Cannula method

Filtration by Cannula. The cannula method is a simple and effective means for transferring liquid. When a rubber septum is fitted at the inlet of the Schlenk flask under nitrogen, extra air trapped inside should be removed promptly by inserting the needle into the septum. The tip of the cannula can be covered with fine glass fiber for filtration. 

Simple Filtration by Celite. A disposable pipet filled with celite is fitted with a rubber septum and is placed at the inlet of a Schlenk flask by means of a thermometer holder. Then the whole system is evacuated and filled with inert gas. Transfer of liquid is carried out by the cannula method. The Schlenk receiver should be at ambient pressure, although careful evacuation can accelerate the filtration. 

New or improved methods are needed to measure local uptake experimentally. Such data can be used to verify the detailed dosage distribution predicted by the models. For example the retrograde catheter and tracheal cannula system used by Com et al. appears promising for transfer-coefficient measurements within segments of the tracheobronchial tree. A similar method was used by Battista and (3oyer to measure the absorption of acetaldehyde vapor in the dog lung. 

The submitters preferred to transfer the phenylsulfenyl chloride via cannula. The sodium nitromethane-ethanol slurry Is added by attaching the Erlenmeyer flask containing it to the reaction flask via an angle adapter and then simply inverting the Erlenmeyer flask. In either method additional absolute ethanol may be necessary to complete the latter addition. 

Method B. (THF)3Li[Si(SiMe3)3] (5.0 g, 11 mmol) and tellurium powder (1.3 g, 11 mmol) are combined in a 100-mL, round-bottomed Schlenk flask equipped with a magnetic stir bar. The flask is cooled to 0°C, THF (50 mL) is added via cannula, and stirring is initiated. The ice bath is removed and the orange mixture is stirred at room temperature for 1 h. Trifluoromethanesulfonic acid (0.94 mL, 11 mmol) is added dropwise and the resulting black mixture is stirred for 2 h. Using the workup and purification procedure described in Method A yields 2.2 g (56%) of colorless, waxy product. 

Experimental methods overview additions and cannula transfers, 1, 205 chromatography, 1, 209 crystallization, 1, 207... 

Gallo-Torres et al. (1979) described in detail a method for the bioassay of antisecretory activity in the conscious rat with acute gastric fistula with additional collection of the biliary and pancreatic secretion by means of a catheter in the common bile duct. The gastric secretions are collected by gravity via a cannula in the most gravity dependent site of the glandular stomach. 

Boldyreff WN (1925) Surgical method in the physiology of digestion. Description of the most important operations on digestive system. Ergebn Physiol 24 399-444 Herrera F, Kemp DR, Tsukamoto M et al. (1968) A new cannula for the study of pancreatic function. J Appl Physiol 25 207-209... 

Caution The possibility of explosions when handling bis(trimethylsilyl) peroxide (BTMSPO) has been reported,2 especially in the presence of metal needles, cannulas, etc., although the product was prepared using a different procedure that included the use of 85% H202 and pyn dine. Our method never gave rise to explosions in the general practice of an organic chemistry laboratory. Nevertheless all the reactions were carried out in safety cupboards and behind blast shields (Note 1). 

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