Peroxyacetyl nitrate: Difference between revisions

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 411625303

| ImageFile = Peroxyacetyl nitrate Structural formula V1.svg

| PIN = Acetic nitric peroxyanhydride

|Section1={{Chembox Identifiers

| Abbreviations = PAN

| CASNo_Ref = {{cascite|correct|CAS}}

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = SQ8V0P4N89

| EINECS = 218-905-6

| PubChem = 16782

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 15907

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C2H3NO5/c1-2(4)7-8-3(5)6/h1H3

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| StdInChIKey = VGQXTTSVLMQFHM-UHFFFAOYSA-N

| ChEBI_Ref = {{ebicite|correct|EBI}}

}}

|Section2={{Chembox Properties

| MeltingPt_notes =

| BoilingPt_notes =

| HenryConstant = 0.000278 m³ atm mol⁻¹ at 298 K

| AtmosphericOHRateConstant = 10⁻¹³ cm³ molecule⁻¹ s⁻¹ at 298 K

|Section3={{Chembox Structure

|Section4={{Chembox Thermochemistry

|Section5={{Chembox Pharmacology

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|Section6={{Chembox Explosive

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|Section7={{Chembox Hazards

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|Section8={{Chembox Related

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'''Peroxyacetyl nitrate''' is a [[peroxyacyl nitrates|peroxyacyl nitrate]]. It is a secondary [[pollutant]] present in [[photochemical smog]].<ref name=Singh2015>{{cite book |doi=10.1016/B978-0-12-382225-3.00433-3 |chapter=TROPOSPHERIC CHEMISTRY AND COMPOSITION &#124; Peroxyacetyl Nitrate |title=Encyclopedia of Atmospheric Sciences |year=2015 |last1=Singh |first1=H.B. |pages=251–254 |publisher=Elsevier |isbn=978-0-12-382225-3 |editor1-first=Gerald R. |editor1-last=North |editor2-first=John A. |editor2-last=Pyle |editor3-first=Fuqing |editor3-last=Zhang }}</ref> It is thermally unstable and decomposes into peroxyethanoyl radicals and [[nitrogen dioxide]] gas.<ref>{{cite book |title=Chemistry of the Upper and Lower Atmosphere |url=https://www.sciencedirect.com/book/9780122570605/chemistry-of-the-upper-and-lower-atmosphere |isbn=978-0-12-257060-5 |last1=Finlayson-Pitts |first1=Barbara J. |last2=Pitts |first2=James N. |year=2000 |publisher=Academic Press }}{{page needed|date=December 2020}}</ref> It is a [[Tears|lachrymatory]] substance, meaning that it irritates the lungs and eyes.<ref>{{cite book |title=Encyclopedia of Physical Science and Technology |year=2002 |url=https://www.sciencedirect.com/referencework/9780122274107/encyclopedia-of-physical-science-and-technology |isbn=978-0-12-227410-7 |last1=Meyers |first1=Robert A. |publisher=Elsevier Science }}{{page needed|date=December 2020}}</ref>

Peroxyacetyl nitrate, or PAN, is an oxidant that is more stable than [[ozone]]. Hence, it is more capable of long-range transport than ozone. It serves as a carrier for [[Nitrogen oxide|oxides of nitrogen]] (NOx) into rural regions and causes ozone formation in the global [[troposphere]].<ref name=Singh2015/>

== Atmospheric chemistry ==

PAN is produced in the atmosphere via photochemical oxidation of [[hydrocarbon]]s to [[peroxyacetic acid]] radicals in the presence of [[nitrogen dioxide]] (NO₂). Since there are no direct emissions, it is a secondary pollutant. Next to [[ozone]] and [[hydrogen peroxide]] (H₂O₂), it is an important component of [[smog|photochemical smog]].

Further [[peroxyacyl nitrates]] in the atmosphere are peroxypropionyl nitrate (PPN), peroxybutyryl nitrate (PBN), and peroxybenzoyl nitrate (PBzN). Chlorinated forms have also been observed. PAN is the most important peroxyacyl nitrate. PAN and its homologues reach about 5 to 20 percent of the concentration of ozone in urban areas. At lower temperatures, it is stable and can be transported over long distances, providing nitrogen oxides to otherwise unpolluted areas. At higher temperatures, it decomposes into NO₂ and the peroxyacetyl radical.

The decay of PAN in the atmosphere is mainly thermal. Thus, the long-range transport occurs through cold regions of the atmosphere, whereas the decomposition takes place at warmer levels. PAN can also be photolysed by UV radiation. It is a reservoir gas that serves both as a source and a sink of RO_x- and NO_x radicals.<ref>J. S. Gaffney et al.: ''Peroxyacyl Nitrates''. In: ''The Handbook of Environmental Chemistry.'' Vol. 4, Part B, S. 1–38; Hrsg.: Hutzinger, O., Springer, '''1989'''.</ref> Nitrogen oxides from PAN decomposition enhance ozone production in the lower [[troposphere]].

The natural concentration of PAN in the atmosphere is below 0,1&nbsp;μg/m³. Measurements in German cities showed values up to 25&nbsp;μg/m³. Peak values above 200&nbsp;μg/m³ have been measured in [[Los Angeles]] in the second half of the 20th century (1 ppm of PAN corresponds to 4370&nbsp;μg/m³). Due to the complexity of the measurement setup, only sporadic measurements are available.

PAN is a [[greenhouse gas]].

== Synthesis ==

PAN can be produced in a lipophilic solvent from [[peroxyacetic acid]].<ref name="talukdar">{{cite journal | doi = 10.1029/95JD00545 | title = Investigation of the loss processes for peroxyacetyl nitrate in the atmosphere: UV photolysis and reaction with OH | date = 1995 | last1 = Talukdar | first1 = Ranajit K. | last2 = Burkholder | first2 = James B. | last3 = Schmoltner | first3 = Anne-Marie | last4 = Roberts | first4 = James M. | last5 = Wilson | first5 = Robert R. | last6 = Ravishankara | first6 = A. R. | journal = Journal of Geophysical Research: Atmospheres | volume = 100 | issue = D7 | pages = 14163–14173 | bibcode = 1995JGR...10014163T }}</ref><ref name="nielsen">{{cite journal | doi = 10.1016/0004-6981(82)90134-2 | title = A convenient method for preparation of pure standards of peroxyacetyl nitrate for atmospheric analyses | date = 1982 | last1 = Nielsen | first1 = Torben | last2 = Hansen | first2 = Anne Maria | last3 = Thomsen | first3 = Erling Lund | journal = Atmospheric Environment (1967) | volume = 16 | issue = 10 | pages = 2447–2450 | bibcode = 1982AtmEn..16.2447N }}</ref><ref name="gaffney">{{cite journal | doi = 10.1016/0004-6981(84)90245-2 | title = An improved procedure for high purity gaseous peroxyacyl nitrate production: Use of heavy lipid solvents | date = 1984 | last1 = Gaffney | first1 = J.S. | last2 = Fajer | first2 = R. | last3 = Senum | first3 = G.I. | journal = Atmospheric Environment (1967) | volume = 18 | issue = 1 | pages = 215–218 | bibcode = 1984AtmEn..18..215G }}</ref><ref name="fry">J. L. Fry ''Spectroscopy and kinetics of atmospheric reservoir species: HOONO, CH₃C(O)OONO₂, CH₃OOH and HOCH₂OOH''. ''Ph.D. Thesis'', 2006</ref> For the synthesis, concentrated sulfuric acid is added to degassed ''n''-[[tridecane]] and peroxyacetic acid in an ice bath. Next, concentrated nitric acid is added.

As an alternative, PAN can also be synthesized in the gas phase via photolysis of [[acetone]] and NO₂ with a [[mercury lamp]].<ref name="warneck">{{cite journal | doi = 10.1021/es00025a005 | title = Synthesis of peroxyacetyl nitrate in air by acetone photolysis | date = 1992 | last1 = Warneck | first1 = Peter | last2 = Zerbach | first2 = Thomas | journal = Environmental Science & Technology | volume = 26 | issue = 1 | pages = 74–79 | bibcode = 1992EnST...26...74W }}</ref> [[Methyl nitrate]] (CH₃ONO₂) is created as a by-product.

== Toxicity ==

The toxicity of PAN is higher than that of ozone. Eye irritations from photochemical smog are caused more by PAN and other trace gases than by ozone, which is only sparingly soluble. PAN is potentially involved in the creation of skin cancer. Especially chlorine-containing derivatives are considered [[mutagen]].

==References==

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[[Category:Organic peroxides]]

[[Category:Nitrate esters]]

[[Category:Organic peroxide explosives]]

[[Category:Explosive chemicals]]