Vapor pressure difluoroethane

Silva and Weber (1993) reported vapor pressure measurements for the 1-ch oro-l,l-Difluoroethane (RI42b) and 1,1 -Difluoroethane (R152a) refrigerants. The data are given in Tables 3.5 and 3.6 respectively. Use Antoine s equation to correlate the data for R142b and the following equation for R152a (Silva and Weber, 1993)... 

Silva, A.M., and L. A. Weber, "Ebulliometric Measurement of the Vapor Pressure of 1-Chloro-l,l-Difluoroethane and 1,1-Difluoro Ethane, J. Chem. Eng. Data, 38, 644-646 (1993). 

Maezawa, Y., Sato, H., Watanabe, K. (1990) Saturated liquid densities of HCFC 123 and HFC 134a. J. Chem. Eng. Data 35,225-228. Maezawa, Y., Sato, H., Watanabe, K. (1991a) Liquid densities and vapor pressures of l-chloro-l,l-difluoroethane (HCFC 142b). J. Chem. Eng. Data 36, 148-150. 

Takagi, T., Sawada, K., Urakawa, H., Ueda, M., Cibulka, I. (2004) Speeds of sound in dense liquid and vapor pressures for 1,1-difluoroethane. J. Chem. Eng. Data 49, 1652-1656. 

Difluoroethane is a liquefied gas and exists as a liquid at room temperature when contained under its own vapor pressure, or as a gas when exposed to room temperature and atmospheric pressure. The liquid is practically odorless and colorless. Difluoroethane is noncorrosive and nonirritating. 

For design calculations involving Refrigerant 500, a minimum-boiling azeotrope of 39.4 mol % of 1,1-difluoroethane and 60.4 mol % of difluorodichloromethane, reliable real gas thermodynamic properties are required which have been calculated from 0.2 to 100 bar and from 220 to 540 K using the recently proposed Boublik-Adler-Chen-Kreglewski equation of state and the PVT data reported in the literature. This equation of state has 21 universal constants and only five adjustable constants which have been calculated for R-500 from the PVT data, saturated vapor pressure and liquid density, and the critical constants. In order to calculate the absolute values of the real gas properties, the reference state properties, which are also reported here, are required. All properties are given in SI units. 

Blow-off of particulates is often done with dusters using canned pressurized gases, or liquids that have a high vapor pressure at room temperature. One common duster uses difluoroethane, which liquefies under pressure, as the duster gas. When a gas under pressure is released it expands and cools - remember, excessive cooling of a surface may cause moisture contamination and that may leave residuals on the surface. Residuals from the blow-off gases should be checked, particularly with the spray can in the inverted position where liquid sprays out instead of vapor. 

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