Inorganic filtration

If the filtrate has a faint p>ermanganate colour, add a few drops of sodium bisulphite solution until the solution is colourless. In this case (compare o-chlorobenzoic acid) concentration of the solution before precipitation only increases the yield by about 1 g. and may cause occlusion of inorganic salts. 

Eor most industrial inorganic sohds such as minerals etc, the increase in with Ap is not too great, and thus should the material to be filtered be too fine for vacuum filtration, pressure filtration may be advantageous and give better rates. 

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. 

Pretreatment Chemicals Even though the suspended solids concentration of the slurry to be tested may be correct, it is frequently necessary to modify the sluriy in order to provide an acceptable filtration rate, washing rate, or final cake moisture content. The most common treatment, and one which may provide improvement in all three of these categories, is the addition of flocculating agents, either inorganic chemicals or natural or synthetic polymers. The main task at this point is to determine which is the most effective chemical and the quantity of chemical which should be used. 

Dimethyl-l,10-phenanthrolinedisulfonic acid, di-Na salt (H2O) (bathocuproine-disulfonic acid di-Na salt) [52698-84-7] M 564.5, pKEst 0 (for free acid). Inorganic salts and some coloured species can be removed by dissolving the crude material in the minimum volume of water and precipitating by adding EtOH. Purified reagent can be obtained by careful evapn of the filtrate. 

Ash content (DIN 52 005). Unwanted presence of inorganic impurities due to incorrect filtration of neutralization residues and rust contaminants is undesirable because may contribute to premature ageing. Ash determination provides some interesting information. In general, most resins have ash content lower than 0.1%. 

White, D.A., Assabumrungrat, S., Puttick, S., Sizing of inorganic micro filtration monoliths for water and air purification, Trans.of the IChemE, V.73B, pp. 108-114, 1995. 

A solution of 3jS-hydroxy-5a-androstan-17-one tosylate (193, 60 mg) in tetrahydrofuran (10 ml, freshly distilled from lithium aluminum hydride) is added dropwise to a boiling suspension of lithium aluminum deuteride (60 mg) in tetrahydrofuran (10 ml). The resulting suspension is heated under reflux for 30 min and after cooling the excess reagent is decomposed by the careful addition of a few drops of water. The heating is continued for a few minutes to coagulate the inorganic salts which are removed by filtration... 

A mixture of 6/l-chloroandrost-4-ene-3/ ,17/l-diol dibenzoate (223 1.5 g) and lithium aluminum deuteride (0.5 g) in anhydrous ether (75 ml) is heated under reflux for 2 hr and then stirred overnight at room temperature. The excess hydride is decomposed by the careful addition of saturated sodium sulfate solution, and the inorganic salts are removed by filtration and washed with... 

The reactions are generally run at room temperature or below. With steroids the product is usually isolated by addition of the reaction mixture to water followed by filtration or extraction. The inorganic product of the reaction, chromium III, is soluble in neutral or aqueous acid solutions and can be removed by washing. When steroidal amines are oxidized, the work-up is usually modified such that the steroid may be extracted from the insoluble basic chromium III salts. °... 

The dry tosylhydrazone (20 g, 45.5 mmol) is dissolved in 750 ml of 1,2-dimethoxyethane (freshly distilled from lithium aluminum hydride) in a flame-dried 1 liter round bottom flask fitted with a 240 ml addition funnel, a drierite tube and a magnetic stirrer. A 2.05 M ether solution of methyllithium (130 ml, Alfa Inorganics, Inc.—Caution to avoid the mineral oil impurity the methyllithium solution is decanted from a cold solution which contains a precipitate) is placed in the dropping funnel and added over a 60 min period. The temperature of the reaction mixture increases to ca. 35° during the addition however, no cooling precautions are required. The highly colored reaction mixture is stirred for 7 hr and then poured into 1.5 liters of ice water. The flocculent precipitate is digested for 12 hr at room temperature to speed the filtration. After filtration the filter cake is washed with 500 ml water and dried under vacuum at 50° for several hr. The androsta-5,16-dien-3l5-ol is obtained in ca. 70% yield after recrystallization from methanol mp 138-139°. 

To a solution of 2a-bromo-5a-cholestan-3-one (7.1 g, 15.2 mmol) in 175 ml dry acetone is added dropwise a solution of potassium ethyl xanthate (2.6 g, 16.2 mmol) in 90 ml acetone. The reaction mixture is stirred at 20° for 12 hr and then evaporated to dryness under vacuum. The resulting solid is treated with 100 ml hexane to dissolve the organic material and the inorganic salts are removed by filtration. The hexane filtrate is concentrated under vacuum and the resulting yellow solid ca. 7.5 g) is crystallized from chloroform-ethanol to give the xanthate (137) as white needles, ca. 5 g mp 114-115°. 

Reduction of 6p, 9-Oxidoprogesterone to 9-Hydroxyprogesterone. Zinc powder Note 2) (4. g) is added in small portions to a solution of 2 g of 6)5,19-oxidoprogesterone in 40 ml glacial acetic acid Note i). The mixture is stirred for 40 min, then an additional 4 g zinc is added and stirring is continued for another 40 min at 30°. The cooled solution is filtered, the inorganic residue washed with methanol and the filtrate evaporated under reduced pressure. The resultant crude product is dissolved in 60 ml of chloroform and filtered. Concentrated hydrochloric acid (0.6 ml) is added and the solution stirred for 10 min at 25°. The reaction mixture is diluted with ether, washed successively with water, sodium bicarbonate solution and again with water, dried and evaporated under reduced pressure. The... 

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