User:Florencio Q/Bromuro de hidrógeno

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New article name Bromuro de hidrógeno.

Florencio Q/Bromuro de hidrógeno
Skeletal formula of hydrogen bromide with the explicit hydrogen and a measurement added Spacefill model of hydrogen bromide
Identifiers
CAS number 10035-10-6 YesY
PubChem 260
ChemSpider 255 YesY
EC number 233-113-0
UN number 1048
KEGG C13645 N
MeSH Hydrobromic+Acid
ChEBI CHEBI:47266 YesY
ChEMBL CHEMBL1231461 N
RTECS number MW3850000
Beilstein Reference 3587158
Jmol-3D images Image 1
Properties
Molecular formula HBr
Molar mass 80.91 g mol−1
Appearance colorless gas
Odor Acre
Density 3.307 g/dm3
Melting point −86.9 °C (−124.4 °F; 186.2 K)
Boiling point −66.8 °C (−88.2 °F; 206.3 K)
Solubility in water 221 g/100 mL (0 °C)
204 g/100 mL (15 °C)
193 g/100 mL (20 °C) 130 g/100 mL (100 °C)
Solubility soluble in alcohol, organic solvents
Vapor pressure 2.308 MPa (at 21 °C)
Acidity (pKa) ~–9 [2]
Basicity (pKb) ~23
Refractive index (nD) 1.325
Structure
Molecular shape Linear
Dipole moment 820 mD
Thermochemistry
Specific
heat capacity
C
350.7 mJ K-1 g-1
Std molar
entropy
So298
198.696-198.704 J K-1 mol-1[3]
Std enthalpy of
formation
ΔfHo298
-36.45--36.13 kJ mol-1[3]
Hazards
MSDS hazard.com

physchem.ox.ac.uk

GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H314, H335
GHS precautionary statements P261, P280, P305+351+338, P310
EU Index 035-002-00-0
EU classification Corrosive C
R-phrases R35, R37
S-phrases (S1/2), S7/9, S26, S45
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Related compounds Hydrogen chloride

Hydrogen fluoride
Hydrogen iodide

Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Maintenance categories
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El bromuro de hidrógeno es una molécula diatómica de fórmula HBr. El HBr es una gas en condiciones estandar. La disolución de HBr en agua forma ácido bromhídrico. Por el contrario, se puede liberar HBr de una disolución de ácido bromhídrico por adición de un agente deshidratante, pero no por destilación. El bromuro de hidrógeno y el ácido bromhídrico, por tanto, no son lo mismo, pero se encuentran relacionados.

General description[edit]

A temperatura ambiente, el HBr es un gas no inflamable con un olor acre, con aire húmedo forma humos debdio a la formación de ácido bromhídrico. El HBr es muy soluble en agua, formando una solución de ácido bromhídrico, la cual se satura a temperatura ambiente al 68.8 % en peso de HBr. Las disoluciones acuosas que son del 47.38% de HBr en peso forman una mezcla de punto de ebullición constante que hierve a 126 ºC. La ebullición de disoluciones menos concentradas desprenden H2O hasta que se obtiene una mezcla de puntod de ebullición constante.

Usos de HBr[edit]

Hay muchos usos del HBr en síntesis química. Por ejemplo, HBr es utilizado para la producciónn de bromuros de alquilo a partir de alcoholes:

ROH + HBr → RBr + H2O

HBr se adiciona a alquenos para dar bromoalcanos, una importante familia de compuestos orgánicos de bromo:

RCH=CH2 + HBr → RCH(Br)–CH3

HBr se adiciona a alquinos para dar bromoalquenos. La estereoquímica de este tipo de adición suele ser anti :

RC≡CH + HBr → RC(Br)=CH2

HBr adds to the haloalkene to form a geminal dihaloalkane. (This type of addition follows Markovnikov's rule):

RC(Br)=CH2 + HBr → RC(Br2)–CH3

Also, HBr is used to open epoxides and lactones and in the synthesis of bromoacetals. Additionally, HBr catalyzes many organic reactions.[4][5][6][7]

HBr has been proposed for use in a utility-scale flow-type battery.[8]

Industrial preparation[edit]

Hydrogen bromide (along with hydrobromic acid) is produced on a much smaller scale than the corresponding chlorides. In the primary industrial preparation, hydrogen and bromine are combined at temperatures between 200-400 °C. The reaction is typically catalyzed by platinum or asbestos.[5][9]

Laboratory synthesis[edit]

HBr can be synthesized by a variety of methods. It may be prepared in the laboratory by distillation of a solution of sodium or potassium bromide with phosphoric acid or diluted sulfuric acid[10]:

2 KBr + H2SO4 → K2SO4 + 2HBr

Concentrated sulfuric acid is ineffective because HBr formed will be oxidized to bromine gas:

2 HBr + H2SO4 → Br2 + SO2 + 2H2O

The acid may be prepared by several other methods, as well, including reaction of bromine either with phosphorus and water, or with sulfur and water[11]:

2 Br2 + S + 2 H2O → 4 HBr + SO2

Alternatively, it can be prepared by the bromination of tetraline (1,2,3,4-tetrahydronaphthalene):[12]

C10H12 + 4 Br2 → C10H8Br4 + 4 HBr

Alternatively bromine can be reduced with phosphorous acid:[5]

Br2 + H3PO3 + H2O → H3PO4 + 2 HBr

Anhydrous hydrogen bromide can also be produced on a small scale by thermolysis of triphenylphosphonium bromide in refluxing xylene.[4]

HBr prepared by the above methods can be contaminated with Br2, which can be removed by passing the gas through Cu turnings or through phenol.[9]

References[edit]

  1. ^ "Hydrobromic Acid - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. Retrieved 10 November 2011. 
  2. ^ Perrin, D. D. Dissociation constants of inorganic acids and bases in aqueous solution. Butterworths, London, 1969.
  3. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. ISBN 0-618-94690-X. 
  4. ^ a b Hercouet, A.;LeCorre, M. (1988) Triphenylphosphonium bromide: A convenient and quantitative source of gaseous hydrogen bromide. Synthesis, 157-158.
  5. ^ a b c Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements; Butterworth-Heineman: Oxford, Great Britain; 1997; pp. 809-812.
  6. ^ Carlin, William W. U.S. Patent 4,147,601, April 3, 1979
  7. ^ Vollhardt, K. P. C.; Schore, N. E. Organic Chemistry: Structure and Function; 4th Ed.; W. H. Freeman and Company: New York, NY; 2003.
  8. ^ http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/30535ag.pdf
  9. ^ a b Ruhoff, J. R.; Burnett, R. E.; Reid, E. E. "Hydrogen Bromide (Anhydrous)" Organic Syntheses, Vol. 15, p.35 (Coll. Vol. 2, p.338).
  10. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  11. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  12. ^ WebElements: Hydrogen Bromide


Categoria:Compuestos inorgánicos Category: Compuestos de hidrógeno Category:Bromuros Category:Haluros no metálicos