Safety Vacuum Release System

Equip the flask for vacuum distillation. Cool the receiving flask with an ice-salt bath, and attach the vacuum adapter to an aspirator by means of a safety trap such as that shown in Figure 2.42a. Evacuate the system and distill the excess thionyl chloride. When the thionyl chloride has been removed, cautiously release the vacuum. Tightly stopper the flask containing thionyl chloride. To the residue in the stillpot. which is 3,5-dinitrobenzoyl chloride, add 1 mL of the alcohol and 0.3 mL of... 

Air filtration, the real heart of the system, was a major concern for the safety community. It was necessary to build in redundancy with every major component to ensure a fail-safe system. This consisted of dual High Efficiency Particulate Air (HEPA) and carbon filters, dual vacuum gauges, dual air pressure alarms, dual motor blowers to draw air through the glovebox, dual sources of electricity and a Hame Photometric Detector (FPD) to monitor between the carbon beds for possible breakthrough of chemical compounds. This was necessary because the effluent air from the filter beds was being released into the working environment of the operators. Army... 

Vacuum-transferrable volatile materials (b.p. up to about 180-200 C) often encountered include (aside from those prepared as intermediates in the radiochemical laboratory) commercial building blocks such as [ C] methyl iodide and other low-molecular-weight carbon-14-labeled alkyl halides, methanol, ethanol, benzene, acetic and haloacetic acids, acetyl and haloacetyl chlorides and dimethylformamide. These compounds are most appropriately handled on vacuum manifolds in the same way as gases, but some may, with proper experimental design, be used without such systems. In the latter case, it is strongly recommended that safety measures be taken against the possibility of the release of volatile radioactivity. 

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