Air sensitivity

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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]

Contents

Method

Glovebox Glovebox.jpg
Glovebox

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, explode or oxidise with air, such as organometallic compounds (chemical compounds containing at least one chemical bond between a metal and carbon atom, including alkaline earth, alkaline and transition metals). They may include metalloids like tin, boron and sometimes silicon encountered in chemistry, which are sensitive to oxygen and moisture. Alkali metals and other pyrophoric compounds which react violently with water [11] can be handled safely using air free techniques.

Some semiconductors are air-sensitive. [12]

See also

Related Research Articles

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Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934%. It is more than twice as abundant as water vapor, 23 times as abundant as carbon dioxide, and more than 500 times as abundant as neon. Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.

<span class="mw-page-title-main">Explosive</span> Substance that can explode

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<span class="mw-page-title-main">Nitrogen</span> Chemical element, symbol N and atomic number 7

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<span class="mw-page-title-main">Organometallic chemistry</span> Study of organic compounds containing metal(s)

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<span class="mw-page-title-main">Glovebox</span> Sealed container with gloves in the side for manipulating the objects inside

A glovebox is a sealed container that is designed to allow one to manipulate objects where a separate atmosphere is desired. Built into the sides of the glovebox are gloves arranged in such a way that the user can place their hands into the gloves and perform tasks inside the box without breaking containment. Part or all of the box is usually transparent to allow the user to see what is being manipulated. Two types of gloveboxes exist. The first allows a person to work with hazardous substances, such as radioactive materials or infectious disease agents, and the second allows manipulation of substances that must be contained within a very high purity inert atmosphere, such as argon or nitrogen. It is also possible to use a glovebox for manipulation of items in a vacuum chamber.

<span class="mw-page-title-main">Gas syringe</span>

A gas syringe is a piece of laboratory glassware used to insert or withdraw a volume of a gas from a closed system, or to measure the volume of gas evolved from a chemical reaction. A gas syringe can also be used to measure and dispense liquids, especially where these liquids need to be kept free from air.

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<span class="mw-page-title-main">Wilhelm Schlenk</span> German chemist (1879–1943)

Wilhelm Johann Schlenk was a German chemist. He was born in Munich and also studied chemistry there. Schlenk succeeded Emil Fischer at the University of Berlin in 1919.

<span class="mw-page-title-main">Diethylzinc</span> Chemical compound

Diethylzinc (C2H5)2Zn, or DEZ, is a highly pyrophoric and reactive organozinc compound consisting of a zinc center bound to two ethyl groups. This colourless liquid is an important reagent in organic chemistry. It is available commercially as a solution in hexanes, heptane, or toluene, or as a pure liquid.

<span class="mw-page-title-main">Schlenk line</span> Glass apparatus used in chemistry

The Schlenk line is a commonly used chemistry apparatus developed by Wilhelm Schlenk. It consists of a dual manifold with several ports. One manifold is connected to a source of purified inert gas, while the other is connected to a vacuum pump. The inert-gas line is vented through an oil bubbler, while solvent vapors and gaseous reaction products are prevented from contaminating the vacuum pump by a liquid-nitrogen or dry-ice/acetone cold trap. Special stopcocks or Teflon taps allow vacuum or inert gas to be selected without the need for placing the sample on a separate line.

<span class="mw-page-title-main">Schlenk flask</span> Reaction vessel used in air-sensitive chemistry

A Schlenk flask, or Schlenk tube, is a reaction vessel typically used in air-sensitive chemistry, invented by Wilhelm Schlenk. It has a side arm fitted with a PTFE or ground glass stopcock, which allows the vessel to be evacuated or filled with gases. These flasks are often connected to Schlenk lines, which allow both operations to be done easily.

Air-free techniques refer to a range of manipulations in the chemistry laboratory for the handling of compounds that are air-sensitive. These techniques prevent the compounds from reacting with components of air, usually water and oxygen; less commonly carbon dioxide and nitrogen. A common theme among these techniques is the use of a fine (100–10−3 Torr) or high (10−3–10−6 Torr) vacuum to remove air, and the use of an inert gas: preferably argon, but often nitrogen.

In chemistry, the term chemically inert is used to describe a substance that is not chemically reactive. From a thermodynamic perspective, a substance is inert, or nonlabile, if it is thermodynamically unstable yet decomposes at a slow, or negligible rate.

<span class="mw-page-title-main">Cannula transfer</span>

Cannula transfer or cannulation is a set of air-free techniques used with a Schlenk line, in transferring liquid or solution samples between reaction vessels via cannulae, avoiding atmospheric contamination. While the syringes are not the same as cannulae, the techniques remain relevant.

Iron phosphide is a chemical compound of iron and phosphorus, with a formula of FeP. Its physical appearance is grey, hexagonal needles.

<span class="mw-page-title-main">Plutonium compounds</span> Chemical compounds containing the element plutonium

Plutonium compounds are compounds containing the element plutonium (Pu). At room temperature, pure plutonium is silvery in color but gains a tarnish when oxidized. The element displays four common ionic oxidation states in aqueous solution and one rare one:

References

  1. Handling and Storage of Air-Sensitive Reagents, Technical Bulletin AL-134, Sigma-Aldrich
  2. Dr. P. Wipf. "Techniques for handling air and moisture sensitivity" (PDF).
  3. W. Bouwkamp, Marco (2008). working with air and moisture sensitive compounds. Stratingh Institute for Chemistry, University of Groningen. pp. 4, 6.
  4. Glove Boxes, The Glassware Gallery
  5. Wipf, Dr. P (30 August 2015). techniques of handling air sensitivity compound (PDF).
  6. "Air Sensitive Sample Analysis | Reduced Oxygen Moisture-Free Handling". Analysis of Carbon, Hydrogen, Nitrogen, Oxygen, and halogens including Fluorine. Retrieved 2018-02-27.
  7. "Handling air‐sensitive compounds" (PDF).
  8. "The Glassware Gallery: Schlenk Lines and Vacuum Lines". www.ilpi.com.
  9. 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.
  10. "Air-Sensitive Chemistry - Labware | Sigma-Aldrich". Sigma-Aldrich.
  11. "Pyrophoric Control - FQE Chemicals". FQE Chemicals.
  12. "Application of Air-sensitive Semiconductors in Nanoelectronics". www.sciencenewsline.com.[ permanent dead link ]