Dichloromethane To Extract Caffeine

This experiment was designed in order to extract caffeine from coffee grounds. In order to do this, filtration and extraction techniques with solvents such as calcium carbonate, magnesium sulfate, and dichloromethane were used1. Decaffeination is something that’s used around the world, and there is much discussion on the different methods that can be used. In this case, using solvents and heat was the preferred method in order to extract the caffeine. Decaffeination is often used to in order to prevent the addictive properties of coffee that can often cause drinkers, of coffee or tea, symptoms of headaches, nausea, etc1. Extraction is done by isolating compounds from liquids by using a solvent. The type of solvent is important, because having a
solvent that caffeine is more soluble in than the coffee helps to dissolve the caffeine within the solvent instead. It’ll “move” out of the coffee and into the new solvent2.
This is ideal because then the solvent can be evaporated, and crystals from the caffeine can be formed from it, which allows for the decaffeination of the coffee. It’s important that the solvent that’s used is immiscible with the other liquid however2. This will ensure that the solvent and coffee don’t mix together, and will instead form two separate layers that will allow for extraction in the separatory funnels. Dichloromethane is the ideal solvent because it is immiscible with the water, and will allow caffeine to be dissolved in it2. The filtration that happens in the separatory funnels isolates the caffeine and the dichloromethane. The magnesium sulfate helps dry the combined layers of caffeine and dichloromethane, and then the evaporation is what helps to remove the dichloromethane. Then, you’re only left with the caffeine, effectively isolating it. In order to bring it back from the current state its in due to the evaporation however, acetone hot acetone and petroleum ether are needed2. These cause the caffeine to “bottom out”, and turn to a solid. Acetone is polar so it’ll allowed for the dissolving of the caffeine, and the cooling is what helped form the
solid. From our experiment, the amount of caffeine that was isolated was only .245 percent, but this was due to loss of product during the experimental procedure. During the drying of the filtrate using the magnesium sulfate, a large portion of the liquid was spilled and that drastically effected our results. That would be a reason why the percentage was below 100. In future experiments, being careful about how the procedure is carried out and clearing any clutter in the work area would prevent this from occurring. However, the loss of product did not effect our results for the boiling point, as it was still around the right range. The expected results were 178 degrees Celsius and the ones that we found was around 180 degrees Celsius.