Separatory stopper

Semimicro separatory apparatus. The separatory tube (described on page 113) has been found more suitable and economical for students than micro separatory funnels. The separatory stopper, shown in Figure 2, can be constructed to flt any size test tube. TTius it is possible to separate two immiscible liquids having a total volume of 1-2 milliliters by using a three-inch tube, or 60 milliliters by using an eight-inch tube. 

F) Separation of Two Immiscible Liquids (Sm.). The separation of two immiscible liquids is a common procedure in the organic laboratory, since most organic liquids are immiscible with water. For the separation of small quantities (semimicro) a separatory stopper is used. Stoppers are made by each student to fit six- and eight-inch test tubes, in accordance with the following directions ... 

Separation by Means of Separatory Stopper. Figure 41 shows diagrammatically the separatory stopper inserted into a tube, thus... 

Insert the separatory stopper in the reaction tube. Be sure that... 

Place in an eight-inch tube 5 ml of the unsaturated hydrocarbon and 5 ml of cold 70 per cent sulfuric acid. Cool the mixture in tap water, place a solid rubber stopper in the mouth of the tube, and shake with cooling until the hydrocarbon dissolves and a clear liquid results. Add 6 g of ammonium sulfate dissolved in 8 ml of water. Insert the separatory stopper, and remove the aqueous acid layer. The liquid which is left in the reaction tube can be tested with bromine water or alkaline permanganate to show that it is not an olefin. If it is desired to purify the alcohol, add 1 g of anhydrous calcium sulfate and shake from time to time over a period of fifteen minutes. Pour the crude alcohol into a distilling tube. Heat with a small flame and collect the proper fraction. If amylene is used, and the water is not completely removed by the drying agent, a constant boiling mixture will be formed which boils at 87°. 

C) tert-Butyl Bromide (Sm.). Place in an eight-inch test tube 6 ml of butyl alcohol and 15 ml of 48 per cent hydrobromic acid. Shake at intervals for 5-10 minutes. Separate the upper layer by means of the separatory stopper and wash successively with 5 ml of water and 5 ml of 5 per cent sodium bicarbonate solution. Dry the halide with 1 g calcium chloride, and after 15 minutes distill it from a micro distilling tube. The portion which boils at 72-75° is collected. The yield is about 4 g. 

To decompose the addition compound, immerse the tube in ice-salt mixture and add slowly, by means of a dropper, diluted acid obtained by mixing 5 ml concentrated hydrochloric acid with 5 g of ice. Add only sufficient hydrochloric acid to dissolve the precipitate which forms. Allow to stand until all the residual magnesium has reacted with the acid. The ether layer should have a volume of at least 10-12 ml. If it is le.ss, add ordinary ether to make up this volume. Insert the separatory stopper and remove the aqueous layer. Dry the ether layer by adding 0.5-1 g of anhydrous calcium sulfate. Care must be taken to drj the ether thoroughly, since the carbinol forms an azeotropic mixture with water. Transfer the dry ether mixture to an eight-inch distilling tube, and distill from a water bath until the temperature rises to 70°. Remove the water bath and heat over a small smoky flame. The fraction which boils at 77-84° is collected. 

Heat slowly with a small flame until the temperature reaches 139-140°. Bemove the flame and allow the tube to cool, working in the meantime with the distillate. Insert a separatory stopper in the receiving tube and separate the lower aqueous layer. Return the upper layer (chiefly n butyl alcohol and some ether) to the distilling tube. Repeat the heating and separation twice, but discontinue the heating when the temperature reaches 135° instead of 139°. 

Mix and place in the distilling tube, arranging the thermometer so that it nearly touches the bottom of the tube. Heat with a free flame to 285-290°. Move the burner to and fro so that the heat is directed towards all sides of the tube. When the mixture has melted, adjust the flame so that the temperature remains about 290°. If the temperature is allowed to rise above 295°, adipic acid distills over and the side tube becomes clogged. Continue the distillation until only a small residue remains in the flask. Add 2 ml of saturated salt solution to the receiving tube, insert the separatory stopper, shake gently, and then withdraw the lower aqueous layer. Dry with 0.5 g of anhydrous calcium chloride and distill. The yield is 1.3-1.5 g. If a refractometer is available, determine the refractive index of your product. 

L) Cannizzaro Reaction. Place in an eight-inch test tube or a small flask 2 ml benzaldehyde and 4-5 ml of 50 per cent sodium hydroxide solution. Cork well. Place a piece of cloth over the stopper and shake until a permanent emulsion results. Allow to stand overnight. Crystals of sodium benzoate separate out. Add 10 ml of water and note the layer of benzyl alcohol which separates on the top. Add 10 ml of ether, shake gently, and separate the ether layer by means of the separatory stopper. Withdraw the aqueous layer into a small beaker. The ether layer is placed in a bottle designated by the instructor. The benzyl alcohol may be separated by uniting the extracts of several reactions. The ether solution is shaken with saturated bisulfite solution, dried with 2-3 g anhydrous sodium carbonate and most of the ether distilled. The residue is transferred into a distilling tube and fractionated. The fraction which boils at 203-208° is collected. 

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