Electrophilic Aromatic Iodination of Vanillin
Electrophilic Aromatic Iodination of Vanillin
Purpose:
The purpose of this laboratory experiment is for an aromatic compound to undergo an electrophilic substitution reaction. To carry this out, our method combines sodium iodide and common bleach as the oxidizing agent in aqueous alcohol as the solvent.
Balanced Chemical Equations:
Physical Properties:
Name of Chemical Chemical Structure Molar Mass (g/mol) BP/MP (ºC) Density (g/mL) Mass/Vol. Used Purpose
3-methoxy-4-hydroxybenzaldehye C8H8O3 152.1494 MP=81-83, BP=285 NA 0.1g Solute
Ethanol CH3CH2OH 46.0688 MP=-114.1, BP=78.3 0.789 2.0mL Solvent
Sodium Iodide NaI 149.8943 MP=661, BP=1300 3.667 0.117g Catalyst
Bleach NaOCl 74.4422 MP=NA, BP=40dec 1.209 1.1mL Oxidizing Agent
Sodium Thiosulfate Na2O3S2 158.0977 NA 1.667 1.0mL Extraction
Hydrochloric Acid HCl 36.4609 MP=-114.2, BP=-85.1 0.909 0.6mL Acid Agent
Limiting Reagent and Theoretical Yield:
(0.1g Vanillin/152g/mol) = 6.58 x 10^-4 mol Vanillin Limiting Reagent
(0.117g NaI/150g/mol) = 7.8 x 10^-4 mol NaI
Theoretical Yield:
(6.58 x 10^-4 mol Vanillin/1)(279g/mol) 0.18g product
Procedure:
In an Erlenmeyer flask (or beaker), dissolve ~ 0.1 g of 3-methoxy-4-hydroxybenzaldehyde in 2.0 mL of ethanol. Cool the flask in an ice bath for a few minutes. To the ice-cold solution, add 0.117 g of sodium iodide. Over a period of 10 minutes, add 1.1 mL of Bleach (5.25% w/w NaOCl) dropwise to the cooled flask. The solution should turn a yellow color. Once the addition is complete, let the solution warm to room temperature and stir for about 10 minutes.
Stir the solution gently, and then add ~ 1 mL of sodium thiosulfate (10% w/w). The solution will turn a cloudy, grayish yellow. Acidify the solution with 3.2 M HCl, using pH paper to check the acidity of the solution (it will take approximately 0.6 mL of added HCl). Gently evaporate any excess ethanol. (Apply gentle heat only if necessary). Cool in an ice bath for
Purpose:
The purpose of this laboratory experiment is for an aromatic compound to undergo an electrophilic substitution reaction. To carry this out, our method combines sodium iodide and common bleach as the oxidizing agent in aqueous alcohol as the solvent.
Balanced Chemical Equations:
Physical Properties:
Name of Chemical Chemical Structure Molar Mass (g/mol) BP/MP (ºC) Density (g/mL) Mass/Vol. Used Purpose
3-methoxy-4-hydroxybenzaldehye C8H8O3 152.1494 MP=81-83, BP=285 NA 0.1g Solute
Ethanol CH3CH2OH 46.0688 MP=-114.1, BP=78.3 0.789 2.0mL Solvent
Sodium Iodide NaI 149.8943 MP=661, BP=1300 3.667 0.117g Catalyst
Bleach NaOCl 74.4422 MP=NA, BP=40dec 1.209 1.1mL Oxidizing Agent
Sodium Thiosulfate Na2O3S2 158.0977 NA 1.667 1.0mL Extraction
Hydrochloric Acid HCl 36.4609 MP=-114.2, BP=-85.1 0.909 0.6mL Acid Agent
Limiting Reagent and Theoretical Yield:
(0.1g Vanillin/152g/mol) = 6.58 x 10^-4 mol Vanillin Limiting Reagent
(0.117g NaI/150g/mol) = 7.8 x 10^-4 mol NaI
Theoretical Yield:
(6.58 x 10^-4 mol Vanillin/1)(279g/mol) 0.18g product
Procedure:
In an Erlenmeyer flask (or beaker), dissolve ~ 0.1 g of 3-methoxy-4-hydroxybenzaldehyde in 2.0 mL of ethanol. Cool the flask in an ice bath for a few minutes. To the ice-cold solution, add 0.117 g of sodium iodide. Over a period of 10 minutes, add 1.1 mL of Bleach (5.25% w/w NaOCl) dropwise to the cooled flask. The solution should turn a yellow color. Once the addition is complete, let the solution warm to room temperature and stir for about 10 minutes.
Stir the solution gently, and then add ~ 1 mL of sodium thiosulfate (10% w/w). The solution will turn a cloudy, grayish yellow. Acidify the solution with 3.2 M HCl, using pH paper to check the acidity of the solution (it will take approximately 0.6 mL of added HCl). Gently evaporate any excess ethanol. (Apply gentle heat only if necessary). Cool in an ice bath for