:Air sensitivity
Air sensitivity is a term used, particularly in chemistry, to denote the reactivity of chemical compounds with some constituent of air. Most often, reactions occur with atmospheric oxygen (O2) or water vapor (H2O),[http://www.sigmaaldrich.com/etc/medialib/flashapps/glassware-center/pdfs/al-techbull-al134.Par.0001.File.dat/al_techbull_al134.pdf Handling and Storage of Air-Sensitive Reagents], Technical Bulletin AL-134, Sigma-Aldrich although reactions with the other constituents of air such as carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2) are also possible.{{Cite web|url=http://ccc.chem.pitt.edu/wipf/Web/Air_sensitive_techniques.pdf|title=Techniques for handling air and moisture sensitivity|last=Dr. P. Wipf}}
Method
A variety of air-free techniques have been developed to handle air-sensitive compounds. Two main types of equipment are gloveboxes and Schlenk lines.{{Cite book|title=working with air and moisture sensitive compounds|last=W. Bouwkamp|first=Marco|publisher=Stratingh Institute for Chemistry, University of Groningen|year=2008|pages=4, 6}} Glove boxes are sealed cabinets filled with an inert gas such as argon or nitrogen.[http://www.ilpi.com/inorganic/glassware/glovebox.html Glove Boxes], The Glassware Gallery Normal laboratory equipment can be set up in the glovebox, and manipulated by the use of gloves that penetrate its walls.{{cite book|last1=Wipf|first1=Dr. P|title=techniques of handling air sensitivity compound|date=30 August 2015|url=http://ccc.chem.pitt.edu/wipf/Web/Air_sensitive_techniques.pdf}} The atmosphere can be regulated to approximately atmospheric pressure and set to be pure nitrogen or other gas with which the chemicals will not react.{{Cite news|url=http://midwestlab.com/air-sensitive/|title=Air Sensitive Sample Analysis {{!}} Reduced Oxygen Moisture-Free Handling|work=Analysis of Carbon, Hydrogen, Nitrogen, Oxygen, and halogens including Fluorine|access-date=2018-02-27|language=en-US}} Chemicals and equipment can be transferred in and out via an airlock.{{Cite web|url=http://web.uvic.ca/~berryde/chem222/McIndoe%20air-sensitive.pdf|title=Handling air‐sensitive compounds}}
A Schlenk line is a vacuum and inert-gas dual-manifold that allows glassware to be evacuated and refilled with inert gas specially developed to work with air sensitive compounds. It is connected with a cold trap to prevent vapors from contaminating a rotary vane pump.{{cite web|title=The Glassware Gallery: Schlenk Lines and Vacuum Lines|url=http://www.ilpi.com/inorganic/glassware/vacline.html|website=www.ilpi.com}} The technique is modified from the double-tipped needle technique.{{cite journal |last1=Smith Vosejpka |first1=Laura J. |title=A simple and cost-effective technique for the transfer of air-sensitive solutions |journal=Journal of Chemical Education |date=August 1993 |volume=70 |issue=8 |pages=665 |doi=10.1021/ed070p665}} These methods allow working in totally controlled and isolated environment.{{cite web|title=Air-Sensitive Chemistry - Labware {{!}} Sigma-Aldrich|url=https://www.sigmaaldrich.com/labware/labware-products.html?TablePage=9571140|website=Sigma-Aldrich|language=en}}
Air-sensitive compounds
Air-sensitive compounds are substances that would react with components in air. Almost all metals react with air to form a thin passivating layer of oxide, which is often imperceptible.
Many bulk compounds react readily with air as well. The reactive components of air are {{chem2|O2, H2O, CO2, and sometimes N2}}. Very many compounds react with some or all of these species.{{cite web|title=Pyrophoric Control - FQE Chemicals|url=https://fqechemicals.com/contaminants/pyrophoric-control/|website=FQE Chemicals}} Examples:
- O2: organolithium compounds and Grignard reagents
- H2O: anhydrous metal halides and acyl chlorides as well as organolithium compounds and Grignard reagents
- CO2: strong bases such as sodium hydroxide, as well as organolithium compounds and Grignard reagents
- N2: lithium metal (but not organolithium compounds)
Some semiconductors are air-sensitive.{{cite web|title=Application of Air-sensitive Semiconductors in Nanoelectronics|url=http://www.sciencenewsline.com/news/2017092115240054.html|website=www.sciencenewsline.com|language=en}}{{Dead link|date=September 2019 |bot=InternetArchiveBot |fix-attempted=yes }}