Chemistry 30A3 Fall 2011 Labs Dr. Troendle 68

Chemistry 30A3 Fall 2011 Labs Dr. Troendle 68 -...

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Chemical Biology 3OA3, September 2009 Page 68 Recrystallizations Recrystallizations can be carried out using a conical reaction vial and conventional vacuum filtration to collect the crystals on a small filter paper, or in a Craig tube , which is a device designed specifically for recrystallization of very small quantities of materials. In recrystallizations with a conical reaction vial, the conical vial simply takes the place of the Erlenmeyer flask used for macroscale recrystallizations. The isolation of the crystals can be done in a number of ways depending on their form: (i) Once crystallization is complete, the mother liquors and crystals are vacuum-filtered through a small Hirsch funnel. Most commonly, the material is transferred to the filter by pouring, using a microspatula to help transfer the crystals from the vial to the filter. In cases where the crystals are fairly small and fluffy, it may be more convenient to draw the entire mixture of crystals + mother liquors into a Pasteur pipette and transfer them to the Hirsch funnel that way. (ii) If the crystals adhere to the side of the flask, then filtration is unnecessary. Simply use a filter-
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This note was uploaded on 01/08/2012 for the course CHM 30A3 taught by Professor Ricktroendle during the Fall '11 term at UNF.

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