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Demeon > Product Specification > Solvency Power

Solvency Power

Dimethyl Ether (DME) is an excellent solvent with unique solvency power for both polar and a-polar substances. Hairspray- and paint polymers easily dissolve in DME containing aerosol formulations. Perfumes dissolve deeply and the notes of perfumes develop quickly due to the superior expansion from liquid into the vapour state of DME. This makes DME ideal for aerosol products such as body deodorants, perfume sprays and air fresheners. A theoretical value for this property is the solvency power. The value for DME is 7.3. For comparison's sake, the average value for Propane and the Butanes is 6.4.

Formula for calculations
The specific solvency power of Dimethyl ether is good notable in various products in practice. The more theoretical figure, expressed as solubility parameter, is a calculated value. The formula for these calculations is as follows:

Solubility Parameter = Ö ((D H – RT) / V)

D H = heat of vaporisation
R = gas constant
T = temperature
V = molar volume

The solubility parameters for some aerosol propellants are given here. For reasons of comparison the figures for the hydrocarbon propellants are given here also.

Kauri-butanol number
A more practical indication for the solvency power of Dimethyl ether is given by the Kauri-butanol number.
The Kauri-butanol number (KB value) is defined as the number of millilitres of a liquid propellant at 20 ° C required to reach the cloudpoint when titrated against 20 gram of a standard 20% Kauri resin (polar nature) solution. With a value of 91, DME is superior to Propane and the Butane with an average value of 17.