Tuesday, May 31, 2011

Team

Group Name: Omnomnom

Project Supervisor: Dr Linda Sellou, NTU
Teacher Advisor: Mr Andy Sim, SST

Group Members:
Christian Lim (S208) - Group Leader
Tan Siah Wei (S206)
Javin Jason Kang (S203)
Millie Thng (S204)

Monday, May 30, 2011

Overview

In this project, we will be extracting caffeine from tea. This will be done using B├╝chner filtration, Solvent extraction and Distillation using a rotary evaporator. Solvent extraction is based on the rule of thumb "like dissolves like", which means that in general, materials tend to dissolve better in solvents of a similar nature. The distillation is based on the concept of different boiling points of different liquids in the solution.

Mission - Part 1

To understand how to use the different techniques (B├╝chner filtration, Solvent extraction and Distillation using a rotary evaporator) to extract caffeine.

Mission - Part 2(i)

Solvent Extraction:
How can we tell which phase is aqueous and which is organic?

Rotary Evaporator:
Why do we rotate the flask while it is heating in water?
It will evaporate all the solvent (Dichloromethane), leaving the caffeine crystals on the inside of the flask.
Why do we need a condenser?
The condenser will condense all the solvent's vapour, and in turn collect it in a flask.
What is the benefit to work under vacuum?
It brings down the boiling point of the substance.

Mission - Part 2(ii)

Questions from Project Manual (Q1)

Now you have extracted caffeine what techniques can you use to characterize your
compound and make sure you have caffeine?

Mission - Part 2(iii)

Questions from Project Manual (Q2)

How would you prepare decaffeinated coffee that is fit to drink?

Accomplishment

  • What is the end product/ findings? 
We found out that caffeine extraction is a very long process, and that like dissolves like, so dichloromethane can dissolve caffeine.
  • A description/ explanation of your product/ findings.
There were apparatus we used, such as the buchner filtration flask, and funnel, and more.