Condensers connecting tubing

The apparatus consists of a l-l. three-necked flask fitted with a gas inlet tube extending about 3 cm. into the flask and connected to the flask through a bubbler, a thermometer extending to the bottom, a mechanical stirrer, and a reflux condenser connected at the upper end with an exit tube leading to the hood. The reaction is carried out in an atmosphere of illuminating gas (Note 1). 

B. l-Bromo-2-fluorobenzene. Cautionl This step should be carried outm a hood because the PFS evolved on thermal decomposition of the diazonium salt is poisonous. The apparatus consists of a 1-1., three-necked, round-bottomed flask equipped with a thermometer, a condenser, a magnetic stirrer (optional), and a 250-ml. Erlenmeyer flask that is attached by means of a short rubber Gooch connecting tube. The dry powdered hexafluorophosphate salt is placed in the Erlenmeyer flask, and 300 ml. of heavy mineral oil is placed in the round-bottomed flask. The mineral oil is heated to 165-170° by means of an oil bath or electric heating mantle and maintained at this temperature while the salt is added rapidly in portions over a period of 30 minutes. The flask is cooled rapidly to room temperature, the side flask is removed, and 400 ml. of 10% aqueous sodium carbonate is added slowly through the condenser. The mixture is steam-distilled until no more oil is visible in the distillate. 

B. Benzobarrelene. A dry 1-1., three-necked, round-bottomed flask is equipped with a magnetic stirring bar, a combined gas-inlet tube and rubber septum, a 500-ml. pressure-equalizing dropping funnel, and a reflux condenser connected to a Nujol bubbler. The flask is charged with 500 ml. of dry tetrahydrofuran (Note 14) and 17 g. (0.74 mole) of sodium wire with a diameter of ca. 0.5 mm. The mixture is stirred and heated at reflux under an atmosphere of argon or nitrogen, and 50 ml. of freshly distilled tert-butyl alcohol is added. Immediately afterward a solution of 15 g. (0.051 mole) of... 

A 500-ml. three-necked round-bottomed flask is provided with a small dropping funnel, a sealed mechanical stirrer, a reflux condenser connected to a gas-absorption trap, and a hydrogen chloride delivery tube which extends, to the bottom of the flask. 

Fig. 2.20. Water vapor flow density (g/cm2 h) as a function of the ratio ltd of the connecting tube from the chamber to the condenser at four different pressures / h as parameters (/ length, d diameter of the tube).

A 50-ml., round-bottomed flask equipped with a magnetic stirring bar and a 20-ml. calibration mark (Note 1) is charged with 970 mg. (2.5 mmoles) of 4-cholesten-3/9-ol (Note 2). Ethyl vinyl ether is distilled into the flask to the 20-ml. mark (Note 3). The mixture is stirred to effect solution then 820 mg. (2.55 mmoles) of mercuric acetate (Note 4) is added to the reaction mixture. The flask is fitted with a reflux condenser connected to a gas inlet tube and flushed with argon. The reaction mixture is then stirred and heated (Note 5) at reflux under a positive argon pressure for 17 hours. After the solution has cooled to room temperature, 0.062 ml. (1.09 mmoles) of glacial acetic acid (Note... 

A 500 ml resin kettle was fitted with a stirrer, dropping funnel, and a condenser connected with a drying tube. 

The tube is now immersed nearly up to its neck in an oil or metal bath and the -amino-caproic acid melted at a bath temperature of220 °C.Then it is heated quickly to 260 °C and held at this temperature under a continuous stream of nitrogen for 15 min. Should any water condense on the wall of the connecting tube leading to the calcium chloride tube, it can be removed by warming with a hot-air blower before the heating bath is taken away and the melt allowed to cool under nitrogen. Finally, the tube is broken and... 

The flask containing the crude product is equipped with a capillary tube and distilling head and surrounded by a water bath, which may be heated by a hot plate or steam cone. A water-cooled condenser connects the distilling head with the center neck of a two-necked receiver which is surrounded by a Dry Ice bath. The outer neck of the receiver is fitted with a Dry Ice condenser arranged in such a way that vapors which... 

A 200-ml. three-necked flask is equipped with a thermometer, a mechanical stirrer, a gas inlet tube extending as far into the flask as the stirrer permits, and a trap (designed to return the heavier layer of the condensate) (Note 1), which is attached to a bulb and a coil-type reflux condenser connected in series. Methyl p-ethylbenzoate (98 g., 0.597 mole) (Note 2) and a mixture of 1 g. of chromium oxide and 4 g. of calcium carbonate, prepared by grinding the solids together in a mortar, are added. An air line with a bleed control valve (Note 3) is connected from the top of the condenser to a water aspirator. The flask is heated with a hemispherical electric mantle (Note 4). 

In a 2-1. three-necked flask fitted with a mercury-sealed stirrer (Note 1), a reflux condenser connected to a calcium chloride tube, and a thermometer is placed 360 g. (406 ml., 5 moles) of dry tetrahydrofuran (Note 2). The flask is surrounded by an ice bath, stirring is started, and 256 g. (153 ml., 1.67 moles) of phosphorus oxychloride is added rapidly. The mixture is cooled to 10" 15°, and 50 ml. of concentrated sulfuric acid (sp. gr. 1.84) is added during the comse of 3-10 minutes at a rate that does not cause the temperature to rise above 40°. The ice bath is then removed and the mixture is heated cautiously over a low luminous flame until an exothermic reaction becomes evident at about 88-90° (Note 3). By moderate cooling or warming as may be required the temperature is maintained at 90-100° until the exo-thermic reaction ceases, as indicated by the increased rate of licating required to maintain the reaction temperature, and thereafter for an additional 10 minutes (Note 4). Six hundred milliliters of water is added, the mixture is heated under reflux for 30 minutes and then distilled through a downward condenser until the vapor temperature reaches 99 100° (Note 5). 

A 500-mL two-necked round-bottomed Pyrex flask is fitted with a gas dispersion tube and a reflux condenser connected to a bubbler. The flask is charged with 0.191 g (0.20mmol) of (/z-benzenethiolato)-decarbonyl- -hydrido-triosmium and 250 mL of cyclohexane. The solution is purged with carbon monoxide (flow rate 50 mL min 1) for 15 min. Then the flow rate is increased to 100 mL min -1 and the solution is irradiated for 2.0 to 2.5 h by using an external high-pressure mercury lamp (e.g., Philips HPK 125 W). The lamp should be maintained at least 12 in. from the reaction flask to minimize heating of the solution. Heating decreases the yield of 2. 

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