Carbon tetrabromid

It is better not to remove the lower bromoform layer in a separatory funnel, but to do so entirely by steam distillation complete oxidation of the ketone id thus ensured. The weight of recovered bromoform may be somewhat smaller (100-105 g.), but the yield of pure acid is increased to 36 g. The steam distillation must be carefully watched as a solid (carbon tetrabromide) may crystallise in the condenser this can easily be removed by turning ofi the water supply when the solid will soon melt and pass on into the distillate. 

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) ... 

Another halogenated photolysis (30), using carbon tetrabromide to produce hydrogen bromide and subsequent reaction with spiropyran (5), produces a highly colored spiropyrilium bromide salt. 

If bromine is used in equation 8, carbon tetrabromide [558-13-4] is formed. With a minor amount of iodine present, and in the absence of iron catalyst, carbon disulfide and chlorine react to form trichioromethanesulfenyl chloride (perchloromethyl mercaptan [594-42-3]), CCI3SCI, which can be reduced with staimous chloride or tin, and hydrochloric acid to form thiophosgene (thiocarbonyl chloride [463-71-8], CSCI2, an intermediate in the synthesis of many organic compounds (see Sulfurcompounds). 

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... 

Carbon tetrabromide [558-13-4] M 331.7, m 92.5 . Reactive bromide was removed by refluxing with dilute aqueous Na2C03, then steam distd, crystd from EtOH, and dried in the dark under vacuum. [Sharpe and Walker J Chem Soc 157 1962.] Can be sublimed at 70 at low pressure. 

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... 

AP951). Alternatively, reduction of the ester in 586 gave the alcohol 587 that upon reaction with carbon tetrabromide/triphenylphosphine gave the respective bromide which was cyclized under the reaction condition to give 588 (92JMC1076) (Scheme 98). 

When carbon tetrabromide is used, the alkyl bromide is formed. Providing moisture is excluded from the reaction mixture (HX is formed otherwise), the reaction conditions are completely neutral, affording a convenient preparation of the halides of acid-sensitive substrates (for example, sugars). 

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

The flask is then fitted with a separatory funnel and a condenser for distillation, and heated with a Meker burner to steam distil the bromoform and carbon tetrabromide (Notes 2 and 3). 

The bromoform passes over with the steam rather rapidly. In some runs some carbon tetrabromide was also obtained. Toward the end of the steam distillation a heavy oil that is more or less of a lachrymator may come over. This is undoubtedly brominated pinacolone. The bromoform may be purified by vacuum distillation. One run gave 115 g. of product, boiling at 78-79°/22 mm. 

Using the periodic table as a guide, predict which of the following compounds form ionic solutions in water silicon carbide, SiC magnesium bromide, MgBr2 carbon tetrabromide, CBr chromic chloride, CrCl3. 

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... 

Bromocyclopropane has been prepared by the Hunsdiecker reaction by adding silver cyclopropanecarboxylate to bromine in dichlorodifluoromethane at —29° (53% yield) or in tetrachloro-ethane at —20° to —25° (15-20% yield).3 Decomposition of the peroxide of cyclopropanecarboxylic acid in the presence of carbon tetrabromide gave bromocyclopropane in 43% yield.4 An attempt to prepare the bromide via the von Braun reaction was unsuccessful.3... 

Carbon tetrabromide (99%) was purchased from the Aldrich Chemical Company Inc. and was used without further purification. 

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. ... 

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