A Transferable Gas Container (TGC) Improving the Balloon Inert Atmosphere Technique Andrej Bohat Department of Org. Chem., FNS-Comenius University, Mlynska dolina, 842 15 Bratislava, Slovakia
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Advantages of the TGC Construction is fast and inexpensive. Filling the TGC is simple-directly from the reduction valve of the gas cylinder. The TGC can hold 9-10 L of gas. The TCG can be closed with a rubber stopper. Manipulation and transport of the TGC is simple. The equipment saves a lot of gas (after the lab, the TGC can be closed with a stopper and the gas kept for several weeks). The TGC is universal (the rubber tubing ofthe gas container x i allows for a tight and reliable cannee"\ tion to variable apparatuses). \. ktae T h e TGC is safe because of the low :, pressure in the container (pressure difference in the apparatus is re', ,,, .:, ,, fleeted by the change of the volume of I the balloon). The TGC connection with a syringe allows it to work with air- or water-sensitive compounds through a septum (handling of BuLi, anhydrous solvents, &.). See figure at right.
When inert gases a r e to be introduced into reaction flasks in laboratories, storage balloons may he used thus eliminating the need for students to use ;I highly pwssuriztd eili cvldcr w t h a reduct~onv d v e However. these hal" Ions have poorly defined connections with the apparatus t h a t they join. The transferrable gas container (TGC), consisting of two silicon rubber tubings and a toy balloon, solves this problem by forming a well-defined connection. The TGC can be used in all cases where i t is necessary to secure a n inert atmosphere such a s Nz or Ar over a reaction mixture or by filling vacuum apparatuses-the vacuum evaporator, desiccator, distillation equipment, sublimator, and drier-with the inert gas. The TGC i s convenient for chemical reactions withgas materials such a s COz, Hz, and isobutylene. I t prevents volatile poisonous compounds such as benzene and CSz from escaping into the environment. Because the TGC is easy to construct, manipulate, and transport, i t allows many students in experimental chemistry courses to work a t the same time. I t is possible to construct this equipment quickly from a child's balloon and two pieces of silicon rubber tubing using the illustration given below.
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