Drybox

Potassium 3-aniinopropylaniide [56038-00-7] (KAPA), KNHCH2CH2CH2-NH2, pX = 35, can be prepared by the reaction of 1,3-diaminopropane and potassium metal or potassium hydride [7693-26-7] (57—59). KAPA powder has been known to explode during storage under nitrogen in a drybox, and is therefore made in situ. KAPA is extremely effective in converting an internal acetylene or aHene group to a terminal acetylene (60) (see Acetylene-DERIVED chemicals). 

Syringe techniques have been developed for small volumes, while for large volumes or where much manipulation is required, dryboxes (glove boxes) or dry chambers should be used. 

If a drybox is not available, the preparation can also be carried out by use of a dry, unreactive solvent (typically an alkane) as a blanket against hydrolysis. This has been suggested in the patent literature as a method for the large-scale industrial preparation of Eewis acid-based ionic liquids, as the solvent also acts as a heat-sink for the exothermic complexation reaction [28]. At the end of the reaction, the ionic liquid forms an immiscible layer beneath the protecting solvent. The ionic liquid may then either be removed by syringe, or else the solvent may be removed by distillation before use. In the former case it is likely that the ionic liquid will be contaminated with traces of the organic solvent, however. 

Silanol Capping Reaction (3). The synthesis of 3 was carried out by contacting a large excess of hexamethyldisilazane with 2 in anhydrous toluene at room temperature under argon for 24 h. The resulting solid was filtered and washed with toluene and hexanes in a drybox, dried under vacuum at room temperature overnight, and then stored in a drybox. 

Reaction of Chlorodimethyl(2,3,4,5-tetramethyl-2,4-cyclopentadien-l-yl)silane with Silica Materials. Chlorodimethyl-(2,3,4,5-tetramethyl-2,4-cyclopentadien-l-yl)silane (excess) was added to a mixture of amine-functionalized silica with hexanes in a drybox. 2,6-Di-tert-butylpyridine (excess) was added as a proton sponge. The mixture was allowed to react while stirring for 24 h. The solid was filtered and washed with hexanes and THF in the drybox. The solid was then contacted with another aliquot of chlorodimethyl-(2,3,4,5-tetramethyl-2,4-cyclopentadien-l-yl)silane and the procedure was repeated. 

In a typical polymerization, the immobilized precatalyst, toluene, and methylaluminoxane (MAO) at a ratio of 800 1 Al Ti were added to the reactor in a drybox. The mixture was allowed to stir for 20 minutes to allow for sufficient activation of the catalyst. The reactor was then removed from the glovebox, placed in a 25 C water bath, then ethylene at 60 psi was introduced. The polymerization was allowed to continue for 10 minutes, then terminated by adding acidic ethanol. The precipitated polymers were washed with ethanol, then dried at 70 C. 

Chemicals and Nanoparticles. All chemicals were used without further treatment. Anhydrous solvents and chemicals were stored in a drybox and used under dry nitrogen gas. 

Reactions were carried out under argon, in sealed NMR tubes, at room temperature or with mild heating. A stock solution (0.003 M) of catalyst 23 in C6D5-CD3 was prepared. Each reaction was run with 0.5 ml of this solution, to which the appropriate amount of monomer was added, to get the desired molar ratio (50 1 to 100 1) monomer/catalyst. Reagents were mixed, and the NMR tubes were closed in a Vacuum Atmospheres drybox. Reactions were monitored by NMR. 

The polymer films of samples 6 and 7 were synthesized under the drybox (inert atmosphere). 

In a drybox, a 100-mL flask containing a 1-in. magnetic stir bar is loaded with 1.0 g (3.04 mmol) of SalenAlCl. The stopcock is closed, a rubber septum is placed in the neck, and the flask is brought out of the drybox and placed onto a vacuum line equipped with a dry N2 source. While stirring, 20 mL of distilled water is added by syringe over the course of a few seconds. The mixture is stirred for 2 h at 25°C, resulting in a pale yellow solution and a solid. Evaporation of the water over a period of 3 days results in quantitative yields of the product as a crystalline solid. 

Caution. Li[HN Bu] reacts violently with water. After recovering the product, the remaining Li[HN Bu] in the reaction vessel must be destroyed carefully. The closed flask (under an argon atmosphere) is taken out of the drybox, placed into an ice bath, and 200 mL of isopropanol is added carefully. After a few minutes 200 mL of ice water is added to the iso-propanol solution. The mixture is stirred until no solid remains, and then the contents treated as normal organic waste. 

Lithium tert-butyl amide is an air- and moisture-sensitive flammable solid that can be stored for up to 4 months in the drybox. In the solid state it has an... 

Commercially available starting materials are employed for the preparations. Tantalum metal may be used in granular form (with 1 mm diameter) or as a powder. Tantalum pentachloride is extremely moismre-sensitive. It should be handled under strictly anhydrous conditions in a drybox or drybag. 

The simple Vycor reaction tube used for the high-temperature reaction is shown in Fig. 1. It consists of a wide body of 30 mm outside diameter and 100 mm length and of a narrow neck of 9 mm outer diameter and 180 mm length. For handling outside of the drybox, it is equipped with a vacuum hose and a stopcock. Prior to use, it should be flamed out under a dynamic vacuum. To keep the neck of the reaction tube clean, the tube should be filled using a funnel with a narrow neck of 180 mm length. 

In a drybox or drybag, stoichiometric amounts of tantalum pentachloride (25.1 g, 70 mmol) and sodium chloride (5.84 g, 100 mmol) are intimately mixed by grinding in a mortar. The mixture is placed in the Vycor reaction tube (see Fig. 1), and excess tantalum powder (58 g, 320 mmol) is added. Using a gas/ oxygen torch, the reaction vessel is sealed under a dynamic vacuum near the midpoint of its neck. 

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