Cold trap assembly

Figure 11. Cold trap assembly of the vacuum line.

Oydobutanone. A 2-1. three-necked flask is fitted with an efficient mechanical stirrer and a water-cooled condenser assembled for downward distillation to which is attached a 250-rnl. receiver with a side arm. Two cold traps are attached consecutively to the distillation apparatus as shown in Figure 2 (Not 12). The receiver is immersed in an ice-water bath, and the traps are immersed in dry ice-acetone. To the flask is... 

The reaction was studied in a laboratory assembled high-vacuum system (see Figures 9.8 and 9.9), consisting of two vacuum circuits, one for the evacuation of the evaporation chamber and the other for the evacuation of the gas introduction system [119,122,123], Figure 9.8 shows the fore pump, diffusion pumps, cold traps, ionization manometer, and the metal evaporation chamber [119]. The evaporation was carried out al / = 10 6 Torr, with the help of a thread helicoidal filament made of a wolfram (W) wire of 0.5mm diameter and 10cm length [119]. The whole vacuum system was coupled with a mass spectrometer, Hitachi RMU-6D, in order to follow the reaction kinetics [119,122,123] (see Figure 9.9). The procedures followed in order to study the reaction were as follows ... 

Fig. 3.5. Schematic of the gravimetric units, (a) Sub-atmosphere unit (0-100 kPa) 1.Balance assembly. 2. Controlled heaters. 3. Sample. 4. Thermocouple. 5. Gas reservoir. 6. Pressure sensors. 7. Injection assembly. 8. Zeolite trap. 9. Cold trap. 10. Turbomolecularpump. 11. Insulated box. (b)...

Figure 6 depicts a simplified five tap version of our double manifold vacuum line. This assembly is shown as being about 5 feet long but can be made considerably shorter as a four tap line and/or if only one cold trap is used.t In many ways the design is superior... 

Four leaks occurred because of poor-quality manufacture of sodium system units. So, at the BR-5/10 immediately after mounting of the primary circuit impurity cold trap a leak occurred at the trap nozzle through a microcrack in the joint weld at sodium heating up in the pipe. The cause of the leak was poor quality inspection of joint welds after completion of assembling. Similar situations took place at the BN-600 as well. Such leaks were detected immediately after putting into operation of a failed section of the system. 

Figure 6 Typical freeze-drying apparatus. The frozen sample, S, is attached to the condenser assembly and a vacuum is applied. A cold trap, CT, protects the pump as ice sublimes from the sample and subsequently condenses in the refrigerant condensers, RC. On completion of the drying the sample is removed and the collected ice melts and drains from the system through the stopcock, SC.

An integral primary system layout is employed (Fig. 12.4), ie, reactor core, variable frequency submersible coolant pumps, intermediate heat exchanges, safety system heat exchangers, and cold trap filters. The reactor vessel is enclosed in a guard vessel. There are no auxiliary sodium systems in the primary circuit. The reactor core consists of fuel assemblies, boron shield assemblies, and absorber rods. The central part of the core consists of wrap-spaced hexagonal fuel assemblies and cells with absorber rods. The spent fuel is stored in the reactor vessel for up to 2 years, which facilitates spent fuel cooling and eliminates the need for spent fuel storage casks. Assemblies with boron carbide are placed behind the spent fuel to protect the reactor vessel. 

For many applications, gas-phase samples can be prepared using a routine vacuum line consisting of mechanical and diffusion pumps, a cold trap, thermocouple and capacitance manometer gauges and a manifold with attachments for sample tubes and gas inlets. NMR sample tubes are either sealed with a glass torch or constructed with self-sealing top assemblies. Preparation of samples at elevated pressures requires quantitative transfer operations. With few exceptions, gas-phase NMR samples used to study conformational processes contained a volatile bath gas in addition to the sample molecule, which usually has a low vapour pressure. Molecules with low vapour pressures tend to behave nonideally even at very low pressures and this factor must be taken into consideration when converting measured gas pressures into densities. 

To the far left is grouped all of the fuel low-pressure eciuipment, including dump tanks, recombiner, condensate tank, and cold traps. These components are assembled on a rigid structural-steel frame the blanket low-pressure equipment is to the far right. 

Place 29 g. of n-caproamide (Section 111,109) into a 200 ml. distilling flask, and assemble the apparatus shown in Fig. Ill, 28, 1. Remove the trap momentarily and introduce 45 g. (27-5 ml.) of redistilled thionyl chloride no apparent reaction takes place in the cold. Warm the mixture on a water bath or by means of a small flame for 1 hour. Arrange the apparatus for distillation and distil oflF the excess of thionyl chloride (t.c., until the temperature reaches about 90°) and allow to cool. When cold, transfer the residue to a 100 ml. distilling flask (1). Distil from an air bath (Fig. II, 5, 3) the n-capronitrile passes over at 161-163° (2). The yield is 21 g. 

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