Carbon tetrachloride activity

Ignition Temperature of Granular Activated Carbon Carbon Tetrachloride Activity of Activated Carbon Ball-Pan Hardness of Activated Carbon... 

De Toranzo EG, Diaz Gomez Ml, Castro JA. 1978a. Carbon tetrachloride activation, lipid peroxidation and liver necrosis in different strains of mice. Res Common Chem Pathol Pharmacol 19 347- 352. 

Homolytic cleavage of covalent bonds is an alternative means of generating free radicals. This may be assisted by the addition of an electron as in the case of carbon tetrachloride activation. The electron may be donated by cytochrome P-450, allowing the loss of chloride ion and the production of a trichloromethyl radical (Fig. 4.7). This can initiate other radical reactions by reacting with oxygen or unsaturated lipids. 

In industrial circles, many suppliers now evaluate carbons for gas and vapor systems by tests based on the adsorption and desorption of carbon tetrachloride.28 The adsorption stage gives a value designated as the Carbon Tetrachloride Activity, and the desorption stage furnishes a value termed the Carbon Tetrachloride Retentivity. 

Carbon tetrachloride activity it is intended to determine the activation level of activated carbon. The activity is defined as the ratio (in percent) of the weight of carbon tetrachloride adsorbed by an activated carbon sample to the weight of the sample when the carbon is saturated with CCI4. The standard used is ASTM D3467-88. 

Carbon Tetrachloride Activity. The numerical value obtained from this test indicates the adsorptive capacity of the carbon for concentrated organic vapors. It is obtained by measuring the quantity of carbon tetrachloride vapor adsorbed, at 25°C and 760 mm Hg, from air that has been saturated with carbon tetrachloride vapors at 0°C, and is expressed as a percentage of the original charcoal weight. 

A more active product is obtained by the following slight modification of the above procedure. Dissolve the succinimide in a slight molar excess of sodium hydroxide solution and add the bromine dissolved in an equal volume of carbon tetrachloride rapidly and with vigorous stirring. A finely crystalline white product is obtained. Filter with suction and dry thoroughly the crude product can be used directly. It may be recrystallised from acetic acid. 

Iodine is a bluish-black, lustrous solid, volatizing at ordinary temperatures into a blue-violet gas with an irritating odor it forms compounds with many elements, but is less active than the other halogens, which displace it from iodides. Iodine exhibits some metallic-like properties. It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form beautiful purple solutions. It is only slightly soluble in water. 

Much of the early work was inconclusive confusion sprang from the production by the reaction of water, which generally reduced the rate, and in some cases by production of nitrous acid which led to autocatalysis in the reactions of activated compounds. The most extensive kinetic studies have used nitromethane,acetic acid, sulpholan,i and carbon tetrachloride as solvents. 

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... 

Acid Chloride Formation. Monoacid chlorides of maleic and fumaric acid are not known. Treatment of maleic anhydride or maleic acid with various reagents such as phosgene [75-44-5] (qv), phthaloyl chloride [88-95-9] phosphoms pentachloride [10026-13-8] or thionyl chloride [7719-09-7] gives 5,5-dichloro-2(5JT)furanone [133565-92-1] (4) (26). Similar conditions convert fumaric acid to fumaryl chloride [627-63-4] (5) (26,27). NoncycHc maleyl chloride [22542-53-6] (6) forms in 11% yield at 220°C in the reaction of one mole of maleic anhydride with six moles of carbon tetrachloride [56-23-5] over an activated carbon [7440-44-4] catalyst (28). 

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

Aluminum chloride dissolves readily in chlorinated solvents such as chloroform, methylene chloride, and carbon tetrachloride. In polar aprotic solvents, such as acetonitrile, ethyl ether, anisole, nitromethane, and nitrobenzene, it dissolves forming a complex with the solvent. The catalytic activity of aluminum chloride is moderated by these complexes. Anhydrous aluminum chloride reacts vigorously with most protic solvents, such as water and alcohols. The ability to catalyze alkylation reactions is lost by complexing aluminum chloride with these protic solvents. However, small amounts of these "procatalysts" can promote the formation of catalyticaHy active aluminum chloride complexes. 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

Qindamycin, 7(5)-7-chloro-7-deoxyliQcomycin [18323-44-9] (1, R = H, R = Q), also known as Cleocin, first resulted from the reaction of lincomycin and thionyl chloride (54) improved synthetic methods involve the reaction of lincomycin and triphenylphosphine dichloride or triphenylphosphine in carbon tetrachloride (55). Clindamycin is significantly more active than lincomycin against gram-positive bacteria in vitro, and is absorbed rapidly following oral adnainistration. Clindamycin 2-palmitate [36688-78-5], (6, R = R = OC(CH2) 4CH2), 2-palmitate ester of clindamycin, is... 

Methanol, heated at 250°C with chloroform or carbon tetrachloride in contact with active carbon, is converted in part to methyl chloride (52). Methyl chloride has been produced from methoxymagnesium chloride, CH OMgCl, a by-product from the manufacture of certain organo—sHicon compounds, by heating over 200°C (53). 

Pyrolysis. Pyrolysis of 1,2-dichloroethane in the temperature range of 340—515°C gives vinyl chloride, hydrogen chloride, and traces of acetylene (1,18) and 2-chlorobutadiene. Reaction rate is accelerated by chlorine (19), bromine, bromotrichloromethane, carbon tetrachloride (20), and other free-radical generators. Catalytic dehydrochlorination of 1,2-dichloroethane on activated alumina (3), metal carbonate, and sulfate salts (5) has been reported, and lasers have been used to initiate the cracking reaction, although not at a low enough temperature to show economic benefits. 

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... 

Under polymerisation conditions, the active center of the transition-metal haHde is reduced to a lower valence state, ultimately to which is unable to polymerise monomers other than ethylene. The ratio /V +, in particular, under reactor conditions is the determining factor for catalyst activity to produce EPM and EPDM species. This ratio /V + can be upgraded by adding to the reaction mixture a promoter, which causes oxidation of to Examples of promoters in the eadier Hterature were carbon tetrachloride, hexachlorocyclopentadiene, trichloroacetic ester, and hensotrichloride (8). Later, butyl perchlorocrotonate and other proprietary compounds were introduced (9,10). 

Molecular chlorine is believed to be the active electrophile in uncatalyzed chlorination of aromatic compounds. Simple second-order kinetics are observed in acetic acid. The reaction is much slower in nonpolar solvents such as dichloromethane and carbon tetrachloride. Chlorination in nonpolar solvents is catalyzed by added acid. The catalysis by acids is probably the result of assistance by proton transfer during the cleavage of the Cl-Cl bond. ... 

Carbon tetrachloride zero 0.005 Liver problems increased risk of cancer Discharge from chemical plants and other industrial activities... 

Catalysis by hydrogen chloride or iodine monochloride in chlorination in carbon tetrachloride has also been examined. For the chlorination of pentamethylbenzene, the reaction was first-order in both aromatic and chlorine and either three-halves, or mixed first- and second-order in hydrogen chloride, but iodine monochloride was more effective as a catalyst and the chlorination of mesitylene was first-order in iodine monochloride the activation energy for this latter reaction (determined from data at 1.2 and 25.0 °C) was only 0.4 273. 

Trifluoroacetic acid has been examined as a solvent and chlorination of benzene in this is first-order in aromatic and chlorine, but for benzene a higher activation energy (11.4, determined from data at 25.0 and 45.4 °C) was obtained than for chlorination in carbon tetrachloride this unexpected result was attributed to an increase in desolvation energy of the reactants273. 

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