Spinning-band Columns

Cyclobutanone [1191-95-3] M 70.1, b 96-97 , d 0.931, n 1.4189. Treated with dilute aqueous KMn04, dried with molecular sieves and fractionally distd. Purified via the semicarbazone, then regenerated, dried with CaS04, and distd in a spinning-band column. Alternatively, purified by preparative gas chromatography using a Carbowax 20-M column at 80°. (This treatment removes acetone). 

Fractionated through a 90cm Monel spiral column, or other efficient fractionating or spinning band column and collecting the middle fraction. 

Dodecanol (dodecyl alcohol) [112-53-8] M 186.3, m 24°, b 91°/lmni, 135°/10mm, 167°/40mm, 213°/200mm, 259°/atm, d 0.8309 (liquid). Crystd from aqueous EtOH, and vacuum distd in a spinning-band column. [Ford and Marvel Org Synth 10 62 7950.]... 

Ethyl stearate [111-61-5] M 312.5, m 33 , b 213-215 /15mm. The solid portion was separated from the partially solid starting material, then crystd twice from EtOH, dried by azeotropic distn with benzene, and fractionally distd in a spinning-band column at low pressure [Welsh Trans Faraday Soc 55 52 1959]. 

Methyl-2-butanone (methyl isopropyl ketone) [563-80-4] M 86.1, b 93-94 /752mm, d 0.818, n 1.410, pK -7.1 (aq H2SO4). Refluxed with a little KMn04. Fractionated on a spinning-band column, dried with CaS04 and distd. 

Pentyl acetate (n-amyl acetate) [628-63-7] M 130.2, b 147-149 /atm, 149.55 , 149.2 /atm, d4 0.8753, n 1.4028. Purified by repeated fractional distn through an efficient column or spinning band column. [Timmermann and Hennant-Roland J Chim Phys 52 223 7955 Mumford and Phillips J Chem Soc 75 1950 H NMR Crawford and Foster Can J Phys 34 653 7956.]... 

VinyInaphthaIene [826-74-4] M 154.2, b 124-12S /lSnim. Fractionally distd under reduced pressure on a spinning-band column, dried with CaH2 and again distd under vacuum. Stored in sealed ampoules in a freezer. 

A final distillation at 760 mm. through a 50-cm. stainless-steel spinning band column yields 41 g. (64% from methylenecyclopropane) of pure cyclobutanone (b.p. 100-101°) (Notes 19, 20). 

The checkers used a 6 x 350 mm. spinning-band column with a total reflux variable take-off head. The band was spun at 1100 r.p.m. 

N-Cyclohex-l-enylpyrrolidine (9 g 0 06 mol) was dissolved in pentane with A -ethyldiisopropylamine (7.8 g 0.06 mol). Perfluorohexyl iodide (13.4 g, 0.03 mol) IS added to the solution. Aprecipitate of A-ethyldiisopropylamine hydroiodide IS formed instantly After 3 h, the precipitate is filtered off, and the solution is evaporated The crude liquid is hydrolyzed with 6 mL of 40% sulfuric acid The mixture is stirred for 3 h and extracted with ether. The ether layer is neutralized with aqueous sodium hydrogen carbonate, washed with water, and dried over magnesium sulfate. The solvent is evaporated, and the residue is distilled. A second distillation with a spinning-band column yields 7 9 g (63%) of pure 2-(perfluoro-hexyl)cyclohexanone (bp, 71 -73 °C at 0 4 mm of Hg). 

The checkers used a Nester-Faust 44-cm. spinning-band column. 

Farnesol was obtained from Fluka AG (Buchs, CH9470, Switzerland) as a mixture of 65% (E), (E)- and 35% (Z), (E)- isomers. It is also available from the Aldrich Chemical Company, Inc. This procedure works equally well with pure (E), (F)-famesol, which may be obtained from the above mixture by careful distillation, at reduced pressure, through a Nester-Faust Teflon spinning-band column. 

The drying agent is removed by filtration, and the filtrate is distilled under nitrogen through a spinning band column (Notes 6 and 7). The fraction, boiling at 92-93° (725 mm.), is collected to yield 54.2-60.0 g. (66-73%, based on chloroform) of lerf-butyl isocyanide (Notes 8 and 9). 

Pure (A)-1 -chloropropene was obtained by careful distillation of a mixture of (E)- and ( )-l -chloropropene (available from Columbia Organic Chemicals Company Inc.) using a Nester-Faust Teflon annular spinning band column [(Z)-l-chloropropene has b.p. 33° (A)-l-chloropropene has b.p. 37°]. Small quantities of powdered sodium bicarbonate and hydroquinone (1,4-benzenediol) placed in the distillation flask inhibit acid-catalyzed isomerization and polymerization. Gas chromatographic analysis of the material used in these experiments on a 4-m., 15% l,2,3-tris(2-cyanoethoxy)propane (TCEP) on Chromosorb P column, operated at room temperature, typically indicated that it had isomeric purity >99.9%. (A)- 1-Chloropropene is stable for several months at room temperature, but it should be stored in a cool place. 

The submitters used an 18-in. spinning-band column.. The product was shown to be >99.9% pure by gas-liquid chromatography on Carbowax 20M. 

The checkers used a 40-cm. spinning-band column. The product, n2bD 1.4237, was shown to be 98.9% pure by gas-liquid chromatography on a 6-ft. 20% fluorosilicone column. The retention time was 3.75 minutes with a flow rate of helium of 100 ml. per minute, and a column temperature of 125° with the injection port at 170°. The 19 F n.m.r. spectrum (56.4 MHz) consists of four lines of equal intensity centered at +3396 Hz from trichlorofluoromethane (internal) and two sets of two overlapping quartets centered at +4369 Hz and +4461 Hz, respectively. The integrated intensities of the three sets of fluorine resonances are 3 1 1. 

The pentane solution is dried over anhydrous magnesium sulfate and fractionated with an efficient spinning-band column (Note 10). After foreruns of pentane and glyme containing f-nitrosobutane are removed (Note 11), 26-27 g. (42-43%) of red di-/-butyl nitroxide, b.p. 59-60° (11 mm.), is obtained. 

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