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Water aspirator, leaking

Suppose, by luck of the draw, you ve had to prepare and purify 1-octanol (B.P. 195°C). You know if you simply distill 1-octanol, you run the risk of having it decompose, so you set up a vacuum distillation. You hook your setup to a water aspirator and water trap and attach a closed-end stick manometer. You turn the water for the aspirator on full-blast and open the stick manometer. After a few minutes, nothing seems to be happening. You pinch the tubing going to the vacuum distillation setup, (but not to the manometer) closing the setup off from the source of vacuum. Suddenly, the mercury in the manometer starts to drop. You release the tube going to the vacuum distillation setup, and the mercury jumps to the upper limit. You have air leaks in your vacuum distillation setup. [Pg.162]

The ultimate vacuum achievable with a water aspirator is limited by the vapor pressure of the water itself any significant drop in the pressure much below this will be reversed by the vaporization of water. The vapor pressure of water is 12.8 Torr at 15°C, 17.5 Torr at 20°C, and 23.8 Torr at 25°C. A lesser vacuum (higher pressure) can be achieved by reducing the flow of water into the aspirator and/or bleeding air into the system through a controlled leak. [Pg.588]

During the combustion the rate of flow of bubbles in the counter often increases rather appreciably because the rapid absorption in the sodium hydroxide-asbestos tube of the carbon dioxide produced causes a slight decrease in the pressure. If this happens reduce the rate of dropping of water from the aspirator or even stop it altogether temporarily. No harm is done by this decrease in pressure. Should there be any small leaks at the constricted parts of the tube there would, it is true, be a danger that air might be sucked in. In view of the short duration of the reduction in pressure, however, the errors caused would have no appreciable effect on the determination. Obviously no adjustment of the flow from the aspirator must be made while the reduced pressure prevails. The former rate of dropping is automatically restored. [Pg.67]


See other pages where Water aspirator, leaking is mentioned: [Pg.817]    [Pg.87]    [Pg.27]    [Pg.179]    [Pg.102]    [Pg.83]    [Pg.481]    [Pg.128]    [Pg.168]    [Pg.201]    [Pg.525]    [Pg.90]    [Pg.2007]   
See also in sourсe #XX -- [ Pg.102 ]




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