Separatory funnel stopcock, glass

Chromatographic columns (glass with stopcock and solvent reservoir, 10-mm i.d.) Fused-silica capillary column, DB-1701, 60 m x 0.32-mm i.d., O.lS-qm film thickness (14% cyanopropylphenyl)methylpolysiloxane Varian 3400 gas chromatograph equipped with a temperature-programmed SPI injector, a Varian 8100 autosampler, and a Varian Saturn II lontrap mass spectrometer Centrifuge vials, 10- and 250-mL Evaporation flasks, 100- and 250-mL Separatory funnel, 250-mL... 

A 1-1. three-necked round-bottomed flask is fitted with a 50-ml. separatory funnel and a mechanical stirrer sealed with a well-lubricated rubber collar. A stopper in the third neck of the flask carries a glass tube that reaches to the bottom of the flask, enters the top of a 1-1. separatory funnel, and extends down to the stopcock. 

For a run ten times this size, the solution is transferred to a 12-I. round-bottomed flask fitted with a stopper containing a large stopcock which barely pierces the stopper and a glass tube which reaches to the bottom of the flask. A flask so fitted can be used as a large separatory funnel. The stopper is wired when the flask is upturned. 

A. Preparation of ketene. The arrangement of the apparatus is shown in Fig. 2 (Note 1). The graduated separatory funnel, shown in the diagram, filled with 125 cc. of commercial acetone, leads into a 500-cc. round-bottom flask which, in turn, is connected by gas-tight joints (Note 2) to a glass combustion tube filled with broken porcelain, a spiral or bulb condenser, a two-way stopcock, and a reaction flask. In the reaction flask is placed the material with which the ketene is to react (Note 3). A second reaction flask may be placed in series, if desired, to ascertain if any ketene escaped reaction in the first flask. 

Thirty grams of pure iron powder (0.54 mol) is placed in the bottom of a three-necked 2-1. flask equipped with (1) a reflux condenser with a stopper and small glass tube or Bunsen valve at the terminal end to allow venting of the hydrogen and to minimize entrance of air into the system (2) a siphon linej with a glass-wool plug as a strainer, filled with wTater and closed with a stopcock or pinch clamp until needed and (3) a separatory funnel. Twelve hundred milliliters of distilled water and 100 ml. of 45 % formic acid are introduced into the flask. The contents are boiled until... 

I. Two 50-ml conical separatory funnels having short rubber tubing with pinchcock closures instead of glass stopcocks... 

Apparatus. Separatory funnels, with Teflon stopcocks—125-ml. and 4-liter capacities Kudema-Danish evaporators with Snyder three-ball columns Immerex extractor, A. H. Thomas Cat. No. 1228-E chromatographic tubes—25 mm. o.d. x 300 mm. glass tube with sintered glass in bottom and Teflon stopcock. 

The cylindrical separatory funnel A has a volume of 1200 cc. and holds 2 kg. (15.75 gram atoms) of iodine crystals (Note 2). A piece of perforated platinum foil B, or a loose plug of glass wool, is placed in the bottom to prevent clogging of the stopcock by iodine crystals or solid impurities. Stopcock C is as large as 5 mm. in bore as a further precaution. For the production of up to 4 kg. of methyl iodide, a 5-I. round-bottomed Pyrex flask D is used (Note 3). It is partly submerged in a water bath. Tube E, fitted into the reaction flask by a rubber stopper, is at least 2.5 cm. in internal diameter in order to allow the vapor to rise without interrupting the return of the excess distillate. Tube F is 4 cm. in diameter to allow for preliminary condensation. A space (13 cm.) is left above stopcock G as a reservoir for the distillate. Stopcock G has a bore of 2 or 3 mm. (Note 4). The bottom of the tube from this stopcock is flush with the bottom of the rubber stopper to the iodine container, so that thok ... 

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