Experiment 2: Extraction - Organic Chemistry Majors Laboratory I | CHEM 333, Lab Reports of Organic Chemistry

Download Experiment 2: Extraction - Organic Chemistry Majors Laboratory I | CHEM 333 and more Lab Reports Organic Chemistry in PDF only on Docsity! CHEM–333: Experiment 2: Extraction: Prelab Assignment: Read chapter 4. In this lab you will perform an extraction (Chapter 4; Experiment B). Extraction is one of the easiest purification methods in the organic chemist’s tool kit. The method exploits the different solubilities of compounds in immiscible (forms two layers) solvent mixtures. Here we will will take advantage of the observation that many organic acids are insoluble in neutral/acidic water but are soluble in basic water. Follow the protocol and make sure that you vent your funnel. Overview: This experiment involves the separation of a combination of the neutral and acidic compounds listed below; Acids Neutral p-Toluic acid benzil Benzoic acid fluorene The final identification will be by melting point. Dissolve 0.5 g of your unknown in 25 ml of MTBE and place it in a 125 ml separatory funnel. Extract the ethereal solution with 5% aqueous NaOH solution (3 x 15 ml). Combine the aqueous NaOH extractions and back-extract them with MTBE (15 ml). Combine the MTBE extracts and dry them over anhydrous Na2SO4, filter and remove the solvent on the rotary evaporator to give the neutral compound. Air dry the compound and take a melting point. If the melting point is not very sharp, recrystallize using MTBE/hexane. To obtain the acid component of the mixture, cool the combined NaOH extractions to 0 °C using an ice bath and carefully acidify with 10% HCl solution, swirling gently after each addition (NB: Check the pH using indicator paper). Pour the mixture into a 125 ml separatory funnel and extract with MTBE (3 x 15 ml). Combine the MTBE layers and dry over anhydrous Na2SO4, filter and remove the solvent on the rotary evaporator to afford the acidic component. Air dry the product and obtain a melting point as above. If the melting point is not very sharp, recrystallize using MTBE/hexane.