Fimre 3
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Conrover Svrfem for Small Percolators
Pleure 4 - - - F e r c o l n f i oDeparrment, ~ Showing Large Psrcolarors
.i\-aslied and returned to tlie packing station on another line of conveyors, so thnt when a fresh percolator is packed a clean percolate receiver will bo a t hand. A s soon as the drugs arc exhausted it becomes necessary to remove the marc from the percolator. This is accompli.ihed by turning over the percolators on their pivotal projections, the ex11aust.ed drug dropping into a chute leading t o a rotary vacuum drier. The recovered alcohol from this pirm or equipincut then runs into the rectifier, which brings the alcohol back to purity to be used in the manufacture of otlicr fluid extracts. After all the alcohol is recovered, the mmc is dropped out of the rotary vacuum drier upon a drag conveyor, whicli transfers the dried, exhausted drug to a Ijoiler in the power lionee, where it is hurned. One of t,he most n o d features is that all alcohol is handled in closed lines. Evaporation is almost entirely avoidcd.
The exhausts of all vacuum pumps pass out through a scrubber, n-bich prevents the alcohol that cannot be caught by the condensers from passing out as vapor in the air. With this scrubber system also are connect.ed the various storage tanks, so that the alcohol-saturated air remaining in the tanks when they are empty is forced out through the scrubber when the tank is being filled with additional alcohol. Even the tops of tlie percolators are connected to the tops of the percolate receivers wit,h rubber tubes, so that as the air in the receiver is displaced by the percolate running into it, the air passes through the tube into the top of the percolator to occupy the space vacated by the menstruum flowing through the drug. Each stage in the process of manufacturing Lilly Fluid Extracts is carefully controlled and approved b y compet.ent chemists. Ilottling, labeling, and the vork of the scientific division in standardizing, physiological testing, assaying, etc., are other phases that play no small part in their production.
Standard Iodine Solution'
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By Fred C . Bond C o ~ o x a o oSCBOOL YI M m ~ sGOLDXW, , Cow
T H E rert+n E: potassium permanganate on potassium ,odlde I n ac,d solution to liberate free iodine has ions been used as a method of standardizing sodium thiosulfaG dutioo~.? This reaction can also be used to prepare a standard iodine sulution by the use of a standard potassium permangmate solution. When freshly prepared the iodine solution does not need to be st.andardized. The reaction is as follows, using acedic acid in place of the hydrochloric acid used [by 'I'readwell-&ll, since there is some likelihood that the X31ii04will oxidize tlie HC1:
d 0.05 N iodine solution may be prepared as follows: Dissolve 40 grams of potassium iodide (weighed roughly) in a This should bc considered as a stock solution and should preferably be kept in a colored bottle. Put about 100 cc. of this solution into a 250-cc. graduated flask and run in 125 cc. of 0.1 N potassium liter of water and add 25 cc. oi elacial acetic acid.
I
Received February 21, 1927. Treadwell-Hall. ''Analytical Chemistry." 8th ed., Vel. If, p. 564.
permanganate from a buret. Dilute the solution to 250 cc. with distilled water, and use as 0.05 N iodine solution.
If the potassium permanganate is not exactly tenth norinal its nomiality factor divided by two wiil be the normality factor o f the iodine solution, since the volume of the iodine solution is double that of tho notassium uermarmanate solution added. Standard iodine solutions of any desired concentration may be prepared by varying thc amount of potassium permangitnate added to the potassium iodide solution, provided that a considerable excess of potassium iodide is present. (Sufficient excess of potassium iodide should he present to hold tlie iodine in solution; the amount necessary may be calculated by assnming that one potassium iodide molcciile will hold up approximately two atoms of iodine.) The potassium iodide solution should remain colorless on standing, showing the absence of potassium iodate or other oxidizing agents. Experiment has shown that the standard of an iodine solution so prepared will have the same degree of accuracy as that of the permanganate solution which was used in its preparation. I
