Difference between revisions of "Bromine"

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[[File:Bromine.PNG|thumb|255x255px|Bromine liquid and vapor being poured into a test tube (youtu.be/qc4ZhcY09Lk)]]
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{{Infobox element
 +
<!-- top -->
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|image name=Bromine.PNG
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|image alt=
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|image size=280
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|image name comment=Bromine liquid and vapor being poured into a test tube (youtu.be/qc4ZhcY09Lk)
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|image name 2=
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|image alt 2=
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|image size 2=
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|image name 2 comment=
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<!-- General properties -->
 +
|name=Bromine
 +
|symbol=Br
 +
|pronounce=
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|pronounce ref=
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|pronounce comment=
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|pronounce 2=
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|alt name=
 +
|alt names=
 +
|allotropes=
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|appearance=Red-brown liquid
 +
<!-- Periodic table -->
 +
|above=[[Chlorine|Cl]]
 +
|below=[[Iodine|I]]
 +
|left=[[Selenium]]
 +
|right=[[Krypton]]
 +
|number=35
 +
|atomic mass=79.904
 +
|atomic mass 2=
 +
|atomic mass ref=
 +
|atomic mass comment=
 +
|series=
 +
|series ref=
 +
|series comment=
 +
|series color=
 +
|group=17
 +
|group ref=
 +
|group comment=(halogens)
 +
|period=4
 +
|period ref=
 +
|period comment=
 +
|block=p
 +
|block ref=
 +
|block comment=
 +
|electron configuration=[Ar] 3d<sup>10</sup> 4s<sup>2</sup> 4p<sup>5</sup>
 +
|electron configuration ref=
 +
|electron configuration comment=
 +
|electrons per shell=2, 8, 18, 7
 +
|electrons per shell ref=
 +
|electrons per shell comment=
 +
<!-- Physical properties -->
 +
|physical properties comment=
 +
|color=Reddish-brown
 +
|phase=Liquid
 +
|phase ref=
 +
|phase comment=
 +
|melting point K=265.8
 +
|melting point C=−7.2
 +
|melting point F=​19
 +
|melting point ref=
 +
|melting point comment=
 +
|boiling point K=332.0​
 +
|boiling point C=58.8
 +
|boiling point F=137.8
 +
|boiling point ref=
 +
|boiling point comment=
 +
|sublimation point K=
 +
|sublimation point C=
 +
|sublimation point F=
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|sublimation point ref=
 +
|sublimation point comment=
 +
|density gplstp=
 +
|density gplstp ref=
 +
|density gplstp comment=
 +
|density gpcm3nrt=3.1028
 +
|density gpcm3nrt ref=
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|density gpcm3nrt comment=
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|density gpcm3nrt 2=
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|density gpcm3nrt 2 ref=
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|density gpcm3nrt 2 comment=
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|density gpcm3nrt 3=
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|density gpcm3nrt 3 ref=
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|density gpcm3nrt 3 comment=
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|density gpcm3mp=
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|density gpcm3mp ref=
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|density gpcm3mp comment=
 +
|density gpcm3bp=
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|density gpcm3bp ref=
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|density gpcm3bp comment=
 +
|molar volume=
 +
|molar volume unit =
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|molar volume ref=
 +
|molar volume comment=
 +
|triple point K=265.90
 +
|triple point kPa=​5.8
 +
|triple point ref=
 +
|triple point comment=
 +
|triple point K 2=
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|triple point kPa 2=
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|triple point 2 ref=
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|triple point 2 comment=
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|critical point K=588
 +
|critical point MPa=10.34
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|critical point ref=
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|critical point comment=
 +
|heat fusion=10.571
 +
|heat fusion ref=
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|heat fusion comment=
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|heat fusion 2=
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|heat fusion 2 ref=
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|heat fusion 2 comment=
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|heat vaporization=29.96
 +
|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=75.69
 +
|heat capacity ref=
 +
|heat capacity comment=
 +
|heat capacity 2=
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|heat capacity 2 ref=
 +
|heat capacity 2 comment=
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|vapor pressure 1=185
 +
|vapor pressure 10=201
 +
|vapor pressure 100=220
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|vapor pressure 1 k=244
 +
|vapor pressure 10 k=276
 +
|vapor pressure 100 k=332
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|vapor pressure ref=
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|vapor pressure comment=
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|vapor pressure 1 2=
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|vapor pressure 10 2=
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|vapor pressure 100 2=
 +
|vapor pressure 1 k 2=
 +
|vapor pressure 10 k 2=
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|vapor pressure 100 k 2=
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|vapor pressure 2 ref=
 +
|vapor pressure 2 comment=
 +
<!-- Atomic properties -->
 +
|atomic properties comment=
 +
|oxidation states=7, 5, 4, 3, '''1''', '''−1'''
 +
|oxidation states ref=
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|oxidation states comment=(a strongly acidic oxide)
 +
|electronegativity=2.96
 +
|electronegativity ref=
 +
|electronegativity comment=
 +
|ionization energy 1=1139.9
 +
|ionization energy 1 ref=
 +
|ionization energy 1 comment=
 +
|ionization energy 2=2103
 +
|ionization energy 2 ref=
 +
|ionization energy 2 comment=
 +
|ionization energy 3=3470
 +
|ionization energy 3 ref=
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|ionization energy 3 comment=
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|number of ionization energies=
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|ionization energy ref=
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|ionization energy comment=
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|atomic radius=120
 +
|atomic radius ref=
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|atomic radius comment=
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|atomic radius calculated=
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|atomic radius calculated ref=
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|atomic radius calculated comment=
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|covalent radius=120±3
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=185
 +
|Van der Waals radius ref=
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|Van der Waals radius comment=
 +
<!-- Miscellanea -->
 +
|crystal structure=
 +
|crystal structure prefix=
 +
|crystal structure ref=
 +
|crystal structure comment=Orthorhombic
 +
|crystal structure 2=
 +
|crystal structure 2 prefix=
 +
|crystal structure 2 ref=
 +
|crystal structure 2 comment=
 +
|speed of sound=
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|speed of sound ref=
 +
|speed of sound comment=
 +
|speed of sound rod at 20=206
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|speed of sound rod at 20 ref=
 +
|speed of sound rod at 20 comment=
 +
|speed of sound rod at r.t.=
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|speed of sound rod at r.t. ref=
 +
|speed of sound rod at r.t. comment=
 +
|thermal expansion=
 +
|thermal expansion ref=
 +
|thermal expansion comment=
 +
|thermal expansion at 25=
 +
|thermal expansion at 25 ref=
 +
|thermal expansion at 25 comment=
 +
|thermal conductivity=0.122
 +
|thermal conductivity ref=
 +
|thermal conductivity comment=
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|thermal conductivity 2=
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|thermal conductivity 2 ref=
 +
|thermal conductivity 2 comment=
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|thermal diffusivity=
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|thermal diffusivity ref=
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|thermal diffusivity comment=
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|electrical resistivity=7.8×10<sup>10</sup>
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|electrical resistivity unit prefix=
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|electrical resistivity ref=
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|electrical resistivity comment=
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|electrical resistivity at 0=
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|electrical resistivity at 0 ref=
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|electrical resistivity at 0 comment=
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|electrical resistivity at 20=
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|electrical resistivity at 20 ref=
 +
|electrical resistivity at 20 comment=
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|band gap=
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|band gap ref=
 +
|band gap comment=
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|Curie point K=
 +
|Curie point ref=
 +
|Curie point comment=
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|magnetic ordering=Diamagnetic
 +
|magnetic ordering ref=
 +
|magnetic ordering comment=
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|tensile strength=
 +
|tensile strength ref=
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|tensile strength comment=
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|Young's modulus=
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=
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|Mohs hardness ref=
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|Mohs hardness comment=
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|Mohs hardness 2=
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|Mohs hardness 2 ref=
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|Mohs hardness 2 comment=
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|Vickers hardness=
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7726-95-6
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|naming=
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|predicted by=
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|prediction date ref=
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|prediction date=
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|discovered by=
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|discovery date ref=
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|discovery date=
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|first isolation by=
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|first isolation date ref=
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|first isolation date=
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|discovery and first isolation by=Antoine Jérôme Balard and Carl Jacob Löwig (1825)
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|named by=
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|named date ref=
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|named date=
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|history comment label=
 +
|history comment=
 +
<!-- Isotopes -->
 +
|isotopes=
 +
|isotopes comment=
 +
|engvar=
 +
}}
 
'''Bromine''' is a chemical element, the third lightest [[halogen]] on the periodic table, and the only nonmetal that is liquid at room temperature. It has the chemical symbol '''Br '''and atomic number 35. This deep red-brown liquid is highly sought-after as a reagent and collectible specimen, though it is very dangerous and difficult to manage and store.  
 
'''Bromine''' is a chemical element, the third lightest [[halogen]] on the periodic table, and the only nonmetal that is liquid at room temperature. It has the chemical symbol '''Br '''and atomic number 35. This deep red-brown liquid is highly sought-after as a reagent and collectible specimen, though it is very dangerous and difficult to manage and store.  
  
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Bromine properties are a mix [[chlorine]] and [[iodine]], as can be expected. Less oxidizing than chlorine and fluorine, and more so than iodine, bromine will only displace iodine from [[potassium iodide|iodide]] salts.  
 
Bromine properties are a mix [[chlorine]] and [[iodine]], as can be expected. Less oxidizing than chlorine and fluorine, and more so than iodine, bromine will only displace iodine from [[potassium iodide|iodide]] salts.  
  
−
Bromine is quite reactive towards many elements, reacting violently with most metals.  It is also capable of reaction with many nonmetals and metalloids, such as the solid chalcogens, pnictogens, and at high temperature silicon and germanium.
+
Bromine is quite reactive towards many elements, reacting violently with most metals.  It is also capable of reaction with many nonmetals and [[metalloid]]s, such as the solid chalcogens, pnictogens, and at high temperature [[silicon]] and [[germanium]].
  
−
A classic reaction is to put a small amount of [[aluminium]] foil in liquid bromine. After a considerable delay (often 30 seconds or so) due to the [[Passivation|oxide layer]], the aluminium melts and catches fire. This throws out white sparks with large clouds of orange bromine and white [[aluminium tribromide]] vapor. Done intentionally in a controlled environment, this creates a spectacular display. However, if done accidentally without precaution, this reaction is disastrous.
+
A classic reaction is to put a small amount of [[aluminium]] foil in liquid bromine. After a considerable delay (often 30 seconds or so) due to the [[Passivation|oxide layer]], the aluminium melts and catches fire. This throws out white sparks with large clouds of orange bromine and white [[aluminium bromide]] vapor. Done intentionally in a controlled environment, this creates a spectacular display. However, if done accidentally without precaution, this reaction is disastrous.
  
−
Bromine finds many important uses in organic chemistry, primarily in the introduction of bromine atoms into a compound. Bromine will react with alkenes, alkynes, and many aromatic compounds quite readily. In combination with catalytic amounts of phosphorus, it is also capable of α-chlorination of carboxylic acids and is the reagent of choice from the bromination of sensitive alcohols. Both of these reactions occur via a [[phosphorus tribromide]]; alternatively phosphorus tribromide can be used directly instead.
+
Bromine finds many important uses in organic chemistry, primarily in the introduction of bromine atoms into a compound. Bromine will react with alkenes, alkynes, and many aromatic compounds quite readily. In combination with catalytic amounts of phosphorus, it is also capable of α-chlorination of carboxylic acids and is the reagent of choice from the bromination of sensitive alcohols. Both of these reactions occur via a [[phosphorus tribromide]]; alternatively phosphorus tribromide can be used directly instead.
  
 
===Physical===
 
===Physical===
−
Like [[chloride]], the [[bromide]] ion generally has no affect the colour of a compound, but the element itself is a very vivid orange/red both as a liquid and a gas, similar to [[nitrogen dioxide]]. It can be poured with ease as it is not very viscous, and wets glass when it has a water content, but completely dry it does not. Thus, drying bromine samples completely before [[ampoule|ampouling]] them is desired.  
+
Like chloride, the bromide ion generally has no affect the color of a compound, but the element itself is a very vivid orange/red both as a liquid and a gas, similar to [[nitrogen dioxide]]. It can be poured with ease as it is not very viscous, and wets glass when it has a water content, but completely dry it does not. Thus, drying bromine samples completely before [[ampoule|ampouling]] them is desired.  
  
 
The smell of bromine is somewhat difficult to describe, sometimes being called halfway between chlorine and iodine but still very distinct. It is irritating, not to mention dangerous, to breathe.
 
The smell of bromine is somewhat difficult to describe, sometimes being called halfway between chlorine and iodine but still very distinct. It is irritating, not to mention dangerous, to breathe.
 +
 +
Bromine is moderately soluble in water, and readily soluble in bromide solutions. By oxidizing bromides, one gets concentrated solutions of bromine in bromide (they are usually red in color and fume with bromine gas but unlike bromine, they are noticeably transparent), which require distillation to obtain the pure element.
  
 
==Availability==
 
==Availability==
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There are a few methods to producing elemental bromine, none of which should be taken lightly.  
 
There are a few methods to producing elemental bromine, none of which should be taken lightly.  
  
−
Depending on the chemicals available and the level of purity needed, different methods exist. Probably the most popular method involves [http://woelen.homescience.net/science/chem/exps/OTC_bromine/index.html oxidation of bromine to bromate via electrolysis]. Other methods involve displacement with chlorine, but that leads to interhalogen compounds and can be quite difficult.  
+
Depending on the chemicals available and the level of purity needed, different methods exist. Probably the most popular method involves [http://woelen.homescience.net/science/chem/exps/OTC_bromine/index.html oxidation of bromine to bromate via electrolysis]. Other methods involve displacement with chlorine, but that leads to [[interhalogen]] compounds and can be quite difficult.  
  
−
A high-yield synthesis with relative ease involves the oxidation of [[sodium bromide|sodium]] or [[potassium bromide]] with [[potassium permanganate]] and an excess of [[sulfuric acid]], followed by careful distillation in a fume hood or outside. In this process, the potassium permanganate is added to a saturated solution of the bromide salt, and the mixture transferred to the boiling flask of a simple [[distillation]] setup. Sulfuric acid is added dropwise using an addition funnel throughout the distillation, as the addition is very exothermic and can cause a very destructive runaway reaction to proceed if it is not added carefully. Bromine spills, as well as residual bromine remaining in the apparatus afterward, can be neutralized using alkaline solutions of [[sodium bisulfite]] or [[sodium metabisulfite]](the alkalinity coming from [[sodium hydroxide]]), or [[sulfur dioxide]]. Bromine produced in this process will contain a substantial amount of water, which can be removed by a combination of mechanical separation using a [[separatory funnel]] or [[pipette]], and drying using an agent such as concentrated sulfuric acid.  
+
A high-yield synthesis with relative ease involves the oxidation of [[sodium bromide|sodium]] or [[potassium bromide]] with [[potassium permanganate]] and an excess of [[sulfuric acid]], followed by careful distillation in a fume hood or outside. In this process, the potassium permanganate is added to a saturated solution of the bromide salt, and the mixture transferred to the boiling flask of a simple [[distillation]] setup. Sulfuric acid is added dropwise using an addition funnel throughout the distillation, as the addition is very exothermic and can cause a very destructive runaway reaction to proceed if it is not added carefully. Bromine spills, as well as residual bromine remaining in the apparatus afterward, can be neutralized using alkaline solutions of [[sodium bisulfite]] or [[sodium metabisulfite]](the alkalinity coming from [[sodium hydroxide]]), or [[sulfur dioxide]]. Bromine produced in this process will contain a substantial amount of water, which can be removed by a combination of mechanical separation using a [[separatory funnel]] or [[pipette]], and drying using an agent such as concentrated sulfuric acid. Rather than try to shake the separatory funnel with the bromine and sulfuric acid, which is risky, adding sulfuric acid to the bromine in a flask cooled in an ice bath can be much safer. Then separate using a separatory funnel once the mixture has been stirred.
  
 
==Projects==
 
==Projects==
 +
*Make [[phosphorus tribromide]]
 
*Organobromine compounds
 
*Organobromine compounds
−
*[[Bromine water]]
+
*Make [[bromine water]]
 
*Interhalogen bromine compounds
 
*Interhalogen bromine compounds
 
*Make sulfuric acid via the electrobromine process
 
*Make sulfuric acid via the electrobromine process
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One who intends to make or use bromine should do lots of research into the risks, safety considerations and hazards of the element. From the damage that the corrosive bromine does on contact to skin, to the toxic effects the thick vapors have on lung tissue, and to the violent reaction bromine undergoes with reducing agents (especially aluminium), bromine is seen by many who have made it as 'an evil element'. While very intriguing in its properties, it is definitely a chemical for the more experienced chemist.  
 
One who intends to make or use bromine should do lots of research into the risks, safety considerations and hazards of the element. From the damage that the corrosive bromine does on contact to skin, to the toxic effects the thick vapors have on lung tissue, and to the violent reaction bromine undergoes with reducing agents (especially aluminium), bromine is seen by many who have made it as 'an evil element'. While very intriguing in its properties, it is definitely a chemical for the more experienced chemist.  
  
−
Liquid bromine is extremely corrosive, toxic and oxidizing. It fumes very easily even at low temperatures and reactions with reducing agents often heat it up creating large amounts of thick, toxic orange bromine vapour that is not safe to breath.  
+
Liquid bromine is extremely corrosive, toxic and oxidizing. It fumes very easily even at low temperatures and reactions with reducing agents often heat it up creating large amounts of thick, toxic orange bromine vapor that is not safe to breath.  
  
 
Skin contact with this element should be avoided at all costs. Inhaling of bromine vapor and or bromides has shown to cause temporary erectile dysfunction.
 
Skin contact with this element should be avoided at all costs. Inhaling of bromine vapor and or bromides has shown to cause temporary erectile dysfunction.
  
−
Solutions of sodium hydroxide and sodium sulfite/bisulfite/metabisulfite or thiosulphates should be on standby to neutralize any stray bromine to harmless bromide salts.  
+
Solutions of sodium hydroxide and sodium sulfite/bisulfite/metabisulfite or thiosulfates should be on standby to neutralize any stray bromine to harmless bromide salts.  
  
 
=== Storage ===
 
=== Storage ===
−
Bromine is notorious for escaping it's containers. The only lasting solution is to properly seal it in a glass ampule. Glass bottles with a PTFE lid can be used for moderate amounts of time, though the bromine should be kept away from steel objects as the vapor causes them to rust quickly. Usually, if it's stored in a glass container, the bottle is kept in a special cabinet and the lid is sealed with [https://en.wikipedia.org/wiki/Parafilm Parafilm] tape. The paraffin tape is changed periodically, especially when it starts to turn brown. Alternatively, storing the bromine in a laboratory freezer greatly reduces the volatility and, consequently, the ease of storage.
+
Bromine is notorious for escaping its containers. The only lasting solution is to properly seal it in a glass ampule. Glass bottles with a PTFE lid can be used for moderate amounts of time, though the bromine should be kept away from steel objects as the vapor causes them to rust quickly. Usually, if it's stored in a glass container, the bottle is kept in a special cabinet and the lid is sealed with [[parafilm]] tape. The paraffin tape is changed periodically, especially when it starts to turn brown. Alternatively, storing the bromine in a laboratory freezer greatly reduces the volatility and, consequently, eases storage.
  
 
===Disposal===
 
===Disposal===

Latest revision as of 11:41, 25 June 2023

Bromine,  35Br
Bromine.PNG
Bromine liquid and vapor being poured into a test tube (youtu.be/qc4ZhcY09Lk)
General properties
Name, symbol Bromine, Br
Appearance Red-brown liquid
Bromine in the periodic table
Cl
↑
Br
↓
I
Selenium ← Bromine → Krypton
Atomic number 35
Standard atomic weight (Ar) 79.904
Group, block (halogens); p-block
Period period 4
Electron configuration [Ar] 3d10 4s2 4p5
per shell
 2, 8, 18, 7
Physical properties
Reddish-brown
Phase Liquid
Melting point 265.8 K ​(−7.2 °C, ​​19 °F)
Boiling point 332.0​ K ​(58.8 °C, ​137.8 °F)
Density near r.t. 3.1028 g/cm3
Triple point 265.90 K, ​​5.8 kPa
Critical point 588 K, 10.34 MPa
Heat of fusion 10.571 kJ/mol
Heat of 29.96 kJ/mol
Molar heat capacity 75.69 J/(mol·K)
 pressure
Atomic properties
Oxidation states 7, 5, 4, 3, 1, −1 ​(a strongly acidic oxide)
Electronegativity Pauling scale: 2.96
energies 1st: 1139.9 kJ/mol
2nd: 2103 kJ/mol
3rd: 3470 kJ/mol
Atomic radius empirical: 120 pm
Covalent radius 120±3 pm
Van der Waals radius 185 pm
Miscellanea
Crystal structure ​Orthorhombic
Speed of sound thin rod 206 m/s (at 20 °C)
Thermal conductivity 0.122 W/(m·K)
Electrical resistivity 7.8×1010 Ω·m
Magnetic ordering Diamagnetic
CAS Registry Number 7726-95-6
Discovery and first isolation Antoine Jérôme Balard and Carl Jacob Löwig (1825)
· references

Bromine is a chemical element, the third lightest halogen on the periodic table, and the only nonmetal that is liquid at room temperature. It has the chemical symbol Br and atomic number 35. This deep red-brown liquid is highly sought-after as a reagent and collectible specimen, though it is very dangerous and difficult to manage and store.

Properties

Chemical

Bromine properties are a mix chlorine and iodine, as can be expected. Less oxidizing than chlorine and fluorine, and more so than iodine, bromine will only displace iodine from iodide salts.

Bromine is quite reactive towards many elements, reacting violently with most metals. It is also capable of reaction with many nonmetals and metalloids, such as the solid chalcogens, pnictogens, and at high temperature silicon and germanium.

A classic reaction is to put a small amount of aluminium foil in liquid bromine. After a considerable delay (often 30 seconds or so) due to the oxide layer, the aluminium melts and catches fire. This throws out white sparks with large clouds of orange bromine and white aluminium bromide vapor. Done intentionally in a controlled environment, this creates a spectacular display. However, if done accidentally without precaution, this reaction is disastrous.

Bromine finds many important uses in organic chemistry, primarily in the introduction of bromine atoms into a compound. Bromine will react with alkenes, alkynes, and many aromatic compounds quite readily. In combination with catalytic amounts of phosphorus, it is also capable of α-chlorination of carboxylic acids and is the reagent of choice from the bromination of sensitive alcohols. Both of these reactions occur via a phosphorus tribromide; alternatively phosphorus tribromide can be used directly instead.

Physical

Like chloride, the bromide ion generally has no affect the color of a compound, but the element itself is a very vivid orange/red both as a liquid and a gas, similar to nitrogen dioxide. It can be poured with ease as it is not very viscous, and wets glass when it has a water content, but completely dry it does not. Thus, drying bromine samples completely before ampouling them is desired.

The smell of bromine is somewhat difficult to describe, sometimes being called halfway between chlorine and iodine but still very distinct. It is irritating, not to mention dangerous, to breathe.

Bromine is moderately soluble in water, and readily soluble in bromide solutions. By oxidizing bromides, one gets concentrated solutions of bromine in bromide (they are usually red in color and fume with bromine gas but unlike bromine, they are noticeably transparent), which require distillation to obtain the pure element.

Availability

Ampouled bromine is available to chemical companies and institutions, but is not usually available to individuals due to shipping restrictions and health and safety issues for such a dangerous chemical.

Bromide salts can be found online relatively cheap with no shipping restrictions. Bromides can sometimes also be found in pool stores as a replacement to traditional chlorine pool treatments.

Preparation

There are a few methods to producing elemental bromine, none of which should be taken lightly.

Depending on the chemicals available and the level of purity needed, different methods exist. Probably the most popular method involves oxidation of bromine to bromate via electrolysis. Other methods involve displacement with chlorine, but that leads to interhalogen compounds and can be quite difficult.

A high-yield synthesis with relative ease involves the oxidation of sodium or potassium bromide with potassium permanganate and an excess of sulfuric acid, followed by careful distillation in a fume hood or outside. In this process, the potassium permanganate is added to a saturated solution of the bromide salt, and the mixture transferred to the boiling flask of a simple distillation setup. Sulfuric acid is added dropwise using an addition funnel throughout the distillation, as the addition is very exothermic and can cause a very destructive runaway reaction to proceed if it is not added carefully. Bromine spills, as well as residual bromine remaining in the apparatus afterward, can be neutralized using alkaline solutions of sodium bisulfite or sodium metabisulfite(the alkalinity coming from sodium hydroxide), or sulfur dioxide. Bromine produced in this process will contain a substantial amount of water, which can be removed by a combination of mechanical separation using a separatory funnel or pipette, and drying using an agent such as concentrated sulfuric acid. Rather than try to shake the separatory funnel with the bromine and sulfuric acid, which is risky, adding sulfuric acid to the bromine in a flask cooled in an ice bath can be much safer. Then separate using a separatory funnel once the mixture has been stirred.

Projects

Handling

Safety

One who intends to make or use bromine should do lots of research into the risks, safety considerations and hazards of the element. From the damage that the corrosive bromine does on contact to skin, to the toxic effects the thick vapors have on lung tissue, and to the violent reaction bromine undergoes with reducing agents (especially aluminium), bromine is seen by many who have made it as 'an evil element'. While very intriguing in its properties, it is definitely a chemical for the more experienced chemist.

Liquid bromine is extremely corrosive, toxic and oxidizing. It fumes very easily even at low temperatures and reactions with reducing agents often heat it up creating large amounts of thick, toxic orange bromine vapor that is not safe to breath.

Skin contact with this element should be avoided at all costs. Inhaling of bromine vapor and or bromides has shown to cause temporary erectile dysfunction.

Solutions of sodium hydroxide and sodium sulfite/bisulfite/metabisulfite or thiosulfates should be on standby to neutralize any stray bromine to harmless bromide salts.

Storage

Bromine is notorious for escaping its containers. The only lasting solution is to properly seal it in a glass ampule. Glass bottles with a PTFE lid can be used for moderate amounts of time, though the bromine should be kept away from steel objects as the vapor causes them to rust quickly. Usually, if it's stored in a glass container, the bottle is kept in a special cabinet and the lid is sealed with parafilm tape. The paraffin tape is changed periodically, especially when it starts to turn brown. Alternatively, storing the bromine in a laboratory freezer greatly reduces the volatility and, consequently, eases storage.

Disposal

Bromine can be neutralized with reducing agents such as sodium thiosulfate and sodium metabisulfite which reduce it to harmless bromide ions.

References

Relevant Sciencemadness threads

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