Inlet septa

Synthesis of Alkviamines. General Procedures. Method (A). The synthesis of p-phenethylamine is representative. A flame dried, nitrogen-flushed, 100 ml flask, equipped with a septum inlet, magnetic stirring bar and reflux condenser ivas cooled to 0°C. Sodium borohydride (9.5 mmol, 0.36 g) was placed in the flask followed by sequential addition of THF (13-15 ml) and BF3-Et20 (12 mmol, 1.5 ml) at 0°C. After the addition, the ice bath was removed and the contents were stirred at room temperature for 15 min. The solution... 

In a separate, dry, 1-L, two-necked, round-bottomed flask fitted to a nitrogen bubbler and equipped with a magnetic stirring bar and a septum inlet is added a solution of 12.6 g (60.0 mmol) of 2-(hydroxymethylene)cyclododecanone (Note 4) in 500 mL of anhydrous ether. The stirred ethereal solution of the hydroxymethylene ketone is treated at 22°C with 33 mL of a freshly prepared mixture (1/1, v/v) of chlorotrimethylsilane and triethylamine (Note 5). An immediate reaction takes place with deposition of a white precipitate. The mixture is stirred thoroughly at 22°C for 15 min to insure complete conversion to the silyl enol ether. 

B. (3-Bromo-3,3-difluoropropyl)trimethylsilane. A 1-L, four-necked flask is equipped with a mechanical stirrer, thermometer, Claisen adapter, septum inlet, reflux condenser (the top of which is connected to a calcium chloride drying tube), and a solid addition funnel. The flask is charged with (1,3-dibromo-3,3-difluoropropyl)trimethylsilane (78.3 g, 0.25 mol), and anhydrous dimethyl sulfoxide (200 mL), and the solid addition funnel is charged with sodium borohydride (11.5 g, 0.30 mol) (Notes 7 and 8). The stirred solution is warmed to 80°C, and sodium borohydride is added at a rate sufficient to maintain a reaction temperature of 80-90°C (Note 9). Toward the end of the addition, an additional portion of dimethyl sulfoxide (200 mL) is added via syringe to lower the viscosity of the reaction mixture. After the addition is complete, the mixture is cooled in an ice-water bath, diluted with 100 mL of pentane, and cautiously quenched with 12 M hydrochloric acid until no further gas evolution occurs. The mixture is transferred to a separatory funnel and washed with three, 100-mL portions of 5% brine. The pentane extract is dried over calcium chloride and the solvent removed through a 15-cm Vigreux column. Further fractionation yields 41.5 g (72%) of 3-bromo-3,3-difluoropropyltrimethylsilane, bp 139-141 °C (Note 10). 

Methoxycarbonylation of organic tellurides by use of stoichiometric Pd(II) salts (typical procedure) In a two-necked, 50 mL, round-bottomed flask with a septum inlet and a three-way stopcock were placed PdClj (0.177 g, 1.0 mmol) and a telluride (1.0 mmol). The system was then flushed with CO from a CO balloon connected to the flask at 25°C, to which dry methanol (10 mL) and triethylamine (0.202 g, 2.0 mmol) were added by a syringe. After the mixture was stirred with diethyl ether (3x30 mL). The products were determined by GLC using an EGSS-X 3% (1 m) column. 

Figure 6. Diagram of our 1-atm ion mobility spectrometer (IMS) apparatus (a) stainless steel source gas dilution volume, (b) septum inlet, (c) needle valve, (d) Nj source gas supply, (e) source and drift gas exhaust, (f) flow meter, (g) pressure transducer, (h) insulated box, (i) drift tube, (j) ion source, (k) Bradbury-Nielson gate, (I) Faraday plate/MS aperture, (m) drift gas inlet, (n) universal joint, (o) electrostatic lens element, (p) quadrupole mass filter, (q) 6"-diffusion pump, (r) first vacuum envelope, (s) channeltron electron multiplier, (t) second vacuum envelope, (u) 3"-dif-fusion pump, (v) Nj drift gas, (w) leak valve, (x) on/off valves, (y) fused silica capillary, (z) 4-liter stainless steel dilution volume, (aa) Nj gas supply.

A. (E)-l-Deaenyidiisobutylalane. An oven-dried, 300-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, a rubber septum inlet, and an outlet connected to a mercury bubbler is flushed with nitrogen, immersed in a water bath kept at room temperature, and charged with 22.6 ml (125 mmol) of 1-decyne (Note 1) and 80 mL of hexane (Note 2). To this flask is added dropwise, with stirring, 22,3 mL (125 mmol) of diisobutylaluminum... 

A. Lithium triethylcarboxide (Solution 1). A thoroughly dried, 1-1., three-necked, round-bottomed flask is fitted with a septum inlet with serum cap, a reflux condenser, and a magnetic stirrer. The flask is purged with and maintained under an atmosphere of dry nitrogen. A solution of 300 ml. of 1.66 M butyllithium (0.50 mole) in hexane (Note 1) is introduced into the flask by syringe (Note 2) and cooled to 0° in an ice bath. Then 58 g. (0.50 mole) of 3-ethyl-3-pentanol (Note 3) is added slowly but constantly by syringe (Note 4). At the end of addition the yellow tint of the butyllithium solution disappears. The alkoxide solution is standardized by hydrolysis of aliquots in water and by titration of the resulting lithium hydroxide with standard acid to a phenol-phthalein end point (Note 5). 

Injection port. Closure column on one side and a septum inlet on the other through which the sample is introduced into system. 

One of the biggest problems with present-day septum inlet systems is that of septum bleed. Kolloff (13) was the first to note the bleed of monomers and short-chain polymers (used in the production of the synthetic elastomers from which septa are derived) from gas chromatographic septa. Another problem is sorption of solvents and sample components on the septa. A thorough study of this phenomena was made by Adler (14) related to the use of selfsealing elastomer septa for quantitative operations with volatile laboratory solvents. It was found that a silicone septum could absorb over twice its weight of carbon tetrachloride and chloroform and more than its weight of benzene at 25°C. 

The procedure is especially suited to small-scale preparations (25 mmoles or less) where the necessity of evaporating hexane from the lithium bis(trimethylsilyl)amide is much less of a handicap. In such cases, it is convenient to equip the reaction vessel with a septum inlet and transfer all reagents with a syringe. 

A dry 500-ml flask equipped with a septum inlet, magnetic stirrer and gas connecting tube is flushed with dry nitrogen and maintained under static... 

A 25-mL flask containing a magnetic stirring bar and assembled with a septum inlet, a condenser, and a bubbler was charged with [ I r(OMe) (cod) ]2[ 13] (0.015 mmol) and 4,4 -di-tert-butyl-2,2 -bipyridine (0.03 mmol), and then flushed with nitrogen. Dry hexane (6mL), pinacolborane (1.1 mmol), and 3-bromobenzo-nitrile (1.0 mmol) were added, and the mixture was stirred at 25 °C for 2h. The reaction mixture was treated with water at room temperature, extracted with ben-... 

Open the stopcock, and add freshly distilled THF (40 mL) through the septum inlet using a glass syringe. 

Replace momentarily the septum inlet with a wide-stemmed funnel under a slightly positive pressure of nitrogen or argon and introduce Pd(PPh3)4 (1.16 g, 1 mmol). 

Three-necked round-bottomed flask (100 mL) with a septum inlet, a tubing adapter, and an adapter for an ultrasonic probe... 

In a 250 ml three-necked flask was placed (dichloroiodo)benzene (7.25 g, 30 mmol) with light protection, under nitrogen. Then 2,3-dimethylbutane (30.25 g, 350 mmol) and trihexylborane (400 mg, 1.5 mmol) were introduced by syringes through a septum inlet. The mixture was stirred at room temperature for about 2 h during the reaction hydrogen chloride evolved was carried into an aqueous sodium hydroxide solution by a weak stream of nitrogen. The reaction mixture was neutralized with dilute sodium hydroxide, washed with water several times and dried. Fractional distillation afforded 2-chloro-2,3-dimethylbutane (3.22 g, 89%), b.p. 109-110°C. 

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