Experimental Method All experiments were carried out in a high-pressure CO2 apparatus (Speed-SFE from Applied Separations) (see Figure 1) with a 300-mL extractor designed for a maximum pressure of 690 bar and a maximum temperature of 2... Experimental Method
All experiments were carried out in a high-pressure
CO2 apparatus (Speed-SFE from Applied Separations)
(see Figure 1) with a 300-mL extractor designed for a
maximum pressure of 690 bar and a maximum temperature
of 250 °C. The volume of the extractor had to be
reduced to 50 mL by a metallic cylinder， which tightens
to the extractor wall， because as preliminary tests
showed the equilibrium cell has to be completely filled
with material. Otherwise， diffusion is the limiting factor
and time for reaching equilibrium was too long. The
extraction vessel was filled with compressed CO2 by an
air-driven pump at closed outlet valves and under static
conditions， which means desired pressure and temperature;
the cell was incubated for 15 h， maintaining these
conditions to reach equilibrium. In preliminary experiments
the equilibrium time of 15 h was determined to
reach equilibrium.
CO2 Sampling. At equilibrium a CO2 phase sample
is taken by opening the outlet valve and expanding a
certain amount of CO2-substance mixture into a cooling
trap filled with toluene， which has the highest solubility
for the measured substances under atmospheric conditions.
The pure gaseous CO2 passes a rotameter， showing
the actual flow rate， and a gas flowmeter for
determining the expanded CO2 amount. The content of
the cooling trap was filled up with toluene to 30 mL and
analyzed by a gas chromatographic method using an
electron capture detector (GC-ECD). With the mass of
expanded CO2 and composition of the cooling trap
solubility at a certain pressure and temperature was
calculated. Sampling was repeated four times at a given
pressure and temperature and the standard deviation
was lower than 5%.
Gas Chromatographic Method. The tolueneflame
retardant mixture of CO2 sampling was analyzed
in a gas chromatograph (HP 5890 Serie II) with an ECD
using a capillary column (type HP-1， 12 m 0.2 mm 0.2 ím). The injector temperature was held constant at
290 °C and the detector temperature at 300 °C. The oven
temperature was held constant at 290 °C. Calibration
with different amounts of HBCD and TBBA in toluene
has been done before determining the linear range of
calibration line and retention time of substances 展開
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