1. Material (supplied by Nutritional Biochemicals Corp., Cleveland, Ohio) of
[α]25D −32° (
c = 1.98 in water) was used.
2. An applicator stick (available from drug stores) can be used very conveniently to ensure smooth boiling. If a boiling chip is used, it should be colored (Carborundum, for example) to make its separation from the product convenient.
3. This evaporation during which a solid separates is very conveniently carried out in a
rotary vacuum evaporator (manufactured by Rinco Instrument Co., Greenville, Illinois). An equally convenient alternative arrangement for solvent stripping that is in use in some laboratories is shown in
f.htmig. 1. The splash-head
A permits rapid removal of solvent under reduced pressure. Any solid carried beyond the flask
B by spattering is arrested in
A and can be washed down into
B by introducing a low-boiling liquid like
acetone through the port
C. The side arm
D permits continuous feeding into the "stripper." If the feed tube
E is fitted with a plug of glass wool, the feed solution can be automatically filtered from suspended solids such as drying agents. Another advantage of this stripper is that a conveniently small collecting flask
B can be used for a feed solution that is very dilute and large in volume.
Fig. 1. Solvent stripper.
6. The checkers observed a rotation of
−211 to −217°, as against
−207 to −212° reported by the submitter; Sheehan, Chapman, and Roth
2 report
−212°.