Nitrosylsulfuric acid

<h2 id="synthesis-and-reactions">Synthesis and reactions</h2>
A typical procedure entails dissolving <a href="/facts/Sodium_nitrite/t5p4YpvJ">sodium nitrite</a> in cold sulfuric acid:<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a><a class="footnote-ref" id="fnref:4" href="#fn:4">4</a>

HNO2 + H2SO4 → HSO4NO + H2O
It can also be prepared by the reaction of <a href="/facts/Nitric_acid/UDbwGp6s">nitric acid</a> and <a href="/facts/Sulfur_dioxide/jDK1fIDs">sulfur dioxide</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>
HSO4NO is used in <a href="/facts/Organic_chemistry/djxhxaNg">organic chemistry</a> to prepare <a href="/facts/Diazonium_salt/5pkN4G5s">diazonium salts</a> from <a href="/facts/Amine/JvfYJfP6">amines</a>, for example in the <a href="/facts/Sandmeyer_reaction/aJUhDKjY">Sandmeyer reaction</a>. Related NO-delivery reagents include <a href="/facts/Nitrosonium_tetrafluoroborate/NFxIgIkk">nitrosonium tetrafluoroborate</a> [NO]+[BF4]− and <a href="/facts/Nitrosyl_chloride/TxTff8WH">nitrosyl chloride</a>. 
In industry, the nitrosodecarboxylation reaction between nitrosylsulfuric acid and <a href="/facts/Cyclohexanecarboxylic_acid/U0xIRpb1">cyclohexanecarboxylic acid</a> is used to generate caprolactam:<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> This is known as the <a href="/facts/SNIA_S.p.A./rKosqNFF">Snia Viscosa</a> process

<h2 id="safety">Safety</h2>
Nitrosylsulfuric acid is a hazardous material and precautions are indicated.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a>

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

<ol>
<li id="fn:1">Ritz, J.; Fuchs, H.; Kieczka, H.; Moran, W. C. (2002). "Caprolactam". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_031. ISBN 978-3527306732. <a href="978-3527306732" target="_blank">978-3527306732</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">George A. Olah, G. K. Surya Prakash, Qi Wang, Xing-Ya Li (2001). "Nitrosylsulfuric Acid". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn060. ISBN 978-0471936237. {{cite book}}: |journal= ignored (help)CS1 maint: multiple names: authors list (link) <a href="978-0471936237" target="_blank">978-0471936237</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Hodgson, H. H.; Mahadevan, A. P.; Ward, E. R. (1955). "1,4-Dinitronaphthalene". Organic Syntheses; Collected Volumes, vol. 3, p. 341. (diazodization followed by treatment with nitrite) <a href="http://www.orgsyn.org/demo.aspx?prep=cv3p0341" target="_blank">http://www.orgsyn.org/demo.aspx?prep=cv3p0341</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Sandin, R. B.; Cairns, T. L. (1943). "1,2,3-Triiodo-5-nitrobenzene". Organic Syntheses; Collected Volumes, vol. 2, p. 604. (diazodization followed by treatment with iodide) <a href="http://www.orgsyn.org/demo.aspx?prep=cv2p0604" target="_blank">http://www.orgsyn.org/demo.aspx?prep=cv2p0604</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Coleman, G. H.; Lillis, G. A.; Goheen, G. E. (1939). "Nitrosyl Chloride". Inorganic Syntheses. Vol. 1. pp. 55–59. doi:10.1002/9780470132326.ch20. ISBN 9780470132326. This procedure generates the nitrosylsulfuric acid as an intermediate en route to NOCl. <a href="9780470132326" target="_blank">9780470132326</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Ritz, J.; Fuchs, H.; Kieczka, H.; Moran, W. C. (2002). "Caprolactam". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_031. ISBN 978-3527306732. <a href="978-3527306732" target="_blank">978-3527306732</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">George A. Olah, G. K. Surya Prakash, Qi Wang, Xing-Ya Li (2001). "Nitrosylsulfuric Acid". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn060. ISBN 978-0471936237. {{cite book}}: |journal= ignored (help)CS1 maint: multiple names: authors list (link) <a href="978-0471936237" target="_blank">978-0471936237</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
</ol>

Nitrosylsulfuric acid open-in-new

Nitrosylsulfuric acid