7.12: Testing Mixed Solvents for Crystallization
- Page ID
- 93210
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Use \(100 \: \text{mg}\) solid and \(3 \: \text{mL}\) solvent to test the solubility of the compound. Find a miscible pair of solvents: one in which the compound is soluble (called the "soluble solvent") and one in which the compound is insoluble (called the "insoluble solvent"). |
Place a fresh \(100 \: \text{mg}\) of the solid to be crystallized in a test tube and add the "soluble solvent" dropwise with heating in a steam bath or hot water bath, until the solid just dissolves. Immerse the suspension in the heat after each addition, and allow time in between additions for the sometimes slow dissolving process. |
Add the "insoluble solvent" dropwise with heating until the solution becomes faintly cloudy. Add the "soluble solvent" dropwise with heating until the solution is clarified (clear). |
Allow the system to come to room temperature, then submerge in an ice bath for 10-20 minutes. If crystals return, the mixed solvent pair may work for the crystallization. |