Equipment and experimental procedure

Structure determination of unsaturated compounds can be supplemented by thermal desorption (TD) and electron energy loss (EEL) spectroscopies. The two methods use the chemisorption of cis and tram enes or dienes to the Pt(lll) surface over a range of temperatures11. The experimental equipment and procedures described12 show these methods to be employed for dienes such as 1,3-butadiene. At veiy low temperature the diene is adsorbed on Pt(l 11) and the thermal desorption is followed by increasing the temperature. 

Several authors [3-9] studied the solubility of polymers in supercritical fluids due to research on fractionation of polymers. For solubility of SCF in polymers only limited number of experimental data are available till now [e.g. 4,5,10-12], Few data (for PEG S with molar mass up to 1000 g/mol) are available on the vapour-liquid phase equilibrium PEG -CO2 [13]. No data can be found on phase equilibrium solid-liquid for the binary PEG S -CO2. Experimental equipment and procedure for determination of phase equilibrium (vapour -liquid and solid -liquid) in the binary system PEG s -C02 are presented in [14]. It was found that the solubility of C02 in PEG is practically independent from the molecular mass of PEG and is influenced only by pressure and temperature of the system. 

FFF is similar to chromatography in many respects, especially as far as both dynamic aspects and experimental equipment and procedures are concerned. However, all of the processes associated with the separation take place in the fluid phase and there is no stationary phase which would play an active part in the separation process. This simpleness is, however, characteristic of classical FFF only and not of its combination with the chromatographic technique, e.g., with the use of a channel packed with a chromatographic bed. This is why FFF is sometimes classified as a one-phase chromatography [2-6]. The absence of the stationary phase that has a large surface area, which is a condition of efficient separation in chromatography. 

The experimental equipment and procedure used for the experimentation have been described [10]. A small visual cell reactor, 8 mL, was employed to visually check the solubility of the catalyst and the miscibility of reactants and products in SCCO2 at reaction conditions (Figure 2). Also, a 100 mL batch reactor with sampling on-line was installed to take samples at different times in order to determine the conversion and selectivity profiles against time (Figure 3). After each experiment the reactor was carefully washed and a blank test (without catalyst) was performed to ensure no catalyst was left in the reactor. 

In order to approximate column profiles by collecting experimental data points, it is important that the experimental equipment and procedure be carefully laid out, such that results are easily obtainable, but more importantly that they are reliable. The setup used for profile validation of rectifying sections throughout this chapter can be seen in Figure 4.3. 

A previous paper [ ] presented much of the experimental data which are analyzed in this report and the reader is referred to this work for a detailed description of the experimental equipment and procedures. Briefly, the experimental apparatus consisted of a cylinder containing liquid nitrogen in a cross-flow of air with the air velocity, humidity, and temperature as controlled variables over the following range air velocity 5 to 60 mph, air temperature 40° to 120°F, and specific humidity 16 to 325 gr/lb. 

A conductance technique [7] was used to provide instantaneous measmements of cross-sectionally averaged liquid holdup. More details concerning the experimental equipment and procedures can be found elsewhere [5,6]. 

A detailed description of the experimental equipment and procedures can be found elsewhere [21]. 

---