Reflux vessels

First stage suction piping and vessels can be constructed from carbon steel since it is the same design pressure and conditions as amine regeneration reflux vessel. All other downstream piping, vessels, coolers, and equipment should be constructed from stainless steel. 

White Jr., R.T. Open reflux vessels for microwave digestion botanical, biological, and food samples for elemental analysis. In Kingston, H.M., lassie, L.B. (eds.) Introduction to Microwave Sample Preparation. Theory and Practice. ACS, Washington, DC (1988)... 

Analysis of fat-soluble vitamins may require saponification, generally either overnight at room temperature or by refluxing at 70°C. In the latter case, an air-cooled reflux vessel provides an excellent control of conditions conducive to oxidation. 

It is possible to use chemical methods to depolymerize PS into monomer, which could then be used for making new polystyrene. Some years ago, the Toyo Dynam company in Japan developed a prototype system in which polystyrene foam was groimd and then sprayed with styrene monomer to dissolve the PS and separate it from contaminants, including other plastics and food scraps. The resultant solution was cracked and vaporized in a heated reflux vessel. ... 

Reflux vessels feed cool liquid to columns and vessels. Therefore, during an emergency, the reflux system will generally be kept in operation to ensure that heat continues to be removed. The reflux vessel and its associated pumps and piping should be protected against external fire, either with fireproofing or water sprays. 

The heating of the vessels is accomplished by means of a small bath or a micro-Bunsen burner. The vessel can be clamped at such a distance from the burner that the contained liquid boils gently under reflux. Smooth boiling is ensured by the addition of 1-2 minute pieces of unglazed porcelain, or of a short piece of melting-point tubing open at both ends. 

For temperatures up to 100°, a water bath or steam bath is generally employed. The simplest form is a beaker or an enamelled iron vessel mounted on a suitable stand water is placed in the vessel, which is heated by means of a flame. This arrangement may be used for non-inflammable liquids or for refluxing liquids of low boiling point. Since numerous liquids of low boiling point are highly inflammable, the presence of a naked flame will introduce considerable risk of fire. For such liquids a steam bath or an electrically-heated water bath, provided with a constant-level device, must be used. If the laboratory is equipped with a... 

Mercury-sealed stirrers are used in the following operations (1) simultaneous stirring and refluxing of a reaction mixture (2) stirring the contents of a closed vessel (3) agitation with prevention of the escape of a gas or vapour and (4) stirring in an inert atmosphere, such as... 

Place 45 g. (43 ml.) of benzal chloride (Section IV,22), 250 ml. of water and 75 g. of precipitated calcium carbonate (1) in a 500 ml. round-bottomed flask fltted with a reflux condenser, and heat the mixture for 4 hours in an oil bath maintained at 130°. It is advantageous to pass a current of carbon dioxide through the apparatus. Filter off the calcium salts, and distil the filtrate in steam (Fig. II, 40, 1) until no more oil passes over (2). Separate the benzaldehyde from the steam distillate by two extractions with small volumes of ether, distil off most of the ether on a water bath, and transfer the residual benzaldehyde to a wide-mouthed bottle or flask. Add excess of a concentrated solution of sodium bisulphite in portions with stirring or shaking stopper the vessel and shake vigorously until the odour of benzaldehyde can no longer be detected. Filter the paste of the benzaldehyde bisulphite compound at the pump... 

Solvent Process. In the solvent process, or solvent cook, water formed from the reaction is removed from the reactor as an a2eotropic mixture with an added solvent, typically xylene. Usually between 3 to 10 wt % of the solvent, based on the total charge, is added at the beginning of the esterification step. The mixed vapor passes through a condenser. The condensed water and solvent have low solubiUty in each other and phase separation is allowed to occur in an automatic decanter. The water is removed, usually to a measuring vessel. The amount of water collected can be monitored as one of the indicators of the extent of the reaction. The solvent is continuously returned to the reactor to be recycled. Typical equipment for this process is shown in Figure 2. The reactor temperature is modulated by the amount and type of refluxing solvent. Typical conditions are ... 

The process of sulfurization is usually carried out by a sulfur bake, in which the dry organic starting material is heated with sulfur between 160 and 320°C a polysulfide bake, which includes sodium sulfide a polysulfide melt, in which aqueous sodium polysulfide and the organic starting material are heated under reflux or under pressure in a closed vessel or a solvent melt, in which butanol, CeUosolve, or dioxitol are used alone or together with water. 

Most distillations conducted commercially operate continuously, with a more volatile fraction recovered as distillate and a less volatile fraction recovered as bottoms or residue. If a portion of the distillate is condensed and returned to the process to enrich the vapors, the Hquid is called reflux. The apparatus in which the enrichment occurs is usually a vertical, cylindrical vessel called a stiU or distillation column. This apparatus normally contains internal devices for effecting vapor—Hquid contact the devices may be categorized as plates or packings. 

In a 2-1. three-necked flask, fitted with a separatory funnel, reflux condenser and stirrer, is placed 27 g. (-i.i moles) of magnesium turnings. A mixture of 30 g. of bromobenzene and 70 cc. of dry ether is run in and the flask warmed gently with a free flame until the reaction becomes rapid. Stirring is then started and the vessel is surrounded by a dish of cold water. A mixture of 151 g. of bromobenzene (total 181 g., 1.15 moles) and 380 cc. of dry ether is run in at such a rate as to cause vigorous refluxing when the addition is complete (one hour) the whole is stirred for ten minutes. 

This article deals enly with reflux drums. Use only the larger vessel volume determined. Do not add two volumes such as reflux plus product. If a second liquid phase is to be settled, additional time is needed. For water in hydrocarbons, an additional 5 minutes is recommended. 

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