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synthesis of organic compounds
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Experiment No.: 7 Experiment Title: SYNTHESIS OF PEAR ESTER Surname: Matsididi First Names: Precious Olorato ID Number: 201903636 Day: Friday Lab Slot: 3-6pm Date of the experiment: 29 April 2022 CONTACTS; [email protected] +267 72 443 074
Wavenumbers from IR spectra of 1744.1, 2953.6 and 3098.3cm-1^ giving C-O stretching, C=O stretching, and C-H stretching. As well as mass of 15.62g and volume of 18.0ml which both gave the density of 0.87g/ml and light brown appearance with fruity odor. Esterification by carboxylic acid and alcohol. Which then give crude product with percentage yield of 98.9% AIM The aim of this experiment was to synthesis by esterification a pear ester by use of acetic acid and propanol. INTRODUCTION Esterification is the process of synthesizing esters, esters being compounds with functional group of -CO 2 - which have a pleasing smell. This process is done by combining an organic acid with an alcohol to form an ester and water in the presence of sulphuric acid. Esterification can either be by carboxylic acid paired with an alcohol, acid anhydride and alcohol or from acid chloride and alcohol. Esters are usually used for artificial flavors or perfumes (OSHA, 2021). For this experiment carboxylic acid being acetic and alcohol being propanol are used to synthesis propyl acetate or 1-acetoxypropane the pear ester. It has density of 0.88g/ml and it is a clear colorless pleasant liquid. The general reaction for esterification below: A
Table1; SOLUTIONS AND THEIR AMOUNTS Flavor Ester Alcohol Carboxylic acid Name Pear Propanol Acetic acid Molecular weight (g/mol) 60.0952 60. Boiling point ( C)⁰ 97-8 118- Density (g/ml) 0.87g/ml 0.803 1. Moles needed (mol) 0.35 1. Grams needed (g) 21.03 60. ml needed (ml) 26.2 57. Table 2; MASS, VOLUME AND ESTER APPEARANCE Mass of measuring cylinder + ester 143.16g Mass of measuring cylinder 127.54g Mass of esters 15.62g Volume of ester 18.0ml Appearance of ester Light brown solution Odor of ester Mild pear odor Density =mass/ volume = 15.62g/18ml = 0.87g/ml Percentage yield=(actual density/expected density) × 100% = (0.87g/ml)/(0.888g/ml) × 100% =98.9%
Table 3; PROPYL-ACETATE IR SPECTRA PEAKS AND THEIR INTENSITY AND SHAPE WAVENUMBER(cm-1) and BOND Intensity and shape 1744.1 C-O stretching Strong intensity, sharp peak 2953.6 C=O stretching Weak intensity, sharp peak 3098.3 C-H stretching Medium intensity, sharp peak
following the removal of water. and the last step being deprotonation to form the ester being propyl acetate.
IR spectra of propyl acetate peak wavenumbers of 1744.1, 2953.6 and 3098.3cm-1^ are seen and determined to be bonds of C-O stretching, C=O stretching, and C-H stretching. As well as mass of 15.62g and volume of 18.0ml which both gave the density of 0.87g/ml and light brown appearance with fruity odor. Lastly crude product of percentage yield of 98.9%. This experiment showing that ester synthesis by use carboxylic acid and alcohol successful but in need of a method for further purification being distillation of crude product to get pure for it to be more quality to organic synthesis. REFERENCES OSHA, 2021: , (OSHA, 2021), IR Spectrum Table & Chart, 2022: , (IR Spectrum Table & Chart, 2022), Strouse, 1997: , (Strouse, 1997), OSHA, 2021: , (OSHA, 2021),
