What is the chemistry behind caffeine extraction with Na2SO4, CH2CL2 and NaCO3. I know that Na2SO4 some how aborbs the water from a solution leaving the undissolved soilds or something...

http://en.wikipedia.org/wiki/Caffeine

Caffeine extraction with Na2SO4, CH2Cl2 (also known as dichloromethane), and NaCO3 (sodium carbonate) involves several steps and chemicals that help to isolate and purify the caffeine compound from its natural source, such as coffee beans.

Let's break down the process step by step:

1. Grinding and Extraction: First, the coffee beans are ground to increase the surface area, allowing for better extraction. Then, the ground beans are placed in a solvent, usually water, to extract the caffeine and other soluble compounds.

2. Na2SO4 (Sodium Sulfate): Sodium sulfate is an inorganic compound that is used as a drying agent. In this extraction process, Na2SO4 is added to the solution containing caffeine to absorb any water present. The presence of water can interfere with the subsequent extraction steps or cause the formation of emulsions. By adding Na2SO4, the water is absorbed, helping to separate the aqueous (water-containing) layer from the organic layer.

3. CH2Cl2 (Dichloromethane): Dichloromethane is an organic solvent that is immiscible (does not mix) with water. It has a higher density than water and can act as a solvent for caffeine. After adding Na2SO4 and allowing the mixture to separate into two layers (organic and aqueous), the organic layer, which contains dissolved caffeine, is separated from the aqueous layer.

4. NaCO3 (Sodium Carbonate): Sodium carbonate is added to the organic layer containing caffeine to form a water-soluble salt of caffeine (sodium caffeine). Sodium carbonate reacts with the acidic impurities present in the organic layer, neutralizing them. Additionally, the formation of a salt makes caffeine extraction more efficient because the solubility of caffeine in water increases when it is in the form of a salt.

5. Extraction and Isolation: The solution containing sodium caffeine is then extracted with water. Caffeine, being highly soluble in water, will dissolve while the impurities remain in the organic layer. The aqueous solution is separated from the organic layer, and the caffeine is isolated by further purification methods like filtration, evaporation, or crystallization.

It's important to note that this extraction process involves the use of chemicals that can be hazardous if not handled properly. Always follow proper safety protocols and guidelines when working with these chemicals.

This explanation provides an overview of the general chemistry-based process. If you require more specific details or want to explore the topic further, I suggest referring to scientific literature or textbooks on organic chemistry and extraction techniques.