Methanol, properties liquid density

The temperature dependence of many properties of methanol has been described in figures, tables, and equations. Plots of vapor pressure, liquid density, liquid heat capacity, vapor heat capacity, heat of vaporization, surface tension, liquid thermal conductivity, vapor thermal conductivity, liquid viscosity, and vapor viscosity against temperature have been given by Yaws [13] and by Flick [14]. Tables of vapor pressure [3,1517], liquid density [3,15,17], liquid volume [16], vapor density [15,17], vapor volume [16], liquid viscosity [15,18], vapor viscosity [15], surface tension [15,19], liquid heat capacity [15,17,20], vapor heat capacity [3,15,17], solid heat capacity [11], liquid thermal conductivity [15,17], vapor thermal conductivity [15], second viral coefficient [16], dielectric constant [21], refractive index [3], and heat of vaporization [16] have also been published. Thermodynamic properties of methanol in the condensed phases have been tabulated by Wilhoit et al. [11], and those in the gas phase have been given by Chao et aL [9]. 

Methyl alcohol (methanol, wood alcohol, CH3OH boiling point 64.7°C, density 0.7866, flash point 110°C) is a colorless, mobile liquid with a mild characteristic odor (and narcotic properties) that is miscible in all proportions with water, ethyl alcohol, or ether. When ignited, methyl alcohol burns in air with a pale blue, transparent flame, producing water and carbon dioxide. The vapor forms an explosive mixture with air. The upper explosive limit is 36.5% and the lower limit is 6.0% by volume in air. 

With areal power outputs only 20-30% that of a PEFC and an energy-conversion efficiency of 30% near peak power versus 50% in the case of the PEFC, the DMFC remains of great interest because of the attractive properties of methanol fuel, a liquid of high energy density under ambient conditions, and because the DMFC enables direct conversion of this liquid carbonaceous fuel to electric power. Particularly in portable applications, these features help minimize the overall dimensions of the power system (fuel + fuel cell + auxiliaries) and achieve high system energy density. 

The viscosity of liquids is a material property, whose value can span several orders of magnitude. Whereas, for example, the surface tension a and the density p of liquids differ not more than hy a factor of 3 from one another (e.g. a of methanol and water and p of methanol and concentrated sulfuric acid), the differences in the viscosity between water and e.g. sugar syrup at room temperature amounted to 5 x lO This fact has a large influence on flow behaviour and on momentum, mass and heat transfer. 

In this project, distinguishing properties of the 10 organic liquids should be observed (Part A) and unknowns subsequently identified (Part B) according to an SOP which I wrote for this. The properties are (1) water miscibility, (2) density, (3) viscosity, (4) refractive index, and (5) odor. The 10 organic liquids are acetone, methanol, ethanol, isopropyl alcohol, heptane, cyclohexane, toluene, methyl ethyl ketone, butanol, and ethyl acetate. 

Chapter 8 briefly introduced the concept of supercritical fluids in the context of undersea thermal vents. The supercritical point for water occurs at a temperature of 705°F (374°C) and a pressure of 222.3 bar (atmosphere). Above this temperature, no pressure can condense water to its liquid state. For carbon dioxide (CO2), the critical temperature (88.0°F or 31.1°C) and critical pressure (73.8 bar) are much lower. Above the supercritical point, CO2 behaves as a liquidlike gas liquidlike densities, gaslike viscosities. The solubility properties of supercritical CO2 are mnable by varying temperature and/or pressure. Density and dielectric constant increase with increasing pressure and decreasing temperature. Water and ionic substances are insoluble in supercritical CO2. The ability of supercritical CO2 to dissolve and extract relatively non-polar substances has been known for decades. The range may be extended by adding polar solvents such as methanol or acetone. The addition of surfactants helps to disperse microscopic particles to form colloidal suspensions. Carbon dioxide is nonflammable, nontoxic, and inexpensive. 

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