Aspirator trap

The aspirator is not a very fast pump (1-2 gallons/minute), nor does it create a powerful vacuum ( 10 mm Hg) (with proper liquid nitrogen trapping, aspirators can achieve vacuums as great as 10 2 torr). 1 It is ideally suited for emptying large containers of liquids down a sink or for supplying the vacuum necessary for a filter flask. 

These electrodes can be tested by appropriate software as SIMION [31] or other finite-element based programs. The suitability of the electrodes can be evaluated also by calculating their ability to store ions, in comparison with the ideal quadru-polar hyperboloidal geometry [32], to which the designers of micro traps aspire, and by dedicated experiment. 

Procedure for filtering through a filtering crucible. The trap is used to prevent water from a water aspirator from backwashing into the suction flask. 

The function of the trap is to condense the hexane from the n-butyl-lithium solution. The checkers used a 1-L three-necked flask fitted with a short delivery tube (a quick fit air bleed tube was used), stopper, and rubber tubing connection. The submitters used a water aspirator and a 1-L filter flask with a drying tower between. 

A solution of 30 g (0.1 mole) of 17j5-hydroxy-5a-androstan-3-one (androstano-lone), 20 ml of pyrrolidine and 200 ml of benzene is heated at reflux temperature for 2.5 hr under a Bidwell-Sterling water trap. The benzene solution is evaporated to dryness in a rotating evaporator connected to a water aspirator. The white cake which remains is broken up and dried further by immersing the flask in a water bath at 60-75° and evacuating the flask with a mechanical vacuum pump. After 0.5 hr the solid cake is broken up again and dried for another 0.5 hr at 60-75°. The enamine (9) obtained should smell only faintly of pyrrolidine. 

A dry ice-isopropyl alcohol trap was inserted before the aspirator to catch any uncondensed product The checkers also inserted a manometer between this trap and the aspirator, and maintained the pressure during the reaction at 130-170 mm. by careful adjustment of the regulator valve of the nitrogen cylinder. 

B. Pyridine-N-oxide. The acetic acid solution is evaporated on the steam bath under the pressure of a water aspirator, and the residue (180-190 g.) is distilled at a pressure of 1 mm. or less in an apparatus suitable for collecting a solid distillate (Note 5). The vacuum pump must be protected with a Dry Ice trap capable of holding about 60 ml. of acetic acid, which distils as the pyridine-N-oxide acetate dissociates at low pressure. Heat is provided by an oil bath, the temperature of which is not allowed to rise above 130° (Note 6). The product is collected at 100-105°/1 mm. (95-98°/0.5 mm.). The yield is 103-110 g. (78-83%) of colorless solid, m.p. 65-66° (sealed capillary). The base is deliquescent and must be stoppered immediately. 

The water trap is in turn connected to a source of vacuum, most likely, a water aspirator (Fig. 47). 

When the crystals are dry, and you have a water trap, just turn off the water aspirator. Water won t back up into your flask. [If you ve been foolhardy and filtered without a water trap, just remove the rubber tube connected to the filter flask sidearm (Fig. 47)]. 

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. 

If you re going to pull a vacuum in the sublimator, do it now. If the vacuum source is a water aspirator, put a water trap between the aspirator and the sublimator. Otherwise you may get depressed if, during a sudden pressure drop, water backs up and fills your sublimator. Also, start the vacuum slowly. If not, air, entrained in your solid, comes rushing out and blows the crude product all over the sublimator, like popcorn. 

Since the calcium chloride contains basic constituents the filling must be saturated with carbon dioxide before the absorption tube is used. For this purpose connect the side tube which leads to the water trap to the Kipp apparatus, interposing a drying tube, pass a strong current of carbon dioxide for 10 minutes, close the outlet, and allow to stand for half an hour, maintaining the pressure of the Kipp. After 200 c.c. of dry air have been drawn through the tube by means of the aspirator, the tube is ready for use. 

A -78°C trap to collect all volatile materials should be placed between the aspirator and the reaction vessel during this evaporative distillation. 

Lubricant laxatives. Liquid paraffin (paraffinum subliquidum) is almost nonabsorbable and makes feces softer and more easily passed. It interferes with the absorption of fat-soluble vitamins by trapping them. The few absorbed paraffin particles may induce formation of foreign-body granulomas in enteric lymph nodes (paraffinomas). Aspiration into the bronchial tract can result in lipoid pneumonia. Because of these adverse effects, its use is not advisable. 

Pour the contents of the flask into a Buchner funnel and rinse the flask with 300 ml of anhydrous ethyl ether. Pour this into the funnel. Filter with vacuum from an aspirator equipped with a dry ice/acetone trap. Wash the filter cake with two 300ml portions of anhydrous ethyl ether. The filter cake is X, n-diethyaniline hydrochloride and is not used in this process. It may be saved and converted back to its original form for reuse. 

In order to change solutions, the electrodes are first carefully removed (very little effort should be required to do this - be careful, these cells are expensive) and are then stored in distilled water. The old solution is aspirated out and the cell rinsed and aspirated with distilled water. Finally, the new solution is poured into the cell and the electrodes carefully replaced so that no air bubbles are trapped near the electrodes. The new solution should be left to equilibrate (at 25 °C) for about 15 minutes before measurement. A typical rectangular quartz cell is shown in Figure 6.18. The speed of the colloid particles is measured at a stationary fluid layer within the rectangular cell. These cells are expensive and must be handled carefully. At the end of the experiment the electrodes should be removed and placed in distilled water and the cell should be rinsed and filled with distilled water. 

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