Jacketed dropping funnel

To a three-necked 100-mL flask equipped with mechanical stirrer, jacketed dropping funnel and rubber septum, under argon, are added 3.52 g (15 mmol) of (-)-sparteine, 20 mL of anhvd pentane, 3 mL of cyclohexane and 2.99 g (15 mmol) of ( )-2-bulenyl diisopropylcarbamate. The mixture is chilled to below -70 C in a dry ice/acetone bath. 10 mL of 1.6 N butyllithium in hexane are slowly added with rapid... 

C. Fuxyt S,N,N, S -tetramethytdiamidophoaphate. To 180 mL of dry diethyl ether, chilled to -30°C, is added 56.7 g (4.2 equiv) (1.26 mmol) of dimethylamine (Note 17). This solution is added during 1-2 hr from a double Jacketed dropping funnel, protected from moisture by a calcium chloride-tube and connected to a cryostat regulated to -30°C, to a stirred mixture (Note 18) of 60 g (0.30 mol) of the freshly distilled furyl phosphorodichloridate and 250 mL of ether in a two-necked, 1-L flask equipped with a condenser, protected from moisture by a calcium chloride-tube and connected to the cryostat. This flask is chilled in an ice bath during the addition of the first two equivalents of the dimethylamine. After the addition of... 

A. /3-Isovalerolactam-N-sulfonyl chloride. A 200-ml. fournecked flask fitted with a mechanical stirrer, a dry ice-jacketed dropping funnel (Note 1), and a thermometer is cooled with a dry ice-methylene chloride slush bath while 67 ml. of sulfur dioxide (Note 2) is condensed into the flask Both the dry ice condenser and the dropping funnel are protected with drying... 

If the solution to be added from the dropping funnel requires cooling rnor to addition it is possible to use a jacketed dropping funnel, with the -doling mixture (e.g. dry-ice/acetone) placed in the jacket. This is a zammon set-up encountered for low temperature reactions on larger scales Fig. 13.1). 

The feed is supplied to the evaporator from a jacketed dropping funnel (.4). The feed rate can be controlled exactly by means of a needle valve (B) and the funnel itself which works on the principle of the Matiotte bottle. Before entering the evaporation zone the feed is passed through a heated coil (G) and heated to about boiling temperature. Thus, full use can be made of the evaporation zone for actual evaporation. Besides, the product is already degassed in the coil and spraying in the evaporator tube is avoided. 

The checkers used a dropping funnel with temperature-control Jacket (Normag N 8055, Otto Fritz GmbH, Normschliff-Aufbaugerate (Norraag), D-6238 Hofheim am Taunus). 

A reaction flask was equipped with stirrer, thermometer, dropping funnel, and a steam-jacketed condenser that would allow ethyl... 

The solution is stirred and cooled to —75° with a dry ice-acetone bath, and 2.90 g. (0.05 mole) of propionaldehyde (Note 18) is added through a dropping funnel. The solution is stirred at —75° for 5 minutes. The dry ice-acetone bath is replaced by a water bath, and the solution is stirred at 20° for 30 minutes. The solution is diluted with 250 ml. of ether and washed with two 100-ml. portions of 5M aqueous ammonium chloride, two 100-ml. portions of water, and 100 ml. of saturated aqueous sodium chloride. Each of the aqueous washes is extracted with the same 250-ml. portion of ether. The combined ethereal solution is dried over anhydrous magnesium sulfate (Note 4), filtered, and evaporated at 40° under a pressure of 25 mm. The residual liquid is distilled under reduced pressure through a 10 x 0.7 cm., unpacked, vacuum-jacketed column, and the material boiling at 93-98° (2 mm.) furnishes 7.90-7.99 g. (82-83%) of l,3-bis(methylthio)-l-hexen-4-ol (Notes 19, 20). 

The evacuated apparatus is dried with a flameless heat gun at 150°C and then flushed with dry argon. An atmosphere of dry argon is maintained during the course of the reaction. The jacket of the dropping funnel is charged with acetone and dry ice or with ethanol and liquid nitrogen. 

Fig. 1. Jacketed 250-mL pressure-equalizing dropping funnel (A) 24/40 female ground joint, (B) 10-mm glass tubing, (C) 80-mm tubing, (D) solid glass braces, (E) 250-mL graduated cylinder, (F) three-way, 2-mm glass stopcock, (G) 2-mm glass stopcock, (H) 24/40 male ground joint.

A 250-ml. three-necked, round-bottomed flask is fitted with a dropping funnel, a mechanical stirrer, and a steam-jacketed column (15-20 cm. long) terminating in a still head. The still head carries a thermometer and is connected to a condenser set for downward distillation. In the flask are placed 42.2 g. (0.22 mole) of ethyl benzoylacetate 1 (Note 1) and 50 ml. of dry xylene, and the flask is immersed in an oil bath. The bath is heated to 145-150°, stirring is begun, and 18.2 ml. (18.6 g., 0.20 mole) of... 

A jacket which is suitable for holding dry ice may be made easily for use with a cylindrical dropping funnel. The neck and... 

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