TLC-Thin Layer Chromatography Lab Report

In the reaction of the saponification of methyl salicylate, the percent yield of crude salicylic acid is 149.8% and the percent yield of purified salicylic acid is 72.7%. Also in the reaction of the synthesis of aspirin, the percent yield of crude acetylsalicylic acid is 145.9% whereas the percent yield of purified acetylsalicylic acid is 92.1%. In both these reactions, it can be clearly seen that the percent yield of the crude products or crude yields is much higher than the percent yield of the purified products. The percent yield of the crude product is for the product that has been initially isolated before the product has undergone a purification step. The crude yield gives an indication of how well the reaction went and provides an indication …show more content…
In TLC, chromatography was run on 7 samples, methyl salicylate, standard salicylic acid, standard acetylsalicylic acid, crude salicylic acid, purified salicylic acid, crude acetylsalicylic acid and purified acetylsalicylic acid. Chromatography is used to separate and identify mixtures of different compounds. The procedure we use to identify the compounds is by comparing the Rf value of the compounds with the standard’s Rf value. The larger an Rf value of a compound means the distance travelled by the compound is the largest. Also, the compound is less polar because it interacts strongly with the polar adsorbent on the TLC plate. Conversely, it can be said that compound of low polarity will have a larger Rf value than a polar compound run on the same TLC …show more content…
By theory, the functional groups present in salicylic acid is phenol (alcohol) and carboxylic acids. In the infrared spectrum, there is a peak at 3229.157 cm-1 which indicates there is an O-H bond of the alcohol group is present as the literature value range for O-H bonds of alcohol groups are 3500-3200 cm-1. There is a peak at 1205.134 cm-1 indicating C-O bond of alcohol group is present as the literature value of C-O of alcohol group is 1320-1000 cm-1. There is a peak at 2994.552 cm-1 indicating presence of C-H bonds, the literature value for C-H bonds are 3000-2850 cm-1. There are 3 peaks present at 2845.864 cm-1, 2589.538 cm-1, and 2529.417 cm-1 which indicates there is O-H bond of the carboxylic acid group present because the literature value of O-H bond of carboxylic acid is 3300-2500 cm-1. There is a peak at 1654.709 cm-1 which indicates that there is C=O of the carboxylic acid is present because the literature value range of C=O bond of carboxylic acid is 1760-1690 cm-1. The position of this peak is slightly shifted from the original peak value might be because there are other functional groups present too in the molecule. All these peaks present in the infrared spectrum proves that there is phenol and carboxylic acid present in salicylic

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