"Purification of caffeine by sublimation" Essays and Research Papers

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    Abstract: Caffeine‚ (C8 H10 N4 O2) a white‚ crystalline alkaloid known as a nervous system stimulant found commonly in tea leaves and coffee‚ can be extracted using the method of sublimation with the use of Methylene Chloride (CH2Cl2) and Sodium Hydroxide; both can repeatedly rinse the green (unroasted) coffee beans from the caffeine. Keywords: Caffeine‚ Methylene Chloride‚ Sodium Hydroxide‚ Anhydrous Sodium Sulfate I. Introduction Caffeine is an alkaloid of the methylxanthine family. Its chemical

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    Nitration and Purification of Bromobenzene Abstract: An electrophilic aromatic substitution reaction was performed on bromobenzene with nitric acid producing both 2-bromonitrobenzene and 4-bromonitrobenzene. Products of the reaction were purified through multiple recrystallizations and column chromatography creating multiple crops of a yellow powder. The percent yield of products was determined to be 51%. The melting point of Crop 1 was found to be 110-115 °C‚ and Crop 2 was found to be 37-90

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    Abstract: Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction‚ solubility‚ crystallization and vacuum filtration. The experiment was carried out two times‚ both of which were successful. Background Information: This experiment combined all the knowledge of the previous labs performed throughout the semester. An unknown mixture containing

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    of Submission: November 28‚ 2012 Experiment No. 1 ISOLATION OF CAFFEINE FROM TEA I. Introduction Caffeine is a very common substance and is found in coffee‚ tea‚ soft drinks‚ chocolate‚ and "stay-awake" pills such as Vivarin. It can be synthesized or isolated from natural sources. Caffeine constitutes approximately 4% of tea and coffee leaves‚ and is also found in cola nuts and cacao beans. Caffeine is a member of the class of compounds organic chemists call alkaloids. Alkaloids

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    Purpose This experiment deals with separating substances. The objective was to become familiar with the methods of separating substances from one another using decantation‚ extraction‚ sublimation techniques. Brief Introduction This experiment was set to teach research students different methods of separating substances from one another. Materials that are not uniform in composition are set to be impure or heterogeneous and are called mixtures. The separation of the components of mixtures is

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    Extraction of Caffeine from Tealeaves Perez‚ Albert Solomon K.*; Quiambao‚ Marie Angela C;.Pascua‚ Hanna Harriette R.; Patricio‚ Maria Roxanne DC.; 2-Chemistry‚ Department of Chemistry‚ College of Science University of Santo Tomas España St.‚ 1015‚ Manila Abstract Caffeine is soluble in both water and organic solvents‚ solid-liquid extraction and liquid-liquid extraction were used in the experimentation process. Caffeine was extracted using hot water‚ however‚ due to its

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    Isolation‚ purification and characterization of alkaloid caffeine from tea leaves Date Submitted: September 3‚ 2014 Abstract Caffeine is one of the main constituents of tea leaves. In this experiment‚ 0.0039 g of pure caffeine was isolated from tea leaves. This was done through solid-liquid extraction followed by multiple liquid-liquid extraction. Then crude material obtained was then purified by sublimation. The isolated caffeine was subjected to thin layer chromatography (TLC) together

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    Preparation and purification of acetylsalicylic acid Results and Data treatment (A) Preparation of aspirin i) Details about the reactants Reaction of the acetylation of salicylic acid is following From the balanced reaction above‚ it can be seen that the stoichiometry between salicylic acid and acetic anhydride is 1: 1. In this experiment‚ 21.7mmol of salicylic acid was used to react 6.0mL of acetic anhydride and salicylic acid was limiting reagent. The expected amount of salicylic

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    without having a cup of coffee‚ or some sort of caffeine to give that boost of energy in the morning. Have you tried to quit caffeine and it made you feel even worse? In this essay I will talk to you about caffeine effects on people‚ and caffeine addiction. Have you ever heard anyone say that caffeine helps you sober up? If you have don’t get too excited because this is actually a myth. The only reason people thinks this is true is because caffeine can affect your drunken state by making you think

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    Article: “Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance Journal: Psychopharmacology Publication Date: 30 October 2012 Is Caffeine Helping or Hindering Your Performance? Have you ever drunk coffee just for the taste? Studies show that that might be just what you’re doing when you take a sip of that bitter beverage. Whether you’re in high school and didn’t get enough sleep between sports and academics‚ you’re in college and finals are around the

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