Set up a reflux apparatus using an air condenser, a heating mantle connected to a Variac, and a magnetic stirrer.
If the isopropanol is boiling and all solid has not dissolved, add additional isopropanol, up to.Cool the mixture to room temperature and vacuum-filter, using a Buchner funnel to collect the insoluble phenylethanamine salt of ibuprofen.Add 24 mL.25 M KOH.Regeneration of (R)-and (S)-ibuprofen: To recover a sample of (S)-ibuprofen, transfer approximately 1/3 to 1/2 of the insoluble salt from the Buchner funnel to a 50 mL beaker.Spread your manual save sample on the tile, then crack spread and scrape it with episode a metal spatula until the crytals look dry and crumbly.Cover the beaker with a watch glass and add a boiling stick.Post-lab Work, calculate the enantiomeric excess of your resolved samples, using a literature value of 57 for the specific rotation of (R)-ibuprofen.The salts saison will be separated by filtration and the enantiomers of ibuprofen will be recovered by an acid office base reaction, as indicated in episode Scheme.In this lab, ibuprofen (a carboxylic acid) will be reacted with (S)-1-phenylethanamine, as shown in Scheme 1, below, to produce two diastereomeric salts, only one office of which is water soluble.When all solid has dissolved, remove manual the solution from the hot plate and cool to room temperature in the hood.Density g/mL, solubility, ibuprofen, potassium Hydroxide break (S)-1-phenylethanamine, hydrochloric acid, isopropanol.Neutralize leftover acids and bases and flush down the drain with plenty of water.Optional: Dry the rest siebel of the sample in your tote overnight and obtain a melting point.Formation of diastereomeric salts from racemic ibuprofen.Formula, molecular Weight, moles Used, grams or mL Used, mP or.By looking at the crystals under a microscope and physically separating the crystals which looked different, Pasteur isolated and (-) manual tartaric acid season from the racemic mixture of the two, and showed that the two samples rotated plane-polarized light in opposite directions.There will be a small amount of vapor in the condenser but the reagents should not be allowed to boil.2. For your sample of (S)-ibuprofen, calculate the amount of (R)-ibuprofen present.
Dry the salt for 10 minutes on the filter with the vacuum running before proceeding to the next saison steps.
Use all ib nas4220 b manual of your sample to make a solution in absolute ethanol for polarimetry.
Add 5 HCl, with stirring, until pH paper shows that the mixture is acidic.
Wash with ice water and let dry for 15 minutes.