Editing Vanadium (section)

=== Catalysts ===
[[File:Vanadium pentoxide powder.jpg|thumb|upright|[[Vanadium(V) oxide]] is a catalyst in the [[contact process]] for producing sulfuric acid.]]

Vanadium compounds are used extensively as catalysts;<ref>{{cite journal |last1=Langeslay |first1=Ryan R. |last2=Kaphan |first2=David M. |last3=Marshall |first3=Christopher L. |last4=Stair |first4=Peter C. |last5=Sattelberger |first5=Alfred P. |last6=Delferro |first6=Massimiliano |date=8 October 2018 |title=Catalytic Applications of Vanadium: A Mechanistic Perspective |journal=Chemical Reviews |volume=119 |issue=4 |pages=2128–2191 |doi=10.1021/acs.chemrev.8b00245 |osti=1509906 |pmid=30296048 |s2cid=52943647}}</ref> [[vanadium(V) oxide|Vanadium pentoxide]] V<sub>2</sub>O<sub>5</sub>, is used as a [[catalyst]] in manufacturing sulfuric acid by the [[contact process]]<ref>{{cite journal |last1=Eriksen |first1=K.M. |last2=Karydis |first2=D.A. |last3=Boghosian |first3=S. |last4=Fehrmann |first4=R. |date=August 1995 |title=Deactivation and Compound Formation in Sulfuric-Acid Catalysts and Model Systems |journal=Journal of Catalysis |volume=155 |issue=1 |pages=32–42 |doi=10.1006/jcat.1995.1185}}</ref> In this process [[sulfur dioxide]] ({{chem|SO|2}}) is oxidized to the [[sulfur trioxide|trioxide]] ({{chem|SO|3}}):<ref name="HollemanAF" /> In this [[redox reaction]], sulfur is oxidized from +4 to +6, and vanadium is reduced from +5 to +4:
:V<sub>2</sub>O<sub>5</sub> + SO<sub>2</sub> → 2 VO<sub>2</sub> + SO<sub>3</sub>

The catalyst is regenerated by oxidation with air:
:4 VO<sub>2</sub> + O<sub>2</sub> → 2 V<sub>2</sub>O<sub>5</sub>
Similar oxidations are used in the production of [[maleic anhydride]]:
:C<sub>4</sub>H<sub>10</sub>  + 3.5 O<sub>2</sub>  →   C<sub>4</sub>H<sub>2</sub>O<sub>3</sub>  +  4 H<sub>2</sub>O
[[Phthalic anhydride]] and several other bulk organic compounds are produced similarly. These [[green chemistry]] processes convert inexpensive feedstocks to highly functionalized, versatile intermediates.<ref name="Ullmann">{{Ullmann|doi=10.1002/14356007.a27_367|title=Vanadium and Vanadium Compounds|year=2000|last1=Bauer|first1=Günter|last2=Güther|first2=Volker|last3=Hess|first3=Hans|last4=Otto|first4=Andreas|last5=Roidl|first5=Oskar|last6=Roller|first6=Heinz|last7=Sattelberger|first7=Siegfried|isbn=3-527-30673-0}}</ref><ref>{{cite journal |last1=Abon |first1=Michel |last2=Volta |first2=Jean-Claude |date=September 1997 |title=Vanadium phosphorus oxides for n-butane oxidation to maleic anhydride |journal=Applied Catalysis A: General |volume=157 |issue=1–2 |pages=173–193 |doi=10.1016/S0926-860X(97)00016-1|bibcode=1997AppCA.157..173A }}</ref>

Vanadium is an important component of mixed metal oxide catalysts used in the oxidation of propane and propylene to [[acrolein]], acrylic acid or the ammoxidation of propylene to [[acrylonitrile]].<ref>{{cite book |title=Metal Oxides, Chemistry and Applications |date=2006 |publisher=CRC Press |isbn=978-0-8247-2371-2 |editor1-last=Fierro |editor1-first=J. G. L. |pages=415–455}}</ref>