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synthesis of organic compounds
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Experiment No.: 6 Experiment Title: SYNTHESISING ACETYL SALICYCLIC ACID Surname: Matsididi First Names: Precious Olorato ID Number: 201903636 Day: Friday Lab Slot: 3-6pm Date of the experiment: 11 March 2022 CONTACTS; [email protected] +267 72 443 074
Here acetyl salicylic acid is synthesized through reaction of salicylic acid and acetic anhydride and purified with sodium bicarbonate. Aspirin of 2.12g and it’s a substance of white crystals in which has a temperature range of 132.5 C-135.1 C. from the IR spectrum of the product bonds of C=C⁰ ⁰ bending, C=O stretch, C=O stretch and O-H stretch thus confirming this product to be aspirin. AIM The aim of this experiment was to synthesize acetyl salicylic acid(aspirin) from salicylic acid and acetic anhydride. INTRODUCTION Acetylsalicylic acid also commonly known as aspirin is a drug quite often used for pain and fevers, it mostly taken orally but a point to note is continuous intake reduces the chances of cancers (DrugBank, 2005) hence regarded as great help to the pharmaceutical industry and medical.. It is also a common cause of poisoning to toddlers and infants. In this experiment salicylic acid is reacted with actin anhydride to give aspirin in the presence of a strong acid such as sulphuric acid this being to speed up the process: This aspirin produced is insoluble in water but has by product which are removed by sodium bicarbonate making aspirin salt soluble and HCl converting the salt back to the insoluble aspirin:
= 2g / 138.121g/mol =0.0145mol Mole ratio of salicylic acid : acetyl salicylic acid 1 : 1 0.0145mol : x X= 0.0145mol Mass of acetyl salicylic acid expected= moles × molar mass = 0.0145mol × 180.158g/mol = 2.61g Percentage yield= (actual mass/ expected mass) ×100% = (2.12g/ 2.61g) × 100% = 81.2% TABLE1 Acetyl salicylic acid IR spectra peaks and their intensity and shape WAVENUMBER(cm-1) and BOND Intensity and shape 1603.7 C=C bending Medium intensity, sharp peak 1680.4 C=O stretch Strong intensity, sharp peak 1748.3 C=O stretch Medium intensity, sharp peak 3455.0 O-H stretch Medium intensity, broad peak
From the acetyl salicylic acid IR spectra the bonds C=C bending, C=O stretching, C=O stretching from literature value (Strouse, 1997) as well as bond O-H stretching from literature value (IR Spectrum Table & Chart, 2022) found from wavelengths 1603.7cm-1, 1680.4 cm-1, 1748.3cm-1^ and 3455.0cm- respectively. The C=C bond was determined to be of an aromatic ring as it is bent, giving the only ring present in acetyl salicylic acid, as for C=O stretching was due to conjugation of electrons that move from a directly C=C that is present in acetyl salicylic acid ring. C=O stretch wavelength indicated presence of a carboxylic acid(-COOH) group which was also determined at the wavelength of bond alcohol(-OH) group. The aspirin was found to be white and crystals as which conform with the literature (Annotation Record for ACETYLSALICYLIC ACID, 2022). The temperature range of product aspirin was recorded to be 132.5 C-135.1 C⁰ ⁰ in which literature value states it to be 135 C⁰ (Annotation Record for ACETYLSALICYLIC ACID, 2022) which is a value found in the range. The percentage of this product was 81.2% thus giving a high product attained from this method. This high yield also suggesting that this method is an effective way of synthesizing Acetyl salicylic acid. As seen from the mechanism below sulphuric acid is the catalyst where salicylic acid is the alcohol reacting with a small amount of acetic anhydride producing an ester in presence of water. then the acetic acid reacting with OH of salicylic acid and dehydration giving aspirin and water. Sodium bicarbonate here is used to clear the polymers from the formed aspirin followed by reaction with HCl giving a purified aspirin.
Aspirin (acetyl salicylic acid) of 2.12g giving percentage yield of 81.2% and it’s a substance of white crystals in which has a temperature range of 132.5 C-135.1 C. from the IR spectrum of the⁰ ⁰ product bonds of C=C bending, C=O stretch, C=O stretch and O-H stretch thus confirming this product to be aspirin. Aspirin is important in healing headaches, and which helps other industries related in research done in chemistry. Testing of this could be used on lab rats before administered to humans. REFERENCES REFERENCES DrugBank, 2005: , (DrugBank, 2005), Strouse, 1997: , (Strouse, 1997), IR Spectrum Table & Chart, 2022: , (IR Spectrum Table & Chart, 2022), Annotation Record for ACETYLSALICYLIC ACID, 2022: , (Annotation Record for ACETYLSALICYLIC ACID, 2022), (Annotation Record for ACETYLSALICYLIC ACID, 2022: , (Annotation Record for ACETYLSALICYLIC ACID, 2022),
Sodium Hydroxide Health effects of exposure to the product If inhaled may lead to chemical pneumonitis and pulmonary edema. Cause severe irritation to upper respiratory tracts causing coughing, burns and breathing difficulties. To eyes causes burns and possible blindness, chemical conjunctivitis and corneal damage. Contact with skin causes burns, penetrating ulcers. Ingestion may cause severe and permanent damage to the digestive tract, cause gastrointestinal burns. Handling and storage precautions Wash hands thoroughly after handling, do not allow water into its container because of violent reaction. Store in tightly closed container in cool, dry ventilated area away from metals and acids. First aid measures Skin contact; take off contaminated clothing and flush skin with plenty of water for 15 minutes. Inhaled; move to area with fresh and rest in a position comfortable for breathing, if not breathing give artificial respiration or in difficulty give oxygen. In eyes; flush with plenty flowing water for 15mins. Ingestion; do not induce vomiting if fully conscious give full cup of water. Stability and reactivity Stable at room temperature in closed containers. Avoid contact with water, exposure to moist air. Benzaldehyde Health effects of exposure to the product To eyes causes irritation. Contact with skin causes irritation Ingestion may cause gastrointestinal irritation
