Lab1 Isolation of Caffeine from a Tea Bag.docx

Lab1 Isolation of Caffeine from a Tea Bag.docx - Organic...

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Organic Chemistry 211 Experiment 1: Isolation of Caffeine from a Tea Bag Objective To extract caffeine from tea powder using polar - nonpolar solvent extraction technique. Theory Extraction Extraction is a technique in which a solvent is used to remove/isolate a compound of interest from a liquid substance. For example, coffee is a liquid which contains dissolved caffeine Caffeine is a bitter, white crystalline xanthine alkaloid. It is found in varying quantities in the seeds, leaves and fruits of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants, as well as enhancing the reward memory of pollinators. Caffeine has a molecular formula of C 8 H 10 N 4 O 2 . Its molecular weight is 194.1906 g/mol. It has a molecular structure as follow. Caffeine’s most notable pharmalogical effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes smooth muscles, stimulates cardiac muscle, stimulates dieresis and appears to be useful in the treatment of some types of headache. Material 100mL beaker, 50mL beaker , Small separatory funnel , Cotton wool , Measuring cylinder , Analytical balance , Filter funner , Filter paper , Round bottomed flask , Rotary evaporator. Chemical Sodium carbonate, Methylene chloride / dichloromethane , Anhydrous sodium sulphate , Water Procedure
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The tea bag was teared and the tea leaves was weighed, then the weighed tea was transfered into a 100ml beaker. 50ml water was added into the beaker containing tea leaves and the mixture was heated on the hot plate and was frequently stirred. Sodium carbonate was weighed approximately 0.5g and then the tea solution was boiled, put aside and the sodium carbonate was added to the solution. The solution was filtered using a cotton wool into a small separatory funnel and then 15ml of dichloromethane was added into the separatory funnel and the extraction was started. The lower dichloromethane was drained off after the emulsion was completely break and this step was repeated with another 10ml dichloromethane added. Then the combined dichloromethane was dried by
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