Hydrobromic acid

<h2 id="uses">Uses</h2>
<p>Hydrobromic acid is mainly used for the production of inorganic bromides, especially the bromides of zinc, calcium, and sodium.  It is a useful reagent for generating <a href="/facts/Organobromine_compound/7v9NP0Ak">organobromine compounds</a>.  Certain ethers are cleaved with HBr. It also catalyzes alkylation reactions and the extraction of certain ores. Industrially significant organic compounds prepared from hydrobromic acid include allyl bromide, tetrabromobis(phenol), and <a href="/facts/Bromoacetic_acid/muQtrEmL">bromoacetic acid</a>.  HBr participates in anti-Markovnikov <a href="/facts/Hydrohalogenation/23tPcKP7">hydrohalogenation</a> of alkenes in the presence of peroxides.  The resulting 1-bromoalkanes are versatile <a href="/facts/Alkylating_agent/1rd5SNbt">alkylating agents</a>, giving rise to fatty amines and quaternary ammonium salts.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a>
</p>
<h2 id="synthesis">Synthesis</h2>
<p>Hydrobromic acid can be prepared in the laboratory via the reaction of <a href="/facts/Bromine/oLfj3C7D">Br2</a>, <a href="/facts/Sulfur_dioxide/jDK1fIDs">SO2</a>, and water.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p>
Br2 + SO2 + 2 H2O  →  H2SO4 + 2 HBr
<p>More typically laboratory preparations involve the production of anhydrous <a href="/facts/Hydrogen_bromide/rUw1duLA">HBr</a>, which is then dissolved in water.
</p><p>Hydrobromic acid has commonly been prepared industrially by reacting bromine with either <a href="/facts/Sulfur/IK0amTfM">sulfur</a> or <a href="/facts/Phosphorus/27xCeIqs">phosphorus</a> and water.  However, it can also be produced electrolytically.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> It can also be prepared by treating bromides with non-oxidising acids like phosphoric or acetic acids.
</p><p>Alternatively the acid can be prepared with dilute (5.8<a href="/facts/Molarity/P2WL5b9q">M</a>) <a href="/facts/Sulfuric_acid/Wom6fymJ">sulfuric acid</a> and <a href="/facts/Potassium_bromide/mGWPW1zd">potassium bromide</a>:<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
H2SO4 + KBr  →  KHSO4 + HBr
<p>Using more concentrated sulfuric acid or allowing the reaction solution to exceed 75 °C further <a href="/facts/Oxidizes/Pyd5RVcj">oxidizes</a> HBr to elemental bromine. The acid is further purified by filtering out the KHSO4 and by distilling off the water until the solution reaches an <a href="/facts/Azeotrope/ItfBAN1N">azeotrope</a> (124.3 °C). The yield is approximately 85%.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p><p>Hydrobromic acid is available commercially in various concentrations and purities.
</p>

<h2 id="external-links">External links</h2>
<p> Media related to Hydrogen bromide at Wikimedia Commons
</p>
<ul><li><a href="http://www.inchem.org/documents/icsc/icsc/eics0282.htm">International Chemical Safety Card 0282</a></li>
<li><a href="https://www.cdc.gov/niosh/npg/npgd0331.html">NIOSH Pocket Guide to Chemical Hazards</a></li>
<li>Carlin, W. W. <a href="https://patents.google.com/patent/US4147601">U.S. patent 4,147,601</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. (2012). "Bromine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_405. ISBN 978-3-527-30673-2. <a href="978-3-527-30673-2" target="_blank">978-3-527-30673-2</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Scott, A. (1900). "Preparation of Pure Hydrobromic Acid". Journal of the Chemical Society, Transactions. 77: 648–651. doi:10.1039/ct9007700648. <a href="https://zenodo.org/record/1429698" target="_blank">https://zenodo.org/record/1429698</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Scott, A. (1900). "Preparation of Pure Hydrobromic Acid". Journal of the Chemical Society, Transactions. 77: 648–651. doi:10.1039/ct9007700648. <a href="https://zenodo.org/record/1429698" target="_blank">https://zenodo.org/record/1429698</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry. Vol. 1 (2nd ed.). New York: Academic Press. p. 285. ISBN 978-0121266011. <a href="978-0121266011" target="_blank">978-0121266011</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry. Vol. 1 (2nd ed.). New York: Academic Press. p. 285. ISBN 978-0121266011. <a href="978-0121266011" target="_blank">978-0121266011</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
</ol>

Hydrobromic acid open-in-new

Hydrobromic acid