Extraction/purification caffeine - help

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In summary, the conversation is about extracting caffeine from tea leaves using CH2Cl2 + NaOH and then evaporating the organic phase. The person then mentions using toluene for crystallization and asks why they should use petroleum ether. Another person responds saying that ether is a good extraction solvent and is used as a transfer/rinse solvent in this case.
  • #1
soundlover
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lo all, i´m having a small prob here
-extract the caffein of the tea leaves with CH2Cl2 + NaOH

- after the liquid-liquid extraction the organic phase (that contains the caffeine) was evaporated. then i joined some hot "toluen" (C6H5CH3) to the caffeine to occur a cristalization by slow evaporation of the solvent..
ok,i understand that but why the heck should i join some PETROLEUM ETHER to the cristals?

good lord,my english is painfull,sry

tks for any tip
 
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  • #2
because ether is a good extraction solvent.
 
  • #3
I believe it is used in this case as a transfer/rinse solvent, in which caffeine is moderately soluble. Usually the crude caffeine is dissolved in acetone, to remove the impurities and subsequently the former is used.
 

Related to Extraction/purification caffeine - help

1. How is caffeine extracted from plants?

Caffeine is typically extracted from plants such as coffee beans, tea leaves, and cocoa beans using a solvent extraction method. This involves immersing the plant material in a solvent, such as water or ethyl acetate, which extracts the caffeine molecules from the plant. The solvent is then evaporated, leaving behind pure caffeine crystals.

2. What is the purpose of purifying caffeine?

Purifying caffeine involves removing any impurities or other compounds that may be present in the extracted caffeine. This is important for ensuring the caffeine is of high quality and does not contain any harmful substances that could impact its effectiveness or safety.

3. What techniques are used for caffeine purification?

There are several techniques that can be used for caffeine purification, including recrystallization, chromatography, and sublimation. Recrystallization involves dissolving the caffeine in a solvent, then allowing it to crystallize again in a purified form. Chromatography uses a stationary phase and a mobile phase to separate the caffeine from other compounds. Sublimation involves heating the caffeine to a temperature where it turns directly from a solid to a gas, leaving behind any impurities.

4. What are some common sources of caffeine for extraction?

Caffeine can be extracted from a variety of plants, including coffee beans, tea leaves, cocoa beans, kola nuts, and yerba mate. It can also be synthesized in a laboratory setting.

5. Are there any potential health risks associated with caffeine extraction and purification?

When performed properly, caffeine extraction and purification should not pose any significant health risks. However, it is important to use appropriate safety precautions, such as wearing protective gear and working in a well-ventilated area, when handling solvents and other chemicals. It is also important to properly label and store any extracted or purified caffeine to prevent accidental ingestion.

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