Stoppering and removal

After the product has been dried to a desired moisture content, the vials are stoppered and removed from the freeze-drier before oversealing. Vials may be back-filled with an inert gas such as nitrogen or helium just prior to stoppering. When open ampoules or trays (which cannot be stoppered within the freeze-drier) are used instead of vials, it is necessary to use alternative sealing techniques in order to prevent the ingress of moist air into the dried product. 

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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°. 

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. 

At the end of the extraction test remove the tubes from the heating bath, shake well and wipe clean. While still hot remove the stopper and remove the plastic. Wash any DLTDP containing solution from the surface of the plastic into the extraction tube with a jet of warm distilled water (not exceeding 50 ml) delivered from a glass wash-bottle. 

Oleum is marketed in all strengths up to ca. 70 per cent. SO3. From 0 to 40 per cent, free SO3, it is a liquid from 40 to 60 per cent, free SO3, it is a solid from 60 to 70 per cent, free SO3, it is liquid above 70 per cent, free SO3, it is a solid. The acid must be kept in ground glass stoppered, thick-walled bottles. If it is required to melt the acid, the stopper is removed, a watch glass placed on the mouth of the bottle, and the bottle placed in a layer of sand in an air bath which is warmed with a small flame. The bottle is fitted with a wash bottle attachment, and any desired quantity of acid is forced out by gentle air pressure from a hand or foot bellows (the mouth must not be used) this procedure is far more satisfactory than that of pouring the liquid acid from the bottle. 

Cuprous bromide. The solid salt may be prepared by dissolving 150 g. of copper sulphate crystals and 87 5 g. of sodium bromide dihydrate in 500 ml. of warm water, and then adding 38 g. of powdered sodium sulphite over a period of 5-10 minutes to the stirred solution. If the blue colour is not completely discharged, a little more sodium sulphite should be added. The mixture is then cooled, the precipitate is collected in a Buchner funnel, washed twice with water containing a little dissolved sulphurous acid, pressed with a glass stopper to remove most of the liquid, and then dried in an evaporating dish or in an air oven at 100 120°. The yield is about 80 g. 

Make a thin paste of 21 5 g. of finely-powdered o-tolidine (a commercial product) with 300 ml. of water in a 1-litre beaker, add 25 g. (21 ml.) of concentrated hydrochloric acid, and warm until dissolved. Cool the solution to 10° with ice, stir mechanically, and add a further 25 g. (21 ml.) of concentrated hydrochloric acid (1) partial separation of o tolidine dihydrochloride will occur. Add a solution of 15 g, of sodium nitrite in 30 ml. of water as rapidly as possible, but keep the temperature below 15° a slight excess of nitrous acid is not harmful in this preparation. Add the clear, orange tetrazonium solution to 175 ml. of 30 per cent, hypophosphorous acid (2), and allow the mixture to stand, loosely stoppered, at room temperature for 16-18 hours. Transfer to a separatory funnel, and remove the upper red oily layer. Extract the aqueous layer with 50 ml, of benzene. Dry the combined upper layer and benzene extract with anhydrous magnesium sulphate, and remove the benzene by distillation (compare Fig. II, 13, 4) from a Widmer or similar flask (Figs. II, 24, 3-5) heat in an oil bath to 150° to ensure the removal of the last traces of benzene. Distil the residue at ca. 3 mm. pressure and a temperature of 155°. Collect the 3 3 -dimethyldiphenyl as a pale yellow liquid at 114-115°/3 mm. raise the bath temperature to about 170° when the temperature of the thermometer in the flask commences to fall. The yield is 14 g. 

Method 2. Place 90 g. of sodium benzenesulphonate (Section IV,29) (previously dried at 130-140° for 3 hours) and 50 g. of powdered phosphorus pentachloride (1) in a 500 ml. round-bottomed flask furnished with a reflux condenser heat the mixture in an oil bath at 170-180° for 12-15 hours. Every 3 hours remove the flask from the oil bath, allow to cool for 15-20 minutes, stopper and shake thoroughly until the mass becomes pasty. At the end of the heating period, allow the reaction mixture to cool. Pour on to 1 kilo of crushed ice. Extract the crude benzenesulphonyl chloride with 150 ml. of carbon tetrachloride and the aqueous layer with 75 ml. of the same solvent. Remove the solvent under atmospheric pressure and proceed as in Method 1. The yield is about 170 g., but depends upon the purity of the original sodium benzenesulphonate. 

In a 3-I. round-bottomed flask 250 g. of commercial calcium hypochlorite is dissolved in i 1. of warm water and a warm solution of 175 g. of potassium carbonate and 50 g. of potassium hydroxide in 500 cc. of water is added. The flask is stoppered and shaken vigorously until the semi-solid gel which first forms become quite fluid. The suspended solid is removed by filtration on a large Buchner funnel, washed with 200 cc. of water, and sucked as dry as possible with the aid of a rubber dam and an efficient suction pump. The filtrate of approximately 1500 cc. is placed in a 3-I. round-bottomed flask and is ready for the addition of methyl /3-naphthyl ketone. 

After sampling, remove the glass stopper and stem from the impinger flask. 

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