Methanol, properties vapor pressure

Dimethyl sulfate (CAS 77-78-1) Powerful vesicant action hydrolyzes to sulturic acid and methanol. Extremely irritating upon direct contact severe bums have resulted. Vapors irritating to eyes and respiratory tract delayed pulmonary edema may result. Skin absorption is rapid. A carcinogen in test animals (lARC 2A). 0.1 ppm, S,A3 7 ppm 4 2 0 Colorless, oily liquid. Very mild onion odor is barely perceptible and Is a poor warning property. Vapor pressure is 0.5 mm Hg at 20°C (68°F). Combustible. Thermal-breakdown products Include sulfur oxides. 

Formic acid (CAS 64-18-6) Acid is corrosive severe bums may result from contact of eyes and skin with concentrated acid. Vapors highly Irritating to eyes and respiratory tract. Ingestion may produce severe metabolic acidosis (see methanol, p 260). 5 ppm 30 ppm 3 2 0 Coloriess liquid. Pungent odor and Irritation occur near the TLV and are adequate warning properties. Vapor pressure is 30 mm Hg at 20°C (68°F). Combustible. 

Methyl acetate (CAS 79-20-9) Vapors moderately irritating to the eyes and respiratory tract. A CNS depressant at high levels. Hydrolyzed to methanol in the body with possible oonsequent toxioity similar to that of methanol (see p 250). 200 ppm 3100 ppm [LEL] 1 3 0 Colorless liquid with a pleasant, fmity odor that is a good warning property. Vapor pressure is 173 mm Hg at 20°C (68°F). Flammable. 

It has often been pointed out that the electrical conductivity of sintered samples of ZnO and of other n-conducting oxides is frequently caused by the conductivity of thin layers near the surface, and not by the conductivity of the bulk (25-28). According to our present knowledge, these thin layers near the surface of oxides are caused by electron transfer from the layers to the chemisorbate during the chemisorption, and the amount of chemisorption may be related to the electronic properties of the gas molecules and of the solids. The dependence of the electrical conductivity of some semiconductors on the pressure of CO, COj, and on the vapor pressure of ethanol, methanol, acetone, and water, as observed by Ljaschenko and Stepko (29), can be explained by the same mechanism. The dependence of conductivity of some mixed oxides at high temperatures can be explained in a similar way (30). 

Water has interesting and unusual thermal properties, which have only recently been significantly exploited by chromatographers [56-58], As the temperature is increased, thermal motion weakens the hydrogen-bonding so that the polarity of water is reduced (Figure 18-8). At 200°C, water has a polarity similar to that of methanol in addition, the viscosity also drops markedly with temperature and the diffusion rate increases. Flowever, the vapor pressure remains low and by 250°C has only reached 30 bar, well within the normal... 

However, the vapor pressure of molecular liquids, their miscibility with water and/or methanol and their viscous properties, lead to severe limitations in current fuel cell technology (see Section 23.2). Therefore, the development of non-liquid electrolytes with proton conduction properties close to these of hydrogen-bonded liquids is a key issue of current PEM fuel cell research. However, the fuel cell requirements do not allow much of a compromise with respect to proton conductivity, which should not drop below about ct = 5 x S cm i. Such high conduc-... 

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