Mineralization carbon tetrachloride

In the literature a number of different techniques for the preparation of a-sulfo fatty acid esters can be found. There is equipment for small-scale and commercial scale sulfonation. Stirton et al. added liquid sulfur trioxide dropwise to the fatty acids dispersed or dissolved in chloroform, carbon tetrachloride, or tetrachoroethylene [44]. The molar ratio of S03/fatty acid was 1.5-1.7 and the reaction temperature was increased to 65 °C in the Final stage of sulfonation. The yield was 75-85% of the dark colored a-sulfonated acid. The esterification of the acid was carried out with either the a-sulfonic acid alone, in which case the free sulfonic acid served as its own catalyst, or with the monosodium salt and a mineral catalyst. 

A project at the University of Arizona (FEDRIP 1996) will study microbial dehalogenation of several compounds, including chloroform. A major part of the study will focus on the facultative anaerobic bacteria Shewanella putrefaciens sp., which is known to catalyze the transformation of carbon tetrachloride to chloroform and other as yet unidentified products. The organic substrates will also contain metals. It is hoped that the end-products from the biochemical treatment can be subjected to a photolytic finishing process that will completely mineralize any remaining halogenated compounds. 

Carbon tetrachloride slowly reacts with hydrogen sulfide in aqueous solution yielding carbon dioxide via the intermediate carbon disulfide. However, in the presence of two micaceous minerals (biotite and vermiculite) and amorphous silica, the rate transformation increases. At 25 °C and a hydrogen sulfide concentration of 0.001 M, the half-lives of carbon tetrachloride were calculated to be 2,600, 160, and 50 d for the silica, vermiculite, and biotite studies, respectively. In all three studies, the major transformation pathway is the formation of carbon disulfide. This compound is... 

Chlorination of natural rubber (NR) is carried out with chlorine in carbon tetrachloride solution at 60-90°C to yield a chlorinated rubber containing about 65% chlorine, which corresponds to 3.5 chlorine atoms per repeat unit. The process is complex and includes chlorine addition to the double bond, substitution at allylic positions, and cyclization. Chlorinated rubber has high moisture resistance and is resistant to most aqueous reagents (including mineral acids and bases). It is used in chemical- and corrosion-resistant paints, printing inks, and textile coatings. Bromination of butyl rubber is also practiced [Parent et al., 2002]. 

S.A. (1980) Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbon tetrachloride. J. Chem. Soc. Faraday Trans. I. 76 302-313 Buerge, I.J. Hug, S.J. (1999) Influence of mineral surfaces on chromium(VI) reduction by iron(II). Environ. Sci. Techn. 33 4285-4291 Buerge-Weirich, D. Hard, R. Xue, H. Behra, P. Sigg, L. (2002) Adsorption of Cu, Cd and Ni on goethite in the presence of natural groundwater ligands. Environ. Sci. Techn. 36 328-336... 

Water freezes to ice at 0°C expands by about 10% on freezing boils at 100°C vapor pressure at 0°, 20°, 50°, and 100°C are 4.6, 17.5, 92.5, and 760 torr, respectively dielectric constant 80.2 at 20°C and 76.6 at 30°C dipole moment in benzene at 25°C 1.76 critical temperature 373.99°C critical pressure 217.8 atm critical density 0.322 g/cm viscosity 0.01002 poise at 20°C surface tension 73 dynes/cm at 20°C dissolves ionic substances miscible with mineral acids, alkalies low molecular weight alcohols, aldehydes and ketones forms an azeotrope with several solvents immiscible with nonpolar solvents such as carbon tetrachloride, hexane, chloroform, benzene, toluene, and carbon disulfide. 

Ukrainczyk, L., Chibwe, M., Pinnavaia, T.J. Boyd, S. A. (1995). Reductive dechlorination of carbon tetrachloride in water catalyzed by mineral-supported biomimetic cobalt macrocycles. Environmental Science Technology, 29, 439-45. 

Selenium Monochloride, Se2Cla.—This chloride is most easily obtained by the action of chlorine on heated selenium, but it is always accompanied by a certain quantity of the more stable tetrachloride which, however, is less volatile.2 It may be prepared by saturating with chlorine a suspension of selenium or a selenium mineral in carbon tetrachloride.3 The selenium monoehloride is soluble in carbon tetrachloride, whilst the chlorides of other elements present are insoluble. The monochloride is therefore obtained by evaporation of the solvent after filtration. 

Lithium dispersion (0.5% sodium in mineral oil, Aldrich) is washed with hexane to remove the oil before use and dried by passing a stream of nitrogen over it. Di-tert-butyldichlorosilane is commercially available (Huls, bp 191°C) or can be prepared by chlorination of di-tert-butylchlorosilane (benzoyl peroxide in refluxing carbon tetrachloride for 8 h, yield > 90%). trans-Butene is commercially available (Aldrich) in lecture bottles and is used as is. Tetrahydrofuran is freshly distilled under nitrogen from sodium ketyl benzophenone immediately prior to use. 

The biodegradation of trichloroethylene is the most studied since this is probably the most widespread halogenated solvent contaminant. Several substrates drive ttichlorethylene co-oxidation, including methane, propane, propylene, toluene, isopropylbenzene, and ammonia (25). The enzymes that metabolize these substrates have subtly different selectivities with regard to the halogenated solvents, and to date none are capable of co-oxidizing carbon tetrachloride or tetrachloroethylene. Complete mineralization of these compounds can, however, be achieved by sequential anaerobic and aerobic process. Biorem edia tion. 

Cerium metal in the form of small rectangular billets approximately 5 X X 2 in. is used in this preparation. The surfaces of the billets are filed down under a bath of mineral oil to ensure removal of any oxide layer. Caution is advised as the metal may be pyrophoric. The billets are rinsed in carbon tetrachloride to remove the mineral oil and are then transferred to the vacuum glove box. All subsequent handling of the metal is done in the vacuum glove box in a high-purity argon or helium gas environment. 

The boiling point is 155-175°, but about 80% should distil below 163° and 90% below 170° old resinified oils boil at higher temperatures. Adulterants alter the boiling point appreciably resin spirit, light mineral or tar oils, or carbon tetrachloride increase the fractions boiling below 150°, whilst pinewood oils or petroleum increase those between 160° and 170°. 

The solvents more generally used are oil of turpentine, pinewood oil, methyl, ethyl or amyl alcohol, amyl acetate, acetone, ether, carbon disulphide, carbon tetrachloride, chloro-derivatives of ethane and ethylene, chlorohydrins, light mineral oils, light oils from tar, from resin or from shale, and camphor oil. 

B) Examination of the Solvents insoluble in Water. These may be carbon disulphide, chloroform, carbon tetrachloride, a chloro-derivative of ethane or ethylene, a chlorohydrin, amyl alcohol, amyl acetate, ether, benzene or a homologue, oil of turpentine, pinewood oil, light mineral oil, resin oil, tar oil, shale oil, or camphor oil. 

An especially convenient aspect of IR spectroscopy is its practice. A small amount of sample can be pressed between two NaCl or KBr (Table 6.19) disks and the spectrum can be determined without further preparation. A spectrum so obtained is recorded as neat or between salts. If the sample is a solid, it may be mixed in a mortar and pestle with KBr and then pressed into a disk. The salt disk may be placed directly in the IR beam. In neither case is there a concern about solvent peaks. Of course, solvents may be used. Carbon tetrachloride and chloroform are the most commonly used solvents when the compound requires dissolution. Alternately, the sample may be intimately mixed (mulled) with mineral oil (a hydrocarbon oil). The thick slurry may then be smeared on a salt disk and placed in the spectrometer. The brand of mineral oil used historically is Nujol and such slurries are still called Nujol mulls. The transmission characteristics of potential solvents for IR spectroscopy may be found in Table 6.20. 

Workers come in contact with a large number of chemical substances in work areas, as does the general public. The commonly found chemical carcinogens are grouped under (1) polycyclic aromatic hydrocarbons (PAHs), (2) nitroso compounds, (3) halogenated hydrocarbons (solvents e.g., carbon tetrachloride, chloroform, trichloroethylene, and methylene chloride), (4) inorganic metals and minerals (beryllium, cadmium, nickel, cobalt, chromium, asbestos and arsenic), and (5) naturally occurring chemical substances (aflatoxins). 

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