Charcoal activated

Activated charcoal is ultrafinely divided carbon with lots of places to suck up big, huge, polar, colored impurity molecules. Unfortunately, if you use too much, it ll suck up your product And, if your product was white, or yellow, it ll have a funny gray color from the excess charcoal. Sometimes, the impurities are untouched and only the product gets absorbed. Again, it s a matter of trial and error. Try not to use too much. Suppose you ve got a hot solution of some solid, and the solution is highly colored. Well, 

make sure your product should not be colored  

Take the flask with your filthy product off the heat and swirl the flask. 

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Fig. XVII-29. Nitrogen isotherms the volume adsorbed is plotted on an arbitrary scale. The upper scale shows pore radii corresponding to various relative pressures. Samples A, Oulton catalyst B, bone char number 452 C, activated charcoal F, Alumina catalyst F12 G, porous glass S, silica aerogel. (From Ref. 196).

Indoleacetic acid In a 1-litre flask, fitted with a reflux condenser, place a solution of 35 2 g. of sodium cyanide in 70 ml. of water, then add 25 g. of gramine and 280 ml. of 95 per cent, ethanol. Reflux the mixture (steam bath) for 80 hours. Dilute the cooled reaction mixture with 35 ml. of water, shake with a little activated charcoal (e.g., Norit), filter and concentrate to about 350 ml. imder reduced pressure (water pump) in order to remove most of the alcohol. Cool to about 5°, filter off the solid and wash it with a little cold water keep the filtrate (A). Recrystallise the solid from alcohol-ether to give 5-0 g. of 3-indoleacetamide, m.p. 150-151°. 

For other adsorptives the experimental evidence, though less plentiful than with nitrogen, supports the view that at a given temperature the lower closure point is never situated below a critical relative pressure which is characteristic of the adsorptive. Thus, for benzene at 298 K Dubinin noted a value of 017 on active carbons, and on active charcoals Everett and Whitton found 0-19 other values, at 298 K, are 0-20 on alumina xerogel, 0-20-0-22 on titania xerogel and 017-0-20 on ammonium silicomolybdate. Carbon tetrachloride at 298 K gives indication of a minimum closure point at 0-20-0-25 on a number of solids including... 

Many municipal water sources are chlorinated and contain sufficiently high levels of chlorine so as to be toxic to aquatic life. Chlorine can be removed by passing the water through activated charcoal filters or through the use of sodium thiosulfate metered into the incoming water. Municipal water is usually not used in aquaculture operations that utilize large quantities of water, either continuously or periodically, because of the initial high cost of the water and the cost of pretreatment to remove chlorine. 

Hydrogen sulfide has traditionally been a problem in the tarnishing of silver and the discoloration of bronze patinas. This gas can be dealt with in the filters of the climate-control system as well as through the use of proper absorbing agents. For example, a paper treated with activated charcoal is fabricated especially for absorbing H2S within a microclimate. 

Natural gas Hquids are recovered from natural gas using condensation processes, absorption (qv) processes employing hydrocarbon Hquids similar to gasoline or kerosene as the absorber oil, or soHd-bed adsorption (qv) processes using adsorbants such as siHca, molecular sieves, or activated charcoal. Eor condensation processes, cooling can be provided by refrigeration units which frequently use vapor-compression cycles with propane as the refrigerant or by... 

Castor oil may be obtained by cold expression of the decorticated seed. The oil is steamed under vacuum to eliminate odors and coagulate the toxic albumin. Fuller s earth or activated charcoal may be used for further purification. 

The rationale for the development of such fibers is demonstrated by their appHcation in the medical field, notably hemoperfusion, where cartridges loaded with activated charcoal-filled hoUow fiber contact blood. Low molecular weight body wastes diffuse through the fiber walls and are absorbed in the fiber core. In such processes, the blood does not contact the active sorbent direcdy, but faces the nontoxic, blood compatible membrane (see Controlled RELEASE TECHNOLOGY, pharmaceutical). Other uses include waste industrial appHcations as general as chromates and phosphates and as specific as radioactive/nuclear materials. 

Potassium Graphite. Potassium, mbidium, and cesium react with graphite and activated charcoal to form intercalation compounds CgM, C24M, C gM, C gM, and C qM (61,62). Potassium graphite [12081 -88-8] 8 P gold-colored flakes, is prepared by mixing molten potassium with graphite at 120—150°C. 

Ma.nufa.cture. The preparation of sulfuryl chloride is carried out by feeding dry sulfur dioxide and chlorine into a water-cooled glass-lined steel vessel containing a catalyst, eg, activated charcoal. Alternatively, chlorine is passed into Hquefted sulfur dioxide at ca 0°C in the presence of a dissolved catalyst, eg, camphor, a terpene hydrocarbon, an ether, or an ester. The sulfuryl chloride is purified by distillation the commercial product is typically 99 wt % pure, as measured by ASTM distillation method D850. 

Composition and Methods of Manufacture. The vaccine consists of a mixture of purified capsular polysaccharides from 23 pneumococcal types that are responsible for over 90% of the serious pneumococcal disease in the world (47,48). Each of the polysaccharide types is produced separately and treated to remove impurities. The latter is commonly achieved by alcohol fractionation, centrifugation, treatment with cationic detergents, proteolytic en2ymes, nucleases or activated charcoal, diafiltration, and lyophili2ation (49,50). The vaccine contains 25 micrograms of each of the types of polysaccharide and a preservative such as phenol or thimerosal. 

Various types of detector tubes have been devised. The NIOSH standard number S-311 employs a tube filled with 420—840 p.m (20/40 mesh) activated charcoal. A known volume of air is passed through the tube by either a handheld or vacuum pump. Carbon disulfide is used as the desorbing solvent and the solution is then analyzed by gc using a flame-ionization detector (88). Other adsorbents such as siUca gel and desorbents such as acetone have been employed. Passive (diffuse samplers) have also been developed. Passive samplers are useful for determining the time-weighted average (TWA) concentration of benzene vapor (89). Passive dosimeters allow permeation or diffusion-controlled mass transport across a membrane or adsorbent bed, ie, activated charcoal. The activated charcoal is removed, extracted with solvent, and analyzed by gc. Passive dosimeters with instant readout capabiUty have also been devised (85). 

Heating a mixture of tetrachloroethane vapors and chlorine over active charcoal at 400°C gives carbon tetrachloride and hydrogen chloride (125). Miscellaneous. Air oxidation of 1,1,2,2-tetrachloroethane under ionizing radiation gives dichloroacetyl chloride (117). Contact of... 

Ethyl Acetate. Catalysts proposed for the vapor-phase production of ethyl acetate include siUca gel, zirconium dioxide, activated charcoal, and potassium hydrogen sulfate. More recendy, phosphoric-acid-treated coal (65) and calcium phosphate (66) catalysts have been described. 

Charcoal is generally satisfactorily activated by heating gently to red heat in a crucible or quartz beaker in a muffle furnace, finally allowing to cool under an inert atmosphere in a desiccator. Good commercial activated charcoal is made from wood, e.g. Norit (from Birch wood), Darco and Nuchar. If the cost is important then the cheaper animal charcoal (bone charcoal) can be used. However, this charcoal contains calcium phosphate and other calcium salts and cannot be used with acidic materials. In this case the charcoal is boiled with dilute hydrochloric acid (1 1 by volume) for 2-3h, diluted with distilled water and filtered through a fine grade paper on a Buchner flask, washed with distilled water until the filtrate is almost neutral, and dried first in air then in a vacuum, and activated as above. To improve the porosity, charcoal columns are usually prepared in admixture with diatomaceous earth. 

Because of their selectivity, molecular sieves offer advantages over silica gel, alumina or activated charcoal, especially in their very high affinity for water, polar molecules and unsaturated organic compounds. Their relative efficiency is greatest when the impurity to be removed is present at low concentrations. Thus, at 25° and a relative humidity of 2%, type 5A molecular sieves adsorb 18% by weight of water, whereas for silica gel and alumina the figures are 3.5 and 2.5% respectively. Even at 100° and a relative humidity of 1.3% molecular sieves adsorb about 15% by weight of water. 

Acetamide [60-35-5] M 59.1, m 81 , pK -1.4, pKl +0.37. Crystd by soln in hot MeOH (0.8mL7g), diltd with Et20 and allowed to stand [Wagner J Chem Educ 7 1135 1930]. Alternate cry sms are from acetone, benzene, chloroform, dioxane, methyl acetate or from benzene-ethyl acetate mixture (3 1 and 1 1). It has also been recrystd from hot water after treating with HCl-washed activated charcoal (which had been... 

Aminomalononitrile toluene-4-sulfonate [5098-14-6] M 253.4, m 168-170 , 172 (dec), pKe 1.3. Colourless crysts on recrystn from MeCN (1.8g in lOOmL) using activated charcoal. Wash the crystals with dry Et20 and dry at 25 /lmm. Recovery of -80%. [Ferris et al. Org Synth Coll Vol V 32 7973.]... 

Aminophenol [95-55-6] M 109.1, m 175-176 , pKj 4.65, pKj 9.75. Purified by soln in hot water, decolorised with activated charcoal, filtered and cooled to induce crystn. Maintain an atmosphere of N2 over the hot phenol soln to prevent its oxidation [Charles and Preiser J Am Chem Soc 74 1385 7952]. Can also be crystd from EtOH. 

Carbon tetrafluoride [75-73-0] M 88.0, b -15 . Purified by repeated passage over activated charcoal at solid-C02 temperatures. Traces of air were removed by evacuating while alternately freezing and melting. Alternatively, liquefied by cooling in liquid air and then fractionally distilled under vacuum. (The chief impurity originally present was probably CF3CI). 

Refluxed with activated charcoal in CHjClj, followed by recrystn from diethyl ether/pet ether or pet ether [Koolar and Kochi J Org Chem 52 4545 1987]. 

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