Removable Vacuum Connectors for Filter Flasks W. R. Doty
J. Chem. Educ. 1960.37:292. Downloaded from pubs.acs.org by UNIV OF EDINBURGH on 01/29/19. For personal use only.
S.
Kasman and L
E.
Rubin
California Research Corporation, Richmond, California
Polaroid Corporation, Cambridge 39, Mass.
Almost all breakage of the common filter flask occurs at the point where the vacuum connection is sealed to the filter flask To reduce the body. breakage problem, we
Flash distillation is a common technique for concentrating a dilute solution of a nonvolatile solute. A distilling flask is heated on a steam bath, or by other suitable means, and subjected to the vacuum of an aspirator or vacuum pump to which it is connected through a trap, receiver, and efficient condenser. The solution is aspirated into the distilling flask from a reservoir or an addition funnel. We have found that the rate of distillation of solvent can be enhanced considerably by a trivial change in the above apparatus. A preheater condenser (Liebig, West, bulb, or coil) is mounted on the distilling flask and steam is passed through its jacket. The dilute solution is introduced to the distilling flask through the preheater condenser. By a suitable choice of preheater condenser and of the rate of flow of influent it is easily possible to concentrate the dilute solution to “dryness” in the condenser itself. Using an ordinary four-bulb 24/20 standard taper condenser as the preheater and a steam heated threeneck 2-liter distilling flask fitted with a bubbler, we have concentrated alcohol solutions at the rate of six liters per hour for several hours running, A simple, highly effective, nonrestrictive spray trap was made from a one-neck, 24/40 500 ml flask by sealing a 24/40 male joint in the bottom.
tooled glass tubulation, using a Neoprene rubber grommet1 at the base. This is inserted into a drilled hole in the flask neck. The flexibility of the joint prevents breakage of the assembly in normal use. An additional advantage is that the tubulation and grommet can be removed and inserted into a clean flask. The rubber vacuum tubing need not be disconnected. The design has been tested for several months in this laboratory and has received broad acceptance. The cost of the change is small. We estimate that the reduction in breakage is at least 80%. have developed
a
A mold for these grommets and the grommets themselves were fabricated by the Oliver Tire and Rubber Company, Oakland. Calif, 1
292
Acceleration of Flash Distillation
Journal of Chemical Education
