Vapor pressure ethylene oxide

C2H4O (liq.). Berthelot81 reported a value for the heat of vaporization of ethylene oxide. Vapor pressure data were reported by Ever-sheim.1... 

In the glycol reactor (2), sufficient residence time is provided to react (noncatalytically) all of the ethylene oxide. Operating pressure of the reaction is controlled at a level that limits or avoids vaporization of ethylene oxide from the aqueous solution. 

Ethylene oxide storage tanks ate pressurized with inert gas to keep the vapor space in a nonexplosive region and prevent the potential for decomposition of the ethylene oxide vapor. The total pressure that should be maintained in a storage tank increases with Hquid temperature, since the partial pressure of ethylene oxide will also increase. Figure 5 shows the recommended minimum storage pressures for Hquid ethylene oxide under nitrogen or methane blanketing gas. 

Liquid Hazards. Pure liquid ethylene oxide will deflagrate given sufficient initiating energy either at or below the surface, and a propagating flame may be produced (266,267). This requites certain minimum temperatures and pressures sensitive to the mode of initiation and system geometry. Under fire exposure conditions, an ethylene oxide pipeline may undergo internal decomposition either by direct initiation of the Hquid, or by formation and subsequent decomposition of a vapor pocket (190). 

While the deflagration pressure ratio for ethylene oxide vapor is about 11 or less, Hquid mist decomposition can give much greater pressures and very fast rates of pressure rise (190). 

Explosion prevention can be practiced by mixing decomposable gases with inert diluents. For example, acetylene can oe made nonexplosive at a pressure of 100 atm (10.1 MPa) by including 14.5 percent water vapor and 8 percent butane (Bodurtha, 1980). One way to prevent the decomposition reaction of ethylene oxide vapor is to use methane gas to blanket the ethylene oxide hquid. 

Adsorption of ethylene at 90 K on oxide coated thermionic emission cathodes was measured (Wooten Brown, JACS 65 113, 1943). The volume adsorbed is in V ml measured at 1 Torr and 25 C. The vapor pressure is Ps = 30.6(10-3) Torr. 

Ethylene Cyanohydrin or /3-Hydroxypropio-nitrile, HO.CH8.CH2.CN mw 71.08, N 19.71% poisonous straw-colored Uq, sp gr 1.0404 at 25°/4, fr p -46°, bp 227-28°(dec), vapor pressure 20mm at 117 miscible with w, acet, ethanol, chlf, methyl-ethyl ketone si sol in eth insol in benz, CC14 naphtha. It can be prepd by interaction of ethylene oxide with... 

Explosibility. Liquid ethylene oxide is stable to detonating agents, but the vapor will undergo explosive decomposition. Pure ethylene oxide vapor will decompose partially however, a slight dilution with air or a small increase in initial pressure provides an ideal condition for complete decomposition. Copper or other acetylide-forming metals such as silver, magpesium, and alloys of such metals should not be used to handle or store ethylene oxide because of the danger of the possible presence of acetylene. Acetylides detonate readily and will initiate explosive decomposition of ethylene oxide vapor. In the presence of certain catalysts, liquid ethylene oxide forms a poly-condensate. 

This reaction is highly exothermic. If the heat of the reaction is not conducted thru the walls of a closed container at a rate capable of maintaining an equilibrium temperature, an increase in pressure results with an increase in reaction rate, leading to explosive conditions. Acid salts, such as stannic chloride and zinc chloride, and bases, such as alkali metal hydroxides, either solid or in aqueous solution, and tertiary amines are all effective catalysts. It is, therefore, imperative that the concentration of such contaminants be kept at a minimum when transporting or storing sizeable quantities of ethylene oxide Accdg to Hess Tilton (Ref 16), a 90% decompn takes place if 100% vapor of EtnO in a closed container is. initiated with MF. There is no upper limit of EtnO in air (the previously reported value of 80% was in error), but the lower expl limit is 3% (Ref 17, p 87)... 

The enthalpy of ethylene oxide, measured calorimetrically, has been reported 817 to be 408 kcal./mole. Measurement of the enthalpy of ethylene oxide over a wide range of pressures has been conducted in at least two laboratories, 2 1181 and entropy calculations have been made from these results. The entropy of ethylene oxide vapor was likewise determined by Giauque and Gordon. 6 Their experimental value of 57.38 caL/degree-mole after a suitable correction for deviation from ideality is not far from the value 57.56 calculated from theory. 

Higher ammonia-ethylene oxide ratios favor high yields of diethanolamine and triethanolamine, whereas lower ratios are used where maximum production of monoethanolamine is desired. The reaction is noncatalytic. The pressure is moderate, just sufficient to prevent vaporization of components in the reactor. The bulk of the water produced in the reaction is removed by subsequent evaporation. The dehydrated ethanolamines then proceed to a further drying column, after which they are separated in a series of fractionating columns, not difficult because of the comparatively wide separation of their boiling points. 

Choose as standard states for water and ethylene glycol the pure liquids at 1 bar and for ethylene oxide the pure ideal gas at 1 bar. Assume that the Lewis/Randall rule applies to the water in the liquid phase and that the vapor phase is an ideal gas. The partial pressure of ethylene oxide., river the liquid phase is given by, ... 

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