Isolation of caffeine from tea leaves pdf

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Isolation of caffeine from tea leaves pdf

We use cookies to give you the best experience possible. Words:Paragraphs: 22, Pages: 5. The essay sample on Caffeine Extraction From Tea dwells on its problems, providing a shortened but comprehensive overview of basic facts and arguments related to it.

To read the essay, scroll down. Extraction of Caffeine from Tea Leaves Marc Tugaoen, Kristine Vanzuela, Rafael Villanueva, Justeen Wong Department of Chemistry, University of Santo Tomas, Manila, Philippines Abstract This experiment has been divided into 4 set-ups, first was the solid-liquid extraction, next was the liquid-liquid extraction, then the sublimation and last was the melting point determination.

The solid-liquid and liquid-liquid extraction were both done during the first meeting, the DCM layer was filtered and dried in the evaporating dish and kept inside the locker.

The dried was light green, somewhat powdery flakes and was rough, this was purified through sublimation. The last part was determining the melting point of the pure caffeine collected, standard started to melt at ? The objectives of the experiment are to a.

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The active ingredient in the tea and coffee is the caffeine, which is an alkaloid. Don't use plagiarized sources. Alkaloids contain nitrogen and have properties of an organic amine base. Caffeine has a mild stimulating effect on the central nervous system.

Caffeine belongs to the family of xanthine, which is known as stimulants. Caffeine is the most powerful xanthine because of its ability to increase alertness, put off sleep and increase ones capacity for thinking. It also relaxes blood vessels and increases urination. Other than tea leaves, caffeine can also be found in coffee, cocoa beans and kola nuts.

Many consumers still try to avoid caffeine, and because of these reason that decaffeinating coffee and tea has been an important industrial process. It is the process of obtaining mixture or compound through chemical, physical and mechanical means.

In order to extract the caffeine from the tea leaves the solid-liquid extraction and liquid-liquid extraction were done first.

To make sure that the solvent moves in all the tea leaf particles to extract caffeine, the separatory funnel was gently shaken. The stopcock was also slightly opened to let out any pressure. Sodium hydroxide was used to make sure that other substances, which are slightly soluble to dichloromethane, are eliminated by converting them to their salts that remain in the water [5]. The boiled tea leaves had two layers the aqueous and the CH2Cl2 layer, and these two were separated, this is the liquid-liquid extraction part.

The liquid-liquid extraction resulted in a CH2Cl2 layer which was kept in the evaporating dish and dried.

isolation of caffeine from tea leaves pdf

Sublimation process was done to purify the crude caffeine; this was a delicate part because we must be careful in handling the test tube for the purified caffeine might fall from its attachment into the test tube. The purified caffeine was colored white, fine, and also somewhat powdery and flakey. In this part we are able to tell the purity of the caffeine through the range of the melting point.

Table 2. Based on the result caffeine is more pure than the standard because the range of its melting point is less compared to the standard.

Table 3. After weighing the tea leaves were returned in the tea bags and were secured with strings and staple wire.

isolation of caffeine from tea leaves pdf

Teabags were then boiled in ml water for 5 minutes. Then the ice cube was mixed in the teas extract cooling to room temperature. The tea extract was then transferred in the separatory funnel which has 20ml of CH2Cl2. Separatory funnel was gently shaken in an upside down manner and the stopcock was also opened a bit to release pressure.

The CH2Cl2, lower layer was drained into a clean flask.Maria Noeri B. Fabella, Angela C.

Extraction of Caffeine From Tea Leaves Formal Report

Caffeine was extracted from dried tea leaves using single extraction technique. From the solution, caffeine was extracted using 60 ml dichloromethane. The mixture was then decanted to collect the residue. The residue was first placed in the hood to allow the dichloromethane to evaporate. After that, it was covered by a perforated filter paper so that everything in the mixture except caffeine could evaporate as well.

The percent yield was computed by getting the ratio of the weight of the caffeine and weight of the tea leaves used. The theory of extraction lies in the concept of immiscibility between two phases to separate a solute from the other phase.

Liquid-liquid technique has two types: the single extraction and the multiple extraction. The single extraction involves single extraction process and it uses the whole solvent to extract the mixture. Multiple extraction involves repeated extraction process and each extraction process uses a divided solvent. This is more efficient because the mixture is being extracted approximately with a specific amount of divided solvent.

In addition, when the entire amount of solvent is used, not all of the components will be extracted. However, the group was assigned to do the single extraction method. Ten grams of tea leaves in tea bags was then placed in the mixture and was boiled for ten minutes. After boiling, the tea bags were removed. The tea bags were then squeezed using a spatula to get the liquid that was in them. Single Extraction The solution was extracted with a 60 ml dichloromethane in a separatory funnel.

It was mixed for better separation. After mixing, the solution was left to stand for two minutes until the separation between two layers was clearly visible.

The organic layer was decanted into a different container while the aqueous layer was. Boiling of Tea leaves A solution of 4. Obtainment of Weight of Caffeine The weight of the evaporating dish containing the collected caffeine was obtained using a weighing balance.

The weight of the residue was obtained by subtracting the weight of the empty evaporating dish to the weight of the evaporating dish with caffeine. Calculation of Percentage Yield The percentage yield was calculated by getting the ratio of the weight of caffeine residue and weight of tea leaves used then multiplying it with Learn more about Scribd Membership Home. Read Free For 30 Days. Much more than documents. Discover everything Scribd has to offer, including books and audiobooks from major publishers.

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isolation of caffeine from tea leaves pdf

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International Hazard. Hazard to Self. Links for Chemists. Not logged in [ Login ]. Back to:. Printable Version. Extraction of caffeine from tea or coffee! Caffeine is found both in tea and coffee, IIRC to a greater extent in tea per gram of material. The method of extraction depends on its solubility in chloroform, CHCl3.

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The extraction from tea is preferred as emulsions form less readily, and as there are less coloured impurities. Protocol: 1.

Weigh out 50 g tea, or coffee roast groundor 20 g of instant coffee, and warm in a beaker with ml H2O. Boil this gently for 15 minutes. Remove solids by filtering, and wash with a little hot H2O.To browse Academia.

Skip to main content. Log In Sign Up. Isolation of caffeine from tea. Introduction Tea is one of the most commonly used caffeinated beverages in the world.

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The caffeine C8H10N4O2 found in tea is a bitter, white, crystalline methylxanthine and a member of a class of compounds known as alkaloids Wang, Alkaloids are basic nitrogen containing compounds present in plants. The structure of caffeine affects the functions it performs.

Lab Report: Extraction of Caffeine from Tea Bags Essay

Alkaloids, such as caffeine, are often physiologically active in humans and are known central nervous system stimulants and diuretics Wang, Caffeine also causes an increase in respiration and heart rate, as well as nervousness and insomnia. Though caffeine has demonstrated to have physical dependence, it is also capable of improving alertness, learning capacity, and exercise performance NCBI, Tea leaves, in which caffeine is found, also contain acidic tannins, undecomposed chlorophyll, cellulose, and pigments.

In order to extract caffeine from tea leaves, caffeine must be present as the free base Amrita, In order to do so, the above-mentioned acidic substances must remain water-soluble.

In order to extract caffeine from tea, several methods are used. This can be done simply brewing a cup of tea. The reaction involves a homogenous mixture of an organic and aqueous layer. The ideal solvent in the extraction should have a low boiling point, not react with the solute or other solvents, not be toxic or highly flammable, not miscible with water, be inexpensive, and should readily dissolve caffeine at room temperature.

Because water is present in the pairing, it possible to separate inorganic compounds from organic compounds due to the fact that organic substances are immiscible in water Amrita, When mixing the liquid pairs, the density of the both solvents predict which solvent is the top and which is the bottom layer.

Caffeine, which was present in the organic layer, was located below the aqueous layer Williamson, The product that is collected after extraction still has many impurities. Sublimation is one way to purify the sample, because caffeine has the ability to pass directly from the solid to vapor and reverse to form a solid all without undergoing the liquid phase.

Caffeine has the ability to undergo sublimation under different conditions than the impurities, and can thus be isolated Tello, A series of techniques were used to extract pure caffeine from tea leaves.

The percent error and percent recovery were calculated to assess how much pure caffeine was obtained, and to account for errors that may have occurred that led to a loss of product.

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This experiment illustrates the isolation of a naturally occurring product from plant material -- caffeine from tea leaves. The experiment will provide experience in handling relatively small amounts of material and at the same time you will be exposed to several techniques and procedures which are fundamental for survival in an organic chemistry lab.We use cookies to give you the best experience possible. The purpose of this experiment was to perform a liquid-liquid extraction method to extract the caffeine from the tea bags that were provided, and then recrystallize the caffeine.

The solvents used in the experiment were an aqueous sodium carbonate and dichloromethane DCM. Anhydrous calcium chloride pellets were used to dry the solution and emulsion layer and the DCM was then decanted.

After washing the anhydrous calcium chloride pellets with more DCM, the solvent was evaporated, leaving greenish-white crystalline caffeine residue weighing about.

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Don't use plagiarized sources. The solution was cooled and a vacuum filtration was done to remove the caffeine crystals. The final product weighed about 3 mg. Introduction Caffeine is an organic compound that is found in tea leaves and coffee beans. It is a basic substance due to the nitrogen atoms in its structure and it appears as a white crystalline solid at room temperature.

In this experiment, we aimed to extract caffeine from the tea leaves in the tea bags provided beginning with a solid-liquid extraction method and then a liquid-liquid extraction. Extraction techniques are used to isolate and remove particular compounds form another substance.

For both solid-liquid and liquid-liquid extraction techniques, solvents should be chosen by their miscibility in water should be immisciblethey should have relatively low boiling points for faster and easier extraction, and they should be unreactive with the other substances being used in the experiment. Sodium carbonate and hot water were added to the tea bags and was let to stand for about 7 minutes in order to bring the caffeine molecules out of the tea bags and into the aqueous solution.

A liquid-liquid extraction was then performed to extract the caffeine from the mixture by adding dichloromethane. In a liquid-liquid extraction, two layers are needed- an organic layer and an aqueous layer- that are both immiscible in water. Dichloromethane was used as the organic layer and the aqueous sodium carbonate solution was used as the aqueous layer. Caffeine is more soluble in organic substances so the dichloromethane was used with a separatory funnel to extract the caffeine from the aqueous sodium carbonate the aqueous layer and into the organic layer.

The remaining organic layer that included the caffeine was dried using anhydrous calcium chloride pellets since they are neutral and unreactive and would not disrupt any further reactions. It was then distilled, and then the remaining dichloromethane was evaporated, leaving crude, greenish-white crystalline caffeine.

The most common method for purifying solid compounds is from recrystallization. Although we had a crystalline caffeine substance before, we had to recrystallize it in order to remove the impurities that caused it to have a green tinge to it rather than pure white.

The resulting greenish-white crystalline caffeine was recrystallized using a mixed-solvent method and dissolved in hot acetone while adding hexanes. A vacuum funnel using a Buchner funnel was used to remove the liquid and impurities and the remaining crystals were washed and transferred using a few drops of hexanes. The solution was decanted into a separate Erlenmeyer flask after it soaked for about 8 minutes. An additional 50 mL of hot water was added to the Erlenmeyer flask with the remaining tea bags and was then immediately decanted and added to the first extracted solution.

We rocked the separatory funnel several times and then extracted the dichloromethane from the funnel into a beaker, excluding the emulsion layer that had formed.

We extracted some more dichloromethane into the same beaker, but included the emulsion layer and added anhydrous calcium chloride pellets to dry the solution and emulsion layer. We added several spoon fulls until the anhydrous calcium chloride pellets stopped clumping together.

The dichloromethane solution was then filtered into a clean Erlenmeyer flask using filter paper and a Hirsch funnel. The anhydrous calcium chloride was then washed with dichloromethane and then placed on a hot plate to evaporate it.

A wood stick served as a boiling stick to prevent superheating. A greenish-white residue was left over, coming out to weigh. We added hexane to the left over residue and then dissolved the greenish-white caffeine residue in 5 mL of hot acetone the solution was a cloudy white.

After we let the solution cool, we vacuum filtered it, using a small Buchner funnel. We added some additional hexane to help transfer and wash the crystals through the vacuum filtration. We did not repeat the process. After we recrystallized it with the acetone and hexane to remove the impurities, the final weight was. Discussion We were successful in extracting caffeine from the tea bags, but based on the percent yield, we were not successful in extracting a large amount of caffeine.Caffeine is an alkaloid stimulant with a cyclic backbone structure analogous to the purine structures of DNA, giving it the ability to affect biochemical pathways in the body 1.

In commercial application, caffeine supplements pharmaceuticals and certain beverages such as coffee or tea.

Standard tea bags contain 2. Using the proper extraction methods, the caffeine within a tea bag could potentially be isolated to yield a pure solid; the mass of this solid would reflect the actual yield of caffeine in the tea.

To do so, caffeine must be introduced to a solvent that is both volatile and insoluble to water; a perfect example is methylene chloride [2]. Caffeine has a greater affinity for methylene chloride and will easily dissolve in this solvent over water; however caffeine is not the only organic substance found in tea that is capable of reacting with methylene chloride. Along with caffeine, tea bags contain organic substances called tannins, or gallic acid 1.

Both caffeine and gallic acid are capable of dissolving in water; however, caffeine has a stronger attraction to water due to the dipole-dipole interaction that results from the greater polarity of caffeine and the hydrogen bonds that form between caffeine and water 1. Theoretically, the intermolecular forces of gallic acid can be manipulated to induce a stronger dipole-ion interaction.

If a common salt like sodium carbonate was introduced to the solution, gallic acid could revert back into phenol salt: a polar, inorganic molecule that is insoluble in methylene chloride [3].

In methylene chloride, caffeine will have a greater attraction for the organic solvent and the hydrogen bonds between caffeine and water will be broken. Using a separatory apparatus, two insoluble solutions can be separated, isolating caffeine and the new phenol anion from one another.

The denser methylene chloride layer can then be released from the funnel to render a pure solution of caffeine and methylene chloride.

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To ensure that no water interferes with the interaction of caffeine and methylene chloride, sodium sulfate could be used to absorb any excess water that may have escaped from the tea solution 1. If heated, the solvent would quickly evaporate due to low boiling point of methylene chloride 2. The remaining solid would then be pure caffeine. To start, a mL beaker containing 50 mL deionized water and 2 boiling stones was prepared to dissolve 2. The beaker was allowed to heat until the water started to boil, at which point the temperature was lowered and 2 tea bags were placed into the water.

The solution was heated for 10 to 12 minutes to achieve the highest concentration of tea. At the same time, the insoluble cellulose components of tea separated from the solution rendering the tea concentrate, caffeine, and the new phenol anion product.

The final saturated solution was poured into a mL beaker while the fluids trapped within the tea bags were simultaneously rinsed with an additional 10 mL of deionized water. Once cooled, the solution was transferred into a mL separatory apparatus, a glass funnel used to separate unmixable solutions.

From the top of the funnel, methylene chloride was poured into the solution in increments of 5 mL. Following every addition of methylene chloride, the funnel was inverted to release the built-up pressure from the reaction. The reaction rendered brown top layer of tea and a clear bottom layer of dense methylene chloride. The bottom layer was released from the stopcock and collected into a mL beaker leaving behind a thin layer of methylene chloride to prevent contamination.

Methylene chloride was added 2 more times to assure that all of the caffeine was reacted with. Sodium sulfate was added to the extraction to absorb any water that escaped from the tea and the remaining fluid was decanted and rinsed into a pre-weighed 50 mL beaker with boiling stones using an additional 2.

When boiled, the volatile methylene chloride evaporated, rendering pure, solid caffeine. 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.Tea is a popular daily beverage worldwide.

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Modulation and modifications of its basic components like catechins, alkaloids, proteins and carbohydrate during fermentation or extraction process changes organoleptic, gustatory and medicinal properties of tea. Through these processes increase or decrease in yield of desired components are evident. Considering the varied impacts of parameters in tea production, storage and processes that affect the yield, extraction of tea biomolecules at optimized condition is thought to be challenging.

Implementation of technological advancements in green chemistry approaches can minimize the deviation retaining maximum qualitative properties in environment friendly way. Existed extraction processes with optimization parameters of tea have been discussed in this paper including its prospects and limitations.

This exhaustive review of various extraction parameters, decaffeination process of tea and large scale cost effective isolation of tea components with aid of modern technology can assist people to choose extraction condition of tea according to necessity. Tea is the mostly used daily beverage throughout the world, with estimated daily consumption of more than 3 billion cups Chen and Zhou It is valued due to potential health benefits confirmed with preclinical and epidemiological studies, its aroma content, and cultural association.

There is increasing demand of tea extract and isolated tea biomolecules in pharmaceutical and food industries as natural antioxidant and for other uses. Mostly each component of any variety of tea is known for some amount of bioactivity or sensory attributes. Tea biomolecules mainly consists of non protein amino acid theanine, free sugars Unachukwu et al. Cumulatively they are often called as polyphenols. Catechin and caffeine content and sensory attributes determines the quality of tea Choung and Lee Nowadays decaffeinated tea is more preferred because caffeine causes irritation in gastrointestinal tract, sleeplessness, cerebral cortex stimulation and excites central nervous system in people Ye et al.

Still awareness of the antioxidant properties and other health benefit like anti carcinogenic and chemopreventive effect Fujiki ; Chen and Dou ; George et al. These attributes designates tea polyphenols as functional food too Liang et al.

The components responsible for sensory attributes are zhexanol, benzyl alcohol, linalool, 2-pheylethanol, methyl salicylate, geraniol, nerolidol Xia et al. Commercially available tea is mainly hybrid of two types: Camellia sinensis var.

Lab Report: Extraction of Caffeine from Tea Bags Essay

The green tea is not allowed to ferment. Steaming and panning are the processes for impeding catechin oxidation by polyphenol oxidase in it used in Japan and China respectively. Black tea requires complete fermentation of leaves while oolong tea is partially fermented during processing. Thearubigins, red—brown colored components, and Theaflavins, a reddish coloured pigment are main constituent of it Anesini et al.


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