Funnel introduction

A FUNNEL INTRODUCTION BEGINS WITH A BROAD, GENERAL SUBJECT AND NARROWS TO A SPECIFIC TOPIC. It THEN INTRODUCES YOUR THESIS QUESTION OR YOUR THESIS STATEMENT. 

Introduce 197 g. of anhydrous brucine or 215 g. of the air-dried dihydrate (4) into a warm solution of 139 g. of dZ-acc.-octyl hj drogen phthalate in 300 ml. of acetone and warm the mixture vmder reflux on a water bath until the solution is clear. Upon cooling, the brucine salt (dA, IB) separates as a crystalline solid. Filter this off on a sintered glass funnel, press it well to remove mother liquor, and wash it in the funnel with 125 ml. of acetone. Set the combined filtrate and washings (W) aside. Cover the crystals with acetone and add, slowly and with stirriug, a slight excess (to Congo red) of dilute hydrochloric acid (1 1 by volume about 60 ml.) if the solution becomes turbid before the introduction of... 

Methyl-2-propen-l-ol, purchased from Aldrich Chemical Company, was distilled from anhydrous potassium carbonate. It was added directly to the n-butyllithium solution using a long needle. The checkers quickly replaced the pressure-equalizing dropping funnel with a serum cap to carry out this addition. The funnel was fitted to a small dry flask to prevent the introduction of moisture during the addition period and replaced on the reaction flask immediately afterwards. 

The end of the dropping funnel extends about 2 in. into the flask from the opening and is drawn into a capillary. This is done to ensure the introduction of the chromic acid solution in the form of small droplets. 

An apparatus with four necks makes possible the introduction of solid reactants without removal of the condenser or dropping funnel. 

By working quickly, the imidazolium chloride may be removed by suction filtration through a Buchner funnel. However, the precipitate should not be freed of solvent completely because imidazolium chloride is extremely hygroscopic. If the moist precipitate is washed with 50-100 ml. of anhydrous tetrahydrofuran, the yield of 1,1 -carbonyldiimidazole may be slightly increased however, there is some danger of the introduction of too much moisture into the reaction solution. 

Discontinuous methods are performed in conventional separating funnels in one or more steps. In ultratrace analyses, tapered or specially profiled quartz tubes are recommended because of their easier cleaning (more compact size), the introduction of less contaminating material, and easier centrifugation in the case of difficulties with phase separation. Shaking must be continued until equilibrium is reached, which may last seconds, minutes, or (rarely) hours, depending on the physicochemical properties of the system more than 2-5 min requires a mechanical shaker. Microscale extraction carried out in autosampler tubes, followed by direct automatic introduction of the organic phase into the atomizer, is recommended. 

Introduction of alkali metal into the flask containing liquid ammonia is most easily done with a powder funnel, which temporarily replaces a part of the equipment The cleaned lumps of metal are held above the funnel and cut into pieces (for handling alkali metals see our previous book "Preparative Polar Organometallic Chemistry , Springer-Verlag, 1987.)... 

Apparatus 3-1 round-bottomed, three-necked flask, equipped with a gas inlet tube, a mechanical stirrer and a powder funnel (fig. 15), the powder funnel is replaced by a vent as soon as the introduction of the metal is completed. 

The gas inlet tube is replaced by a dropping funnel protected by a calcium chloride drying tube. Isocaproyl chloride (84.7 g., 0.63 mole) (Note 5) is added to the reaction mixture with stirring over a period of 20 minutes. The dropping funnel is replaced by the gas inlet tube (inlet tube wiped with a dry towel), and, with stirring, acetylene is bubbled just below the surface of the mixture at a rate noticeably above the saturation rate. After 15 minutes to 1 hour the rate of absorption of acetylene suddenly becomes very rapid, and the acetylene is passed through as rapidly as it is absorbed (Note 6). The introduction of acetylene is continued for 30 minutes after the rapid absorption (which lasts 1-2 hours) has subsided. 

It is convenient to seal a short inner tube inside the stem of the dropping funnel so that the rate of addition can be observed readily. The introduction of the bromine below the surface of the 0-xylene through an extended stem, about 4-mm. inside diameter, results in better mixing of reactants and less loss of bromine vapors. 

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