Presentation on theme: "Preparation of N,N-Diethyl-m-toluamide"— Presentation transcript:
1Preparation of N,N-Diethyl-m-toluamide The Insect Repellent “OFF”
2Reaction 1: Production of acid chloride + SOCl2+ HCl + SO2m-toluic acid thionyl m-toluoyl chloridechloride
3Reaction 2: Production of N,N-Diethyl-m-toluamide “OFF” ++HClm-Toluoyl chloride Diethylamine N,N-Diethyl-m-toluamide
4Special concerns All glassware must be dry! Be sure you are using anhydrous ether.
5safety concerns for using thionyl chloride and diethylamine Dispense thionyl chloride and diethylamine in the hood.Keep the bottles closed when not in useStopper test tubes when transferring chemicals to your hoodCool diethylamine prior to using
6Procedure Assemble apparatus in the hood Add 1.81 g m-toluic acid (3-methylbenzoic acid) into a dry RBFUse a dry graduated pipette to transfer 2.0 mL of thionyl chloride into a test tube. STOPPER THE TEST TUBE BEFORE BRINGING IT TO YOUR HOOD.Remove the rubber septum and use a Pasteur pipet to add thionyl chloride to the RBFAdd a boiling stone, reattach the rubber septum them reflux the mixture for 15 minutesRaise the apparatus from the heating mantle and let flask cool to RT
7Procedure continuedRemove septum and add 25.0 mL of anhydrous ether to the reaction flaskReattach septum and swirl mixture until it is homogeneousPut 4.5 mL of ice-cold diethylamine in a small Erlenmeyer flask with 8 mL of anhydrous etherUse a dry syringe to draw up diethylamine mixture and inject the solution into the RBF dropwise over minutes through the rubber septumSwirl mixture occasionallyOnce all the diethylamine is added swirl the mixture occasionally for 10 minutes.Remove septum and add 14 mL 10% aqueous sodium hydroxide to the reaction flask in small portions.Swirl the flask occasionally for 15 minutes
8Procedure continued: Extraction of product Disassemble glassware and transfer liquid to a separatory funnelInvert funnel for 2-3 minutesRemove and discard aqueous layerAdd another 14 mL of 10% sodium hydroxide to the funnel, shake for 2-3 minutes, remove and discard aqueous layerAdd 14 mL 10% HCl to the separatory funnel, shake, remove and discard aqueous layerAdd 14 mL water to the separatory funnel, shake, remove and discard aqueous layerTransfer ether layer to a dry Erlenmeyer flask and dry with granular anhydrous sodium sulfateDecant ether into another dry preweighed flask. Use a small amount of ether to rinse the drying agent.Evaporate etherWeight flask with product to determine yield
12Column chromatography Clamp column vertically to wall of hoodWeigh out 7.3 grams of aluminaPlace 14 mL hexane into a 125 mL Erylenmeyer flaskSwirl hexane while incrementally adding the 7.3 g aluminaStir mixture with pipette then quickly pipette or pour slurry onto the columnCollect hexane in a flaskPreweigh collection beakerDissolve product in 2 mL hexaneWhen solvent level begins to enter alumina carefully add solution of N,N-diethyl-m- toluamide and hexane with a Pasteur pipetteOnce mixture in on column add rinse product flask with 4 mL hexane and add to the column with pipetteOnce wash mixture is on column add 14 mL hexane in small portions to the column to elute the N,N-diethyl-m- toluamideCollect all the eluting liquid in the preweighed beakerEvaporate hexane using a stream of air and heatDetermine yield and obtain an FTIR
13Additional information Remove a small amount of crude product prior chromatography for a back up FTIR.Do not let column run dry!Dispose of N,N-Diethyl-m-toluamide in the container provided.