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),[1] although reactions with the other constituents of air such as carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2) are also possible.[2]
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.[3] Glove boxes are sealed cabinets filled with an inert gas such as argon or nitrogen.[4] Normal laboratory equipment can be set up in the glovebox, and manipulated by the use of gloves that penetrate its walls.[5] 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.[6] Chemicals and equipment can be transferred in and out via an airlock.[7]
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.[8] The technique is modified from the double-tipped needle technique.[9] These methods allow working in totally controlled and isolated environment.[10]
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 Page Module:Chem2/styles.css has no content.O2, H2O, CO2, and sometimes N2. Very many compounds react with some or all of these species.[11] 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.[12]
See also
References
Page Template:Reflist/styles.css has no content.
- ^ Handling and Storage of Air-Sensitive Reagents, Technical Bulletin AL-134, Sigma-Aldrich
- ^ Page Module:Citation/CS1/styles.css has no content.Dr. P. Wipf. "Techniques for handling air and moisture sensitivity" (PDF).
- ^ Page Module:Citation/CS1/styles.css has no content.W. Bouwkamp, Marco (2008). working with air and moisture sensitive compounds. Stratingh Institute for Chemistry, University of Groningen. pp. 4, 6.
- ^ Glove Boxes, The Glassware Gallery
- ^ Page Module:Citation/CS1/styles.css has no content.Wipf, Dr. P (30 August 2015). techniques of handling air sensitivity compound (PDF).
- ^ Page Module:Citation/CS1/styles.css has no content."Air Sensitive Sample Analysis | Reduced Oxygen Moisture-Free Handling". Analysis of Carbon, Hydrogen, Nitrogen, Oxygen, and halogens including Fluorine. Retrieved 2018-02-27.
- ^ Page Module:Citation/CS1/styles.css has no content."Handling air‐sensitive compounds" (PDF).
- ^ Page Module:Citation/CS1/styles.css has no content."The Glassware Gallery: Schlenk Lines and Vacuum Lines". www.ilpi.com.
- ^ Page Module:Citation/CS1/styles.css has no content.Smith Vosejpka, Laura J. (August 1993). "A simple and cost-effective technique for the transfer of air-sensitive solutions". Journal of Chemical Education. 70 (8): 665. doi:10.1021/ed070p665.
- ^ Page Module:Citation/CS1/styles.css has no content."Air-Sensitive Chemistry - Labware | Sigma-Aldrich". Sigma-Aldrich.
- ^ Page Module:Citation/CS1/styles.css has no content."Pyrophoric Control - FQE Chemicals". FQE Chemicals.
- ^ Page Module:Citation/CS1/styles.css has no content."Application of Air-sensitive Semiconductors in Nanoelectronics". www.sciencenewsline.com.[permanent dead link]
