Mercury filtration

Coarse 40-60 Filtration of coarse materials. Gas dispersion, gas washing, gas absorption. Mercury filtration. For extraction apparatus. 

Type C filtering coarse materials mercury filtration. Type M gas dispersion salt bridges Type F salt bridges. 

Blocking or contamination of the dropping mercury electrode c q>illary is prevented only by using mercury of the highest degree of purity. Mercury should be transferred to ftie electrode reservoir through a pin hole in the cone of a No. 40 Whatman filter paper. The filter paper should be cleaned and unmarked at the end of the mercury filtration. 

In the previous classical modelling, the elements mentioned above were supposed to be independent. At present, it is obvious that this assumption leads to a distortion in description of various processes occurring in porous solids, such as desorption of sorbate, intrusion of mercury, filtration, molecular-sieve adsorption. Por this reason, modelling of the primary elements may be considered as the first step, which is necessary though insufficient. The second step must be the modelling of interconnection between the elements. At present, it is conducted by the network models, and processes in them — by percolation theory (refs.4-7) ... 

Place a mixture of 53 g. of A.R. lactic acid (85-88 per cent, acid), 75 g. (85-5 ml.) of commercial anhydrous isopropyl alcohol, 300 ml. of benzene and 20 g. of Zeo-Karb 225/H (1) in a 700 ml. bolt-head flask, equipped with an automatic water separator (e.g., a large modified Dean and Stark apparatus with a stopcock at the lower end, see Fig. Ill, 126, 1) carrying an efficient reflux condenser at its upper end, and a mercury-sealed stirrer (alternatively, the hquid-sealed stirrer shown in Fig. 11,7,11, c. may be used). Reflux the mixture, with stirring, on a steam bath for 5 hours or until water no longer collects in appreciable amount in the water separator run off the water from time to time. Filter off the resin at the pump and wash it with two 25 ml. portions of benzene. Shake the combined filtrate and washings with about 5 g. of precipit-ated calcium... 

Equip a 1 Utre three-necked flask or a 1 litre bolt- head flask with a reflux condenser and a mercury-sealed stirrer. Dissolve 50-5 g. of commercial 2 4-dinitro-l-chlorobenzene in 250 ml. of rectified spirit in the flask, add the hydrazine solution, and reflux the mixture with stirring for an hour. Most of the condensation product separates during the first 10 minutes. Cool, filter with suction, and wash with 50 ml. of warm (60°) rectified spirit to remove unchanged dinitrochlorobenzene, and then with 50 ml. of hot water. The resulting 2 4-dinitrophenylhydrazine (30 g.) melts at 191-192° (decomp.), and is pure enough for most purposes. Distil oflF half the alcohol from the filtrate and thus obtain a less pure second crop (about 12 g.) recrystallise this from n-butyl alcohol (30 ml. per gram). If pure 2 4-dinitrophenylhydrazine is required, recrystallise the total yield from n-butyl alcohol or from dioxan (10 ml. per gram) this melts at 200° (decomp.). 

The purified commercial di-n-butyl d-tartrate, m.p. 22°, may be used. It may be prepared by using the procedure described under i o-propyl lactate (Section 111,102). Place a mixture of 75 g. of d-tartaric acid, 10 g. of Zeo-Karb 225/H, 110 g. (136 ml.) of redistilled n-butyl alcohol and 150 ml. of sodium-dried benzene in a 1-litre three-necked flask equipped with a mercury-sealed stirrer, a double surface condenser and an automatic water separator (see Fig. Ill, 126,1). Reflux the mixture with stirring for 10 hours about 21 ml. of water collect in the water separator. FUter off the ion-exchange resin at the pump and wash it with two 30-40 ml. portions of hot benzene. Wash the combined filtrate and washings with two 75 ml. portions of saturated sodium bicarbonate solution, followed by lOu ml. of water, and dry over anhydrous magnesium sulphate. Remove the benzene by distillation under reduced pressure (water pump) and finally distil the residue. Collect the di-n-butyl d-tartrate at 150°/1 5 mm. The yield is 90 g. 

Fine 4-5.5 Filtration of fine precipitates. As a mercury valve. In extraction apparatus. 

Magnesium haUde and alkyl magnesium haUde precipitate and the alkyl magnesium compound remains in solution. Filtration (qv) followed by drying the filtrate yields soHd magnesium alkyl (11). Another preparation method is that of metal exchange using mercury alkyl in ether. 

The mercury contained in the mother Hquid and washings of either method is recovered by treatment with sodium hydroxide solution. Yellow mercuric oxide is precipitated and filtered. The filtrate is treated further to remove the last traces of mercury before it is discarded. 

Problems of removal of mercury from aqueous effluents are more comphcated in plants that manufacture a variety of inorganic and organic mercury compounds it is generally best to separate the effluent streams of inorganic and organic mercurials. When phenyhnercuric acetate is precipitated from its solution in acetic acid by addition of water, the filtrate is collected and reused for the next precipitation. This type of recycling is necessary not only for economic reasons but also to minimise recovery operations. 

Purified via the mercury salt [see Kern J Am Chem Soc 75 1865 1953], which was crystd from benzene as needles (m 121°), and then dissolved in CHCI3. Passage of H2S gas regenerated the mercaptan. The HgS ppte was filtered off, and washed thoroughly with CHCI3. The filtrate and washings were evaporated to remove CHCI3, then residue was fractionally distd under reduced pressure [Mackle and McClean, Trans Faraday Soc 58 895 1962]. 

A 500-ml three-necked flask is fitted with a mechanical stirrer, a thermometer, a gas outlet, and a gas inlet tube dipping into the solution. The flask is charged with a solution of cyanuric acid (15 g, 0.116 mole) dissolved in 300 ml of 5% aqueous potassium hydroxide solution. The flask is cooled in an ice-salt bath with stirring to 0° and irradiated with a mercury lamp. A rapid stream of chlorine is passed into the flask (approx. 5 ml/sec), whereupon a heavy white precipitate forms. The addition of gas is continued until the solid material no longer forms (approx. 2 hours). The flask is briefly flushed with air, the product is collected by suction filtration in an ice-cooled funnel, and the residue washed with several small portions of cold water. Since it undergoes slow hydrolysis, the product should be dried in a vacuum oven. The crude product has a variable melting point (195-225°) the yield is about 20 g (approx. 75%). 

Bromo-2 -(3"-dimethylaminopropyl)-amino4 potassium carbonate (5 g) and copper powder (0.4 g). It is then heated under reflux for 4B hours, cooled, and the insoluble matter filtered off. After washing with dimethylformamide (20 cc), the filtrate is taken up in distilled water (200 cc). The base formed is extracted with ether (3 times with 50 cc), the ethereal solution is dried over sodium sulfate, the ether driven off on a water-bath and the residue distilled. In this way there is obtained 3ethereal hydrogen chloride on the base dissolved in acetone this hydrochloride melts at 180°C. 

A mixture of 20 g (0.1 mol) of 1 -azaphenothiazine, 4.3 g (0.11 mol) of sodamide and 300 ml of dry toluene is stirred and refluxed for eight hours. A slow stream of dry nitrogen gas is used to sweep out the ammonia as formed. The mixture is cooled and 110 ml of a 1 M solution of 3-dimethylaminopropyl chloride in toluene is added dropwise, with stirring. Subsequently, the mixture is stirred and refluxed for fifteen hours, cooled, and concentrated in vacuo. The viscous residue is refluxed with 500 ml of chloroform and filtered hot. The chloroform filtrate is treated with activated charcoal and again filtered. The filtrate is concentrated and the residue distilled to give about 19.B g (69% yield) of product, an oil distilling at about 195 C to 19B°C (under 0.5 mm pressure of mercury). 

Preparation of 3 5-diiodo-4-(4 -hydroxyphenoxy)phenylacetic acid (diac) A solution of ethyl 3 5-diiodo-4-(4 -methoxyphenoxy)phenyl acetate (9.5 g) in acetic acid (60 ml) was heated under reflux with hydriodic acid (SG 1.7, 50 ml) and red phosphorus (0.5 g) for 1 hour. The hot solution was filtered and the filtrate concentrated at 50°C and 15 mm of mercury to above 20 ml. The residue was treated with water (70 ml) containing a little sodium thiosulfate to decolorize the product. The solid was collected by filtration and purified by the method of Harington and Pitt-Rivers [Biochem. J. (1952), Vol. 50, page 438]. Yield 8,36 g (95%). After crystallization from 70% (v/v) acetic acid it melted at 219°C. 

Pipette 25.0 mL of the potassium ion solution (about 10 mg K + ) into a 50 mL graduated flask, add 0.5 mL 1M nitric acid and mix. Introduce 20.0 mL of the sodium tetraphenylborate solution, dilute to the mark, mix, then pour the mixture into a 150mL flask provided with a ground stopper. Shake the stoppered flask for 5 minutes on a mechanical shaker to coagulate the precipitate, then filter most of the solution through a dry Whatman No. 40 filter paper into a dry beaker. Transfer 25.0 mL of the filtrate into a 250 mL conical flask and add 75 mL of water, 1.0 mL of iron(III) nitrate solution, and 1.0 mL of sodium thiocyanate solution. Titrate with the mercury(II) nitrate solution as described above. 

B. Amalgamated, Zinc [Mercury alloy (Hg, Zn)]. Zinc powder (206 g., 3.15 moles) is placed in a 1-1. beaker, covered with 250 ml. of aqueous 10% hydrochloric acid, and stirred for 2 minutes. The acid is then decanted and replaced by distilled water, the mixture is stirred, and the supernatant is decanted. Washing is continued in this way until the water is neutral to litmus. A warm solution of 40 g. (0.15 mole) of mercuric chloride [Mercury chloride (HgCl2)] in 250 ml. of distilled water is then poured onto the zinc, and the mixture is stirred gently for 10 minutes. After filtration, the powder is washed with 250 ml. of distilled water, five 250-ml. portions of 95% ethanol, and five 250-ml. portions of anhydrous ether. Drying under vacuum gives 196 g. of zinc amalgam. 

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