Extraction stopper

It is possible to place a soil sample in an Erlenmeyer flask or other suitable container, add the desired extractant, stopper and shake for a specified period of time, filter, and analyze the extract for the analyte of interest. For an example of this type of extraction, see Procedure 12.1.4 The extract obtained from the simple extraction of 10 g of soil with water using a magnetic stirrer is shown in the right-hand flask in Figure 12.4 (see also Section 12.2.2). 

Without delay measure the odinction against a cell containing 90% acetone at 4500 A (Ei). Add one small drop (ca. 0.02 ml) of concentrated hydrochloric acid to the extract, stopper the cell, and invert it several times to mix the acid and acetone. Re-read the extinction immediately at 4500 A (E ) (Note c). 

Mix 50 ml. of formalin, containing about 37 per cent, of formaldehyde, with 40 ml. of concentrated ammonia solution (sp. gr. 0- 88) in a 200 ml. round-bottomed flask. Insert a two-holed cork or rubber stopper carrying a capillary tube drawn out at the lower end (as for vacuum distillation) and reaching almost to the bottom of the flask, and also a short outlet tube connected through a filter flask to a water pump. Evaporate the contents of the flask as far as possible on a water bath under reduced pressure. Add a further 40 ml. of concentrated ammonia solution and repeat the evaporation. Attach a reflux condenser to the flask, add sufficient absolute ethyl alcohol (about 100 ml.) in small portions to dissolve most of the residue, heat under reflux for a few minutes and filter the hot alcoholic extract, preferably through a hot water fuimel (all flames in the vicinity must be extinguished). When cold, filter the hexamine, wash it with a little absolute alcohol, and dry in the air. The yield is 10 g. Treat the filtrate with an equal volume of dry ether and cool in ice. A fiulher 2 g. of hexamine is obtained. 

Benzoates. Dissolve 0-5 g. of the amino acid in 10 ml. of 10 per cent, sodium bicarbonate solution and add 1 g. of benzoyl chloride. Shake the mixture vigorously in a stoppered test-tube remove the stopper from time to time since carbon dioxide is evolved. When the odour of benzoyl chloride has disappeared, acidify with dilute hydrochloric acid to Congo red and filter. Extract the solid with a little cold ether to remove any benzoic acid which may be present. RecrystaUise the benzoyl derivative which remains from hot water or from dilute alcohol. 

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. 

Equip a 500 ml. three-necked flask with a powerful mechanical stirrer and a separatory funnel leave the third neck open or loosely stoppered. Introduce, while the flask is cooled in a freezing mixture of ice and salt, 90 ml. of concentrated ammonia solution (sp. gr. 0 -88) and 54 g. (43 ml.) of pure (e.g., A.R.) carbon disulphide. Stir the mixture and run in 56 g. (55ml.)of pure aniline from the separatory funnel during about 20minutes stir for a further 30 minutes, and allow to stand for another 30 minutes. A heavy precipitate of ammonium phenyldithiocarbamate separates. Transfer the salt to a 5 litre round-bottomed flask by four extractions with 200 ml. portions of water. Add to the resulting solution, with... 

Method 2. Place a 3 0 g. sample of the mixture of amines in a flask, add 6g. (4-5 ml.) of benzenesulphonyl chloride (or 6 g. of p-toluenesulphonyl chloride) and 100 ml. of a 5 per cent, solution of sodium hydroxide. Stopper the flask and shake vigorously until the odour of the acid chloride has disappeared open the flask occasionally to release the pressure developed by the heat of the reaction. AUow the mixture to cool, and dissolve any insoluble material in 60-75 ml. of ether. If a solid insoluble in both the aqueous and ether layer appears at this point (it is probably the sparingly soluble salt of a primary amine, e.g., a long chain compound of the type CjH5(CH2) NHj), add 25 ml. of water and shake if it does not dissolve, filter it off. Separate the ether and aqueous layers. The ether layer will contain the unchanged tertiary amine and the sulphonamide of the secondary amine. Acidify the alkaline aqueous layer with dilute hydrochloric acid, filter off the sulphonamide of the primary amine, and recrystaUise it from dilute alcohol. Extract the ether layer with sufficient 5 per cent, hydrochloric acid to remove all the tertiary amine present. Evaporate the ether to obtain the sulphonamide of the secondary amine recrystaUise it from alcohol or dilute alcohol. FinaUy, render the hydrochloric acid extract alkaline by the addition of dilute sodium hydroxide solution, and isolate the tertiary amine. 

To a mixture of 10 g. of the compound and 3-5 ml. of 33 per cent, sodium hydroxide solution in a test-tube, add 2-5 ml. of 50 per cent, chloroacetic acid solution. If necessary, add a little water to dissolve the sodium salt of the phenol. Stopper the test-tube loosely and heat on agently-boiling water bath for an hour. After cooling, dilute with 10 ml. of water, acidify to Congo red with dilute hydrochloric acid, and extract with 30 ml. of ether. Wash the ethereal extract with 10 ml, of water, and extract the aryloxyacetic acid b shaking with 25 ml. of 5 per cent, sodium carbonate solution. Acidify the sodium carbonate extract (to Congo red) with dilute hydrochloric acid, collect the aryloxyacetic acid which separates, and recrystallise it from hot water. 

Place 45 g. (43 ml.) of benzal chloride (Section IV,22), 250 ml. of water and 75 g. of precipitated calcium carbonate (1) in a 500 ml. round-bottomed flask fltted with a reflux condenser, and heat the mixture for 4 hours in an oil bath maintained at 130°. It is advantageous to pass a current of carbon dioxide through the apparatus. Filter off the calcium salts, and distil the filtrate in steam (Fig. II, 40, 1) until no more oil passes over (2). Separate the benzaldehyde from the steam distillate by two extractions with small volumes of ether, distil off most of the ether on a water bath, and transfer the residual benzaldehyde to a wide-mouthed bottle or flask. Add excess of a concentrated solution of sodium bisulphite in portions with stirring or shaking stopper the vessel and shake vigorously until the odour of benzaldehyde can no longer be detected. Filter the paste of the benzaldehyde bisulphite compound at the pump... 

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 the simplest case, the feed solution consists of a solvent A containing a consolute component C, which is brought into contact with a second solvent B. Eor efficient contact there must be a large interfacial area across which component C can transfer until equiHbrium is reached or closely approached. On the laboratory scale this can be achieved in a few minutes simply by hand agitation of the two Hquid phases in a stoppered flask or separatory fuimel. Under continuous flow conditions it is usually necessary to use mechanical agitation to promote coalescence of the phases. After sufficient time and agitation, the system approaches equiHbrium which can be expressed in terms of the extraction factor S for component C ... 

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