Friedrichs condenser

Mg. 11, 56, 17 (Davies types) and Fig. 11, 56, 18 (double coil type) are examples of efficient double surface condensers. Fig. 11, 56, 19 depicts a screw type of condenser (Friedrich pattern) the jacket is usually 10, 15 or 25 cm. long and the cone and sockets are fil9 or 24 this highly efficient condenser is employed for both reflux and for downward distillation. 

Friedrichs condenser. A "cold-finger" type of condenser sealed into a glass Jacket open at the bottom and near the top. The cold finger is formed into glass screw threads. 

A cold finger condenser packeFriedrichs condenser in combination with a circulating low-temperature bath (— 70°) is more convenient. 

Two hundred and seventy-six grams (94.3 cc., 1.72 moles) of bromine (Note 7) is now added as rapidly as possible through the dropping funnel, the rate of addition being so controlled that the Friedrichs condenser is continuously about half full of the refluxing liquid (Note 8). This operation takes about one hour (Note 9). After about 100 g. of bromine has been added, the dibromo-succinic acid forms rapidly and separates in tiny white needles. At the completion of the reaction there should be a slight excess of bromine, as indicated by the red color of the solution. Occasionally 5-10 g. of bromine has to be added at this point to insure an excess. 

K] the excess escapes at the top through the side arm D which is connected to a Friedrichs condenser E. The bottom of the condenser is connected to a Y-shaped section with an outlet F for effluent gas and a return G which extends below the surface of the liquid in the reservoir. At the top of the column is a 250-ml. dropping funnel II for admitting reactants to the column. Since oleic acid is a liquid at room temperature, heating of this funnel is not required in the present preparation. At the bottom of the column is a 500-ml. flask I for receiving the product. 

A 65-cm. Liebig condenser surmounted by a 150-cm. Friedrich condenser was found to be satisfactory. A 100-cm. Liebig condenser may be used if the inner tube is packed with glass wool. The bubbler for the air should have 4-5 fine jets to provide a broken stream and fine bubbles. 

O. Friedrichs, L. Kolodziejczyk, J.C. S4nchez-L6pez, C. Lopez-Cartes, A. Fernandez, Synthesis of nanocrystaUine MgH powder by gas-phase condensation and in situ hydrida-tion TEM, XPS and XRD study, J. Alloys Compd. 434-435 (2007) 721-724. 

Water lipid partition, 3, 21 Wittig condensation, 148, 339 Wohler, Friedrich, 5... 

A. Cyclopentadiene. Two hundred milliliters (195 g.) of technical dicyclopentadiene (Note 1) is placed in a 500-ml. twonecked round-bottomed flask equipped with thermometer and an upright Friedrichs-type condenser (through which water at 50° (Note 2) is circulated). The ground-glass (Note 3) outlet of the Friedrichs condenser is connected to the side arm of a simple distilling head fitted with a thermometer and attached to an efficient water-cooled condenser held in a vertical position. At the lower end of this condenser is a receiver which consists of a carefully weighed 500-ml. two-necked round-bottomed flask immersed in a Dry Ice bath (Note 4) and protected from the air by a calcium chloride drying tube. 

The flask containing dicyclopentadiene is now heated by means of an electric heating mantle or oil bath to approximately 160°, or until cyclopentadiene distils smoothly at 38-46° and a little dicyclopentadiene refluxes from the cold-finger (Friedrichs) condenser. After two-thirds of the dicyclopentadiene has been pyrolyzed (during the course of 4 5 hours), the residue in the Mask may lend to become viscous and a higher temperature for... 

A. Reduction and hydrolysis. A solution of 129 g. (0.75 mole) of 0-naphthyl ethyl ether in 1.5 1. of 95% ethanol is prepared in a 5-1. three-necked flask fitted with a mechanical stirrer, a bulb condenser topped by a Friedrichs condenser, and a Y-tube to allow for the introduction of nitrogen and sodium. The apparatus is llushed thoroughly with nitrogen, the nitrogen flow is reduced, and 225 g. (9.8 gram atoms) of sodium is added in small portions (Note 1), wilh efficient stirring, at a rate suffi-... 

Hopkins condenser. A cold-finger type of condenser resembling that of Friedrichs. 

A Friedrichs condenser is recommended. This efficient condenser has an inner cooling coil around which the vapors pass and condense. The submitters used rubber stoppers throughout. 

A 1-L, 3-necked, round-bottomed flask was equipped with magnetic stirrer, pressure-equalizing addition funnel with N2 inlet, low temperature thermometer, and a Friedrich condenser with N, outlet. The outlet was attached to two traps in series. The first was cooled in a Dewar of salt/ice water (- 15 C) and the second in a Dewar of dry ice/i-PrOH (— 78 C). 2-Bromo-3,3,3-trifluoropropene (50 g, 0.286 mol) and hexane (250 mL) were added to the flask. 1.6 M BuLi in hexane (190 mL, 0.304 mol, commercial) was added to the addition funnel. The flask was cooled with a hexane slush bath by addition of liquid N2 until the temperature of the solution inside the flask was - 85 °C. Then the BuLi soln was added over a period of 25 min at such a rate that the temperature remained below - 80 C. The slightly cloudy, yellowish solution was allowed to stir for an additional 10 min. Then, the hexane slush was removed, Upon reaching - 30 C, a gelatinous precipitate formed and the temperature rapidly rose to 28 "C. The volatile product was removed from solution by heating the mixture at reflux for 30 min with a slow flow of N2 through the system. The product was obtained from the dry ice trap yield 21 g (97%). 

A West condenser and a Friedrich condenser in tandem are recommended... 

This procedure may prove useful in other cases where impurities are strongly adsorbed on alumina, it avoids the use of enormous volumes of solvent The heating mantle is controlled by a Variac, set so that the liquid level remains constant. The plastic tubing should not be of Tygon , since this is attacked by the solvent, polyethylene tubing is suitable. An efficient condenser is essential, the use of a West condenser and a Friedrich condenser in tandem is recommended A similar but more complicated apparatus is described by Meier and Fletschinger3... 

C. Hexahydro-4,4,7-trimethyl-4H-l,3-bensoxathiin. To a 1-L, one-necked, round-bottomed flask equipped with a magnetic stirrer and charged with 325 nt of benzene (Note 12) is added 140.0 g (0.753 mol) of 5-methyl-2-(1-methyl-1-thioethyl)cyclohexanol, 26.0 g (0.87 mol) of paraformaldehyde (Note 13) and 1 g of p-toluenesulfonic acid monohydrate (Note 14). The flask is fitted with a Dean-Stark trap and a Friedrich condenser and the contents are refluxed for... 

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