Iodination of Salicylmaide First Draft Lab Report - Ciara Bell (PDF)

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Dec 6, 2023

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Ciara Bell Tuesdays/Thursdays at 11AM Title : Iodination of Salicylamide Authors : Ciara Bell, Rayna Tyler Reaction Scheme : Abstract: The iodination of salicylamide by electrophilic aromatic substitution can aid the usage of iodine as a safer chemical to use in teaching laboratories. predicted that if iodine for the iodination of salicylamide, then 2-hydroxy-5-iodobenzamide would be produced rather than the other three possible substituted products. The product 2-hydroxy-5-iodobenzamide was observed and supported by the TLC Analysis and IR Spectrum obtained. Future uses of this experiment can support the usage of safer chemicals in teaching laboratories. Introduction : Iodination of Salicylamide is an experiment that uses electrophilic aromatic substitution. Electrophilic aromatic iodination substitution can be used for a wide variety of things such as pharmaceutical uses and x-raying but reacts slow and is a cheap reagent (Iida et al 7411) With this type of experiment and in organic labs in general, there can be a tendency for harsh chemicals to be used to teach these concepts. Both Bromine and Chlorine are mainly used in Electrophilic aromatic substitution, but they may not be the best chemicals to use in teaching laboratories. Iodine can be a more manageable and efficient chemical to use rather than ones like Bromine or Chlorine that are either more harsh or less efficient in experiments (Eby and Deal 1426). Using Iodine can allow organic laboratories to have a more safe and friendly environment

Ciara Bell Tuesdays/Thursdays at 11AM in these settings. The hypothesis generated is that iodine will yield 2-hydroxy-5-iodobenzamide through electrophilic aromatic substitution. It is predicted that if iodine is used as a reagent in the electrophilic aromatic substitution of salicylamide, then 2-hydroxy-5-iodobenzamide will be produced. Figure 1. TLC Analysis Figure 2. IR Spectrum of Isolated Product Results & Discussion:

Ciara Bell Tuesdays/Thursdays at 11AM In the experiment, a hot filtration was used. The purpose of the hot filtration was to isolate the crude product if the full amount of boiling ethanol was used. The TLC analysis was used to verify if the reaction was complete. The three spots on the TLC plate represent that starting material, reactant plus reaction mixture, and the reaction mixture work-up. If the reaction was not fully completed the dots would all look like the starting material which means that it would not be fully reacted. The result obtained was 2-hydroxy-5-iodobenzamide. This was obtained rather than the other products because OH and NH 2 are both activator groups, so iodine would add on the para position on the benzene ring based off OH because it is a stronger activator. The percent yield calculated was 21.5%. The low percent can be attributed to adding over 50mL of boiling Ethanol. A hot filtration was also performed, so a lot of the product was lost due to this. Due to adding to much Ethanol and utilizing a hot filtration, the percent yield achieved was low. The purity of the product is reasonably pure. The IR of the isolated product had peaks of 815cm -1 and 843cm -1, which represent the Iodine being added in the para position based off the hydroxyl group on the benzene ring. There’s also a signal of 3441.87cm -1 observed, which indicated the OH group in the product. Conclusions : It was found that the isolated product was reasonably pure. The isolated product was 2- hydroxy-5-iodobenzamide. This was concluded due to the readings from the IR spectrum. This experiment was significant because it can support the use of iodine as a reagent in electrophilic aromatic substitution in teaching laboratories rather than bromine and chlorine. There could be more studies or experiments of iodine being used to yield a certain product to support the use of iodine in teaching laboratories.

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Ciara Bell Tuesdays/Thursdays at 11AM Experimental Section: a. Reaction A reaction setup was assembled, with a dropper funnel, 250mL Erlenmeyer flask, and a metal pan. 40mL of Ethanol was transferred into the 250mL Erlenmeyer flask with a stir bar. 2g (2.015g) of Salicylamide was weighed out, added to the reaction flask, and dissolved completely in the Ethanol over 5 minutes. 2g (2.563g) of Sodium Iodide was weighed out and added to the reaction flask. The solid reagents were fully dissolved in Ethanol at room temperature and then cooled using an ice-water bath for 10 minutes. Bleach was then poured into the dropper funnel and slowly added dropwise to reaction flask. b. TLC Analysis 3-5mL of 3M HCl solution was added to a scintillation vial and diluted by adding 8-10 mL of water. 5 drops of the reaction mixture were added to the vial and then shaken. 3- 5mL of Ethyl Acetate were added to the vial, shaken again, and the layers separated. The TLC chamber was made with 5mL of Ethyl Acetate and 5mL of Hexanes. The starting material, reactant and reaction mixture, and reaction mixture work-up was spotted on the TLC plate and developed in the TLC chamber. Once the TLC plate was fully developed, the plate was looked at under a UV Lamp for analysis. c. Isolation of Crude Product The reaction mixture was acidified with 3M HCl and verified by testing the acidity with pH paper. 30mL of ice-cold water was added to the reaction flask and cooled. The precipitate formed by the reaction mixture cooling was isolated through vacuum filtration for 15 minutes. d. Recrystallization of Crude Product e. 60mL of Ethanol was added into a new 125mL Erlenmeyer flask and set to boil on a hot plate. The crude product was added to a new 125mL Erlenmeyer flask. Boiling ethanol was then added to the flask. All the solids weren't fully dissolved, so a hot filtration was performed. The solution cooled to room temperature and crystals were formed. The Erlenmeyer flask was put into an ice bath to maximize the crystal yield. The crystals where then isolated by vacuum filtration for 20 minutes. The weight of the recrystallized product and IR spectrum was recorded.

Ciara Bell Tuesdays/Thursdays at 11AM References : Eby, Eric, and Scott Deal. “A Green, Guided -Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory.” Journal of Chemical Education , vol. 85, no. 10, American Chemical Society, Oct. 2008, p. 1426. https://doi.org/10.1021/ed085p1426. Iida, Keisuke, et al. “Disulfide -Catalyzed Iodination of Electron-Rich Aromatic Comp ounds.” Journal of Organic Chemistry , vol. 84, no. 11, American Chemical Society, Apr. 2019, pp. 7411 – 17. https://doi.org/10.1021/acs.joc.9b00769.