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R-22 use is being phased out in developing countries, where it is largely used for air conditioning applications. R-22 is prepared from chloroform: HCCl 3 + 2 HF → HCF 2 Cl + 2 HCl. An important application of R-22 is as a precursor to tetrafluoroethylene. This conversion involves pyrolysis to give difluorocarbene, which dimerizes: [3]
According to ASHRAE standard 34, the R-number of a chemical refrigerant is assigned systematically according to its molecular structure and has between two and four digits. If there are carbon -carbon multiple bonds , there are four digits in all: the number of these bonds is the first digit and the number of carbon atoms minus one (C-1) is next.
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure.
R─N─C (isocyanides) any 2165–2110 R─N═C═S (isothiocyanates) any 2140–1990 C─X: fluoroalkanes: ordinary 1000–1100 trifluoromethyl 1100–1200 two strong, broad bands chloroalkanes: any 540–760 weak to medium bromoalkanes: any 500–600 medium to strong iodoalkanes: any 500 medium to strong N─O nitro compounds: aliphatic ...
In statistical process control (SPC), the ¯ and R chart is a type of scheme, popularly known as control chart, used to monitor the mean and range of a normally distributed variables simultaneously, when samples are collected at regular intervals from a business or industrial process. [1]
Here is a similar formula from the 67th edition of the CRC handbook. Note that the form of this formula as given is a fit to the Clausius–Clapeyron equation, which is a good theoretical starting point for calculating saturation vapor pressures: log 10 (P) = −(0.05223)a/T + b, where P is in mmHg, T is in kelvins, a = 38324, and b = 8.8017.
R-407C is a mixture of hydrofluorocarbons used as a refrigerant. It is a zeotropic blend of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a). Difluoromethane serves to provide the heat capacity, pentafluoroethane decreases flammability, tetrafluoroethane reduces pressure. [ 1 ]
Each of the phase saturations must be larger than the irreducible saturation, and each phase is assumed continuous within the porous medium. Based on data from special core analysis laboratory (SCAL) experiments, [2] simplified models of relative permeability as a function of saturation (e.g. water saturation) can be constructed. This article ...