Carbon tetrachloride, reduction

An investigation of the reduction of chlorodeoxy sugars with lithium aluminum hydride has been reported.68 In one experiment, 3-deuterio-l,2 5,6-di-0-isopropylidene-a-D-allofuranose (197) was prepared, and converted into 3-chloro-3-deoxy-3-deuterio- l,2 5,6-di-0-isopropyl-idene-a-D-glucofuranose (198) by treatment with triphenylphos-phine-carbon tetrachloride reduction with lithium aluminum hydride gave 3-deoxy-3-deuterio-1,2 5,6-di-O-isopropylidene-a-D-r/foo-hexofuranose (199), a result which established that the reduction must have occurred with, retention of configuration at C-3. 

Scherer, M.M., J.C. Westall, M. Ziomek-Moroz, and PG. Tratnyek. 1997. Kinetics of carbon tetrachloride reduction at an oxide-free iron electrode. Environ. Sci. Technol. 31, 2385-2391. 

Ekstrom G, von Bahr C, Ingelman-Sundberg M. Human liver microsomal cytochrome P-450IIE1. Immunological evaluation of its contribution to microsomal ethanol oxidation, carbon tetrachloride reduction and NADPH oxidase activity. Biochem Pharmacol 1989 38 689-693. 

Methylene chloride CHjCl, b.p. 41°, is obtained as a by product in the com mercial preparation of chloroform by the reduction of carbon tetrachloride with moist iron and also as one of the products in the chlorination of methane it is a useful extraction solvent completely immiscible with water. 

In 1976 the United States banned the use of CFCs as aerosol propellants. No further steps were taken until 1987 when the United States and some 50 other countries adopted the Montreal Protocol, specifing a 50% reduction of fully halogenated CFCs by 1999. In 1990, an agreement was reached among 93 nations to accelerate the discontinuation of CFCs and completely eliminate production by the year 2000. The 1990 Clean Air Act Amendments contain a phaseout schedule for CFCs, halons, carbon tetrachloride, and methylchloroform. Such steps should stop the iacrease of CFCs ia the atmosphere but, because of the long lifetimes, CFCs will remain ia the atmosphere for centuries. 

Preparation. Thiophosgene forms from the reaction of carbon tetrachloride with hydrogen sulfide, sulfur, or various sulfides at elevated temperatures. Of more preparative value is the reduction of trichi oromethanesulfenyl chloride [594-42-3] by various reducing agents, eg, tin and hydrochloric acid, staimous chloride, iron and acetic acid, phosphoms, copper, sulfur dioxide with iodine catalyst, or hydrogen sulfide over charcoal or sihca gel catalyst (42,43). 

Tetrachloride-Reduction Process. Titanium tetrachloride for metal production must be of very high purity. The requited purity of technical-grade TiCl for pigment production is compared with that for metal production in Table 4. Titanium tetrachloride for metal production is prepared by the same process as described above, except that a greater effort is made to remove impurities, especially oxygen- and carbon-containing compounds. 

Section 5.10.3.2). Treatment of methyl 6-phthalimido penicillinate (jR)-sulfoxide (40) with JV-chlorosuccinimide in refluxing carbon tetrachloride gives an epimeric mixture of sulfinyl chlorides (41) which are ring closed to epimeric 3-methylenecepham sulfoxides (42a) using tin(IV) chloride. Reduction with phosphorus tribromide gives the desired methyl 7-phthalimido-3-methylenecepham 4-carboxylate (42b). 

Use of the trapping agent is recommended as the most efficient method for running acyloin condensations for many reasons. Among them are (a) the work-up is very simple filter and distil (b) the bis-(silyloxy)olefin is usually easier to store than the free acyloin and is readily purified by redistillation (c) unwanted base-catalyzed side reactions during reduction are completely avoided and (d) the bis-(silyloxy)olefin can be easily converted directly into the diketone by treatment with 1 mole of bromine in carbon tetrachloride.Other reactions are described in Riihlmann s review and in Organic Reactions ... 

In addition, EPA must ensure that Class I chemicals be phased out on a schedule similar to that specified in the Montreal Protocol—CFCs, halons, and carbon tetrachloride by 2000 methyl chloroform by 2002—but with more stringent interim reductions. Class II chemicals (HCFCs) will be phased out by 2030. Regulations for Class I chemicals will be required within 10 months, and Class II chemical regulations will be required by December 31, 1999. 

The following reductions have been carried out at 80° with the use of an excess of 2-propanol as the reaction medium (see Note 3) carbon tetrachloride to methane (47%), 1-bromonaph-thalene to naphthalene (90%), /3-bromostyrene to styrene (72%), jfi-bromoaniline to aniline (61%), p-bromophenol to phenol (66%), and monochloroacetone to acetone (30%). 

One type of fatty liver that has been smdied extensively in rats is due to a deficiency of choline, which has therefore been called a lipotropic factor. The antibiotic puromycin, ethionine (a-amino-y-mercaptobu-tyric acid), carbon tetrachloride, chloroform, phosphorus, lead, and arsenic all cause fatty liver and a marked reduction in concentration of VLDL in rats. Choline will not protect the organism against these agents but appears to aid in recovery. The action of carbon tetrachloride probably involves formation of free radicals... 

Doong R-A, H-C Chiang (2005) Transformation of carbon tetrachloride by thiol reductants in the presence of quinone compounds. Environ Sci Technol 39 7460-7468. 

Workman SL Woods, YA Gorby, JK Fredrickson, and MJ Trnex (1997) Microbial reduction of vitamin B,2 by Shewanella alga strain BrY with snbseqnent transformation of carbon tetrachloride. Environ Sci Technol 31 2292-2297. 

Curtis GP, M Reinhard (1994) Reductive dehalogenation of hexachloroethane, carbon tetrachloride, and bromoform by anthrahydroquinone disulfonate and humic acids. Environ Sci Technol 28 2393-2401. 

Jin G, AJ Englande (1997) Biodegradation kinetics of carbon tetrachloride by Pseudomonas cepacia under varying oxzidation-reduction potential conditions. Water Environ Res 69 1094-1099. 

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