Separation for Solid Liquid & Liquid Liquid mixture presentation
Separation of Liquid Liquid mixture-Youtube video
Tuesday, November 10, 2020
Separation for Solid Liquid & Liquid Liquid mixture
Separation of Liquid Liquid mixture-Youtube video
Wednesday, October 28, 2020
Binary mixture separation - 1
Experimental Aims: The objective of this lab is to separate a two organic mixture.
Experimental learning objectives: At the end of this experiment you should be able to:
(i) use a different method of separation
(ii) identification of solubility of compounds for solvent for separation;
(iii) use solvent for separation for physical and chemical separation;
(iv) identify the organic phase and aqueous phase in chemical separation;
(v) use acid/base reactions to impact the solubility of organic compounds and
Binary mixture separation - 1 Presentation
Solid solid mixture separation Practical Demonstration- YouTube video
Monday, August 17, 2020
Practical-2 Recrystallization
Practical-2 Recrystallization
How to Make Fluted Filter Paper
Recrystallization is a purification technique for solid compounds.
To perform recrystallization, an impure solid compound is mixed with hot solvent to form a saturated solution. As this solution cools, the solubility of the compound decreases, and pure crystals grow from solution.
Recrystallization is often used as a final step after other separation methods such as extraction, or column chromatography. Recrystallization may also be used to separate two compounds with very different solubility properties. This video will illustrate solvent selection for recrystallization, purification of an organic compound from solution, and will introduce a few applications in chemistry.
Crystallization begins with nucleation. Solute molecules come together to form a stable small crystal, which is followed by crystal growth. Nucleation occurs faster on nucleation sites such as seed crystals, scratches, or solid impurities than spontaneously in solution. Agitation may also encourage rapid nucleation. However, rapid growth can lead to incorporation of impurities if not grown in optimal conditions.
The solubility of a compound tends to increase with temperature, and is highly dependent on the choice of solvent. The greater the difference in solubility at high and low temperature, the more likely it is for the solute to come out of the solution as it cools, and form crystals.
The solvent chosen should have a boiling point of at least 40 °C so there is a significant temperature difference between boiling and room temperature. The solvent's boiling point must also be below the melting point of the solute to enable crystallization. Rapid cooling of the solution induces the formation of many nucleation sites, thus favors the growth of many small crystals. However, slow cooling induces the formation of fewer nucleation sites, and favors larger and purer crystals. Thus, slow cooling is preferred.
Additionally, a solvent can be selected to minimize impurities. If a solution impurity is more soluble than the solute itself, it can be washed off of the fully formed crystals with cold solvent. However, if an impurity is less soluble, it will crystalize first, and can then be filtered out of the heated solution, prior to recrystallization of the solute.
If no single solvent has the necessary properties, a mixture of solvents can be used. For a solvent pair, the first solvent should readily dissolve the solid. The second solvent must have a lower solubility for the solute and be miscible with the first solvent. Common solvent pairs include ethyl acetate and hexane, toluene and hexane, methanol and dichloromethane, and water and ethanol.
Practical 1-Introduction to Organic Chemistry Lab-II
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