Selection of Recrystallization Solvent In organic and organometallic syntheses where crude solid products usually weigh 50-100 mg, the problem is to use the minimum amount of this solid while determining a n appropriate recrystallization solvent or solvent pair. The following procedure has been adopted in our laboratory for the past year with excellent results. Twelve reagent bottles with different solvents are permanently arranged on the laboratory shelf. Using 12 5-mL beakers, put a 1-2 mg sample in each, and add 1mL solvent: the solubility may be observed by just shaking the beakers. If a clear solution is obtained then note the solvent, otherwise slightly warm and note the solubility. Adapting this procedure, in a minimum time and with minimum samnle one can select the solvent or even solvent air for recrvstallization. The choice of solvents and their arrnngerncnt dcprnds on one's uwn pr~ferenres'The set of 12 snlwnts in our lnhoratury i s 1120. C I H ~ O ~ I , CH1011, CHCI?, CCI*, CHzClr acetone, n-pentanc, n-hcxnnt, pet ether, ether, and henzenc.
Saqib Ali a n d Abida K a l s o o m Quaid-i-Azam University Islamabad, Pakistan
Volume 68
Number 10 October 1991
877
