlorides (Reaction 13, Table I). A known mixture of the three salts was tested for its stability to the reaction conditions. The salts were ozonized as a solution/mixture with methylene chloride. Powder x-ray diffraction showed no difference in the mercury salt mixture after a 2-hour ozonation at 10°C. 

If the C=C bonds are more than 4.6 A apart, the reaction does not take place. As molecules need to have double bonds aligned and about 4 A apart for such photoreactions, it is sometimes possible to force the required molecule to crystallize with a unit cell dimension of this length. For example, mercuric chloride crystallizes with one unit cell dimension of 4.33 A, and its complex with coumarin maintains this unit-cell length. The required 4 A packing distance can also be obtained by use of chlo-... 

Other Carbon-Heteroatom Bonds. Carbon-mercury bonds are readily formed by treating the metalated species with mercuric chloride (Reaction 21) (27). The resulting chloromercury derivative in one case is a useful intermediate in the preparation of 2-iododimethylaminomethyl-ferrocene (27). 

HgjCU Noncombustible solid. Violent reaction with sodium. Slow decomposition in light, forming mercury and mercuric chloride. Incompatible with acetylene, alkali chlorides, ammonia, bromides, azides, carbonates, chlorine dioxide, cocaine hydrochloride, cyanides, copper and copper salts, hydrogen peroxide, hydroxides, iodides, iodine, iodoform, lead salts, lithium, potassium iodide, mbidium, silver salts, sodium carbide, sulfates, sulfides, sulfites. On small fires, use any kind of extinguishers. 

Directions (a) Dilute 5 c.c. of mercuric chloride solution with an equal volume of water in a test tube and add to it ten drops of stannous chloride solution. (1) State the chemical name, the commercial name, the color, and the solubility of the mercury compound formed. (2) Write an equation for the reaction. (3) What kind of a process has the mercuric chloride undergone (4) What was the agent ... 

Reaction of pentafluorophenyl-lithium with tungsten pentachloride in diethyl ether yields the bright-green complex LiW(C,F5)5,2Et,0, which is stable for several months at -10 °C, and decomposes only slowly at room temperature. It yields (C F5)2Hg with mercuric chloride, CeFsI with iodine, and is hydrolysed to pentafluorobenzene. When heated to 100 °C it gives pentakis(pentafluorophenyl)tungsten as an orange-red solid in low yield and a tungsten(iv) derivative, (C,F5)iW, may be formed, but is too unstable to isolate. ... 

Procedure. 1) Mercuric chloride Spot with ammonium sulflde (mercuric sulfide formation). Wood that has been impregnated for a long time will give the reaction more clearly if it is moistened with dilute hydrochloric acid prior to the test. 

An alternative method of laboratory preparation of mercury fulminate is based on decomposition of the mercury salt of nitromethane published by Nef [14]. The mercuric salt is prepared in the first step of a reaction when mercuric chloride reacts with the sodium salt of nitromethane. The mercuric salt of nitromethane decomposes in a second step by boiling with dilute hydrochloric acid to produce MF [14] ... 

Method 2 (Martin, 1942). A mixture of 200 g. of zinc wool, 15 g. of mercuric chloride, 10 ml. of concentrated h3 drochloric acid and 250 ml. of water is stirred or shaken for 5 minutes. The aqueous solution is decanted, and the amalgamated zinc is covered with 150 ml. of water and 200 ml. of concentrated hydrochloric acid. The material to be reduced, usually about 0-3-0-4 mole, is then added immediately, and the reaction is commenced. 

Health and Safety Factors. Although butynediol is stable, violent reactions can take place in the presence of certain contaminants, particularly at elevated temperatures. In the presence of certain heavy metal salts, such as mercuric chloride, dry butynediol can decompose violently. Heating with strongly alkaline materials should be avoided. 

Reference Electrodes and Liquid Junctions. The electrical cincuit of the pH ceU is completed through a salt bridge that usually consists of a concentrated solution of potassium chloride [7447-40-7]. The solution makes contact at one end with the test solution and at the other with a reference electrode of constant potential. The Hquid junction is formed at the area of contact between the salt bridge and the test solution. The mercury—mercurous chloride electrode, the calomel electrode, provides a highly reproducible potential in the potassium chloride bridge solution and is the most widely used reference electrode. However, mercurous chloride is converted readily into mercuric ion and mercury when in contact with concentrated potassium chloride solutions above 80°C. This disproportionation reaction causes an unstable potential with calomel electrodes. Therefore, the silver—silver chloride electrode and the thallium amalgam—thallous chloride electrode often are preferred for measurements above 80°C. However, because silver chloride is relatively soluble in concentrated solutions of potassium chloride, the solution in the electrode chamber must be saturated with silver chloride. 

Mercuric Nitrate. Mercuric nitrate [10045-94-0] Hg(N02)2, is a colorless dehquescent crystalline compound prepared by the exothermic dissolution of mercury in hot, concentrated nitric acid. The reaction is complete when a cloud of mercurous chloride is not formed when the solution is treated with sodium chloride solution. The product crystallizes upon cooling. Mercuric nitrate is used in organic synthesis as the starting material and for the formulation of a great many other mercuric products. 

Diuretics. Chlomieodrin [62-37-3] (methoxy(urea)propylmercuric chloride) (8), is prepared ia the same sort of reaction used for chloromethoxypropylmercuric acetate. Ahyl urea is used instead of aHyl chloride, together with methanol and mercuric acetate. The product, after dilution with water and neutralization, is precipitated with sodium chloride ... 

Qualitative. The classic method for the quaUtative determination of silver ia solution is precipitation as silver chloride with dilute nitric acid and chloride ion. The silver chloride can be differentiated from lead or mercurous chlorides, which also may precipitate, by the fact that lead chloride is soluble ia hot water but not ia ammonium hydroxide, whereas mercurous chloride turns black ia ammonium hydroxide. Silver chloride dissolves ia ammonium hydroxide because of the formation of soluble silver—ammonia complexes. A number of selective spot tests (24) iaclude reactions with /)-dimethy1amino-henz1idenerhodanine, ceric ammonium nitrate, or bromopyrogaHol red [16574-43-9]. Silver is detected by x-ray fluorescence and arc-emission spectrometry. Two sensitive arc-emission lines for silver occur at 328.1 and 338.3 nm. 

Chlorination of bismuth or mercuric oxides results in precipitation of relatively insoluble basic chlorides, ie, BiOCl and HgO HgCl2. However, the reaction with is slow and does not produce high concentrations of HOCl (121). With HgO, the HOCl solutions may contain significant amounts of... 

Halogenation and dehalogenation are catalyzed by substances that exist in more than one valence state and are able to donate and accept halogens freely. Silver and copper hahdes are used for gas-phase reactions, and ferric chloride commonly for hquid phase. Hydrochlorination (the absoration of HCl) is promoted by BiCb or SbCl3 and hydrofluorination by sodium fluoride or chromia catalysts that form fluorides under reaction conditions. Mercuric chloride promotes addition of HCl to acetylene to make vinyl chloride. Oxychlori-nation in the Stauffer process for vinyl chloride from ethylene is catalyzed by CuCL with some KCl to retard its vaporization. 

Hydrochloric acid may conveniently be prepared by combustion of hydrogen with chlorine. In a typical process dry hydrogen chloride is passed into a vapour blender to be mixed with an equimolar proportion of dry acetylene. The presence of chlorine may cause an explosion and thus a device is used to detect any sudden rise in temperature. In such circumstances the hydrogen chloride is automatically diverted to the atmosphere. The mixture of gases is then led to a multi-tubular reactor, each tube of which is packed with a mercuric chloride catalyst on an activated carbon support. The reaction is initiated by heat but once it has started cooling has to be applied to control the highly exothermic reaction at about 90-100°C. In addition to the main reaction the side reactions shown in Figure 12.6 may occur. 

The exchange of aromatic protons can be effected in the absence of any -OH or —NH2 activating group during the course of a Clemmensen reduction in deuteriochloric and deuterioacetic acid mixture (see section Ill-D). This reaction has been carried out with various tricyclic diterpenes and is best illustrated by the conversion of dehydroabietic acid into its 12,14-d2-labeled analog (40 -+ 41).Amalgamated zinc is reportedly necessary for the exchange reaction since the results are less satisfactory when a zinc chloride-mercuric chloride mixture is used. 

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