INDUSTRIAL AND ENGINEERING CHEMISTRY
December 1950
for their cost is relatively low and their solubility in water is not appreciable. In general, the efficiency of these solvents is greater a t the higher temperatures. Three exceptions are 1,4dichlorobutane, xylene, and dichloroethyl ether, which are more efficient at -25’ than a t 10’ or 40’. This phenomenon also/occurred in the case of toluehe in Bowen’s (a) study of the distribution of anabasine between water and certain organic solvents. With nicotiqe, however, the extraction efficiency of toluene increased with temperature. Bowen also found that chloroform and. ethylene dichloride were better solvents than kerosene for extraction of anabasine from aqueous solutions.
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LITERATURE CITED
(1) Askew, H. O., New ZeaEand J . Sci. Technol., 24B,39-41 (1942). ‘(2)Bowen, C. V.,IND.ENG.CHEM.,41,1295 (1949). (3) Claffey, J. B., Badgett, C. 0.. Skalamera, J. J., and Phillips, G . W.Macpherson, Ibid., 42, 166 (1950). (4) Hope, P. H., and Esperh, M. E., Anales escueta nacl. c i m . b i d . ( M e r . ) 4,391-403 (1947). (5) Kolosovskir, N.A., and Kulikov, F. S., Acta. Univ. Asiae Mediae (Tashkent) Ser. VI, 1, No. 8,1-28 (1935). (6)Norton, L.B., IND. ENG.CHEM.,32,241 (1940). (7) Ibid., 33,812-13(1941). ( 8 ) Reilly, J., Kelly, D. F., and O’Connor, M., J . Chem. Soc., 1941, 276-8. RECEIVED April22,1950.
High Capacity Laboratory Condensers and Adapters E. B. HERSHBERG Schering Corporation, Bloomfield, N. J .
Figure 1 shows a glass condenser with a gooseneck adapter. This novel adapter, which replaces the Claisen distilling adapter, provides an effective splash guard and decreases entrainment because of the lowered vapor velocity. This is particularly important in vacuum distillations and in distillations at atmospheric pressure where large volumes of vapor must pass from the flask to the condenser. I n this design it is usually the conderiser whose capacity is exceeded f i s t because of the poor rate of heat transfer of glass; such condensers are not generally employed on flasks above lZliter size except for high boiling liquids.
COIL LENGTH-7”
Figure 1. Glass Coil Laboratory Condenser
Glass adapter and condenser designs are presented for large scale laboratory and pilot plant work. High capacity is obtained by using metalcoil condensers in conjunction with glass fittings.
3
10/18 THERMOMETER OPENING
A
RAPID and convenient distillation or vacuum concentration of large volumes of liquids is difficult because suitable apparatus is not available. A variety of glass tubular water-jacketed or spiral glass-coil condensers may ,be obtained, but these are invariably out of proportion to the volume of vapor and the supply of cooling water. Metals are neglected in the laboratory because the use of glass is firmly established; also, glass is noarly corrosionproof for most purposes. Few chemists realize that when experiments in the laboratory are transferred to industrial equipment the materials of construction are most often stainless steel or other alloys. These metals are available in forms easily adapted to the design of lttboratory equipment which is far more efficient than the glass counterparts. The combination of metal and glass components described herein is difficult to esecute in either medium alone. These condensers are so superior in performance that they may be advantageously employed in the pilot plant.
Y 4 ” D I A Y . TYPE 3 0 4 S T A I N L E S S STEEL TUBING - c o n LENGTH 9
CORNINO FLANOE WlTEFLON L I N E 0 GAS
Figure 2. Metal Coil Laboratory Condenser
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
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Figure 2 shows the same design executed in light gage-stainless steel tubing. The condenser is silver-soldered into a stainless steel plate about '/a inch thick which is clamped onto the Corning glass flange using an asbestos gasket protected by a Teflon liner (U. S. Gasket Company, Camden, N. J.). Here the gooseneck is slanted downward to prevent any condensate from returning to the distilling flask.
Vol. 42, No. 12
To be filled with metal, the tubc: is sealed a t one end by clamping i t in a vise and soldering the crack. The tube is then pla.ced inside a length of 3/g- to 'lrinch iron pipe through which steam is blown. It is inclined a t a slight angle from the horizontal to permit the escape of entrapped air while the molten Wood's metal is introduced. The tube is cooled in this position. A hairpin bend, which constitutes one end of the condenser, is made first. A mandrel is constructed from a piece of iron pipe with a slot in one end to engage this bend. To form the spiral, the mandrel is held in the chuck of a lathe running a t slow speed and the tubing is fed through a short length of narrow pipe in order to maintain sufficient tension to form a tight coil.
CORNING
FLANGE
S B 65/40
Figure 3.
Gooseneck Adapter
The substitution of copper tubing ill this design has been tried, this arrangement finds many laboratory applications such 8s the distillation of ether, alcohols, and hydrocarbons. The superior heat transfer and ease of fabrication compensate for any corrosion which the copper suffers in some cases. Figures 3 and 4 illustrate a larger gooseneck adapter and a larger condenser. The combination of these has been used successfully for rapid steam distillations. With a copper roil it will condense about 20 liters of water per hour. With a stainless steel coil 8 to 10 liters of acetic acid an hour may be distillrd a t a pressure of 20 to 30 mm. from a 22-liter flask warmed in B water bath. A straight tube carrying a male and female semiball joint a t either end is used to connect the adapter to the condenser. This connector provides flexibility through the semiball joints and permits considerable movement of the flask without breakage. Such a combination possesses a remarkable ruggedness. Another variation of the condenser shown in Figure 2 consists of a cylindrical tantalum tube, 1 inch in diameter, which extends into the glass portion of the jacket and which carries an attached tantalum flange. Water is circulated in this shell; the combination is effective for the distillatign of acids which attack stainless steel. CONSTRUCTION OF METAL SPIRAL COILS
The smaller condensers (Figure 2) consist of 10 to 12 feet of 20gage tubing, 1/0 inch in diameter, whereas the larger condensers (Figure 4 ) are made from 15 to 20 feet of 20-gage tubing, 6/,6 inch in diameter. I n order to form a spiral the tube is bent around a narrow mandrel, and to prevent kinking it is loaded with a so-called bending metal Wood's metal or other low melting alloy is most convenient for this purpose in the laboratory; whec the coil is formed the metal may be recovered completely by immersing the coil in hot water and pouring out the molten alloy.
-5/16"01AH STAlNLESS STEEL COIL
i
Figure 4. High Capacity Metal Coil Condenser
WATER CONNECTIONS
The smaller condensers are usually connected with rubber tubing to the cooling water supply using the same precautions as for glass condensers. With the larger condensers, however, advantags may be taken of higher water pressure, and fabricreinforced rubber tubing is then serured to the hose nipples and to the water source with hose clamps. From 60 to 80 pounds of water pressure may be applied without danger. ACKNOWLEDGMENT
The author is indebted to Hayden Brown of Schering Corporation, Engineering Division, for the illustrations. All of the designs shown may be obtained from the Scientific Glass Apparatus Company, Inc., Bloomfield, N. J. RECEIVED October 8, 1949.
