To obtain the caffeine, the methylene chloride was removed from the extract, leaving us with our solid caffeine residue. Sublimation: We purified our solid caffeine through sublimation. By constructing a side-arm test tube apparatus, we vaporized and condensed the caffeine using a Bunsen burner. Upon cooling, the apparatus was carefully disassembled and the sublimed caffeine was scraped off of the test-tube collection surface and weighed. The melting point range was then determined by utilizing a melting point apparatus.
* Pour a little ether over the nutmeg residue on the filter paper so that any Diethyl ethanol traces clinging to it is washed down and mixed with the filtered liquid underneath. * Filter the mixture by gravity filtration, washing the nutmeg residue with 10ml of diethyl ether. Evaporate the Ether from the filtrate * Recrystallize the product from ethanol. Filter using a Buchner funnel and wash them with cold water as shown in the diagram (see figure 2). * Let the crystals dry for one week, record the weight and take a sample and put into a glass capillary tube to obtain a melting point using the Melt-Temp machine.
Conclusion: The purpose of this experiment is about the synthesis and characterization of aspirin. Salicylic acid and acetic anhydride will be mixed to produce acetylsalicylic acid and acetic acid. The catalyst is H3PO4. After crystallization, the aspirin was filtered using a vacuum filtration system and dried in an oven. A melting point will be ran on the aspirin when completely dry.
Then, sodium hydroxide would have to be titrated against the potassium hydrogen phthalate to standardize sodium hydroxide to 0.1M as well. Titration is the procedure used to determine the concentration of some substance by the controlled addition of a solution into a reaction vessel (flask) from a burette. By using titration, the volume of the solution delivered from the burette may be determined very precisely. This reliable primary standard solution became useful as a titration was made against the orange juice to find the molarity of the citric acid. The indicator Phenolphthalein was the substance used to signal when the titration reached the point at which the reactants are stoichiometrically equal as defined by the balance reaction equation.
Methods My group used the method of titration to test whether the Vitamin C and lime juice nutritional facts where correct from their manufacture. First, we started with the standardized solutions, NaOh and HCl, to get familiar with how titrations work and start the titration of potassium hydrogen phthalate (KHP). We begun by gathering up all the necessary materials needed for the titration including: the general laboratory glassware from the bins, standard safety equipment, 50mL burette, phenolphthalein, NaOh (3 mol/L), HCl (3mol/L), KHP, ascorbic acid, and lime juice. The standardization of NaOh came first, which started by gathering the KHP and putting 1.5 g into 3 flasks with 50 mL of water in each. After we added the KHP to the 50 mL of water, we placed each one of the flasks onto a stir plate with a magnet in each flask so we achieved maximum stirring.
After filtration, the crystals collected were washed thoroughly with water and then dried with filter paper. The weight of the crude material was determined and percentage yield was calculated. The melting point of the sample was also determined. The crude material was recrystallized from boiling methanol and the melting point of the purified Trityl methyl ether was measured. Results: 0.03g of the crude material was collected after initial filtration.
Preparing Isopentyl Acetate by the Fischer Esterification Preparing Isopentyl Acetate by the Fischer Esterification Leah Monroe May 8, 2003 Organic Chemistry Lab II Experiment performed on April 29 and May 1, 2003 Abstract: The purpose of this experiment was to synthesize isopentyl acetate via an esterification reaction between acetic acid and isopentyl alcohol, using concentrated sulfuric acid as a catalyst. The product was washed with sodium hydrogen carbonate, as well as with water, then dried with anhydrous sodium sulfate. The product was then distilled using a Hickman still and characterized using infrared spectroscopy. The percent yield of isopentyl acetate was 61.52%. This may have been low due to not all of the condensed product being removed from the Hickman still, some product being lost during transfer of the product from the reaction tube into the Hickman still, or the loss of some product due to evaporation during distillation.
The normality of the unknown base is calculated after the solution has reached the end point. The amount of substance being delivered is calculated in units of equivalents per litre using the formula: VaNa = VbNb Experimental In order to titrate the acid with the unknown base, a solution of the acid was prepared. 5.1722 (±10%)g of potassium hydrogen phthalate acid is obtained using a weighing boat and transferred into a volumetric flask containing 250mL of boiled distilled water. Volumetric flask was shaken several times in order to assist the powder to dissolve. Once dissolved, 24.9734 (± 0.0045)mL of acid was pipetted into an Erlenmeyer flask along with 25mL of cool (recently boiled) distilled water.
After that, a pH sensitive color indicator, phenolphthalein, was added, and the solution was titrated with 1M sodium hydroxide. The sodium hydroxide was added drop by drop until the solution turned pink, meaning all of the remaining acid that was not neutralized in the reaction with the antacid was now neutralized. The amount of HCl left over from the reaction could be determined by measuring the amount of sodium hydroxide that was needed to neutralize the solution. Since the 1 M sodium hydroxide and the 1 M HCl react with a 1:1 ratio, the amount of sodium hydroxide needed to neutralize the solution was equal to the amount of HCl remaining in the solution after the reaction with
Each organic extract is then dried over anhydrous calcium chloride pellets and evaporated to dryness. The extract is then wet with a minimal amount of dichloromethane and a sample of each is obtained and mixed together with 200 mg of alumina and again evaporated to dryness. This mixture is then placed in the prepared chromatography column and eluted with hexanes until the yellow β-carotene band is collected. The solvent is then switched to a 90/10 mix of hexanes and acetone to speed up the elution of the more polar lycopene band, which is also collected in its own flask. Each of these samples is evaporated to dryness and rehydrated with a minimal amount of dichloromethane.