Compound Observations [color, crystal type, size, shape etc] Melting Range, °C Mass/Volume Obtained, g or mL
Crude Fine white powder
Crude, 110-130 111 mg
138 mg w/added caffeine
Purified Thin white flakes 215-220 9 mg
Acid-base liquid-liquid extraction was done to separate the individual components of Excedrin so that caffeine could be extracted. Acid base liquid-liquid extraction works by converting an acid or base to the alternate form by adding a strong acid or base, which allows it to become more polar and move between solvents. The solvents can then be extracted off, allowing for the individual components to be extracted. This is important for organic chemists, because being able to separate components allows for reactions to take
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place with the certainty that the desired substance can be separated from the other components. 111 mg caffeine were extracted from the Excedrin which was about 85.38% of the expected recovery.
This tells that some of the material was lost through various means, such as sticking to the original solvent layer or sticking to the glass.
Recrystallization was then done to purify the caffeine that was extracted from the Excedrin of any impurities that might be within. Recrystallization works by finding a solvent that will dissolve the solute only under higher temperatures but will not dissolve under lower temperatures. The minimal amount of hot solvent needed to dissolve the solute and then the solution is allowed to cool, which crashes out the desired substance in crystals if allowed to cool slowly.
Through recrystallization, 9 mg of crystals were extracted from the crude caffeine. The purity was then tested by comparing the melting range of the crude caffeine to the melting range of the caffeine crystals. The melting range was narrower and much closer to the projected value which indicated that the caffeine crystals were much purer than that of the crude caffeine. The recrystallization was done poorly because there was too much solvent added, which then had to be evaporated off, giving much less caffeine crystals than expected, at 6.52% of the expected
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recovery. Rf Values Acetaminophen Aspirin Caffeine Hexane 0 0 0 Ethyl Acetate 1.4/2.9 = 0.48 1.6/2.9 = 0.55 0.5/2.9 = 0.17 1:1 0.5/4.5 = 0.11 1.8/4.5 = 0.40 0.3/4.5 = 0.07 Methanol 3.7/4.5 = 0.82 3.6/4.5 = 0.80 3.1/4.5 = 0.69 Rf Values Spot 1 Spot 2 Spot 3 Excedrin 3/4.9 = 0.61 1.8/4.9 = 0.37 0.9/4.9 = 0.18 Week 1 2.5/3.9 = 0.64 0.9/3.9 = 0.23 Week 2 2.6/3.9 = 0.67 1.0/3.9 = 0.26 To assess the purity of our caffeine again, a thin layer chromatography was conducted.
Thin layer chromatography is done by placing samples on a chromatography plate, which is then placed in a beaker into a solvent. The solvent then crawls up the plate through capillary action and takes the samples with it through intermolecular forces. The sample should then drop out of the solvent at some point, depending on the strength of the attraction to the solvent versus the strength of the attraction to the chromatography plate. More polar substances should be attracted to the chromatography plate, which is coated in silica gel, whereas less polar substances should be more attracted to the solvent. Rf values, which are the distance the solute travels from the baseline divided by the length of the solvent front, are then calculated, with the more polar substances being closer to 1. These Rf values ensure that the data is accurate and consistent, even when the solvent fronts are different
lengths. Ethyl acetate was chosen because it showed the most variance between the different components allowing an easier visual as to whether the sample is pure. The extraction from week 1, as well as the crystals from week 2 were tested on ethyl acetate, with Excedrin tested for comparison. The results showed that there was caffeine, as the Rf values were similar, as well as another impurity that was likely aspirin, as the Rf value was closest to that of aspirin. This indicated that the substance was not completely pure in either week, both containing likely the same contaminate.
The purpose of this experiment was to learn and preform an acid-base extraction technique to separate organic compounds successfully and obtaining amounts of each component in the mixture. In this experiment, the separation will be done by separatory funnel preforming on two liquids that are immiscible from two layers when added together. The individual components of Phensuprin (Acetylsalicylic acid, Acetanilide, and Sucrose as a filler) was separated based upon their solubility and reactivity, and the amount of each component in the mixture was obtained. Also, the purity of each component will be determined by the melting point of the component.
* It was almost impossible to tell when the Alka-Seltzer tablet had dissolved, each time the experiment was done. This was a huge problem for the experiment as this could have totally caused problems to the experiment. A special type of detector apparatus, which bleeped when the correct amount of Alka-Seltzer tablet dissolved, could improve this, each time the experiment was done.
The solvent should be easily removed from the purified product, not react with the target substances, and should only dissolve the target substance near it’s boiling point, but none at freezing. A successful recrystallization uses minimum amount of solvent, and cools the solution slowly, if done to fast, many impurities will be left in the crystals. Using the correct solvent, in this case ice water and ethyl acetate, the impurities in the compound can be dissolved to obtain just the pure compound. A mixed solvent was used to control the solubility of the product. The product is soluble in ethanol an insoluble in water. Adding water reduced solubility and saturates the solution and then the crystals
The experiment was conducted in three parts: Part A of the experiment consisted of extracting caffeine from an aqueous solution; Part B consisted of using three different compounds: benzoic acid, succinic acid, and sodium benzoate; and the last part of the experiment consisted of using a solid neutral compound with an acid or base impurity.
Afterwards, we conducted crystallization to evaporate the liquid in an attempt to detect the presence of a salt. Before stating which of the potential
When making an organic compound, it is important to separate the compound from other compounds to make it as pure as possible, this is called crystallization.
Separations are important techniques in chemistry that are used to separate various components of a mixture. They are carried out by mixing two immiscible liquids containing certain solutes together in a separatory funnel, allowing them to separate, then extracting the distinct layers that form. The ratio of the concentration of solute present in the upper layer to the concentration in the lower layer is called the partition coefficient. The efficiency of a separation is described by this partition coefficient. If the coefficients for the two layers are largely different, then the separation can be carried out in a single step. If they aren’t, a more complex process is necessary.1,2 Countercurrent chromatography is a technique used carry out separations in these kinds of cases. It uses a continuous liquid-liquid partitioning process to streamline the usual extraction procedure.
The distance of the initial extract line to a pigment band was divided by the distance of the marked solvent front to the initial extract line both were measured in cm. The RF (relative to front) was calculated for each pigment band, indicating the travelled distance between the pigment and the front (solvent line) on the chromatography
Caffeine is a mild stimulant that occurs naturally in at least 63 plant species. Caffeine can be found in the leaves, stems, seeds, and roots of these various plants. Caffeine is part of the methylxanthine family. It consists of a xanthine molecule with three methyl groups attached to it. Caffeine can be found in many products like sodas, tea, and coffee, but it also occurs in several other products such as prescription medications, diuretics, and pain relievers. Caffeine’s widespread use and popularity have caused many people to view the substance as an addictive drug. Thus making caffeine the most inexpensive and readily available drug known to man. Then on the other hand there are people who view caffeine as a helpful stimulant that increases the individual’s concentration and awareness as well as many other physical traits. The important thing to remember is that caffeine’s affects vary based on the person, the amount ingested, the frequency of consumption, and individual metabolism. (http://www.pp.okstate.edu/ehs/kopykit/caffeine.html)
The medication of paracetamol can be administered in various ways and they are sold in different formulations. The common dosage comes in tablets form of 500 mg, in dispersible fizzy tablets (500 mg) and oral suspensions. It can also be bought in capsules as a mixture with other API like caffeine and codeine.
Caffeine is a stimulant that has not been given the attention that some says it deserves. Caffeine is found in many everyday substances. It can be found in coffee, tea or sodas. Caffeine can be found on almost every street corner. There is a coffee place in just about every town. Sodas and coffee are found...
Analysis of Aspirin Tablets Aim --- To discover the percentage of acetylsalicylic acid in a sample of aspirin tablets. ----------------------------------------------------------------- In order to do this, the amount of moles that react with the sodium hydroxide must be known. This is achieved by using the method of back titration.
HPLC (High Performance Liquid Chromatography) is an analytical technique which separates a complex mixture of components into its specific individual components. It is a powerful tool in analysis, as it combines high speed with extreme sensitivity compared to traditional methods of chromatography because of the use of a pump which creates a high pressure and forces the mobile phase to move with the analyte in high speed. It is been used as a principle technology in various automated analyzers used for diagnostic purpose.
Caffeine is the single most widely consumed psychoactive substance in the United States (Einöther & Giesbrecht, 2013). According to Einöther and Giesbrecht (2013), 80% of the world’s population consumes caffeinated products every day, with coffee and tea being the primary sources. In the recent years, the demand for
Sereshti, H. & Samadi, S. (2014). A rapid and simple determination of caffeine in teas, coffees and eight beverages. Food Chemistry, 158, 8-13.