Mercury dimethyl, decomposition

Two allyl cyclopropane-c s in equivalent amounts are actually observed to be formed. In the mercury sensitized decomposition of 5,5-dimethyl bicyclo [2.1.1] hexanone-2 (XXXI), the only cyclic hydrocarbons found are those derived from cyclopropane (38). 

All the compounds of the type R2Hg are liquids the methyl and ethyl derivatives are volatile at ordinary temperatures, and are said to be very poisonous. Mercury dimethyl, diethyl, and di-n-propyl may be distilled under ordinary pressure without decomposition mercury di-isopropyl, di-n-butyl, di-isobutyl and di-sec-butyl, have only been distilled under reduced pressure mercury di-tert-butyl and -tert-amyl show considerable decomposition even when distilled at 5 mm. mercury di-isoamyi also undergoes decomposition when distilled in vacuo, but is volatile in steam, whilst mercury di-sec-octyl cannot be distilled at all, since it decomposes even at 3 mm. 

The compound crystallises in pearly plates, M.pt. 143° C., insoluble in water, fairly soluble in alcohol, easily in methyl iodide and ether. It sublimes without decomposition and yields the oxide with alkalies or ammonium hydroxide, whilst ammonium sulphide jorecipitates the sulphide in faint yellowish flocks.Distillation with potassium cyanide, >otassium hydroxide, or metallic potassium gives mercury dimethyl. Its molecular w eight in methyl or ethyl sulphide is normal. 

Studies of the mercury-photosensitised decomposition of 2-azetidinone and 4,4-dimethyl-2-azetidinone have been described the major products in the latter case were carbon monoxide, 2-methylpropene and 2,2-dimethylaziridine. Examples of photo-chemically induced N-dealkylation have again been reported. 

Pottie, R.F..A.G. Harrison, and F. P. Lossing Free Radicals by Mass Spectrometry XXII. Primary Decomposition Steps in the Mercury-Photosensitized Decomposition of Methanol and Dimethyl Ether. Can. J. Chem. 39, 102 (1961). 

SuIfona.tlon, Sulfonation is a common reaction with dialkyl sulfates, either by slow decomposition on heating with the release of SO or by attack at the sulfur end of the O—S bond (63). Reaction products are usually the dimethyl ether, methanol, sulfonic acid, and methyl sulfonates, corresponding to both routes. Reactive aromatics are commonly those with higher reactivity to electrophilic substitution at temperatures > 100° C. Tn phenylamine, diphenylmethylamine, anisole, and diphenyl ether exhibit ring sulfonation at 150—160°C, 140°C, 155—160°C, and 180—190°C, respectively, but diphenyl ketone and benzyl methyl ether do not react up to 190°C. Diphenyl amine methylates and then sulfonates. Catalysis of sulfonation of anthraquinone by dimethyl sulfate occurs with thaHium(III) oxide or mercury(II) oxide at 170°C. Alkyl interchange also gives sulfation. 

The thermal decomposition of dimethyl mercury in the presence of radical scavengers has been thoroughly investigated61-65. The basic mechanism, the preexponential factor and the activation energy are all well established. There is still considerable doubt about the mechanism of the pyrolysis in the absence of chemically active additives. Consequently, the quantitative interpretation of rate data from such systems is of doubtful value. Systems using effective scavengers will be discussed first. The quantitative results from these systems will be used in assessing the data obtained in the absence of additives. 

Fig. 3. Arrhenius plots for the decomposition of dimethyl mercury. All rate coefficients are at or near the high-pressure limit. If a radical scavenger has been used it is shown in brackets following the authors names. 1, Krech and Price (benzene) 2, Kallend and Purnell (propene) 3, Russell and Bernstein (cyclopentane) 4, Russell and Bernstein 5, Laurie and Long 6, Kominar and Price (toluene) O, Weston and Seltzer (cyclopentane) , point calculated from the steady-state equation of Kallend and Purnell.

The gas-phase thermal decomposition of dimethyl mercury by itself and in the presence of inert gas has been extensively investigated61,63,67,71-79. The... 

Fig. 4. Arrhenius plots for the pressure-dependent flow system decomposition of dimethyl mercury. 1, Gowenlock, Polanyi and Warhurst (7 torr C02+3 torr toluene), Kominar and Price (4.4 torr toluene) 2, Price and Trotman-Dickenson (16 torr toluene, rate coefficients corrected for methyl radicals found as ethylbenzene) 3, Krech and Price (16 torr benzene). O, Lossing and Tickner (6-20 torr helium).

Methylnitramine decomposes explosively in contact with concentrated sulfuric acid. If the substance is dissolved in water, and if concentrated sulfuric acid is added little by little until a considerable concentration is built up, then the decomposition proceeds more moderately, nitrous oxide is given off, and dimethyl ether (from the methyl alcohol first formed) remains dissolved in the sulfuric acid. The same production of nitrous oxide occurs even in the nitrometer in the presence of mercury. If methylnitramine and a small amount of phenol are dissolved together in water, and if concentrated sulfuric acid is then added little by little, a distinct yellow color shows that a trace of nitric acid has been formed. The fact that methylnitramine gives a blue color with the diphenylamine reagent shows the same thing. 

Experimental evidence of the part played by free radicals in a chemical reaction was soon forthcoming. In 1934 Frey24 found that butane decomposed very slowly at 525° but that if one per cent of dimethyl mercury was introduced the decomposition proceeded rapidly. In the same year Sickman and Allen25 found that acetaldehyde was stable at 300° but that it was decomposed completely when a few per cent of azomethane was added. The introductions of dimethyl mercury or azomethane at these temperatures apparently liberated free radicals which initiated chains. Moreover when mixed gases decomposed simultaneously they did not do so independently. The products contained groups from each in a way that could be easily explained on the assumption of the liberation and recombination of free radicals. Again the appearance of butane from the decomposition of propane is difficult to explain on any hypothesis except on the assumption that some free radicals of CH3 are split out and that they become attached to propane molecules. More direct examples will be given later in the discussion of photochemistry. 

Dimethyl sulphate is a colourless, inodorous liquid which boils at ordinary pressure at 188° C. with partial decomposition, while at 15 mm. of mercury pressure it boils without decomposition at 96° C. It solidifies at — 317° C. and has a specific gravity of I 333 at 15° C. Its vapour density is 4-3. Its volatility at 20° C. is 3,300 mgm. per cu. m. According to this, dimethyl sulphate is unsuitable for use as an asphyxiant war gas because its volatility is too low and equally unsuitable as a vesicant because its volatility is too high. 

Relatively more attention had been paid to the study of the sensitized thermal decomposition of acetone. In the temperature range 350-400 °C, Rice et al investigated the decomposition of acetone sensitized by dimethyl mercury. The a-mount of acetonyl acetone formed was equal to that of dimethyl mercury decomposed, indicating the absence of chains. At higher temperatures, however, sensitized chain decomposition has been observed. According to Kodama and Takezaki ,... 

AZIDA SODICA (Spanish) (26628-22-8) Reacts with hot water. Explosive decomposition in elevated temperatures above 525°F/274°C. Forms ultra-sensitive explosive compounds with heavy metals copper, copper alloys, lead, silver, mercury, carbon disulfide, trifluoroacryloyl fluoride. Violent reaction with acids, forming explosive hydrogen azide. Violent reaction with bromine, barium carbonate, chromyl chloride, dimethyl sulfate, dibromomalononitrile. Incompatible with caustics, cyanuric chloride, metal oxides, metal sulfides, methyl azide, phosgene. 

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