Iron chloride (III)

Chemical properties

The iron chloride (III) is a Acide of Lewis rather extremely, who reacts with the bases of Lewis to form stable compounds. For example, ferric addition of chloride and oxide of triphénylphosphine form the stable compound FeCl₃ (OPPh₃) ₂ (where pH is a grouping phényl). Several complex S Anion ic exists, most stable containing the tetrahedral form yellow FeCl₄^-. It is possible to extract a solution from FeCl₄^- in the Hydrochloric acid using ether.

When the ferric chloride is heated in the presence of ferric Oxyde with 350°C, it is formed the FeOCl oxychloride. In the presence of a bases, the Atome S of Chlore of ferric chloride can be substituted, for example to form a Alkoxide:

FeCl₃ + 3 C₂H₅OH + 3 NH₃ → Fe (OC₂H₅) ₃ + 3 NH₄Cl

Carboxylate salts of , like the oxalates, the citrates and the tartrates, react with ferric chloride in aqueous solution to form the stable complexes such as for example ^3-.

The iron chloride (III) is also an agent oxidant moderate, able for example to oxidize the Cuprous chloride (I) in Cuprous chloride (II). The reducing agents as the Hydrazine allow the reduction of FeCl₃ in iron complexes (II).

Manufacture

The iron chloride (III) anhydrous can be prepared while making directly react the Fer and the Chlore according to:

2 Fe _(S) + 3 Cl₂ _(G) → 2 FeCl_{3 (S)}

On an industrial scale, the ferric chloride is produced in aqueous solution by two techniques, starting from Fer or of Minerai of iron (Oxyde) in a process in loop:

Dissolution of the iron ore in the Hydrochloric acid :
:: Fe₃O₄ (S) + 8 HCl (aq) → FeCl₂ (aq) + 2 FeCl₃ (aq) + 4:00 ₂O
Transformation of the ferrous Chloride using Dichlore:
:: FeCl₂ (aq) + Cl₂ (G) → FeCl₃ (aq)
Dissolution of the pure Iron in a ferric chloride solution:
:: Fe (S) + 2 FeCl₃ (aq) → 3 FeCl₂ (aq)

The hydrated ferric chloride can be dehydrated to obtain the form anhydrous while heating in the presence of Chlorure of thionyl.

Uses

The ferric chloride is one of the reagents most used for the attack of metals. It in particular is very much used to attack the Cuivre in the Industrie of the printed circuits. This attack implements a reaction of Oxydo-réduction:

FeCl₃ + Cu → FeCl₂ + CuCl
followed : FeCl₃ + CuCl → FeCl₂ + CuCl₂

It is also used as Catalyze ur for the reaction of the ethylene and the Dichlore, implemented in the industrial production of Chlorure of vinyl, the Monomère basic for the manufacture of PVC. A reaction of the same type is used for the manufacture of 1,2-dichloroethane, a chemical compound largely used in industry.

The ferric chloride is also used as alternative to the Ferrous sulfate (III) for the treatment of the Eau. It is then treated with a Ion Hydroxyde to form a floc d'" iron hydroxide (III) " (of formula FeO (OH)) who allows to eliminate the suspended particles.

In laboratory, the ferric chloride is usually used as a Acide of Lewis for Catalyze R of the reactions such as the chlorination of aromatic compounds or the reaction of Friedel and Crafts on the aromatic ones. It is a Acide of Lewis less powerful than the Chlorure of aluminum, but in certain cases this more moderate character makes it possible to obtain better output S, such as for example for the alkylation of the Benzène:

The " test of the chloride ferrique" is a colorimetric test of recognition of the phenol and énol S, which implements solution of a ferric chloride 1% neutralized beforehand by Soude until the appearance of a precipitate of FeO (OH). This solution is filtered before use. The organic substance is then dissolved in the Eau, the Méthanol or the ethanol. The ferric chloride solution is added to the organic solution obtained, and a coloring (transitory or permanent) generally violet, green or blue appears in the presence of phenol or of a énol.

The ferric chloride is sometimes used by the American Numismate S to determine the date of parts of 10 hundred " buffalo" (emitted between 1913 and 1938) whose date is not readable any more.

In electronics, the iron perchloride is used to engrave the printed circuits.

Safety

The ferric chloride is toxic and highly corrosive. The form anhydrous is a very powerful agent dehydrating. It must be handled with precautions.

R: 22 (Harmful in the event of Ingestion)
R: 34 (Causes Brûlure S)
S: 26 (In the event of contact with the eyes, to wash abundantly and consult a Ophthalmologist)
S: 28 (In the event of contact with the Skin, to wash abundantly with… (specified by the manufacturer) )

It has a character of Acide extremely and thus presents all the risks due to the corrosive substances. Projections in the eyes can cause serious burns. It should be carried glasses when it is handled. A splash on the skin must be washed without delay. A prolonged contact causes an irritation and can cause a burn.

It never should be put in a bottle or a container of food use in order to avoid any confusion with a drink.

The labelling of the containers “perchloride of iron C corrosive” is recommended.

See too

Chloride
Acid Iron
salt
of Lewis

References

NR. NR. Greenwood, A. Earnshaw, Chemistry off the Elements , 2nd ED., Butterworth-Heinemann, Oxford, the U.K., 1997.
Handbook off Chemistry and Physics , 71st edition, CRC Close, Year Arbor, Michigan, 1990.
The Merck Index , 7th edition, Merck & Co, Rahway, New Jersey, the USA, 1960.
D. Nicholls, Complex and First-Row Transition Elements , Macmillan Near, London, 1973.
A.F. Wells, Structural Inorganic Chemistry , 5th ED., Oxford University Near, Oxford, the U.K., 1984.
J. March, Advanced Organic Chemistry , 4th ED., p. 723, Wiley, New York, 1992.
B.S. Furnell and Al, Vogel' S Textbook off Practical Organic Chemistry , 5th edition, Longman/Wiley, New York, 1989.
Handbook off Reagents for Organic Synthesis: Acidic and BASIC Reagents , (H.J. Reich, J.H. Rigby, eds.), Wiley, New York, 1999.