Reaction vessel/flask

The reaction occurring under these conditions was found to be a composite one, consisting of a gaseous reaction between hydrogen and the vapour of the sulphur, and of a heterogeneous change at the surface of the liquid sulphur. This was demonstrated directly by using as reaction vessels flasks of different internal surface. 

Hydrogen chloride. Method 1 from concentrated sulphuric acid and fused ammonium chloride). The most convenient procedure is to allow concentrated sulphuric acid to react with lumps of fused ammonium chloride in a Kipp s apparatus. The gas may be dried by passage through a wash bottle containing concentrated sulphuric acid the latter should be followed by an empty wash bottle or flask as a precaution against sucking back of the contents of the reaction vessel. 

An even less complicated reaction vessel may be used for reactions in liquid amtnonia which produce only a small amount of "heat" over a relatively long period and which proceed under homogeneous conditions. The conversion can then be performed in a one-necked flask with a stopper + gas outlet or small hole. 

Isolation of the pure a,0 -ieomer, A 250-mL Erlenmeyer flask equipped with a magnetic stirring bar is charged with the isomeric nitriles (20 g, 0.165 mol), prepared in Part A above, and carbon tetrachloride (20 mL). A solution of bromine in carbon tetrachloride (1/9, v/v, ca. 25-30 mL) is added dropwise until the color of excess bromine persists. The reaction vessel is cooled in an ice bath for 30 min, filtered by gravity and the solvent evaporated under reduced pressure. The crude oil is distilled at reduced pressure (bp 40-42 0/0,15 mm) to give a colorless liquid (11-15 g, 55-75%) which is the pure a.p-1somer (Notes 9 and 10). 

Figure 1. A, Dewar flask B, sintered glass filter C, metal cooling coil D, water inlet E, water outlet F, reaction vessel < , quartz immersion well /f, pyrex filter /, lamp ...

Let us examine some batch results. In trials in which 5 mL of a dye solution was added by pipet (with pressure) to 10 mL of water in a 25-mL flask, which was shaken to mix (as determined visually), and the mixed solution was delivered into a 3-mL rectangular cuvette, it was found that = 3-5 s, 2-4 s, and /obs 3-5 s. This is characteristic of conventional batch operation. Simple modifications can reduce this dead time. Reaction vessels designed for photometric titrations - may be useful kinetic tools. For reactions that are followed spectrophotometrically this technique is valuable Make a flat button on the end of a 4-in. length of glass rod. Deliver 3 mL of reaction medium into the rectangular cuvette in the spectrophotometer cell compartment. Transfer 10-100 p.L of a reactant stock solution to the button on the rod. Lower this into the cuvette, mix the solution with a few rapid vertical movements of the rod, and begin recording the dead time will be 3-8 s. A commercial version of the stirrer is available. 

A 1-liter three-necked flask equipped with a mechanical stirrer and two dropping funnels is charged with a solution of 42 g (0.176 mole) of sodium periodate in 145 ml of acetone and 180 ml of water. To the stirred solution, camphene (6.7 g, 0.049 mole) is added in small portions. The reaction vessel is then flushed with nitrogen and is main-... 

In a dry, 250 ml, three-necked flask equipped with a dropping funnel and magnetic stirrer are placed 40 ml of dry /-butyl alcohol (distilled from calcium hydride) and 4.0 g (0.036 mole) of potassium /-butoxide. The solution is cooled in ice and 40 g (49 ml, 0.49 mole) of dry cyclohexene is added. Bromoform (10 g, 3.5 ml, 0.039 mole) is added to the cooled, stirred reaction vessel dropwise over about hour, and the vessel is stirred an additional hour with the ice bath removed. The reaction mixture is poured into water (approx. 150 ml), and the layers are separated. The aqueous layer is extracted with 25 mi of pentane, and the extract is combined with the organic layer. The combined layers are dried (sodium sulfate), and the solvent is removed. The product is purified by distillation, bp 10078 mm. 

If a solid must be added to a closed system over a period of time, an Erlenmeyer flask containing the solid can be attached to the reaction vessel with a short length of... 

For a catalyst-ignited fire to occur, oxygen must be present exclusion of oxygen permits completely safe handling. Some workers put the catalyst in the reaction vessel and sweep air from the vessel with a gentle flow of nitrogen or carbon dioxide argon is ideal if available, The solvent, which may be cooled to diminish its flammability, is then added. Once all of the catalyst has been wet with solvent, fire will not occur. Air can also be removed from the flask by... 

Polymerization methods [I], [II], and [III] (Fig. 1) indicate, respectively, the dropwise addition of VAc and initiator the dropwise addition of VAc and the stepwise addition of initiator the batch method, in which all ingredients of water, VAc, PVA, and initiator were put into the reaction vessel before starting polymerization. In method [I], when the temperature of the PVA solution in the flask attained 70°C, dropwise additions of 20 g of an aqueous solution containing initiator and 250 g of VAc were started. In method [II], the process was similar to method [I], except the initiator was added stepwise. When the temperature of the contents in the flask was raised to 70°C, 24 g of an aqueous solution containing half the prescribed amount of initiator was first added. 

The reaction vessel is cooled to 30° and the reflux condenser replaced with a distillation head and condenser. The methylene chloride is removed by distillation, b.p. 35-55°. The residue is then transferred to a 500-ml. round-bottomed flask and distilled through a 30-cm. Vigreux column. The yield of a-chloroanisole is 266-271 g. (93-95%), b.p. 74-77° (13 mm.), w23d 1.5342 (Notes 5, 6, 7). 

In a 2-1 three-necked flask equipped with a stirrer, a reflux condenser, and a dropping funnel (Note 1) 832 g (4 0 moles) of phosphorus pentachloride is stirred with 250 ml. of phosphorus oxychloride (Note 2) To this is added with stirring 264 g (272 ml, 4 4 moles) of methyl formate (Note 3). During the addition the reaction vessel is cooled in an ice bath to maintain a reaction temperature of 10-20° The addition requires about 1.75 hours When the addition is complete, the solution is stirred at a temperature under 30° until all the phosphorus pentachloride has dissolved (about 1 hour) Then the stirrer is removed, the reflux condenser is replaced by a distilling head, and the reaction... 

A reaction vessel as shown in Fig. 1 is made from Pyrex tubing (Note 1). The vessel is evacuated and the stopcock closed. A 500-ml. round-bottomed two-necked flask equipped with a gas inlet and a cold finger condenser containing dry ice is charged with 1 g. of finely powdered 4,4 -bis(dimethylamino)benzophenone... 

Br(g) from the thermodynamic data provided in Appendix 2A. (b) What is the vapor pressure of liquid bromine (c) What is the partial pressure of Br(g) above the liquid in a bottle of bromine at 25°C (d) A student wishes to add 0.0100 mol Br2 to a reaction and will do so by filling an evacuated flask with Br2 vapor from a reservoir that contains only bromine liquid in equilibrium with its vapor. The flask will be sealed and then transferred to the reaction vessel. What volume container should the student use to deliver 0.010 mol Br2(g) at 25°C ... 

Irradiation Procedure. Reaction mixtures were prepared at room temperature by transferring desired quantities of reactants from their storage bulbs to the reaction vessel, a 500-cc. spherical borosilicate glass flask attached to the vacuum line by a section of glass capillary tubing and a 4-mm. bore threaded glass valve with a Teflon plug (Fischer and Porter 795-609). Prior to each experiment this vessel was baked under vacuum at 500°C. for 12 or more hours. 

The submitters have used both an addition funnel with a worm gear delivery similar to those manufactured by Normag and an Erlenmeyer flask attached to the neck of the reaction vessel with a piece of Gooch rubber tubing. Normag addition funnels are available from Lab Glass, Inc., P. O. Box 610, Vineland, New Jersey 08360. 

A 57% dispersion of sodium hydride in mineral oil was purchased from Alfa Division, Ventron Corporation. A 5.90-g. portion of the dispersion was placed in the reaction vessel and washed free of mineral oil with three 50-ml. portions of pentane by decanting the supernatant pentane after each washing. The pentane that remains in the flask is evaporated as the assembled apparatus is purged with nitrogen prior to adding the tetr ahy drof ur an. 

The submitters recommend that the solvent be distilled under nitrogen into a two-necked receiving flask fitted with a three-way stopcock. The receiving flask is separated from the distillation apparatus under a rapid nitrogen flow and fitted quickly with a rubber septum. The solvent is then transferred to the reaction vessel by needlestock techniques. 

A stainless steel cannula with a 2-mm. inside diameter and both ends sharpened is inserted through the septum into the receiving flask above the surface of the liquid, and a stream of nitrogen is passed briefly through the stopcock and out the cannula to remove air. The other end of the cannula is then inserted through the septum on the reaction vessel, the end of the cannula in the receiver is pushed below the surface of the liquid, and the solvent is forced into the reaction vessel with nitrogen pressure. 

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