Mercury pressure decomposition

As previously stated, mercury fulminate is hydrolysed by heating in water in boiling water hydrolysis is very rapid. Farmer [31] noticed that on heating with water under pressure, mercury fulminate undergoes decomposition to metallic mercury. Marked decomposition also takes place on heating or standing for long periods at room temperature in an aqueous solution of ammonia or potassium... 

Duncan and Cvetanovic27 studied the reaction with isobutene of methylene generated by the mercury photosensitized decomposition of CH2CO, which is believed to produce triplet methylene. Product ratios reached high-pressure limiting ratios at 200 mm. The observed yield of... 

The pressure should be below 30 mm. of mercury or decomposition will occur. 

The quenching cross section for cyclopropane is considerably smaller than those for olefins.497 However, the fact that cyclopropane-de is, if anything, a more effective quencher of triplet mercury than cyclopropane-/ 6497 favors an energy transfer process over a hydrogen abstraction process. Recently Gunning has reported that methylene-cyclobutane is the major high-pressure product in the mercury-sensitized decomposition of spiropentane.509 This result provides very compelling support for the intermediacy of a biradical species. 

The most conclusive evidence for reaction (16) was recently given by Kohout and Lampe.264 They studied the mercury-sensitized decomposition of H2 and D2 in the presence of a small amount of NO. The products of the reaction were bled through a pinhole into a mass spectrometer for continual analysis. Results are shown in Figure 8-6 for the D2-NO system. They observed mass spectral peaks for DNO, DzO, and N20, but not for (DNO)2. Initially, DNO is produced, but it subsequently decays to form NsO (and D20). The minimum rate constant reported by them for DNO disproportionation was 3.4 x 106 M 1 sec-1. However, more recently Kohout263 in his doctoral dissertation has reported that DaO and N20 are the products of the bimolecular encounter of two DNO molecules. The rate constant is 4.0 x 105 Af-1 sec-1 independent of pressure over the limited pressure range of 30-70 torr. An increase in surface-to-volume ratio of about 50 had no effect on the results. 

Falconer and Cvetanovic (40) attempted to obtain a more quantitative value for the fraction of nonterminal addition in the case of propylene. They produced hydrogen atoms by mercury photosensitized decomposition of H2, using at least 100 times as much H2 as C3H6 and total pressures of 40 and of 250 mm. Under these conditions the reactions of importance were the combination and disproportionation of the iso- and n-propyl radicals and their cross reactions, the combination of the two radicals with H atoms (assumed to be equally probable), and a very small amount of decomposition of hot n-propyl radicals. Disproportionation to combination ratios were taken as 1.64 for two iso-propyl, 1.14 for two w-propyl, and hence 1.39 was taken as the mean of the two values for one iso- and one n-propyl radical. Using these values and the analysis of the products, the nonterminal addition of H atoms to C3H6 and C3D6 was found to amount to 6 1%. 

Monogermane was first shown to undergo mercury photosensitized decomposition at low pressures and at 298 K through the overall equation (31). 

Bromoacetophenone forms white rhombic prisms which become greenish on exposure to light, owing to incipient decomposition. It melts at 50° C. and boils at ordinary pressure at 260° C. with decomposition, and at 12 mm. mercury pressure at 133° to 135° C. with partial decomposition. It is insoluble in water, but soluble in the common organic solvents (alcohol, ether, benzene, etc.). 

The pure product boils at ordinary pressure at 242° C. with decomposition, distilling unaltered at 132° to 134° C. at 12 mm. mercury pressure. 

This is a colourless, inodorous liquid which distils without decomposition only under reduced pressure. The boiling point is 154° C. at 8 mm. mercury pressure. Its S.G. at 20° C. is 1-4622. On cooling it forms a crystalline mass, melting at 11° C. and insoluble in water. It is hydrolysed neither by water nor ammonia. 

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. 

It must be stressed that the co-adsorption of mercury (from the vacuum line) could lead to mercury photosensitization of the adsorbed gas and great care must be taken to distinguish sensitization by the surface or other substances on the surface with mercury sensitized decomposition. The use of low pressure mercury resonance lamps which produce the 253.7 nm mercury line... 

Boiling point is given at atmospheric pressure (760 mm of mercury or 101 325 Pa) unless otherwise indicated thus 82 indicates that the boiling point is 82°C when the pressure is 15 mm of mercury. Also, subl 550 indicates that the compound sublimes at 550°C. Occasionally decomposition products are mentioned. 

Mercuric Chloride. Mercuric c Aon.d.e.[7487-94-7] HgCl2, is also known as corrosive sublimate of mercury or mercury bichloride. It is extremely poisonous, and is particularly dangerous because of high (7 g/L at 25°C) water solubiUty and high vapor pressure. It sublimes without decomposition at 300°C, and has a vapor pressure of 13 Pa (0.1 mm Hg) at 100°C, and 400 Pa (3 mm Hg) at 150°C. The vapor density is high (9.8 g/cm ), and therefore mercuric chloride vapor dissipates slowly (5). 

Chemical Designations - Synonyms. Calochlor Corrosive mercury chloride Corrosive sublimate Mercury bichloride Mercury (II) chloride Mercury perchloride Chemical Formula-. HgClj Observable Characteristics(as shipped)-. Solid Color. White colorless Odor. None. Physical and Chemical Properties - Physical State at 15 X and 1 atm. Solid Molecular Weight-. 271.50 Boiling Point at I atm. 576, 302, 575 Freezing Point 531, 277, 550 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 5.4 at 20 °C (solid) Vapor (Gas) Specific Gravity Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Heat of Decomposition Not pertinent. 

Irradiation of cyclo-S% dissolved in CS2 by a high-pressure mercury lamp at 20 °C produces the homocycles S7, S, S12, S9, Sio, and probably S5 in concentrations decreasing in this order. Irradiation of Se in CS2 gives mainly Ss and S7 while irradiation of S7 generates Ss and S. Similarly, photolysis of S12 in CS2 yields Ss, S7, and Se [51]. For these reasons UV-Vis spectra of compounds containing S-S bonds must be recorded with caution not to trigger decomposition reactions. 

Dining interaction at ambient temperature in a bomb to produce poly (carbon monofluoride), admission of fluorine beyond a pressure of 13.6 bar must be extremely slow and carefully controlled to avoid a violently exothermic explosion [1], Previously it had been shown that explosive interaction of carbon and fluorine was due to the formation and decomposition of the graphite intercalation compound, poly (carbon monofluoride) [2], Presence of mercury compounds prevents explosion during interaction of charcoal and fluorine [3], Reaction of surplus fluorine with graphite or carbon pellets was formerly used as a disposal method, but is no longer recommended. Violent reactions observed when an exhausted trap was opened usually involved external impact on the metal trap, prodding the trap contents to empty the trap, or possibly ingress of moist air... 

Moore [355] used the solvent extraction procedure of Danielson et al. [119] to determine iron in frozen seawater. To a 200 ml aliquot of sample was added lml of a solution containing sodium diethyldithiocarbamate (1% w/v) and ammonium pyrrolidine dithiocarbamate (1 % w/v) at pH to 4. The solution was extracted three times with 5 ml volumes of 1,1,2 trichloro-1,2,2 trifluoroethane, and the organic phase evaporated to dryness in a silica vial and treated with 0.1 ml Ultrex hydrogen peroxide (30%) to initiate the decomposition of organic matter present. After an hour or more, 0.5 ml 0.1 M hydrochloric acid was added and the solution irradiated with a 1000 W Hanovia medium pressure mercury vapour discharge tube at a distance of 4 cm for 18 minutes. The iron in the concentrate was then compared with standards in 0.1 M hydrochloric acid using a Perkin-Elmer Model 403 Spectrophotometer fitted with a Perkin-Elmer graphite furnace (HGA 2200). 

E15, which results in the ( + )E15-C bond cleavage and decomposition of betaines ( + )E15-C-Si-S( ) (E15 = P, As) by the Corey-Chaykovsky type reaction. When a suspension of betaines 20a in benzene is irradiated by a medium-pressure mercury lamp at 20 °C, they decompose to form triphenyl-phosphine and silathiiranes (45a)89 (Scheme 21). 

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