Chemistry 30A3 Fall 2011 Labs Dr. Troendle 22

Chemistry 30A3 Fall 2011 Labs Dr. Troendle 22 - EXPERIMENT...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemical Biology 3OA3, September 2009 Page 22 E XPERIMENT 1 I SOLATION OF C AFFEINE FROM T EA In this experiment, a common alkaloid natural product, caffeine, responsible for the mild stimulating action of tea and coffee, will be isolated from tea leaves, purified and characterized by preparation of a derivative. Caffeine is a derivative of one the bases found in nucleic acids, and provides a good illustration of the chemistry of these bases. The caffeine will be extracted by hot water from tea leaves, where it is present to the extent of about 5%. This treatment also extracts the tannins, another class of compounds present in tea. It is therefore necessary to separate the caffeine from the tannins by adding lead acetate to the extract. The tannins are acidic and form insoluble lead salts, whereas the caffeine remains in solution. The caffeine will be extracted from the aqueous solution with chloroform. It can be purified by recrystallization or sublimation.
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern