Swirl concentrator

Physical, as against biological, treatment is more effective at handling the highly variable flow rates and concentrations of stormwaters. The costs and effectiveness of different physical treatment systems for removal of suspended solids are illustrated in Table 6.10. The latter will approximate the lead removal efficiencies, for which no data are available. The swirl concentrator is clearly the most cost effective and it is currently undergoing development in the US. In this system a circular movement imparted on the inflow water concentrates the solids in a small volume of water which is separated off and can be directed to... 

Place 100 g. of adipic acid in a 750 ml. round-bottomed flask and add successively 100 g. (127 ml.) of absolute ethyl alcohol, 250 ml. of sodium-dried benzene and 40 g. (22 ml.) of concentrated sulphuric acid (the last-named cautiously and with gentle swirling of the contents of the flask). Attach a reflux condenser and reflux the mixture gently for 5-6 hours. Pour the reaction mixture into excess of water (2-3 volumes), separate the benzene layer (1), wash it with saturated sodium bicarbonate solution until eflfervescence ceases, then with water, and dry with anhydrous magnesium or calcium sulphate. Remove most of the benzene by distillation under normal pressure until the temperature rises to 100° using the apparatus of Fig. II, 13, 4 but substituting a 250 ml. Claisen flask for the distilling flask then distil under reduced pressure and collect the ethyl adipate at 134-135°/17 mm. The yield is 130 g. 

Dissolve 180 g. of commercial ammonium carbonate in 150 ml. of warm water (40-50°) in a 700 ml. flask. Cool to room temperature and add 200 ml. of concentrated ammonia solution (sp. gr. 0 88). Introduce slowly, with swirling of the contents of the flask, a solution of 50 g. of chloroacetic acid (Section 111,125) in 50 ml. of water [CAUTION do not allow chloroacetic acid to come into contact with the skin as unpleasant burns will result]. Close the flask with a solid rubber stopper and fix a thin copper wire to hold the stopper in place do not moisten the portion of the stopper in contact with the glass as this lubrication will cause the stopper to slide out of the flask. Allow the flask to stand for 24-48 hours at room temperature. Transfer the mixture to a distilling flask and distil in a closed apparatus until the volume is reduced to 100-110 ml. A convenient arrangement is to insert a drawn-out capillary tube into the flask, attach a Liebig s condenser, the lower end of which fits into a filter flask (compare Fig.//, 1) and connect the... 

Dissolve 10 g. of sym.-tribromoaniline (Section IV,47) in 60 ml. of rectified spirit and 15 ml. of benzene in a 200 ml. bolt-head flask by heat ing on a water bath. Add, from a burette or small graduated pipette, 5-3 g. (3-5 ml.) of concentrated sulphuric acid to the hot solution and gently swirl the liquid. Attach a reflux condenser to the flask and heat on a water bath until the clear solution boils. Detach the condenser, remove the flask from the water bath, and add 3 5 g. of powdered sodium... 

In a 1-litre round-bottomed flask, fitted with a condenser and trap (compare Fig. II, 13, 8), place 62 g. (61 ml.) of aniline. Cool the flask in an ice bath, add 120 ml. of concentrated hydrochloric acid slowly, followed by 90 g. of paraldehyde swirl the contents of the flask to ensure thorough mixing. Remove the flask from the ice bath and shake it frequently at... 

Dissolve 14 g. of p-phenetidine (2) in 240 ml. of water to which 20 ml. of 5N hydrochloric acid (or 9 ml. of the concentrated acid) have been added stir the solution with about 5 g. of decolourising carbon for 5 minutes, warm, and filter the solution with suction. Transfer the cold filtered solution of p-phenetidine hydrochloride to a 700 ml. conical flask, add 13 g. (12 ml.) of acetic anhydride and swirl the contents to dissolve the anhydride. Immediately add a solution of 16 g. of crystallised sodium acetate in 50 ml. of water and stir (or swirl) the contents of the flask vigorously. Cool the reaction mixture in an ice bath, filter with suction and wash with cold water. RecrystaUise from hot water (with the addition of a little decolourising carbon, if necessary), filter and dry. The yield of pure phenacetin, m.p. 137°, is 12 g. 

In the flask were placed a solution of 7 g of anhydrous LiBr in 50 ml of dry THF, 0.40 mol of the allenic bromide (see Chapter VI, Exp. 31) and 0.50 mol of finely powdered copper(I) cyanide. The mixture was swirled by hand and the temperature rose in about 15 min to 60°C. It was kept between 55 and 60°C by occasional cooling in a water-bath. When the exothermic reaction had subsided, the flask was warmed for an additional 30 min at 55-60°C and the brown solution was then poured into a vigorously stirred solution of 30 g of NaCN and 100 g of NH,C1 in 300 ml of water, to which 150 ml of diethyl ether had been added. During this operation the temperature was kept below 20 c. The reaction flask was subsequently rinsed with the NaCN solution. After separation of the layers the aqueous layer was extracted with ether. The extracts were dried over magnesium sulfate and then concentrated... 

A suspension of sodium amide in 500 ml of anhydrous liquid artmonia was prepared from 18 g of sodium (see Chapter II, Exp. 11). To the suspension was added in 10 min with swirling a mixture of 0.30 mol of 1-chloro-l-ethynylcyclohexane (see VIII-2, Exp. 27) and 50 ml of diethyl ether. The reaction was very vigorous and a thick suspension was formed. The greater part of the ammonia was evaporated by placing the flask in a water bath at 50°C. After addition of 500 ml of ice-water the product was extracted three times with diethyl ether. The ethereal extracts were dried over anhydrous KjCOj and subsequently concentrated in a water-pum vacuum. Distillation of the residue afforded the amine, b.p. 54°C/15 mmHg, n 1.4345, in 87% yield. 

The mixture is decanted into an Erlenmeyer flask, the residual green salts are washed with two 15-ml portions of acetone, and the washings are added to the main acetone solution. Cautiously, sodium bicarbonate (approx. 13 g) is added to the solution with swirling until the pH of the reaction mixture is neutral. The suspension is filtered, and the residue is washed with 10-15 ml of acetone. The filtrate is transferred to a round-bottom flask and concentrated on a rotary evaporator under an aspirator while the flask temperature is maintained at about 50°. The flask is cooled and the residue transferred to a separatory funnel, (If solidification occurs, the residue may be dissolved in ether to effect the transfer.) To the funnel is added 100 ml of saturated sodium chloride solution, and the mixture is extracted with two 50-ml portions of ether. The ether extracts are combined, washed with several 5-ml portions of water, dried over anhydrous magnesium sulfate, and filtered into a round-bottom flask. The ether may be distilled away at atmospheric pressure (steam bath) or evaporated on a rotary evaporator. On cooling, the residue should crystallize. If it does not, it may be treated with 5 ml of 30-60° petroleum ether, and crystallization may be induced by cooling and scratching. The crystalline product is collected by filtration and recrystallized from aqueous methanol. 4-r-Butylcyclohexanone has mp 48-49° (yield 60-90 %). 

An alcohol-free solution of diazomethane in ether is prepared as in Chapter 17, Section III. This solution is approximately 0.5 M in diazomethane and may be standardized by titration as follows benzoic acid (0.6 g, approx. 0.005 mole) is weighed accurately into an Erlenmeyer flask and suspended in 5 ml of ether. The diazomethane solution (approx. 5 ml) is added from a buret with swirling, care being taken that an excess of unreacted benzoic acid remains (the yellow color of the diazomethane should be completely discharged). The excess benzoic acid is now titrated with standard 0.2 N sodium hydroxide solution, and the concentration of diazomethane is calculated. 

If the white solid fails to separate after 15-30 minutes, concentrated sulfuric acid is added in 4-ml. portions to the cooled solution with swirling until the white solid appears. 

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