The reaction was carried out by dissolving 1.01 g of vanillin in 20 ml ethanol (EtOH) in a 100 ml round bottom flask. The presence of alcohol in the reaction medium increases the selectivity and yield of the iodinated aromatic compound. 1.17 g of sodium iodide was then added to this mixture prior to cooling it in a water bath. 11 ml of aqueous sodium hypochlorite was added drop-wise using a separatory funnel while mixing the mixture for more than 10 minutes. Sodium hypochlorite was used to produce the iodinated aromatic compound with the presence of alcohol. 10 ml of sodium thiosulfate was then added to the mixture prior to the addition of HCl. The pH of the solution was checked occasionally during he addition of HCl.
The flask was left to cool down for 10 minutes and the product that precipitated was collected by vacuum filtration. The residue was washed well with ice cold water and a small amount of ethanol to ensure high yield.
The crude product was then placed in an Erlenmeyer flask and was heated upon addition of ethyl acetate. Heating dissolved the ethyl acetate. 6 ml of hot water was added gradually while heating until the mixtures became cloudy. 1ml of ethyl acetate was added to generate a clear coloured solution. The solution was left to cool down in an ice water bath for a few minute to ensure complete crystallization. The crystalline product was collected by vacuum filtration and was allowed to dry.
Data
The data for iodination is shown below
Mass, g yieldCrude product 1.70Purified product2.14
Results Discussion
The aryl iodine precipitated at the bottom of the flask. 6 ml was the total volume of HCl used to make the solution acidic. The pH was measure to have a value of 2 which is very acidic. Upon addition of HCl changed from pale yellow to reddish brown. The mass of the of the crude product collected using vacuum filtration is 1.70 grams and the mass of the purified product is 2.14 grams. The theoretical mass of the product (5-iodovanillin) is 1.85 g.
The boiling point observed was 180 oC as compared to the literature value of 183-185 o C. The actual boiling point of the solution is less than the literature value because of its water content which has lower boiling point than the product.
Atom economy is defined as the molecular weight of the desired product(s) (here 278.04 gram per mole for 5-iodovanillin) divided by that of the reactant(s) (here 152.15 gm per mol for vanillin). Therefore, in this experiment the atom economy is 182. In this experiment, 1.01 gm vanillin was used. This corresponds to 0.007 moles of vanillin. As one mole of vanillin can theoretically yield 1 mole of 5-iodovanillin therefore, in this experiment the theoretical yield of 5-iodovanillin is 0.007 mole, which is 1.85 grams. Hence theoretical yield of 5-iodovanillin is 1.85 gram.
Atom Economy (Mass of Product Sum of Mass of Reactants) 100 182
The flask was left to cool down for 10 minutes and the product that precipitated was collected by vacuum filtration. The residue was washed well with ice cold water and a small amount of ethanol to ensure high yield.
The crude product was then placed in an Erlenmeyer flask and was heated upon addition of ethyl acetate. Heating dissolved the ethyl acetate. 6 ml of hot water was added gradually while heating until the mixtures became cloudy. 1ml of ethyl acetate was added to generate a clear coloured solution. The solution was left to cool down in an ice water bath for a few minute to ensure complete crystallization. The crystalline product was collected by vacuum filtration and was allowed to dry.
Data
The data for iodination is shown below
Mass, g yieldCrude product 1.70Purified product2.14
Results Discussion
The aryl iodine precipitated at the bottom of the flask. 6 ml was the total volume of HCl used to make the solution acidic. The pH was measure to have a value of 2 which is very acidic. Upon addition of HCl changed from pale yellow to reddish brown. The mass of the of the crude product collected using vacuum filtration is 1.70 grams and the mass of the purified product is 2.14 grams. The theoretical mass of the product (5-iodovanillin) is 1.85 g.
The boiling point observed was 180 oC as compared to the literature value of 183-185 o C. The actual boiling point of the solution is less than the literature value because of its water content which has lower boiling point than the product.
Atom economy is defined as the molecular weight of the desired product(s) (here 278.04 gram per mole for 5-iodovanillin) divided by that of the reactant(s) (here 152.15 gm per mol for vanillin). Therefore, in this experiment the atom economy is 182. In this experiment, 1.01 gm vanillin was used. This corresponds to 0.007 moles of vanillin. As one mole of vanillin can theoretically yield 1 mole of 5-iodovanillin therefore, in this experiment the theoretical yield of 5-iodovanillin is 0.007 mole, which is 1.85 grams. Hence theoretical yield of 5-iodovanillin is 1.85 gram.
Atom Economy (Mass of Product Sum of Mass of Reactants) 100 182
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