Chlorine vapour pressure

Figure 9.3 Chlorine vapour pressure versus temperature...

Mercury is used in the manufacture of thermometers, barometers and switchgear, and in the production of amalgams with copper, tin, silver and gold, and of solders. A major use in the chemical industry is in the production of a host of mercury compounds and in mercury cells for the generation of chlorine. Mercury has a significant vapour pressure at ambient temperature and is a cumulative poison. 

Miscellaneous friction losses due to the tanker outlet constriction and the pipe fittings in the inlet piping, are equivalent to 1000 equivalent pipe diameters. The vapour pressure of chlorine at the maximum temperature reached at the pump is 685 kN/m2 and its density and viscosity, 1286 kg/m3 and 0.364 mNm 2s. The pressure in the tanker is 7 bara. 

An immersed bundle vaporiser is to be used to supply chlorine vapour to a chlorination reactor, at a rate of 10,000 kg/h. The chlorine vapour is required at 5 bar pressure. The minimum temperature of the chlorine feed will be 10°C. Hot water at 50°C is available for heating. The pressure drop on the water side must not exceed 0.8 bar. 

Liquefaction of chlorine is always incomplete, because the non-condensable impurities carry chlorine at its vapour pressure as they leave the liquefaction process. This exit gas, or tail gas, is handled in any of several different ways. It is of course an intolerable plant emission, and the contained chlorine must at least be destroyed before the gas is released to the atmosphere. There is also a powerful economic incentive for recovering much of the chlorine in some usable form - Silver s estimate of the value of the chlorine in the tail gas produced in the United States alone in 1981 was 50 million [3]. 

Richardson. L.T. and Miller. D.M. Fungitoxicity of chlorinated hydrocarbon insecticides in relation to water solubility and vapour pressure. Can. J. Bot., 38 163-175,1960. 

Strontium chloride has a melting point of 870 °C and exerts a considerable vapour pressure above this temperature. The boiling point of SrCl2 is 1250 °C and at temperatures above this it dissociates forming strontium monochloride and chlorine according to reaction (8.6) ... 

Desflurane is a fluorinated methyl ethyl ether identical to isoflurane except for the substitution of a chlorine by a fluorine atom (Figure 3.2). It is the least soluble of all the volatile anaesthetics with a similar blood/gas solubility to nitrous oxide (0.42). It is non-flammable under all clinical conditions. The vapour pressure of desflurane approaches 1 atm at 23°C making controlled administration impossible with a conventional vaporiser. A desflurane vaporiser is an electronically controlled pressurised device that delivers an accurately metered dose of vaporised desflurane into a stream of fresh gases passing through it. The MAC of desflurane (6.5% in adults) is the highest of any modern fluorinated agent but in common with these the value decreases in the elderly and in other circumstances (see below). 

If we compare two chlorides, NaCl and CC14, we see that the properties of these compounds are so different that we are forced to the conclusion that they must have entirely different structures. NaCl is a solid, easily soluble in water in which it dissociates into ions, but insoluble in organic solvents. It is a good electrical conductor in aqueous solutions and in the molten state. It has a very low vapour pressure, with a boiling point above 1400°C, and it does not dissociate into its elements when heated. Carbon tetrachloride, on the other hand, is a volatile liquid boiling at 76°C, insoluble in water but soluble in a number of organic solvents. It is a non-conductor and at 1000°C decomposes into carbon and chlorine, and thus is, in all respects, the complete opposite of NaCl. 

If pure chlorine is to be liquefied at a constant temperature, it must be compressed to a pressure equalling the equilibrium vapour pressure of the liquid chlorine at the same temperature. The evolved condensation heat must be then lead away. If the chlorine is not entirely pure, compression must be increased by partial pressure of all inert gases. If chlorine containing other gases which cannot be liquefied readily is compressed it will be liquefied alone and its concentration in the gas phase will be decreased. Should further portions of chlorine be liquefied it would be necessary to increase the pressure in proportion to the increasing concentration of the inert gases in the gas phase. 

Secondly, following emission, the relative partitioning between air and dust for a given compound will be influenced strongly by its physicochemical properties. Broadly, more volatile pollutants, like lower chlorinated PCBs, will partition preferentially to air, while those with lower vapour pressures, like BDE-209, HBCDs, and TBBP-A, will partition preferentially to dust (Abdallah, Harrad, and Covaci, 2008 Abdallah et al., 2008 Harrad, Hazrati, and Ibarra, 2006 Harrad et al., 2008b). 

As noted earlier, the comparatively high vapour pressures of some (lower chlorinated) PCBs implies that they will partition principally to indoor air, and this provides a plausible explanation as to why comparatively little attention has been paid to their contamination of indoor dust. However, a review of the available evidence suggests that dust may contain substantial concentrations of PCBs. Table 7.3 summarises reported concentrations of XPCBs in indoor dust (Harrad et al., 2008a Tan et al., 2007b Vorhees, Cullen, and Altshul, 1999). In addition, a few other studies have reported concentrations of a limited... 

Reactions involving OH- and H produced by water sonolysis may also yield chlorine acids from dissolved CCI4. However, this mechanism is less likely for the following reasons (1) the increased vapour pressure of CCI4 favours diffusion of these molecules into bubble cavities, (2) the energy needed to break a C-CI bond (73 kcal/mol) is lower than that for an 0-H bond in water (119 kcal/mol). Thus, aqueous solutions saturated with CCI4 that are sonicated for tens of seconds contain oxidant species such as those from reactions 7.2-7.4, or even CI2 formed as follows ... 

The method has been used to determine the thermal dissociation of chlorine and bromine. 3 The hot-wire manometer (Pirani gauge, 6.VII J) has also been used to measure small vapour pressures. ... 

Fig. 18.VmJ. Vapour Pressure Curves. Abscissae in degrees C., ordinates vapour pressures in mm. Hg. The substances corresponding with the numbers attached to the curves are 1 ammonia, 2 chlorine, 3 methyl ether, 4 cyanogen, 5 sulphur dioxide, 6 ethyl chloride, 7 isopentane, 8 ethyl ether, 9 pentane, 10 carbon disulphide, 11 ethyl formate,...

To the right of the broken line C1fh/bc we are concerned with liquid mixtures, whose composition may vary continuously from pure chlorine to pure iodine the pressure being the maximum vapour pressure. The broken line is the boundary at which a solid separates from the liquid mixture along CIfh iodine trichloride, along h/b iodine monochloride, and along BC iodine. 

Uranium hexafluoride is important because it is used to separate U from 2 U by means of the diffusion of this compound. The pale yellow crystals melt at 69° under 2 atmospheres pressure and have a vapour pressure of 760 mm at 56°, so that they are very easily sublimed. The hexafluoride is made by the action of fluorine on the metal in the presence of some chlorine otherwise UF4 is formed. Fluorination by CIF3 is also employed. UFg is stable to air, oxygen, chlorine and iodine, but is easily hydrolysed and readily reduced to the tetrafluoride by hydrogen at the ordi-... 

Volatilization is usually utilized for separating individual trace elements from the sample before the determination. The methods based on volatilization are concerned mainly with non-metallic and amphoteric elements which have high vapour pressure in the elemental form (e.g., chlorine, bromine, sulphur), or in compounds with halogen, hydrogen, or oxygen. Other volatilization methods exist for the separation of certain elements, such as the distillation of boron as methyl borate. 

A series of seven polyketones was prepared by Friedel-Crafts reaction nsing chloroanisole, chloroacetyl chloride, dichloroethane and dichloromethane with anhydrous alumininm chloride as catalyst and carbon disulphide as a solvent. Characterisation was nndertaken by determination of the chlorine content, IR spectroscopy, vapour pressure osmometry, TGA, and DSC. Antimicrobial properties are discnssed. 13 refs. 

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