Ferric bromide chloride

Feiri-. ferric, ferri-, iron(III). -acetat, n. ferric acetate, iron(IIl) acetate, -ammonsulfat, n. ammonium ferric sulfate, -bromid, n. ferric bromide, iron(III) bromide, -chlorid, n. ferric chloride, iron(lll) chloride, -chlor-wasserstoff, -chlorwasserstoffsMure, /. fer-richloric acid. -cyan, n. ferricyanogen. -cyaneisen, n. ferrous ferricyanide (Turn-bull s blue), -cyanid, n. ferric cyanide, iron(III) cyanide ferricyanide. 

Chlorine and Bromine. Aromatic compounds can be brominated or chlorinated by treatment with bromine or chlorine in the presence of a catalyst, most often iron. However, the real catalyst is not the iron itself, but the ferric bromide or ferric chloride formed in small amounts from the reaction... 

For preparative reactions, Lewis acid catalysts are used. Zinc chloride or ferric chloride can be used in chlorination, and metallic iron, which generates ferric bromide, is often used in bromination. The Lewis acid facilitates cleavage of the halogen-halogen bond. 

Chlorobromobenzene has been prepared by the diazotiza-tion of o-bromoaniline followed by replacement of the diazonium group by chlorine 1 by the elimination of the amino group from 3-chloro-4-bromoaniline 2 by the chlorination of bromobenzene in the presence of thallous chloride,3 aluminum chloride,4 or ferric chloride 4 by the bromination of chlorobenzene without a catalyst6 or in the presence of aluminum,4 iron,4 or ferric bromide 6 by the diazotization of o-chloroaniline followed by replacement of the diazonium group with bromine 4,6 and from o-chlorophenylmercurie chloride by the action of bromine.7... 

Exercise 22-14 Aluminum chloride is a much more powerful catalyst than ferric bromide for bromination of benzene. Would you expect the combination of aluminum chloride and bromine to give much chlorobenzene in reaction with benzene Explain. 

Direct bromide/chloride exchange between ferric chloride and cyclohexyl bromide (equation 20) ... 

Hydrobromic acid, ferric bromide, and the chlorides and bromides of zinc and aluminium all react in an analogous manner.1 With potassium iodide in the presence of a zinc salt the reaction is quantitative, and may be used in the volumetric estimation of ferricyanides —2... 

Instead of ferric bromide, ferrous bromide or anhydrous ferric chloride may be used. The latter decomposes with hydrobromic add to ferric bromide and hydrochloric add -... 

FeBtj + 3 ferric bromide HgCl2 +2 mercuric chloride... 

Ferric bromide and ferric chloride become inactivated if they react with water, including moisture in the air. Therefore, they are generated in situ by adding iron fillings to bromine or chlorine. The mechanism for iodination is slightly different iodine (L) is treated with an oxidizing agent such as nitric acid to obtain the electrophilic iodine (2 I+). 

It would be useful to have ail efficient method for the conversion of the generally cheaper, readily available alkyl chlorides to the more reactive, synthetically useful alkyl bromides and iodides. Ferric bromide and iodide catalyze this reaction but the complete loss of stereochemistry in the bromide exchange with exo-2-norbornyl and cis- and rran.s-4-rerr-butylcydohexyl chlorides reduces its usefulness when stereochemistry is important197. 

The bromination or chlorination of benzene requires a Lewis acid such as ferric bromide or ferric chloride. Recall that a Lewis acid is a compound that accepts a share in a pair of electrons (Section 1.21). 

The highly charged transition metals have a marked tendency to form complexes. The ferric ion, Fe. is one for which numerous studies have been done in an attempt to define its complexing behavior with anions such as hydroxyl, cyanide, bromide and chloride. The complexes occurring between ferric and chloride ions will be discussed here. 

Bromine reacts with ferric bromide to form Br FeBr4, and benzene must react as a Lewis base with Br in order to form 18. It is known that an identical reaction occurs to give 18 when benzene reacts with Br2 and the powerful Lewis acid aluminum chloride (AICI3). Reaction of Br2 and AICI3 gives Br AlClgBr-, which then reacts with benzene. This example is provided to show that many Lewis acids may be used. This example also shows that Br is formed despite the presence of chlorine atoms in AICI3. 

Lewis acids, however, are not limited to compounds that lose protons. Compounds such as aluminum chloride (AICI3), ferric bromide (FeBr3), and borane (BH3) are acids according to the Lewis definition because they have unfilled valence orbitals that can accept a share in an electron pair. These compounds react with a compound that has a lone pair, just as a proton reacts with a compound that has a lone pair. 

Ben2enesulfonic anhydride has been claimed to be superior to ben2enesulfonyl chloride (140). Catalysts used besides aluminum chloride are ferric chloride, antimony pentachloride, aluminum bromide, and boron trifluoride (141). 

Chloride. Chloride is common in freshwater because almost all chloride salts are very soluble in water. Its concentration is generally lO " to 10 M. Chloride can be titrated with mercuric nitrate. Diphenylcarbazone, which forms a purple complex with the excess mercuric ions at pH 2.3—2.8, is used as the indicator. The pH should be controlled to 0.1 pH unit. Bromide and iodide are the principal interferences, whereas chromate, ferric, and sulfite ions interfere at levels greater than 10 mg/L. Chloride can also be deterrnined by a colorimetric method based on the displacement of thiocyanate ion from mercuric thiocyanate by chloride ion. The Hberated SCN reacts with ferric ion to form the colored complex of ferric thiocyanate. The method is suitable for chloride concentrations from 10 to 10 M. 

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

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