U-M CHEM 216 - Honors Cup Synthetic Proposal

Unformatted text preview:

Honors Cup Synthetic ProposalExpected yield: Ideal: 100% yield, 7.16 g. Due to error 60% yield expected, 4.30 g.Expected yield: Ideal 100% 5.45 g. Due to error, 60% yield expected, 3.27 g.Expected yield: Ideal 100% 3.60 g. Due to error, 60% expected, 2.16 g.Honors Cup Synthetic ProposalSection: 210 .Group Members: Sarah Isquick, Aditi Sagdeo, Rebecca RungeTitle: Synthesis of Ethyl SalicylateIntroduction: Ethyl salicylate is a molecule that is naturally occurring in plants, fruits & vegetables. It is a natural preservative that is used in perfume and cosmetics and also has uses asan analgesic, antiseptic, and antipyretic. It has the odor of wintergreen/mint and is used in sweet floral, tutti frutti and spicy balsam essences. Ethyl salicylate is an ideal synthetic product because of the ease with which it can be identified due to its distinctive smell. Methyl salicylate also has a distinctive smell and the olfactory characteristics of these salicylate esters will help to reassure researchers that they are following the procedure correctly. Overall synthetic reaction scheme: OOOHmethyl salicylate2NaOHOOONaNaCH3OHH2OH2SO4OOHOHCH3CH2OHOOOHethyl salicylatesalicylic acidStep 1 Synthetic transformation 1: Experimental 1 Dissolve 16 g of NaOH in 80 mL of water. Allow the solution to cool to room temperature and add it to 8 g of methyl salicylate in a 200 mL round-bottom flask. Add two boiling chips and attach a reflux condenser with greased joints. Using a heating mantle, heat the solution slowly atfirst, then at vigorous boil for 10 to 20 minutes until the oily ester appears to be gone. Set aside one quarter of the solution for characterization. To characterize the resulting ionic intermediate of this step, distill the solution to remove excess ethanol. Prepare the sample for IR, and for H-NMR use D2O as the solvent. (Lambert & Mazzola 2004)The scale has been doubled so that there will be enough product for characterization and further steps.Expected yield: Ideal: 100% yield, 7.16 g. Due to error 60% yield expected, 4.30 g. Safety, disposal and green issues 1:Distillation will result in methanol as a byproduct. This can be disposed in the waste hood. OOOH2NaOHOOONaNamethyl salicylateCH3OHH2OStep 2Synthetic transformation 2: Experimental 2 Cool the reaction solution from experiment 1 in a ice water bath. Pour it into a 100 mL beaker and cautiously add with stirring enough 3 M sulfuric acid to make the pH of the solution about 1.This will be approximately about 5 to 6 mL. With occasional stirring, cool the mixture of liquid and precipitate in an ice water bath to about 5ºC. Collect the precipitate by vacuum filtration, rinse with ice cold water. Recrystallize the impure product from water in a 100 mL Erlenmeyer flask. Characterize the product using IR, NMR and TLC. Expected yield: Ideal 100% 5.45 g. Due to error, 60% yield expected, 3.27 g. Note: These molar amounts will not correspond to those of step 1 due to the fact that one quarter of the solution from step 1 was removed prior to beginning step 2.Safety, disposal and green issues 2:Excess methanol will be filtered out as a byproduct. This can be disposed in the waste hood. OOONaNaH2SO4OOHOHsalicylic acidStep 3 Synthetic transformation 3: Experimental 3 Using 3 g of dried salicylic acid from step 2, put the reagent in a 150 mL Erlenmeyer flask. Add 6 mL of 100% ethanol, 0.25 g boric acid and 2-3 boiling stones. Set up reaction on a heat plate and attach reflux condenser. Heat until the ethanol is boiling, and continue heating under reflux for 2 hours. After the allotted 2 hours, allow the reaction mixture to come to room temperature using an ice bath. Transfer the solution to a separatory funnel. Add 5 mL of 2 M NaOH. The bottom (organic) layer will turn milky. Separate the bottom layer into a beaker, and dry the ester with anhydrous MgSO4, roughly .1 g. Use vacuum filtration to separate remaining aqueous material. The remaining substance in the Erlenmeyer flask will be ethyl salicylate. This can be identified by its less potent wintergreen fragrance and clear/oily appearance. Characterize this compound using IR, NMR, and TLC. The scale has been halved due to the margin of error expected from Step 2. Expected yield: Ideal 100% 3.60 g. Due to error, 60% expected, 2.16 g.Safety, disposal and green issues 3:The aqueous layer will be disposed in the waste hood. The aqueous layer combined with MgSO4 will be disposed in the solid waste bucket in the waste hood. OOHOHCH3CH2OHOOOHethyl salicylatesalicylic acidOverall budget:Chemical Supplier Cost Amt. Available/ Amount per synthesisTotal/ Total per synthesisMethyl salicylate Aldrich 23.30 100 g / 8 g 23.30/ 1.86Boric acid Aldrich 12.60 100 g / 0.25 12.60/ 0.03D2O for H-NMR Aldrich 23.10 5 mL 23.10Other materials such as ethanol, sulfuric acid, sodium hydroxide, magnesium sulfate and boiling stones can be found in the lab.Total costs per synthesis: 1.89Additional cost for H-NMR solvent: 23.10References: 1. Solomon, S.; Hur, C.; Lee, A.; Smith, K. J. Chem. Educ. 1996, 73, 173-175.(Title of article: “Synthesis of Ethyl Salicylate using Household Chemicals”) 2. Kirumaki, S.R.; Nagaraju, N.; Murthy, K.V.; Narayanan, S. Applied Catalysis A: General 2002, 226, 175-182. (Title of article: “Esterification of salicylic acid over zeolites”)3. Kakkar, T.; Maersohn, M.J. Chromatogr. 1998, 718, 69-75. (Title of Article: “Simultaneous quantitative analysis of methyl salicylate, ethyl salicylate and salicylic acid from biological fluids using gas chromatography- mass spectrometry)4. Lamber, J.B.; Mazzola, E.P. Nuclear Magnetic Resonance Spectroscopy: An Introductionto Principus, Applications, and Experimental Methods. New Jersey: Pearson Education, Inc; 2004; pp 33-34.5. Pavia, D.L.; Lampman, G.M.; Kriz J.S. Jr. Introduction to Organic Laboratory Techniques: a contemporary approach. Philadelphia: Saunders; 1976; pp. 362-366.6. Luebke, William. 02 February 2005. The Good Scents Company. 18 January 2005


View Full Document

U-M CHEM 216 - Honors Cup Synthetic Proposal

Documents in this Course
Exam 2

Exam 2

12 pages

Load more
Download Honors Cup Synthetic Proposal
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Honors Cup Synthetic Proposal and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Honors Cup Synthetic Proposal 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?