Extraction of Caffeine from Coffee or Tea Lab

Scott Humason

CH241 MWF 8:30-9:50

Extraction of Caffeine from Coffee or Tea Lab

Summary:
The goal of this lab is to extract caffeine from tea or coffee. This is a two part lab with the first part being the process of extracting and washing the caffeine into a 2-propenol solution. We are not focused on a consumable product with caffeine being removed from it. Our main goal is to extract the caffeine as the caffeine as the final product. The challenge to this lab is that caffeine will not readily separate into water, we need a more polar solvent. To do this we polarize a 2-propenol and CaOH solution with NaCl, making the solution basic. Caffeine in water is a Lewis Acid (electron acceptor, proton donor), while the water is a Lewis Base.

Discussion of Results:
Theoretical Yield of Caffeine

(Assume max mg of caffeine solution before extraction)
Formula for Liquid

1oz. = 29.57mL 1oz. = 28.349g
98mL / 29.57 = 3.314oz 3.314oz * 28.349g = 10.98

Hypothetical Estimate of amount of Caffeine in Tea
(Averaged amount of tea, between 20-120 as 70mg)

3.314oz X-mg
----------- = -------- = 28.9975mg Caffeine
8oz 70mg

% Recovery of Caffeine

Theoretical Yield 28.9775mg Caffeine

--------------------- = % Recovery ------------------------ = 8.55%

Actual Yield 3.39mg Caffeine

Caffeine concentration extracted from original sample in parts per million (ppm)

(Calculated using mg/kg for solids)

.00339g = 3.39mg of caffeine as final product

mg = amount of caffeine produced = 33.98mg

kg = amount of original product = 12g

mg 3.39mg

ppm = ------ ------------ = 282.5 ppm

kg .012kg


Analysis of Error and Quality of Experiment:
There are a number of steps that involve transfer of solution, extraction percentages, and saturation that can easily vary results and percent yield. Specific to my lab, I could not keep all of the tea leaves from sticking to the paper. So for each separation, a small amount of tea was lost. I also supersaturated my solution by heating my solution while I added the salt, not adding the salt when cold. This means that I had to separate the salt each time I passed the separated solution through separation funnel. This means the residue was left on the equipment for each pass through. Also, it is impossible to completely get a pure separation from the sep funnel right where the two layers meet. You will either keep or loose more than what you want. Also, in the final weighing process, I weighed another paper and subtracted it from the paper that I used. There will inherently be some discrepancy from the two papers. Being that the product is very low, this should have a significant and sizeable affect on the results.

Green Evaluation:
All in all this is a decently green experiment. Not to toxic, and largely working with polarities to induce acidity more than starting with acidic compounds. However, are focus is not on a final product that reflects an enjoyable consumable product. This could be a decent solution for a Pharmaceutical industry.