Dsc 2 star system

Differential scanning calorimetry (DSC) of the oil was performed using a DSC 2 Star System (Mettler Toledo). The purge gas (nitrogen) had a flow rate ~60 ml/min 5–7mg of oil were weighed into low pressure aluminium crucibles, and sealed hermetically. The sealed crucibles were pierced prior to analysis [11 ]. An empty, hermetically sealed aluminium crucible with a pinhole was used as a reference. A temperature profile of -80 to 180 °C was run using the following temperature program: -80 °C isotherm for 3 min; dynamic ramp at -80 °C–180 °C (at 10 °C min⁻¹), isotherm at 180 °C for 3 min; isotherm at 30 °C for 2 min. The resulting DSC data was analysed for peak temperature, onset temperature and melting temperature for comparison. All experiments were carried out in triplicate and the average values were reported. Melting temperature was considered to be the temperature at the end of the melting transition [12 ].

The presence of H–C–S and H–C–O–S groups in the sulphonated Afzelia africana aril cap oil (fatliquor) were examined and characterised by FT-IR measurement (600-4000 cm⁻¹), normal resolution of 4 cm⁻¹ using a Shimadzu 8400S FT-IR instrument (Shimadzu, Milton Keynes, UK). ¹H nuclear magnetic resonance (NMR), ¹³C NMR and distortionless enhancement were determined by polarization transfer (DEPT) ¹³C NMR. The spectra of both the sulphonated and unsulphonated oils were acquired on a Brucker Biospin® AV500 – 5mm BBO probe with Z axis gradient, TOPSPIN v 2.1, 1H = 500.13 MHz, 13C = 125.76 MHz (Brucker, Coventry, UK). Their thermal behaviours were also determined using the Mettler DSC 2 Star System in temperature range of -80 to 180 °C, using an identical program given.