Experimental setup for the gas-phase derivatisation procedure can be variable, but should necessary contain the following basic elements: (1) a pump capable of producing vacuum of 10-1-10"2 Torr; (2) a vessel serving as reactor; (3) a heating element such as heating mantle.
In most of our experiments we employed the custom-made Pyrex glassware shown in Fig. 19.1 (Basiuk et al. 2002a). In a typical experiment, 100 mg of CNTs were placed into the bigger reactor 11. To remove volatile contaminants (adsorbed from the environment) from the nanotube material, the reactor was pumped out to a vacuum of ca. 10-2 Torr (valves 2 and 5 open; 1, 3 and 4 closed), and its bottom was heated for 0.5 h at 100-120°C by means of heating mantle 13. Then the reactor was cooled, open and ca. 50 mg of amine was dropped to the bottom containing CNTs. After pumping the reactor out to ca. 1 Torr at room temperature, its valve 2 was closed, and the bottom was heated at 150-170°C for 1-2 h. During this procedure, amine evaporated, reacted with CNTs, and its excess condensed a few centimeters above the heating mantle. The high derivatisation temperature not only facilitates the reaction, but also helps to minimise the amount of amine physically adsorbed on the nanotube material. After finishing the procedure, valve 2 was open again for 15-60 min to remove volatiles. Then the heating mantle was removed, the reactor cooled and disconnected from the manifold. Before taking the derivatised nanotubes out, the upper reactor part with condensed excess amine on the wall was wiped with cotton wool wet with ethanol. For milligram-scale derivatisation procedures, smaller reactor 12 can be used in a similar way.
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