Moisture-sensitive reactions

K.L. Vikse, M.P. Woods, J.S. Mclndoe, Pressurized sample infusion for the continuous analysis of air- and moisture-sensitive reactions using electrospray ionization mass spectrometry, Organometallics 29 (2010) 6615-6618. 

Notes. (1) See Section 2.17.8, p. 120, for a suitable apparatus set-up for this moisture-sensitive reaction. 

Difficulties in excluding trace amounts of water from moisture-sensitive reactions. 

Whenever reactions are performed, material losses are obtained as a consequence of the above problems. Normally these losses only account for a few percent of the total material, however this percentage can increase dramatically as the reaction scale decreases. For example if a moisture-sensitive reaction was carried out on a one mole scale, it would take 18g of water to completely stop the reaction occurring, however if the same reaction is carried out on a O.lmmol scale, then only 1.8mg of water would completely quench the reaction. 

Rhodium(VI) and iridium(VI) occur only in black RhFg and yellow IrFg, formed by heating the metals with F2 under pressure and quenching the volatile products. Both RhFg and IrFg are octahedral monomers. The pentafluorides are made by direct combination of the elements (equation 22.100) or by reduction of MFg, and are moisture-sensitive (reaction 22.101) and very reactive. They are tetramers, structurally analogous to NbFs (22.5). 

Sodium hexamethyldisilazide [sodium bis(trimethyIsilyl)amide] was purchased from the Aldrich Chemical Company, Inc., in 100- or 800-mL bottles as a 1 M solution in tetrahydrofuran. Glassware used for moisture sensitive reactions was dried at 180°C and allowed to cool in a desiccator over self-indicating silica gel. Reactions were carried out under a slight positive static pressure of argon. 

ESI Monitoring air-/moisture-sensitive reactions, pressurized sample Vikse et al. [83]... 

Vikse, K.L., Woods, M.P., Mclndoe, J.S. (2010) Pressurized Sample Infusion for the Continuous Analysis of Air- and Moisture-sensitive Reactions Using Electrospray Ionization Mass Spectrometry. Organometallics 29 6615-6618. 

Handling, Storage, and Precautions moisture sensitive. Reactions are typically conducted under an inert atmosphere. The compound is corrosive and liberates HCl upon contact with moisture may burn exposed skin and can be destructive to eyes, mucous membranes, and upper respiratory tract. Chemically incompatible with water, alcohols, and amines. 

Both these experimental procedures are comparatively straightforward, since no precautions have to be taken to exclude air, moisture, heat or light. Unfortunately, this is rarely the case and more often than not, chemists have to take specific precautions to exclude at least one of these factors, most commonly air (particularly oxygen) or moisture (as water vapour in the air). Our next experimental procedure shows the precautions that must be taken when performing a moisture-sensitive reaction — this case the preparation of the organometallic complex [ Fe(CO)2(i1 -C5H5) 2]... 

The fast polymerization reaction that forms polyurethane at the surface opens a new route for rapid prototyping, as well as the use of ink-jet as a technique for handling moisture-sensitive reactions. 

Since 1901, conventional synthesis of 5-substituted l//-tetrazoles has been reported to proceed via [3-1-2] cycloaddition between azide and nitriles. Drawbacks from this procedure are the use of expensive and toxic azide, highly moisture-sensitive reaction conditions, strong Lewis acids, and hydrazoic acid. 

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