Carbon tetrabromide tetrachloride

A 1 1 complex melting at 24.8°C is formed between PX and carbon tetrachloride (52). The other Cg aromatic compounds do not form these complexes. Carbon tetrabromide and chloral (CCl CHO) form addition compounds with PX. 

Cha.in-Tra.nsferAgents. The most commonly employed chain-transfer agents ia emulsion polymerisation are mercaptans, disulfides, carbon tetrabromide, and carbon tetrachloride. They are added to control the molecular weight of a polymer, by transferring a propagating radical to the chain transfer agent AX (63) ... 

When treated with aluminum bromide at 100°C, carbon tetrachloride is converted to carbon tetrabromide [558-13-4], reaction with calcium iodide, Cal2, at 75°C gives carbon tetraiodide [507-25-5]. With concentrated hydroiodic acid at 130°C, iodoform [75-47-8], CHI, is produced. Carbon tetrachloride is unaffected by gaseous fluorine at ordinary temperatures. Replacement of its chlorine by fluorine is brought about by reaction with hydrogen fluoride at a... 

One of the older preparative free-radical reactions is the addition of polyhalomethanes to alkenes. Examples of addition of carbon tetrabromide, carbon tetrachloride, and bromoform have been recorded. The reactions are chain processes that depend on facile abstraction of halogen or hydrogen from the halomethane ... 

CARBON OXYFLUORIDE see CARBONYL FLUORIDE CARBON REMOVER, LIQUID CARBON TETRABROMIDE CARBON TETRACHLORIDE... 

Tetra-borsMure, /. tetraboric acid, -bromkoh-ienstoff, m. carbon tetrabromide. -chlor-kohlenstofF, m. carbon tetrachloride, -chlor-zinn, n. tin tetrachloride, -eder, n. tetra hedron. 

Halocarbons including carbon tetrachloride, chloroform, bromotrichloroincthane6 (Scheme 6.7) and carbon tetrabromide have been widely used for the production of tclomcrs and transfer to these compounds has been the subject of a large number of investigations." Representative data are shown in Table 6.4. Telomerization involving halocarbons has also been developed as a means of studying the kinetics and mechanism of radical additions.66... 

B. Nucleophilic Attack on Halogen.- (/ )-( +)-2,2-dimethylpropan( H)ol has been converted to the chloride with inversion of configuration using triphenylphosphine and carbon tetrachloride. The corresponding reaction using carbon tetrabromide gave the bromide with considerable racemiza-tion. ... 

Carbon storage, of hydrogen, 23 786 Carbon sulfides, 23 621, incompletely characterized, 23 62 Carbon sulfotelluride, 24 419 Carbon-sulfur surface compounds, 23 621 Carbon tetrabromide, 4 348 Carbon tetrachloride, 6 249 acrylamide solubility in, 2 290t... 

Dorr and Buttgereit (1963), using U.V. measurements of solutions of mesitylene and hexamethylbenzene in chloroform, bromoform, carbon tetrachloride and carbon tetrabromide, were able to demonstrate a weak electron transfer complex formation with these solvents. These investigations show that hexamethylbenzene is a more powerful electron donor than mesitylene. A similar influence on an acceptor property... 

Miscible with ethanol, ether (U.S. EPA, 1985), and many chlorinated solvents including carbon tetrabromide, carbon tetrachloride, bromoform, chloroform, tetrachloroethylene, trichloroethylene, and 1,1,1-trichloroethane. 

FIGURE 6.3 Molecular weight of polystyrene (PS) as a function of solvent and solvent concentration A = -butylmercaptan, B = carbon tetrabromide, C = carbon tetrachloride, D = o-cresol, E = p-cresol, F = m-cresol, G = phenol, H = s-ec-butylbenzene, 1 = cumene, J = ethylbenzene, K = chloroform, L = -heptant, M = toluene, N = benzene, where [S] = concentration of chain-transfer agent and [M] = concentration of styrene monomer. 

This reaction presumably proceeds via the acyl chloride, because it is known that triphenylphosphine and carbon tetrachloride convert acids to the corresponding acyl chloride.104 Similarly, carboxylic acids react with the triphenylphosphine-bromine adduct to give acyl bromides.105. Triphenylphosphine/lV-bromosuccinirnide also generates acyl bromides in situ 06 Alcohols can be esterified by heating in excess ethyl formate or ethyl acetate and triphenylphosphine in carbon tetrabromide.107 All these reactions are mechanistically analogous to the alcohol-to-halide conversions that were discussed in Section 3.1.2. 

The high Cs values for carbon tetrachloride and carbon tetrabromide are due to the weak carbon-halogen bonds. These bonds are especially weak because of the excellent stabilization of the trihalocarbon radicals formed by resonance involving the halogen free pairs of electrons ... 

The greater transfer constant for carbon tetrabromide compared to the tetrachloride is due to the weaker C— Br bond. The low Cs value for chloroform compared to carbon tetrachloride is explained by C—H bond breakage in the former. The thiols have the largest transfer constants of any known compounds due to the weak S—H bond. 

Reacts with carbon tetrachloride at 100°C to form carbon tetrabromide ... 

Carbon tetrabromide, irradiation of, 5 152 Carbon tetrachloride, ionization, 9 230-231 Carbonyl anion and hydride clusters, 13 478-480, 482, 483... 

Hydroxy amides undergo cyclodehydration to oxazolines under very mUd conditions with triphenylphosphine and carbon tetrachloride. Carbon tetrabromide can also be used. The formation of the corresponding p-chloro amide is generally not a significant problem. The major disadvantage is that removal of the byproduct triphenylphosphine oxide may be difficult at times. Representative examples are shown in Table 8.14 (Fig. 8.5).n4,i4o,i73-i8i... 

The use of triphenylphosphine-carbon tetrachloride to convert lincomycin (1) into clindamycin (2) has already been mentioned (see Section I, p. 226) the 7-bromo and 7-iodo analogs of 2 were also prepared by treatment of lincomycin hydrochloride with triphenylphosphine and carbon tetrabromide or carbon tetraiodide, with acetonitrile as the solvent.3... 

Several examples of heavy atom quenching of aromatic hydrocarbon states are known for example, carbon tetrabromide is an efficient quencher of the fluorescence of anthracene167 and carbon tetrachloride behaves similarly with p-terphenyl.188 Since quenching results in formation of the triplet state, it has been possible to use the heavy atom effect to measure intersystem crossing efficiencies ( ). Because of the elegance of this technique 169 and the importance of the results in photochemistry, we shall cover it in some detail. 

The exchange of halogen for fluorine with sulfur tetrafluoride, due to the high temperatures generally required, is of limited use. Carbon tetrachloride and carbon tetrabromide react with sulfur tetrafluoride at 225-325 C to give mixtures of halofluoromethanes, while hexachloro-ethane under similar conditions gives l,1.2,2-tetrachloro-l,2-difluoroethane (59%) as the main product.191... 

While no spectroscopic evidence of a ground-state complex between anthracene and carbon tetrachloride, naphthalene or 1,2-benzanthracene and carbon tetrabromide has been found, Nemzek and Ware [7] were unable to explain their steady-state fluorescence quenching measurements with the parameters deduced from the determination of the time-dependent rate coefficients unless a ground-state complex was present. This cannot be regarded as a satisfactory and consistent analysis because the time-dependent rate coefficient would be modified by the presence of the initial distribution of quencher and fluorophor in the ground state. 

Carbon tetrabromide, AA01 Carbon tetrachloride, AA04 u,-Carbonylhexacarbonyl [u-(5 oxo-2(5H.)-furyl idene)]dicobal t (Co-Co), AS83... 

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