NOTE ON ANALYTICAL PROCEDURES Improved Distilling H e a d for Laboratory Fractionating Columns B. G. Z I M M E R M A N ' , General Aniline Works, Grarselli, N. J. 6. The column may be operated under total reflux without leaks to the product takeoff line. 7. It has very low h o l d u p O F liquid. 8. T h e t e m p e r a t u r e of the reflux may be varied by t h e amount of cooling w a t e r that flows through the condenser. 9. Itismechanically strong.
D
ISTILLING heads are generally of two types, the partial vapor condensation and the total vapor condensation head. The partial vapor condensation head first employed by Peter and Baker (6) now has been almost entirely replaced by the total condensation head. Bruun (1, 2) was among the first to design a satisfactory total vapor condensation head for laboratory columns. His design is generally satisfactory for most purposes, but lacks ease of operation and is not applicable to distillation of immiscible and corrosive liquids. Many other (8-11) different designs, which are generally satisfactory for laboratory distilling columns, are now in use; but each, including the one now proposed, possesses some disadvantage. It is very difficult to design a distilling head which will eliminate all disadvantages, but this paper presents a satisfactory distilling head which has been in operation for more than five years.
1. All parts are made of glass, and therefore may be used for distilling corrosive liquids, including inorganic acids except hydrofluoric. 2. All stopcocks and joints are precision ground. These require very little, if any, lubricant and work well under high vac-
Figure 1 shows. the side view of' t h e distillation. head, while Figure 2 shows the front view. I n a c t u a l operation, the distillation head is en-. tirely covered with asbestos rope to ensure more closely Figure 2. Front View of Distillation Head a d i a b e t i c conditions. The stopcocks, if precision ground, require very little, if any, lubrication. This device requires a degree of skill too great for fabrication by an amateur glass blower. However, i t can easily be made by a professional glass blower or purchased a t relatively low cost from Otto R. Greiner Company, Newark, N. J. This type of' distillation head may be made t o fit any size of fractionatingcolumn for laboratory or pilot-plant use, The design, as illustrated, has been used with a 1.5-inch inside diameter48-inch laboratory column for more than 5 years with excellent results. For ordinary distillations, the thermometer wells for the reflux and distillate may be omitted, thus reducing the cost of the. head.
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3. It is easy to operate. The nipples of the stopcocks are accurately calibrated and the reflux ratio is determined by counting the drops. Once the reflux ratio is set, the ratio will remain constant for an indefinite period of time. 4. The temperature of the reflux and the product is easily determined. 5 . Vapor temperature may be accurately determined during fractionation period. 1
Present address, Morton Chemical Co., Greensboro, N. C.
V m f For Cleaninq Head
ACKNOWLEDGMENT
The author is indebted to J. E. Hunt of the Engineering Department for the drawings. LITERATURE CITED
(2) Bruun, J. H., ISD. EXG.C H E Y . , ANAL.ED., 2, 187 (1930). (1) Ibid., 7, 359 (1935). (3) Carter and Johnson, C . S. Patent 2,261,185 (July 29, 1941). (4) Loveless, I X D . ENG.CHEM., 18,826 (1926). ( 5 ) Marshall, M. J., I b i d . , 20, 1379 (1928). (6) Peter and Baker, Ibid., 18,69 (1926). (7) Podbielniak, V i'. J., Podbielniak Centrifugal Super Contractor Co., Circ.,22, (Nov., 1942). (8) Snyder and Steuber, IND.EKG. CREM., ANAL. ED., 16, 454 (1944). (9) Towne, R. S., Ibid., 16,584-5 (1944). (10) Whitmore and Lux, J . Am. Chem. SOC.,54, 3488 (1932). (11) Willingham and Rossini. J . Research Natl. BUT.S t a n d u r d s , 3 3 . 383-7 (1944).
Figure 1. Side View of Distillation Head
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