Need Help with Homework For Organic Chemisrty Lab 1. Extraction of Caffeine from

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Need Help with Homework For Organic Chemisrty Lab 1.

Extraction of Caffeine from Tea Leaves Caffeine (CsH10N402) example of a class of compounds called alkaloids, which are produced by plants. Alkaloids are organic compounds that usually contain carbon, hydrogen, oxygen and nitrogen, and are weak bases. The name alkaloid means "alkali like", where alkali is a base and hence refers to their basic properties. Other examples of alkaloids include cocaine (a drug of abuse), strychnine (a poison found in the seeds and bark of a tree), morphine pepper), quinine (found in Cinchona trees; added to tonic water, used to treat malaria) and nicotine. It is clear that some alkaloids are beneficial, while others are extremely harmful. Asnoted. Alkaloids have the prefix "ine." The chemical structure of caffeine is shown below (a pain killer obtained from opium) (found in black Caffeine is found naturally in tea, coffee beans, and kola nuts with concentration levels between 2 and 5%. As most of you are aware caffeine is a stimulant. Consequently, it is present in many over-the-counter pharmaceutical products. Caffeine also has some undesirable side effects, such as an increase in the heart rate, nervousness, restlessness and insomnia. One can become addicted to caffeine, resulting in physical dependence to this chemical. Also, there is some research that suggests that the consumption of coffee tends to reduce the onset of certain diseases such as Alzheimer, cancer and diabetes In this experiment, we will extract Caffeine from tea loaves using an aqueous solution of sodium carbonate and methvlene chloride. The sodium carbonate prevents the extraction of acidic compounds called tannins from the tea leaves. Caffeine is more soluble in the organic solvent methvlene chloride than in water, so we will extract caffeine into the organic solvent to separate it from glucose, tannins, and other water-soluble compounds using a separatory funnel Words: 1506 Spell Check

Explanation / Answer

Answer:

1. suppose the mass of crude caffeine is m(from experiment).

Mass of 5 tea bags= 10g (If the mass of one tea bag is 2g)

Approximate percentage of caffeine= (m/10)**100 %

2. Because methylene chloride is denser(d=1.33g/cm3) than water(d=0.99g/cm3).

3. No, because there are loses of caffeine in an experimental procedure at many places which are listed below in 4.

4. Two places where caffeine might be lost:

a) During work-up procedure or extraction, if the organic layer and aqueous layer are not completely distinct, then there might be some caffeine at the interphase of both the layers which we cant extract. (Due to emulsion formation)

b) Caffeine solubility in water might be one of the factors because of No compound is 100% insoluble in any of the solvent.

5. Emulsion: A mixture of two or more than two liquids which are immiscible. In particular, one liquid is dispersed in the other liquid.

6) Two techniques by which crude material can be purified:

a) Crystallization

b) Washing again and again with the solvent(though there will be the compound loss).

c) Column chromatography

7) Alkaloid:  A class of naturally occurring organic compounds, mainly containing nitrogen atoms. True alkaloids originate from Amino acids.

Examples- Caffeine, Quinine, Morphine

8) Amount of caffeine isolated from 5 tea bags= 0.89g

The weight of tea=3.3*5= 16.5g

the percentage recovery of caffeine in tea= (0.89/16.5)*100= 5.39%

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