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This work presents a study on solubility in water and in water/methanol mixture of a set of ILs composed of the bi (trifluoromethylsulfonyl)imide anion and of the N-alkyl-triethyl-ammonium cation (abbrev. [NR222][NTf2]) with the alkyl chain R ranging from 6 to 14 carbons. These ILs were successfully tested for enantioselective hydrogenation of β-ketoesters catalyzed by the chiral complex Ru-BINAP in presence of methanol [1]. From which, it appears that these ILs immobilise the catalyst in the mixture for easier recycling and further re-use and protect it from air/oxygen. The final separation of the product is carried out by rinsing the solution with water, which may also wash out the ILs with catalyst. For this reason, mutual solubilities between ILs and water, as well as between ILs and methanol/water mixture need to be investigated in detail.

A set-up for semiautomatic and quick measurement of liquid–liquid equilibrium in polymer solutions by the cloud point method was assembled and checked. The whole arrangement is shown in Figure 1. It consists of equilibrium cell, programmable thermostat, laser source with a photodiode sensor, and computer with LabVIEW software. The cell is shown in details in Figure 2. Figure 1. Assembly of apparatus Figure 2. Equilibrium cell Only 5 ml of liquid mixture is sufficient for measurement of one experimental point on the coexistence curve, which procedure takes one hour, approximately. The programmable thermostat has been used for temperature control, the turbidity has been detected by measuring intensity of a laser beam scattered by the mixture. A photodiode sensor was used to measure the scattered light intensity. Final phase split temperature as measured with a Pt100 resistance thermometer has been recorded and evaluated using the LabVIEW software. The coexistence curve of the polystyrene + methylcyclohexane system was measured in the region of the upper critical solution temperature (UCST). The obtained results are in a good agreement with available literature data.

This contribution is accomplished by the study of the membrane affinity via contact angle measurements and by structural analysis via electron he transport properties of the TFC PA were studied at various experimental conditions and the obtained results will be discussed.