Filtration of strongly alkaline solution

API Filtration. A filter press is used to determine the wall building characteristics of mud. The press consists of a cylindrical mud chamber made of materials resistant to strongly alkaline solutions. A filler paper is placed on the bottom of the chamber just above a suitable support. The filtration area is 7.1 ( 0.1) in.-. Below the support is a drain tube for discharging the filtrate into a graduate cylinder. The entire assembly is supported by a stand so that a 100-psi pressure can be applied to the mud sample in the chamber. At the end of the 30-min filtration time volume of filtrate is reported as API filtration in milliliters. To obtain correlative results, one thickness of the proper 9-cm filter paper, Whatman No. 50, S S No. 5765, or the equivalent, must be used. 

Care must be taken with both sintered glass and porous base crucibles to avoid attempting the filtration of materials that may clog the filter plate. A new crucible should be washed with concentrated hydrochloric acid and then with distilled water. The crucibles are chemically inert and are resistant to all solutions which do not attack silica they are attacked by hydrofluoric acid, fluorides, and strongly alkaline solutions. 

Excess calcium hydroxide is precipitated by usiag carbon dioxide and the calcium carbonate, calcium hydroxide, and calcium phosphite are removed by filtration. The filtered solution is treated with an equivalent amount of sodium sulfate or sodium carbonate to precipitate calcium sulfate or carbonate. Sodium hypophosphite monohydrate [10039-56-2] is recovered upon concentration of the solution. Phosphinic acid is produced from the sodium salt by ion exchange (qv). The acid is sold as a 50 wt %, 30—32 wt %, or 10 wt % solution. The 30—32 wt % solution is sold as USP grade (Table 12) (63). Phosphinic acid and its salts are strong reduciag agents, especially ia alkaline solution (65). 

OC-Hydroxycarboxylic Acid Complexes. Water-soluble titanium lactate complexes can be prepared by reactions of an aqueous solution of a titanium salt, such as TiCl, titanyl sulfate, or titanyl nitrate, with calcium, strontium, or barium lactate. The insoluble metal sulfate is filtered off and the filtrate neutralized using an alkaline metal hydroxide or carbonate, ammonium hydroxide, amine, or alkanolamine (78,79). Similar solutions of titanium lactate, malate, tartrate, and citrate can be produced by hydrolyzation of titanium salts, such as TiCl, in strongly (>pH 10) alkaline water isolation of the... 

A solution containing 741 g (5.0 mols) of 1-phenyl-2-propylidenylhydrazine, 300 g (5.0 mols) of glacial acetic acid and 900 cc of absolute ethanol was subjected to hydrogenation at 1,875 psi of hydrogen in the presence of 10 gof platinum oxide catalyst and at a temperature of 30°C to 50°C (variation due to exothermic reaction). The catalyst was removed by filtration and the solvent and acetic acid were distilled. The residue was taken up In water and made strongly alkaline by the addition of solid potassium hydroxide. The alkaline mixture was extracted with ether and the ether extracts dried with potassium carbonate. The product was collected by fractional distillation, BP B5°C (0.30 mm) yield 512 g (68%). 

B. 2-Bromoallylatnine. Crude 2-bromoallylhexaminium bromide (204 g., 0.60 mole) is dissolved in a warm solution prepared from 400 ml. of water, 2 1. of ethanol, and 480 ml. (S.8 moles) of 121V hydrochloric acid. A white precipitate of ammonium chloride forms within an hour. The reaction mixture is allowed to stand for 24 hours, and the precipitate is removed by suction filtration. The mother liquor is concentrated to a volume of 600 ml. (Note 3), and the precipitate (Note 4) is removed by suction filtration. The mother liquor is evaporated to dryness (Note 5), and the residue is dissolved in 300 ml. of water. The solution is cooled in an ice bath and made strongly alkaline (pH 13) with 6N sodium hydroxide solution. 

Some agrochemicals bind strongly to the soil component as bound residues, which cannot be extracted without vigorous extraction procedures. In this case, an acidic (e.g., hydrochloric acid, sulfuric acid) or alkaline solution (e.g., sodium hydroxide, potassium hydroxide) can be used as an extraction solvent, and also heating may be effective in improving the extraction of the residues. Analytical procedures after the extraction are the same as above, but a filtration procedure may be troublesome in some of these situations. However, these procedures are rare exceptions or are needed for specific chemicals that are stable under such harsh extraction conditions. 

Desoxycholic Acid, Fatty Acids, Cholesterol.—The first alcoholic filtrate obtained during the crystallisation of the cholic acid (see above) is made strongly alkaline to phenolphthalein paper with 2 N-sodium hydroxide solution and concentrated to a syrupy consistency in a porcelain basin on the water bath. The syrup is taken up in 250 c.c. of water, transferred to a separating funnel, cooled, covered... 

Support a 1-litre three-necked flask, equipped with a sealed stirrer unit and a reflux condenser, on a water bath, and place a solution of 65 g of sodium hydroxide in 150 ml of water, 50 g (41.5 ml, 0.41 mol) of pure nitrobenzene and 500 ml of methanol in the flask. Add 59 g (0.9 mol) of zinc powder (90% purity see Section 4.2.50, p. 467) to the mixture, start the stirrer and reflux for 10 hours (1). Filter the mixture while hot, and wash the precipitate of sodium zincate with a little methanol. The strongly alkaline filtrate is not always clear render it neutral to litmus by the cautious addition of concentrated hydrochloric acid, and filter again. Distil off the methanol from the filtrate, cool the residue in ice and filter off the solid azobenzene. The crude azobenzene contains occluded zinc salts. To remove these, add the crude product to 100 ml of 2 per cent hydrochloric acid, warm to about 70 °C... 

Amides may be hydrolysed by boiling with 10 per cent sodium hydroxide solution to the corresponding acid (as the sodium salt). The alkaline solution should be acidified with dilute hydrochloric acid the liberated acid if sparingly water-soluble is isolated by filtration, otherwise any water-soluble acidic component may be isolated by extraction with ether or by distillation from the acidic aqueous solution. The procedure is illustrated by the following experimental details for benzamide. Place 1.5 g of benzamide and 25 ml of 10 per cent sodium hydroxide solution in a 100-ml conical or round-bottomed flask equipped with a reflux condenser. Boil the mixture gently for 30 minutes ammonia is freely evolved. Detach the condenser and continue the boiling in the open flask for 3-4 minutes to expel the residual ammonia. Cool the solution in ice, and add concentrated hydrochloric acid until the mixture is strongly acid benzoic acid separates immediately. Leave the mixture in ice until cold, filter at the pump, wash with a little cold water and drain well. Recrystallise the benzoic acid from hot water. 

To the reaction mixture, 125.7 g of a 15% sodium hydroxide aqueous solution was dropwise added to make the reaction mixture strongly alkaline. Then, undissolved inorganic salts were separated by filtration, and the inorganic... 

II). trans-m-Bromocinnamic acid (14.8 g), ethanol (173 ml) and concentrated sulfuric acid (0.4 ml) were combined and heated at reflux for 15 hours. About 150 ml of the ethanol was distilled off, and the remaining solution was poured into ice/water (140 ml). The cold mixture was made strongly alkaline with 40% sodium hydroxide and extracted with methylene chloride (4x60 ml). The combined methylene chloride extract was dried over anhydrous potassium carbonate. The potassium carbonate was removed by filtration and the solvent stripped off under reduced pressure. trans-ethyl-3-Bromocinnamate, was obtained as a partially solidified oil. (IR spectrum was consistent with this compound). 

The mixture was extracted with two 100 cc portions of 2N hydrochloric acid solution. The acid solution was made strongly alkaline with 40% potassium hydroxide solution and the oil which separated was taken into ether. The ether solution was washed with two 100 cc portions of water saturated with sodium chloride, and then dried over anhydrous sodium sulfate for 3 hours. The sodium sulfate was removed by filtration and the ether by distillation. Distillation of the residual oil gave a colorless liquid, BP 155°-157°C/3mm. 

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