Spinning band distillation equipment

Infrared spectra were determined using Perkin-Elmer infrared spectrophotometers models 137-B and 21. NMR spectra were run using Varian T-60 and A-60 spectrometers. Gas chromatographic analyses were done on a Hewlett-Packard model 5750B instrument. Fractional distillations were performed on a Nester-Faust 18-inch semimicro spinning band column equipped with a stainless steel band. 

A mixture of 314 g, (1.89 moles) of triethyl phosphitef and 200 g. (1.05 moles) of 1,2-dibromoethane is placed in a two-necked, 500-ml., round-bottomed flask equipped with a thermometer well. The flask is attached to a Nester-Faust 24-in. intermediate-model spinning-band distillation column with a column bore of 8 mm.J The pot temperature is maintained at 145-150°C. After its contents are heated at this temperature for lj-2 hours, ethyl bromide commences to distill. Approximately 130 ml. (180-190 g., 1.6-1.7 moles) of ethyl bromide is collected. After the removal of ethyl bromide is completed, the reaction mixture is cooled to ambient temperature and subsequently fractionated under reduced pressure. The following fractions are obtained ... 

A 45-cm. spinning band column was employed by the submitter, but any distillation column with a low holdup may be used. Since the products have widely different boiling points, careful fractionation during distillation is not needed. Because the phenylsulfur trifluoride and benzenesulfinyl fluoride slowly attack glass, all equipment should be rinsed with water and acetone immediately after use to minimize etching. 

In a Hanovia 550-watt immersion photochemical reactor (Note 1) equipped with a magnetic stirrer and water condenser (Note 2) are placed 1 1. of diethyl ether, 180 g. (1.96 moles) of bicyclo[2.2. l]hepta-2,5-diene (Note 3), and 8 g. of acetophenone. The system is flushed briefly with a stream of nitrogen and then irradiated for a,bout 36-48 hours (Note 4). After irradiation, the ether is removed by distillation through a 20-cm. Vigreux column (Note 5). The residue, a clear liquid weighing about 185 g., is distilled through a spinning-band column under reduced pressure (Note 6). Quadricyclane is obtained as a colorless liquid, b.p. 70° (200 mm.). The yield is 126-145 g. (70-80%) (Note 7). 

The submitter used a 65-cm. Podbielniak type column equipped with partial reflux head.6 For distillation of the sodium-treated phenanthrene the checkers employed a 6-in. Vigreux column. For the fractionation of the dihydrophenanthrene, the checkers employed a 15-cm. spinning-band column obtainable from Nester and Faust, Exton, Pennsylvania. 

SbFj (71.5 g, 0.4 mol) and SbCl (10 mL) were mixed in a 250-mL, three-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel. Then, at rt (25 C) and with stirring, 1,1,1.3.3.3-hexafluoro-2-(trichloromelhyl)propan-2-ol (38 g. 0.113 mol) was added slowly. The resultant slurry was heated until a steady reflux was obtained (100-105 C). and this condition was maintained with vigorous stirring for 30 min. The mixture was cooled to 30 C then distilled to remove the fluorinated products. The crude product was redistilled through a spinning-band column to yield 2-(chlorodifluoromethyl)-... 

A dry flask, equipped with a septum inlet, a pressure-equalizing dropping funnel, and magnetic stirrer, was flushed with N2 and maintained under statie pressure of the gas (e.g. with a bubbler filled with mercury). Into the flask was placed 0.70M 9-BBN in THF (143 mL, 100 mmol). Then 3,4-dichloro-but-l-ene (12.5 g, 100 mmol) was added dropwise at 25 °C over 10 min. The reaction mixture was stirred at 25 °C for 1 h, and then 3M aq NaOH (40 mL, 120 mmol) was added dropwise. After 2h, anhyd KjCOj was added and the upper THF layer was separLated, dried and distilled. GC analysis indicated a yield of 81%. Distillation through a spinning-band column gave 6.3 g (70%) bp 83-90°C/742 Torr. 

Microscale Apparatus. The apparatus shown in Figure 15.2 is the one you are most likely to use in the microscale laboratory. If your laboratory is one of the better-equipped ones, you may have access to spinning-band columns like those shown in Figure 15.10. The distillation temperature can be monitored most accurately by using a partial immersion mercury thermometer (see Technique 13, Section 13.3). 

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