Funnel stopcock

Step 5. To prepare the organic phase, pour 100 mL of 10% TIOA in p-xylene into a clean 1-L separatory funnel (see Fig. 16.1). Add 50 mL of 9 N HC1, cap the separatory funnel, invert funnel and vent the funnel stopcock in a safe direction to release any vapors that build up in the funnel. Perform venting operation after every subsequent shaking. Close the stopcock and shake funnel for two minutes to equilibrate the HC1 between the organic and aqueous phases. Place the separatory funnel on the stand and remove the cap. Allow phases to separate. Drain the lower, aqueous, phase and discard. 

Bulb funnel Stopcock Suction tube Safety bulb Three way tap Outlet tube... 

The sulfuric acid-Dj is transferred to the separatory funnel of the apparatus shown in Fig. 18. Since this device will become part of a high-vacuum gas-handling system, both the funnel stopcock and the standard-taper ground... 

Using a graduated cylinder, measure 8.5 mL of 1-bromopropane and pour it into the funnel (stopcock closed ). Prepare an ice-water bath in case it is needed to cool the reaction mixture. 

II, 36, 1 is almost self explanatory two ground glass joints are used, but these may be replaced by rubber stoppers, if desired. The crude substance is placed in the flask A. Stopcocks 1 and 2 are closed, and the apparatus is exhausted through tap 3 the indifferent gas is then allowed to enter the apparatus to atmospheric pressure. The evacuation and filling with inert gas are repeated several times. The solvent is added through the tap funnel B. 

About 150 ml. of concentrated sulphuric acid is placed in the larger funnel and 100 ml. of concentrated hydrochloric acid in the smaller separatory funnel. The latter is raised until the capillary tube is above the sulphuric acid, the capillary tube is filled with concentrated hydrochloric acid, and the stopper replaced. The rate of evolution of hydrogen chloride is controlled by regulation of the supply of hydro chloric acid this will continue until a volume of hydrochloric acid equal to that of the concentrated sulphuric acid has been used. The diluted sulphuric acid should then be removed and the apparatus recharged. The yield is 31-33 g. of hydrogen chloride per 100 ml. of concentrated hydro chloric acid. If more than an equal volume of hydrochloric acid is employed, the yield of gas decreases and continues to be formed for a tune after the stopcock has been closed. 

A little sulphurous acid may be present. This may be removed by transferring the product to a separatory funnel, shaking gently with 5 ml. of 10 per cent, sodium hydroxide solution (the pressure should be released from time to time by inverting the funnel and turning the stopcock), followed by water. This purihca tion is unnecessary if the amylene is only to be used ibr the experiments in Section 111,11. 

Eosin (Tetrabromofluorescein). Place 16 5 g. of powdered fluorescein and 80 ml. of rectified (or methylated) spirit in a 250 ml. flask. Support a small dropping funnel, containing 36 g. (12 ml.) of bromine, above the flask make sure that the stopcock of the funnel is well lubricated before charging the latter with bromine. Add the bromine diopwise during about 20 minutes. When half the bromine has been introduced, and the fluorescein has been converted into dibromofluor-escein, all the solid material disappears temporarily since the dibromo derivative is soluble in alcohol with further addition of bromine the tetrabromofluorescein (sparingly soluble in alcohol) separates out. Allow the reaction mixture to stand for 2 hours, filter ofiF the eosin at the pump, wash it with alcohol, and dry at 100°. The yield of eosin (orange-coloured powder) is 25 g. 

The apparatus illustrated in Fig. 3 is assembled, in a large hood if possible (Note 3). A is a 5- . round-bottom flask heated by a large ring burner and provided with a specially treated four-hole cork stopper covered with tin foil (Note 4). To these holes are fitted the column Z), the tube B reaching to the bottom of A, the specially bent tube C reaching up the inside of D, and the tube K connected with the tubes leading to the 2-I. separatory funnel H, so that the distance between the stopper of A and the stopcock of H is at least 100 cm. The bottom of the column D is of 20 mm. bore while the main portion is 30 mm. The side arm should be at least 85 cm. above the stopper of 4. The tube C... 

A. 2-(Trimethtjlsiloxymethyl)allyltvimethylBilane. An oven-dried (Note 1) 2-L, three-necked, round-bottomed flask is equipped with an air-tight mechanical stirrer (Note 2), a 500-mL pressure-equalizing dropping funnel (Note 3), and a reflux condenser. The top of the condenser is connected to a three-way stopcock with one branch connected to a nitrogen source and the other to a variable pressure oil pump with a dry-ice trap (Note 4). The apparatus is flamed dry under a steady stream of nitrogen. The flask is... 

Some of the more obvious sources of contamination of solvents arise from storage in metal drums and plastic containers, and from contact with grease and screw caps. Many solvents contain water. Others have traces of acidic materials such as hydrochloric acid in chloroform. In both cases this leads to corrosion of the drum and contamination of the solvent by traces of metal ions, especially Fe. Grease, for example on stopcocks of separating funnels and other apparatus, e.g. greased ground joints, is also likely to contaminate solvents during extractions and chemical manipulation. 

If the chloropyruvic acid remains essentially as a viscous liquid, it may be introduced via a dropping funnel containing a large-bore stopcock. If the material has set up to a waxy solid, it must be introduced in portions through a powder funnel. 

The addition of liquids or solutions to the reaction vessel can usually be carried out by use of a simple dropping funnel surmounted, if necessary, by a drying tube. For reactions carried out under pressure, vacuum, or an inert atmosphere, a pressureequalizing dropping funnel is required (Fig. A3.3). Care must be exercised in either case since a single setting of the stopcock will result in a decreased rate of addition as the liquid head diminishes. 

Hahn-hulse, /. (stop)cock shell or barrel -kegel, m., -kUken, -kiicken, n. (stop)cock plug or stopper, -messer, m. flowmeter, -schllissel, m. cock wrench, cock spanner, -sitz, m. (stop)cock seating or seat, -stopfen, n., -stdpsel, m. (stop)cock stopper or plug, -trichter, m. funnel with stopcock. 

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