Day 1

First Day (24 May, Tuesday)
  • What did you do today?
  • Today we separated caffeine from tea. Firstly we boiled some tea bags in water. After it boiled, we added calcium carbonate into the solution. We continued boiling the solution for 15 mins while stirring it constantly. Next, we filtered the solution using a vacuum filter, to get rid of any solid material from the mixture. After letting the filtrate cool to room temperature, we poured it into a separating funnel. Then we added Dichloromethane into the separating funnel. This separates the mixture so that water and other unwanted substances are separated from caffeine. The caffeine will dissolve in the dichloromethane and the liquid layer will sink to the bottom of the separating funnel, as dichloromethane is denser than water. Next, we shake the mixture gently for a few times, and let the separating funnel rest on a holder. This separates the 2 layers. After the layers have separated, we opened the tap of the separating funnel, letting the dissolved caffeine in dichloromethane flow out, into a beaker. We repeat this process 2 more times. Next, we add magnesium sulphate into the collected caffeine + dichloromethane solution. The magnesium sulphate acts as a drying agent to solidify any remaining water in the solution. Then, we filter the solution using filter paper. Thus there will only be pure caffeine and dichloromethane left. Next, we put the solution into a rotary evaporator. This evaporates the dichloromethane, leaving only caffeine left. We then scratch out the caffeine from the round flask. Next, we bring the caffeine for an IR detection, in order to assess the pureness of the caffeine.
  • What did you learn today?
  • I learned about: 

  1. Dichloromethane is denser than water
  2. Calcium carbonate makes tannins into a salt, so that it becomes dissolvable in water.
  3. Magnesium sulfate is a drying agent which can dry up any excess water.

  • How do you feel about today’s activities?
  •  I learned that each step has to be done properly in order to assure good results. We also learned to be more disciplined as we had to follow the steps properly and abide by the lab rules in order to assure safety.
  • I felt that the activities done today were very interesting as I had never done such experiment before.

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