Mercury trap

The reduction is carried out much as described in Procedure 2. Ammonia (950 ml) is distilled into a 5-liter reaction flask and 950 ml of /-amyl alcohol and a solution of the ketal in 950 ml of methylcyclohexane are added with good stirring. Sodium (57 g, 2.5 g-atoms) is added in portions. The reaction mixture becomes blue within 30-45 min after the sodium is added and the metal is consumed within about 3 hr after the blue color appears. After the mixture becomes colorless, 200 ml of ethanol is added and the ammonia is allowed to boil off through a mercury trap. Then 500 ml of water and 500 ml 0% potassium bicarbonate solution are added and the organic layer is separated. The organic layer is washed once with 10 % potassium bicarbonate... 

In a 1-liter, three-necked, round-bottom flask equipped with a magnetic stirrer, dropping funnel, and a reflux condenser attached to a mercury trap is placed a mixture of 4.7 g (0.125 mole) of sodium borohydride, 23.1 g (0.33 mole) of 2-methyl-2-butene, and 100 ml of anhydrous tetrahydrofuran. This mixture is stirred for 15 minutes and... 

A 2-1. two-necked, round-bottomed flask equipped with a magnetic stirrer (Note 1) is fitted with a 250-ml. pressure-equalizing constant-rate dropping funnel and a condenser, the top of which is connected to a mercury trap to prevent the entrance of air during the reaction and for the detection of gas evolution. The dropping funnel is removed, and 35 g. (0.85 mole) of sodium hydride dispersed in mineral oil is added (Note 2). The mineral oil is removed by washing the dispersion four times with 100-ml. portions of benzene (Note 3). The benzene is removed with a pipet after the sodium hydride is allowed to settle (Note 4). 

The reaction mixture is now surrounded by an ice and salt mixture. The separatory funnel is replaced by a two-hole rubber stopper containing a thermometer (bulb immersed in the reaction mixture) and a glass tube the outer end of which is connected to a mercury trap (Note 3). When the temperature of the reaction mixture has fallen to 0°, the condenser is replaced by a tube 10 mm. in diameter and adjusted so the end is 50 nun. above the surface of the reaction mixture. The reaction mix-... 

The mercury trap enables the operator to adjust the flow of the carbon dioxide according to the rate of absorption, and to apply a pressure of 45 mm. during the last half-hour. The pressure itself has practically no effect. The trap consists merely of a narrow glass test-tube containing mercury, and the tube is made to extend beneath the surface. 

The apparatus is assembled as shown in Fig. 5. Ammonia gas from a commercial cylinder (Note 1) enters the system at K. R is a mercury trap which would serve as a safety valve if the system should become blocked by solidification of the amide owing to an accidental drop in temperature. J is a U-tube containing just enough mercury to seal the bend, and it serves to estimate the rate of ammonia Sow. I is a Kjeldahl trap which prevents any mercury from being thrown into the fusion pot A, which (Note 2) is conveniently supported on a tripod set on bricks to raise it to a convenient height above the burner M. Through the cover of the fusion pot passes an outlet tube B, a thermometer well T, and the combined inlet tube CDE. The... 

SEALING BY MEANS OF A MERCURY TRAP AN ALCHEMICAL COMMON COLD STILL A BALNEUMMARI ... 

Fig. 2.13. The Vacustat or swivel gauge. This instrument is plugged into an outlet from the vacuum line by means of the horizontal B.14 cone A (see (c)). The normal position of the gauge is, as shown in (a), horizontal, so that the whole of it is evacuated the mercury is in reservoir B. When a measurement of the pressure is to be made, the instrument is turned into the vertical position, (b), so that the mercury traps the content of bulb D and compresses it into capillary which has the same diameter as capillary E. The pressure of the gas compressed into is given by the difference in height of the mercury in E and E. ...

On the vacuum line assembly (Fig Et 4) check that stopcock F is turned so that nitrogen does not enter the vacuum line. Then open the valve on the nitrogen cylinder to allow a slow stream of nitrogen to escape thru the mercury trap... 

The excess of silicic acid is deposited as a gelatinous precipitate which would easily stop up a narrow delivery tube. It is to prevent this that the mercury trap is used. Continue the heating as long as the silicic acid... 

Twenty-seven grams (1 mole) of aluminum wire or foil which has just been cleaned with emery paper and wiped with a clean cloth (if turnings are employed, it may be necessary to dean, amalgamate, and dry them according to the procedure of Wislicenus)64 66 is placed in a 1-1. round-bottomed flask containing 300 cc. of anhydrous isopropyl alcohol (distilled from calcjum oxide) and 0.5 g. of mercuric chloride. The flask is attached to an efficient reflux condenser, which is protected from moisture by a mercury trap or a calcium chloride drying tube, and the mixture is heated on the steam bath or a hot plate. When the liquid is boiling, 2 cc. of carbon tetrachloride, which is an effective catalyst for the... 

Invariably, the mercury within a McLeod gauge will get dirty. The telltale evidence is when the mercury does not cleanly run down the glass tubing and/or you see a film on the surface of the mercury. Traps are the best way to avoid this problem. 

A mercury spill occurs in an unventilated stockroom with some of the mercury trapped in several floor cracks. What is the maximum concentration of mercury that can be attained in the storeroom when the temperature is 23°C If the Federal standard permissible exposure limit for mercury in the air is 0.1 mg/m3, is the maximum concentration of mercury in the air acceptable ... 

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