Use your percent purity calculations to determine the percent yield of your synthesis of aspirin. Thus, the peak at 1679.70 cm-1 represents a carboxylic acid. ; Heat the flask gently on the steam bath for at least 10 minutes. With care, put your conical flask into the boiling water bath, ensuring that the level of the liquid in the flask is below that of the beaker. Yield of acetylsalicylic acid. Do not add the water until crystal formation is complete. <>>> Aspirin is an organic ester. The mass of pure acetylsalicylic acid was determined and recorded and the percent yield of the reaction was calculated, Table 2. H. Heat the flask gently on the steam bath for at least 10 minutes. What the research is about, method and summary of the result, Images of the reactant (Salicylic acid) and the product (Acetylsalicylic acid). Calculate the mofecular masses for salicylic acid and aspirin. In this case, one molecule (salicylic acid) provides both the "alcohol" and the carboxylic acid. startxref Prostaglandins function as local hormones produced in the body that aid in the transmission of pain signals, regulate the hypothalamic thermostat, and inflammation2. Mix thoroughly. The complete lab report must be typed (this includes the calculations) Prepare a cover page. Place 2.0 g (0.015 mole) of salicylic acid in a 125-mL Erlenmeyer flask. A spectrophotometer could have been employed to measure the absorbance values at 415 nm wavelength. The reaction in which a Carboxylic acid combines with an alcohol in the presence of a catalyst (commonly concentrated sulphuric acid) to form an ester [CH3COOC2H5] is called Esterification reaction. Unknown compound D was determined to be pure salicylic acid because it had, qualitatively, the darkest, strongest purple color, as can be seen from Table 3. RELATED CONTENT: [ANSWERED] Synthesis of Aspirin Lab Report, Briefly summarise the article. Calibrate the Spectrophotometer by placing the cuvette in the holder, close the lid & press CAL. Cool the solution to room temperature and then in a ice-bath. First, an average molecular weight of 1.7 x 102 g/mol was derived from titrations (table 2.2). Here you will find material for Experiment 21 - Synthesis of Aspirin. Add, distilled water as needed, to fill the volumetric flask up to the 25ml mark. Raw data used in calculations is available upon request. Salicylic acid (1.00 g + 0.005 g) and acetic anhydride (2.0 mL + 0.05 mL) were added to each of four test tubes. As can be seen from Table 1, sulfuric acid best increased the reaction rate of the catalysts because the temperature of the sulfuric acid-catalyzed reaction rose 4 ˚C in only 5.5 s. Therefore, sulfuric acid was the most effective catalyst, followed by boron trifluoride etherate, pyridine, then sodium acetate. Aspirin is an ester that has high molecular weight and it not soluble in water hence the solid can be separated by crystallization process. It should be in a powder form. This second step rapidly precipitated large crystals, likely leading to high impurity. Soc. The intensity of the purple color corresponds with the concentration of phenol functional groups present. A large melting point range would suggest an impure sample and ineffective recrystallization process. 0000001234 00000 n Water is added once removed from heat with addition of cold water and suction filtration is carried out. This will be allowed to dry and used in your next laboratory session for analysis. The main procedures are preparation of aspirin, recrystallisation of aspirin and lastly determining the melting point of the aspirin. 1616 0 obj <> endobj We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Zn&�O���*= �X�*�(�̟��ݽ�*'�+}1���64�l��R�UI�������٬���}v!�!�^G�b5U�n_�b�D^�H�[�����?���X�Z,���9�e&���Z�hg}V��A�s��M�98�AX����� University of Missouri–St. WASTE • Salicylic acid should be disposed of in the solid waste container. RELATED WORK: Synthesis of Aspirin Lab Report . This will zero the spectrophotometer. Based on the results of the absorbance testing with the Spectrophotometer, what is the percent purity of your sample of aspirin? 1920. However, looking at the structure of synthesized aspirin, the remaining component that has not been identified but is present in the structure is carboxylic acid. Thus, the synthesized aspirin was close to the identity of commercial aspirin, but not exactly, so it can be concluded that the synthesized aspirin was not entirely pure. Overall, the purpose of this lab, to synthesis aspirin and prove its purity using organic functional groups, was accomplished successfully. The efficacy of the recrystallization could have been analyzed by determining the melting point range of the acetylsalicylic acid. Turn on the aspirator fully. Collect the product by vacuum filtration and rinse out of the flask with a few milliliters of cold petroleum ether. To summarize, both spectrometers give significant evidence suggesting the purity of the synthesized aspirin product. You will be shown how to use the IR by the technician or tutor. If not, use a pestle & mortar to grind to a powder. This value, compared with the molecular weight of commercial aspirin, C9H8O4, will demonstrate the difference in purity. The final product of synthesized aspirin contained no starting materials and its molecular weight was relatively close to that of pure aspirin, thus it was almost entirely pure. What the research is about, method and summary of the result Introduction: Balanced equation of aspirin production Images of the reactant (Salicylic acid) and the product (Acetylsalicylic acid) What is […] Record the mass of aspirin weighed to the nearest 0.001g. These two qualitative tests could be improved by making them quantitative tests. Squirt a small amount of distilled water over the filter paper to seal the paper to the funnel surface. Acetic acid has a peak at 1704.69 cm-1 and salicylic acid has a peak at 1652.36 cm-1. Members of the class may have also utilized different techniques to measure the time taken for a 4 ˚C temperature change to occur. Four unknown compounds, A, B, C, and D, were provided and each was one of: pure salicylic acid, impure acetylsalicylic acid, pure acetylsalicylic acid, or ground aspirin tablet. Does this percent purity compare well with the results of the melting temperature test? This might explain the large data spread. Add 5 mL (0.05 mole) of acetic anhydride, followed by 5 drops of conc. Lower absorbance values would indicate that a greater concentration of phenol was present and the absorbance value could be used to directly determine the concentration, 1 Cappelli, G. J. Chem. During IR spectroscopy, a pinhead sample of aspirin was placed on the diamond ATR plate of a Nicolet iS10 Infrared Spectrometer and the spectrum was printed. The table below lists IR standards from several IR spectra of functional group chemicals: There are several things to be taken away from the collected data in regards to the purity of the synthesized aspirin sample. endobj To finish the experiment, three titration trials were performed using the synthesized aspirin. Each spectrometer yields further results regarding the purity of the aspirin. Therefore, the second peak from acetic acid pertains to the hydrogen the carboxylic acid, at 11.0 PPM. NMR was the first to be tested: a glass NMR tube was filled with the aspirin sample to a height of approximately 0.5 cm and 0.6 mL of CDCl3 was added in order to avoid large protein peaks. Obtain mass of dry salicylic acid. The product will appear as a solid mass when crystallization is completed. Synthesis of Aspirin … Wash the beaker and the funnel with 5 to 10 mL of water. After the times required for a 4 ˚C temperature increase in each reaction solution had been recorded, the reaction vessels were allowed to sit, with occasional stirring, for a few additional minutes to ensure that each reaction reached completion. Experiment 10 will have you synthesize two esters of salicylic acid. <<7BDF114266388B4F968FC5EE66DF60BF>]>> Prolonged contact with acid catalyst in the presence of water can lead to regeneration of salicylic acid starting material and reduce acetylsalicylic acid yield. Aspirin works by suppressing the synthesis of prostaglandins and thromboxanes in the human body3,4,5.