Aluminum bromide

Aluminum bromide
Aluminum bromide
Are common
Systematic ; name	Aluminum bromide
Chem. formula	AlBr 3 , Al 2 Br 6
Rat formula	AlBr 3
Physical properties
condition	solid
Molar mass	266.69 g / mol
Density	3,205
Thermal properties
T. melt.	97.5
T. bale.	255 ° C
Enthalpy of Education	- 514; ; - 422 (AlBr 3 , gas); ; - 971 (Al 2 Br 6 , gas) kJ / mol
Structure
Crystal structure	monoclinic
Classification
Reg. CAS number	7727-15-3
PubChem
Reg. EINECS number	231-779-7
Smiles
Inchi
RTECS
UN number
ChemSpider
Security
Toxicity	one 3 one ; ;

Aluminum bromide ( aluminum bromide ) is an inorganic binary compound . Chemical formula ${\mathsf {{\stackrel {+3}{Al}}{\stackrel {-1}{Br}}_{3}}}$ ^{${\ displaystyle {\ mathsf {{\ stackrel {+3} {Al}} {\ stackrel {-1} {Br}} _ {3}}}}$} ^{${\ displaystyle {\ mathsf {{\ stackrel {+3} {Al}} {\ stackrel {-1} {Br}} _ {3}}}}$} . The substance is a salt of aluminum and hydrobromic acid . In solid and liquid state, it exists in the form of a dimer : Al ₂ Br ₆ .

Physical Properties

Anhydrous aluminum bromide is a colorless crystalline substance, melting at a temperature of 97.5 ° C; boiling point: 255 ° C.

In the solid and liquid phases, it exists in the form of an Al ₂ Br ₆ dimer , partially dissociating in AlBr ₃ ; in the gas phase, mass spectra show the presence of di-, tetra- and hexaforms: Al ₂ Br ₆ , Al ₄ Br ₁₂ , Al ₆ Br ₁₈ respectively.

The structure of the aluminum bromide molecule Al ₂ Br ₆ is a double tetrahedron , in the center of which there are aluminum atoms covalently bonded to bromine atoms ^[4] .

The coordination number of aluminum in the bromide molecule is 4 ^[5] .

The Al – Br bond breaking energy in the aluminum bromide molecule is approximately 358 kJ / mol ^[6] .

The substance is very hygroscopic : it dissolves in air, easily absorbing moisture to form AlBr ₃ • 6H ₂ O hexahydrate ^[7] . It is soluble in water, alcohol , carbon disulfide , acetone ^[8] ; the density of the aqueous solution at 20 ° C is: 1079.2 kg / m³ (10% solution), 1172.5 kg / m³ (20% solution) ^[9] .

Chemical Properties

Anhydrous aluminum bromide reacts very vigorously with water, generating a lot of heat during dissolution and, partially hydrolyzing :

{\mathsf {AlBr_{3}+4H_{2}O\leftrightarrows [Al(H_{2}O)_{4}]^{3+}+3Br^{-}}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 4H_ {2} O \ leftrightarrows [Al (H_ {2} O) _ {4}] ^ {3 +} + 3Br ^ {-}}}}

{\mathsf {[Al(H_{2}O)_{4}]^{3+}+H_{2}O\leftrightarrows [Al(H_{2}O)_{3}(OH)]^{2+}+H_{3}O^{+}}}

{\ displaystyle {\ mathsf {[Al (H_ {2} O) _ {4}] ^ {3 +} + H_ {2} O \ leftrightarrows [Al (H_ {2} O) _ {3} (OH) ] ^ {2 +} + H_ {3} O ^ {+}}}}

When heating an aqueous solution, hydrolysis can be carried out completely:

{\mathsf {AlBr_{3}+3H_{2}O=Al(OH)_{3}\!\downarrow \!+3HBr\!\uparrow \!}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 3H_ {2} O = Al (OH) _ {3} \! \ downarrow \! + 3HBr \! \ uparrow \!}}}

Reacts with alkalis :

{\mathsf {AlBr_{3}+3NaOH=Al(OH)_{3}\!\downarrow \!+3NaBr}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 3NaOH = Al (OH) _ {3} \! \ downarrow \! + 3NaBr}}}

{\mathsf {AlBr_{3}+4NaOH=Na[Al(OH)_{4}]+3NaBr}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 4NaOH = Na [Al (OH) _ {4}] + 3NaBr}}}

When anhydrous hydrogen sulfide is passed through a solution of aluminum bromide in carbon disulfide, a precipitate of the complex compound precipitates ^[10] :

{\mathsf {AlBr_{3}+H_{2}S=AlBr_{3}}}\cdot {\mathsf {H_{2}S}}

{\ displaystyle {\ mathsf {AlBr_ {3} + H_ {2} S = AlBr_ {3}}} \ cdot {\ mathsf {H_ {2} S}}}

At high temperature decomposes:

{\mathsf {2AlBr_{3}=2Al+3Br_{2}}}

{\ displaystyle {\ mathsf {2AlBr_ {3} = 2Al + 3Br_ {2}}}}

When heating aluminum bromide with aluminum in the gas phase (1000 ° C), an unstable aluminum monobromide is formed ^[2] :

{\mathsf {AlBr_{3}+2Al\leftrightarrows 3AlBr}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 2Al \ leftrightarrows 3AlBr}}}

With lithium hydride forms aluminum hydride :

{\mathsf {AlBr_{3}+4LiH=Li[AlH_{4}]+3LiBr}}

{\ displaystyle {\ mathsf {AlBr_ {3} + 4LiH = Li [AlH_ {4}] + 3LiBr}}}

Aluminum bromide - a strong acceptor of electron pairs ( Lewis acid ) - easily attaches to donor molecules (this, in particular, is based on its use in organic synthesis) ^[7] :

{\mathsf {AlBr_{3}+C_{2}H_{5}Br}}\rightarrow {\mathsf {[C_{2}H_{5}]^{+}[AlBr_{4}]^{-}}}

{\ displaystyle {\ mathsf {AlBr_ {3} + C_ {2} H_ {5} Br}} \ rightarrow {\ mathsf {[C_ {2} H_ {5}] ^ {+} [AlBr_ {4}] ^ {-}}}}

Getting

Anhydrous aluminum bromide is obtained by the interaction of simple substances ( Al and Br ₂ ) ^[11] :

${\mathsf {2Al+3Br_{2}=Al_{2}Br_{6}}}$ ${\ displaystyle {\ mathsf {2Al + 3Br_ {2} = Al_ {2} Br_ {6}}}}$

An aqueous solution can be obtained by the reaction of aluminum chips with hydrobromic acid :

${\mathsf {2Al+6HBr=2AlBr_{3}+3H_{2}\!\uparrow }}$ ${\ displaystyle {\ mathsf {2Al + 6HBr = 2AlBr_ {3} + 3H_ {2} \! \ uparrow}}}$

Application

The commercial use of aluminum bromide is currently relatively small.

Aluminum bromide is included as the main component in the composition of xylene electrolytes for the electrodeposition of aluminum coatings ^[12] .

Anhydrous aluminum bromide is used in organic synthesis, in particular, in the Friedel-Crafts alkylation reaction , by analogy with aluminum chloride .

The compound can act as a catalyst in the reaction of isomerization of bromoalkanes, for example ^[13] :

${\mathsf {CH_{3}\!\!-\!\!CH_{2}\!\!-\!\!CH_{2}Br\ {\xrightarrow {AlBr_{3}}}\ CH_{3}\!\!-\!\!CHBr\!\!-\!\!CH_{3}}}$ ${\ displaystyle {\ mathsf {CH_ {3} \! \! - \! \! CH_ {2} \! \! - \! \! CH_ {2} Br \ {\ xrightarrow {AlBr_ {3}}} \ CH_ {3} \! \! - \! \! CHBr \! \! - \! \! CH_ {3}}}}$

Also, aluminum bromide can act as a brominating agent, for example, in a reaction with chloroform ^[14] :

${\mathsf {CHCl_{3}+HBr\ {\xrightarrow {90\ ^{o}C;\ AlBr_{3}}}\ CHBrCl_{2}+HCl}}$ ${\ displaystyle {\ mathsf {CHCl_ {3} + HBr \ {\ xrightarrow {90 \ ^ {o} C; \ AlBr_ {3}}} \ CHBrCl_ {2} + HCl}}}$

Health Hazard

In contact with skin, aluminum bromide can cause burns.

The compound is moderately toxic: LD ₅₀ (rats) ≈ 1600 mg / kg (oral); LD ₅₀ (rats) ≈ 815 mg / kg (intraperitoneally) ^[15] .

Notes

↑ ¹ ² Lidin R.A., Andreeva L.L., Molochko V.A. Chapter 3. Physical properties // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 74. - ISBN 5-7107-8085-5 .
↑ ¹ ² Turova N.Ya. Inorganic chemistry in the tables. - M .: Higher Chemical College of the Russian Academy of Sciences, 1997. - S. 67.
↑ Lidin R.A., Andreeva L.L., Molochko V.A. Part IV Thermodynamics. Chapter 1. Enthalpy of formation, entropy and Gibbs energy of the formation of substances // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 441. - ISBN 5-7107-8085-5 .
↑ Chambers C., Holliday AK Modern inorganic chemistry. - Chichester: Butterworth & Co (Publishers) Ltd, 1975 .-- P. 153.
↑ Drozdov A.A., Zlomanov V.P., Mazo G.N., Spiridonov F.M. Inorganic chemistry. T.2: Chemistry of Intransitive Elements / Ed. Acad. Yu.N. Tretyakova. - M .: Publishing Center "Academy", 2004. - T. 2. - P. 86. - ISBN 5-7695-1436-1 .
↑ Lidin R.A., Andreeva L.L., Molochko V.A. Chapter 6. Binding energy for polyatomic particles // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 384. - ISBN 5-7107-8085-5 .
↑ ¹ ² Akhmetov N.S. General and inorganic chemistry. Textbook for high schools. - 4th ed., Revised. - M .: "Higher School", 2001. - S. 498. - ISBN 5-06-003363-5 .
↑ Aluminum // Chemical Encyclopedia / Editor-in-Chief I. L. Knunyants. - M .: "Soviet Encyclopedia", 1988. - T. 1. - P. 207.
↑ Lidin R.A., Andreeva L.L., Molochko V.A. Part VII. The density of water and aqueous solutions. Chapter 3. Salts // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 641. - ISBN 5-7107-8085-5 .
↑ Hoffman W., Rüdorf W., Haas A. et al. A Guide to Inorganic Synthesis. - Per. with it., ed. G. Brauer. - M .: "The World", 1985. - T. 3. - S. 899.
↑ Bromine-Aluminum Interaction March 4, 2016 Archived on Wayback Machine - a video experience in the Unified Collection of Digital Educational Resources
↑ Spiridonov B.A., Fedyanin V.I. Study of the process of electrodeposition of aluminum from para-xylene electrolytes. (unopened) (inaccessible link) . Russian Society of Electroplating Technicians and Specialists in the Field of Surface Treatment. Date of treatment October 26, 2009. Archived May 18, 2008.
↑ Douwes HSA The kinetics of the aluminum bromide catalyzed isomerization of 1-propyl bromide (Eng.) // Journal of Molecular Catalysis A: Chemical. - 2005. - Vol. 240 , no. 1-2 . - P. 82-90 .
↑ Unated States Patent 2553518. Production of Organic Bromides (English) (pdf). FreePatentsOnline (May, 1951). Date of treatment October 26, 2009. Archived April 9, 2012.
↑ Safety data for aluminum bromide . The Physical and Theoretical Chemistry Laboratory Oxford University. Date of treatment October 26, 2009. Archived April 9, 2012.

Literature

Downs AJ Chemistry of aluminum, gallium, indium, and thallium. - First edition. - London: Chapman & Hall, 1993 .-- 526 p. - ISBN 0-7514-0103-X .

[const-1] ¹ ² Lidin R.A., Andreeva L.L., Molochko V.A. Chapter 3. Physical properties // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 74. - ISBN 5-7107-8085-5 .

[neorganic-2] ¹ ² Turova N.Ya. Inorganic chemistry in the tables. - M .: Higher Chemical College of the Russian Academy of Sciences, 1997. - S. 67.

[const2-3] Lidin R.A., Andreeva L.L., Molochko V.A. Part IV Thermodynamics. Chapter 1. Enthalpy of formation, entropy and Gibbs energy of the formation of substances // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 441. - ISBN 5-7107-8085-5 .

[4] Chambers C., Holliday AK Modern inorganic chemistry. - Chichester: Butterworth & Co (Publishers) Ltd, 1975 .-- P. 153.

[5] Drozdov A.A., Zlomanov V.P., Mazo G.N., Spiridonov F.M. Inorganic chemistry. T.2: Chemistry of Intransitive Elements / Ed. Acad. Yu.N. Tretyakova. - M .: Publishing Center "Academy", 2004. - T. 2. - P. 86. - ISBN 5-7695-1436-1 .

[6] Lidin R.A., Andreeva L.L., Molochko V.A. Chapter 6. Binding energy for polyatomic particles // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 384. - ISBN 5-7107-8085-5 .

[ahmetov-7] ¹ ² Akhmetov N.S. General and inorganic chemistry. Textbook for high schools. - 4th ed., Revised. - M .: "Higher School", 2001. - S. 498. - ISBN 5-06-003363-5 .

[chemen-8] Aluminum // Chemical Encyclopedia / Editor-in-Chief I. L. Knunyants. - M .: "Soviet Encyclopedia", 1988. - T. 1. - P. 207.

[9] Lidin R.A., Andreeva L.L., Molochko V.A. Part VII. The density of water and aqueous solutions. Chapter 3. Salts // Constants of inorganic substances: reference book / Edited by prof. R.A. Lidina. - 2nd ed., Revised. and additional .. - M .: "Bustard", 2006. - S. 641. - ISBN 5-7107-8085-5 .

[10] Hoffman W., Rüdorf W., Haas A. et al. A Guide to Inorganic Synthesis. - Per. with it., ed. G. Brauer. - M .: "The World", 1985. - T. 3. - S. 899.

[11] Bromine-Aluminum Interaction March 4, 2016 Archived on Wayback Machine - a video experience in the Unified Collection of Digital Educational Resources

[12] Spiridonov B.A., Fedyanin V.I. Study of the process of electrodeposition of aluminum from para-xylene electrolytes. (unopened) (inaccessible link) . Russian Society of Electroplating Technicians and Specialists in the Field of Surface Treatment. Date of treatment October 26, 2009. Archived May 18, 2008.

[13] Douwes HSA The kinetics of the aluminum bromide catalyzed isomerization of 1-propyl bromide (Eng.) // Journal of Molecular Catalysis A: Chemical. - 2005. - Vol. 240 , no. 1-2 . - P. 82-90 .

[14] Unated States Patent 2553518. Production of Organic Bromides (English) (pdf). FreePatentsOnline (May, 1951). Date of treatment October 26, 2009. Archived April 9, 2012.

[15] Safety data for aluminum bromide . The Physical and Theoretical Chemistry Laboratory Oxford University. Date of treatment October 26, 2009. Archived April 9, 2012.

Aluminum bromide


Are common
Systematic name	Aluminum bromide
Chem. formula	AlBr ₃ , Al ₂ Br ₆
Rat formula	AlBr ₃
Physical properties
condition	solid
Molar mass	266.69 g / mol
Density	3,205 ^[1]
Thermal properties
T. melt.	97.5 ^[1]
T. bale.	255 ^[2] ° C
Enthalpy of Education	- 514; - 422 (AlBr ₃ , gas); - 971 (Al ₂ Br ₆ , gas) ^[3] kJ / mol
Structure
Crystal structure	monoclinic
Classification
Reg. CAS number	7727-15-3
PubChem
Reg. EINECS number	231-779-7
Smiles
Inchi
RTECS
UN number
ChemSpider
Security
Toxicity	one 3 one