Flasks: types

Most microbial desulfurization studies have been conducted in the laboratory shake-flask type experiments, and the major drawback cited against such a process has been that the rates of pyritic sulfur removal were not high enough to reduce the reactor size to a reasonable capacity (2,6). In this study an attempt has been made to determine the effectiveness of T. ferrooxidans under simulated pipeline conditions for pyritic sulfur removal. Since the microbial desulfurization process is conducted under acidic environment, an attempt has been made to determine the corrosion rates under dynamic conditions using Illinois //6 and Indiana 3 bituminous coals and to investigate the effectiveness of a commercial corrosion inhibitor for controlling the corrosivity. 

The flask-type combustion apparatus of the Schoniger system is commercially available (Mikro K Heraeus, Germany). 

Two main types of cell have been devised for the accurate measurement of electrolytic conductance there is the pipette type, used by Washburn (1916), and the flask type, introduced by Hartley and Barrett (1913). In the course of a careful study of cells of the pipette form, Parker (1923) found that with solutions of high resistance, for which the polarization error is negligible, there was an apparent decrease of the cell constant with increasing resistance. This phenomenon, which became known as the Parker effect, was confirmed by other workers it was at... 

The Parker effect is absent from cells with dipping electrodes, such as in cells of the flask type there are other sources, of error, however, as was pointed out by Shedlovsky. In the cell represented diagram-matically in Fig. 15, I, the true resistance of the solution between the electrodes is 72o, and there is a capacity Ci between the contact tubes above the electrolyte, and a capacity C2 in series with a resistance r between those parts immersed in the liquid the equivalent electrical circuit is shown by Fig. 15, II. When the cell is placed in the arm of a Wheatstone bridge it is found necessary to insert a resistance R and a capacity C in parallel in the opposite arm in order to obtain a balance (cf. p. 33) it can be shown from the theory of alternating currents that... 

Preparation of Solutions.—When the conductances of a scries of solutions of a given electrolyte are being measured, it is the custom to determine the conductance of the water first. Some investigators recommend that measurements should then commence with the most concentrated solution of the scries, in order to diminish the possibility of error resulting from the adsorption of solute from the more dilute solutions by the finely divided platinum on the electrodes. When working with cells of the flask type it is the general practice, however, to fill the cell with a known amount of pure solvent, and then to add successive small quantities of a concentrated solution of the electrolyte, of known con-... 

Cell mass production and metabolite production by cells developed over the last 50 years. Muir et al. reported the first suspension culture of plant cells and the first cultivation of cells in bioreactors in 1955 by Melchers and Engelmann. The development of bioreactors since this time was extremely fast, from small flask type to multicubic meters. One of the largest bioreactors in the production of alkaloids by transformed hairy roots is reported to be of 500 m in size and has been used in a pilot scale in 1990 by the research group of Wilson. In recent studies, the different bioreactors have been compared to produce galanthamine from shoots of... 

Figure 2 Types of contacting conductivity cells (A) Jones and Bollinger (B) Roseveare (C) Shedlovsky (D) flask type (Shed-lovsky) (E) dipping cell. (From Light TS and Ewing GW (1990) Measurement of electrolytic conductance. In Ewing GW (ed.) Analytical Instrumentation Handbook, pp. 641-658. New York Dekker.)...

Cryogenics We use several types of evacuated stainless steel cryostats of about 1 htre capacity to provide the 77 K cooling with hquid nitrogen. The simplest, best valued and easiest to handle one is a ordinary thermos flask available from the supermarket (see fig.3). It is sufficient for a measurement period of more than 12 hours. A specially designed stainless steel vessel gains cooling periods of 30 hours. 

This type of filtration is almost invariably performed with the aid of a Buchner flask and funnel, by means of which a rapid and almost complete separation can be obtained. The Buchner flask A (Fig. 4) consists of a simple thick-walled conical flask with a short side-arm for connection to a water-pump. Into the neck of the flask is fitted the Buchner funnel B which consists usually of a cylindrical porcelain funnel, the bed of which is pierced by a... 

It has already been pointed out that a liquid even when subjected to simple atmospheric distillation may become superheated and then bump violently in consequence this danger is greatly increased during distillation under reduced pressure and therefore a specially designed flask, known as a Claisen flask, is used to decrease the risk of superheating. In Fig. i2(a) a Claisen flask D is shown, fitted up as part of one of the simplest types of vacuum-distillation apparatus. ... 

Round-bottomed flasks (Fig. 22(A)) of various sizes and having necksof various lengths and widths. They can be closed with stoppers (Fig. 22(B)), or fitted with any of the following units reflux air-condensers (Fig. 22(C)) or water condensers (Fig. 22(D)) distillation heads, of the simple knee-tube type (Fig. 22(E)), or with a vertical joint (Fig. 22(F)) for thermometers, etc., or with... 

Fig. 23(C) shows a reflux assembly with a stirrer fitted. The stirrer A is both held in position in the tube B and allowed to rotate freely by the lubricated rubber sleeve C, as described on p. 39, and is connected to a vertical motor above. The extent to which the stirrer dips into the liquid in the flask can readily be adjusted. The condenser (not shown) is fitted into D. This constitutes for many purposes the best type of stirrer. If desired, the rubber sleeve C can be replaced by a metal fitting E for a horizontal drive. The gas-inlet F is closed when not in use.

For extraction purposes, a Soxhlet apparatus (Fig. 23(H)) can be inserted between a flask of boiling solvent and the reflux condenser A above. This apparatus is similar in design to that shown in Fig. 19, p. 3b in the type shown in Fig. 23(H) the hot extract continuously overflows through the side- tube into the boiling solvent below, but the syphon type shown in Fig. 19 is also available. 

A skilled worker can use a micro-Bunsen burner for most types of heating. Nevertheless, as there is a tendency for a liquid to shoot out of a small test tube when heated, it is preferable to place the tube in a hot water-bath or in a metal heating block. A small glycerol bath is suitable for distillations and heating under reflux, the glycerol being subsequently easily removed from flasks, etc., by washing with water. 

Carefully refractionate the liquid of b.p. 150-160°, either by direct distillation from a small distilling-flask or (preferably) by using a short fractionating column, of the type shown in Fig. ii(b), p. 26. Almost pure bromobenzene is thus obtained, of... 

Place 80 g, of hydroxylamine sulphate (or 68-5 g. of the hydrochloride), 25 g. of hydrated sodium acetate, and 100 ml. of water in a 500 ml. flask fitted with a stirrer and a reflux water-condenser, and heat the stirred solution to 55-60°. Run in 35 g (42 nil,) of -hexyl methyl ketone, and continue the heating and vigorous stirring for ij hours. (The mixture can conveniently be set aside overnight after this stage.) Extract the oily oxime from the cold mixture twice with ether. Wash the united ethereal extract once with a small quantity of water, and dry it with sodium sulphate. Then distil off the ether from the filtered extract, preferably using a distillation flask of type shown in Fig. 41 (p. 65) and of ca, 50 ml, capacity, the extract being run in as fast as the ether distils, and then fractionally distil the oxime at water-pump pressure. Collect the liquid ketoxime, b.p. 110-111713 mm. Yield, 30-32 g. 

A flask is provided with a long side neck (Fig. II, 25, 1) through which a capillary is inserted and attached externally by a short length of rubber pressure tubing. With this type of connexion there is essentially no contact of hot vapours with the rubber and little or no contamination results. The neck of the flask is preferably fitted with a standard ground joint if attack of the organic vapours on the rubber stopper is likely to occur. 

Attention is directed to the fact that ether is highly inflammable and also extremely volatile (b.p. 35°), and great care should be taken that there is no naked flame in the vicinity of the liquid (see Section 11,14). Under no circumstances should ether be distilled over a bare flame, but always from a steam bath or an electrically-heated water bath (Fig.//, 5,1), and with a highly efficient double surface condenser. In the author s laboratory a special lead-covered bench is set aside for distillations with ether and other inflammable solvents. The author s ether still consists of an electrically-heated water bath (Fig. 11, 5, 1), fitted with the usual concentric copper rings two 10-inch double surface condensers (Davies type) are suitably supported on stands with heavy iron bases, and a bent adaptor is fitted to the second condenser furthermost from the water bath. The flask containing the ethereal solution is supported on the water bath, a short fractionating column or a simple bent still head is fitted into the neck of the flask, and the stUl head is connected to the condensers by a cork the recovered ether is collected in a vessel of appropriate size. 

Multi-necked flasks. Various types of multi necked flasks are illustrated in Figs. II, 56, 13-15. The centre socket is usually the largest ( 24 or 34) and the side sockets are generally smaller. The side tube in Fig. II, 56,15, a may be employed for a capillary tube in vacuum distillation b, c and d are different types of thermometer wells . 

Glass stirrers. Numerous varieties of stirrers are marketed. The four types depicted in Fig. 11, 56, 31 are reasonably efficient and possess the advantage of passing through narrow-necked flasks or sockets ( 14 or... 

Extraction of steam distillates by solvents. The apparatus, depicted in Fig. 11,58, 7, may be employed for the continuous extraction of substances which are volatile in steam from their aqueous solutions or suspensions. Solvents of the ether type (i.e., lighter than water) or of the carbon tetrachloride type (i.e., heavier than water) may be used. A reflux condenser is inserted in the Bl9 socket, whilst flasks of suitable capacity are fltted into the lower B24 cone and the upper. B19 cone respectively. For extraction with ether, the flask attached to the upper. B19 cone contains the ether whilst the aqueous solution is placed in the flask fltted to the lower B2i cone the positions of the flasks are reversed... 

Allyl Bromide. Introduce into a 1-litre three-necked flask 250 g. (169 ml.) of 48 per cent, hydrobromic acid and then 75 g. (40-5 ml.) of concentrated sulphuric acid in portions, with shaking Anally add 58 g. (68 ml.) of pure allyl alcohol (Section 111,140). Fit the flask with a separatory funnel, a mechanical stirrer and an efficient condenser (preferably of the double surface type) set for downward distillation connect the flask to the condenser by a wide (6-8 mm.) bent tube. Place 75 g. (40 5 ml.) of concentrated sulphuric acid in the separatory funnel, set the stirrer in motion, and allow the acid to flow slowly into the warm solution. The allyl bromide will distil over (< 30 minutes). Wash the distillate with 5 per cent, sodium carbonate solution, followed by water, dry over anhydrous calcium chloride, and distil from a Claisen flask with a fractionating side arm or through a short column. The yield of allyl bromide, b.p. 69-72°, is 112 g. There is a small high-boiling fraction containing propylene dibromide. 

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