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Determination of Melting Point of Synthesized Compounds by Knoevenagel Condensation by Open Capillary Method (CAT#: STEM-PPA-0078-YJL)
Introduction
The Knoevenagel condensation is one of the important reaction in organic synthesis. In this reaction aromatic aldehydes were reacted with numerous active methylene groups like ethyl acetoacetate, malanonitrile, diethyl malonate etc. It shows number of applications in various areas like drugs, cosmetics, perfumes, insecticides, herbicides, polymers. It has shown significant biological activities like ECG receptor, antiproliferative effects on keratinocytes. It is also useful in the synthesis of fine chemicals and various biologically active heterocyclic compounds.
Principle
Melting point is a characteristic property of solid crystalline substance. It is the temperature at which the solid phase changes to the liquid phase. This phenomenon occurs when the substance is heated.
In all major pharmacopoeias the open capillary method is described to determine the melting point (slip point) for fats, fatty acids, paraffin, and waxes. In a glass capillary tube open at both ends (1), 10 mm of sample is introduced (2), chilled to a given temperature and immersed into a water bath (3/4). The melting point with open capillary, also known as slip point or slip melting point, is the temperature at which the substance begins to rise in the capillary due to the effect of the increasing temperature and buoyancy.
In all major pharmacopoeias the open capillary method is described to determine the melting point (slip point) for fats, fatty acids, paraffin, and waxes. In a glass capillary tube open at both ends (1), 10 mm of sample is introduced (2), chilled to a given temperature and immersed into a water bath (3/4). The melting point with open capillary, also known as slip point or slip melting point, is the temperature at which the substance begins to rise in the capillary due to the effect of the increasing temperature and buoyancy.
Applications
Chemical industry; Cosmetic/pharmaceutical industry
Procedure
1. Prepare the substance.
2. Affix one of the capillaries to a thermometer.
3. Place the thermometer with an affixed capillary into a glass.
4. Increase the temperature.
2. Affix one of the capillaries to a thermometer.
3. Place the thermometer with an affixed capillary into a glass.
4. Increase the temperature.
Materials
• Sample Type: crystalline compounds
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