Isolation of caffeine from tea leave

Process of extraction of Caffeine from tea waste Tea Waste Caffeine also comes from tea leaves and other tea wastes. The isolation of caffeine from tea leaves is a difficult task and presents the chemist with a major problem.

Isolation of caffeine from tea leave

The predetermined masses provided by the Lipton Tea manufacturers are accepted as the experimental measurements of both tea and caffeine. The approximate weight of an individual Lipton tea bag is 2.

In an experiment using 2 tea bags, mg is the expected yield of caffeine to obtain. A 50 mL beaker, along with 2 boiling stones, was weighed in advance with a total mass of To extract caffeine, the heated tea solution, along with 5 mL of methylene chloride, was poured into an isolated separatory funnel and inverted to mix the solution completely.

Isolation of caffeine from tea leave

Due to the reaction, pressure built up inside the funnel, requiring the stopcock to be opened to release excess gas following each inversion.

Once settled, the solution separated into 2 layers: The tea separated above the methylene chloride because while the density of water is 0. Between the two layers sat small bubbles or possible emulsions that restricted the amount of methylene chloride that could be extracted.

In doing so, the volatile methylene chloride began to evaporate into the surroundings due to the increased room temperature. The remaining solution was heated briefly until the volatile solvent evaporated, leaving behind solid caffeine.

When weighed, the beaker, stones, and caffeine rendered a total mass of The difference in mass between the initial weight of the beaker and the final product was then the actual yield of caffeine, 0.

In comparison to the theoretical mass, the experiment provided The solid caffeine product was run through an Infrared Spectrometer that uses bond energies to identify chemical compounds.

The spectrometer produced a graph based on measurements of photon energy within a frequency range between and Hz. Individual spikes on the graph indicate the unique bond energies of certain functional groups.

For example, the photon energy spike visible around the Hz frequency represents amine and amide group apparent in caffeine.

The other important spike appears around Hz and Hz. This spike represents the alkene portion of the caffeine molecule.


Using these individual spikes in photon energy, the infrared spectrometer predicts the composition of the compound present. The spectrometer predicted the probability that the sample produced was caffeine to be out of This value has no relation to the purity of caffeine.

The mass of caffeine from 2 Lipton tea bags was only The error in yield results from a number of unavoidable experimental flaws. The first flaw originates from the reaction between gallic acid and sodium carbonate. Although the conversion of gallic acid is necessary for the reaction of caffeine and methylene chloride to occur, the phenol anion byproduct of this reaction is responsible for necessary error [1].

When phenolic acids are reverted back into salts, anionic surfactants are produced4. These surfactants are responsible for emulsifying water insoluble materials like methylene chloride.

As a result, large soapy bubbles called emulsions are produced by the polar and nonpolar solutions. During the extraction phase of this experiment, these bubbles restricted the amount of caffeine released from the separatory funnel resulting in a lesser yield. Another source of lesser yield originated from techniques used to prevent the contamination of the methylene chloride solution.

While extracting the caffeine, a small layer of methylene chloride needed to be left behind to avoid tainting the final product [2]. By discarding part of the methylene chloride solution, a portion of the caffeine was left behind that affected the overall yield of the product.

The final source of error originates from unpreventable environmental conditions. As a result of the hot plates used prior to the caffeine extraction phase, the temperature of the laboratory was increased.

Methylene chloride does not usually evaporate at room temperature but being out in the open at an increased temperature triggered the solution to react early on leaving less methylene chloride to react with the caffeine.

This would result in a lesser amount of caffeine extracted from the solution and a lesser yield. Look up the structure of caffeine and determine the strongest intermolecular force present. The strongest intermolecular force in caffeine is the dipole-dipole interaction because of the polarity of the molecule.

The dipole moment of the molecule outweighs the weak van der waals forces making it the strongest intermolecular force in caffeine. Why is caffeine more soluble in methylene chloride than in water?Extraction of Caffeine from Tea Leaves.

Introduction. Extraction is a common technique used in organic chemistry to separate or isolate a desired compound from a mixture. Isolation/ Purification: 1.

Place flask in ice water bath and leave over lunch. If sample does not crystalize, add seed crystal of caffeine. Spot the TLC plate with the tea extract, isolated caffeine and with authentic caffeine.

Label the samples on your plate.

Extraction of Caffeine from Tea Leaves - Lab Report

One of the problems with the isolation is that caffeine does not exist alone in tea leaves but is accompanied by other natural substances from which the principal structural material of all plant cells, such as tannins and chlorophylls.

A green tea may have as much caffeine as a black tea, and two black teas from the same region might have totally different caffeine levels. It's even more complicated: The very same tea may yield different amounts of caffeine depending on how it's brewed. The process of the present invention relates to the isolation and purification of caffeine-free mixtures catechins from various different biomass sources, preferably from green tea leaves.

More particularly, the present invention relates to a four-step process whereby highly pure, caffeine-free EGCG is isolated in high catechins may be used in pharmaceutical, nutraceutical and. View allAll Photos Tagged isolation+of+caffeine.

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