2 ANALYSIS

THE SEPARATION OF a miscible cleaning solution into two immiscible solvent combinations considerably changes the nature of our cleaning system. In order to determine the composition of these combinations, five cleaning solutions were prepared as shown in Table 1. Each solution separated into two solvent combinations, one mainly ethanol phase and one mainly hydrocarbon phase. The mainly hydrocarbon phase “floats” on top of the mainly ethanol phase. These were analyzed using gas-liquid-chromatography and the component amounts calculated as percent by volume.1 The results are shown in Tables 2 and 3.

Table 1

Table 2 (mainly hydrocarbon phases)

Table 3 (mainly ethanol phases)

For example, if one prepares cleaning solution system 1 by adding 20 ml ethanol, 78 ml white spirit (Stoddard solvent) and 2 ml water, the water tends to pull the ethanol out of solution with the white spirit: the solvents separate into two phases. They are a mainly ethanol phase (80.2% ethanol, 10.6% hydrocarbons, 9.2% water) and a mainly hydrocarbon phase (96% hydrocarbons, 3.1% ethanol, 0.12% water). The two phases are shaken into a cloudy suspension to produce a cleaning system which is composed of a very active ethanol phase dispersed as tiny droplets in a mainly hydrocarbon phase.