CHE327lecture7

CHE327lecture7 - Announcements Submit the trimyristin...

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Announcements Submit the trimyristin report that is in your lab manual. The only minor difference is that you should replace The only minor difference is that you should replace the word "phenacetin" with "benzoic acid" in question 3. Hand in your trimyristin product. Ester Purification and Analysis 1. Purify esters by distillation. 2. Analyze esters by IR and GC. Ester Synthesis R 1 C O O R 2 R 1 C O OH O R 2 + H + H O H + Carboxylic Acid Alcohol Ester + H 2 O Δ How to purify the ester? Distillation How to analyze the purity? IR – Infrared Spectroscopy GC – Gas Chromatography Purification by Distillation top of bulb level with bottom of side arm thin-walled tubing Do NOT let the thermometer touch water ou the glass wall of the distillation apparatus. clamp water out open to air water in initially should be 1/3 to 1/2 full Plug the Never distil to dryness!! FIRE HAZARD heating mental into the Variac FIRE HAZARD! Purification by Distillation If you have very little crude material, you need to get a refill from the stockroom (which also means you need to re-extract with Na 2 CO 3 ). If you did not rotovap off the ether solvent, do that before starting distillation. Start distillation on voltage setting 50v. Collect fractions based on temperature reading. Purification by Distillation top of bulb level with bottom of side arm thin-walled tubing Do NOT let the thermometer touch the glass all of water ou the glass wall of the distillation apparatus. clamp water out open to air water in initially should be 1/3 to 1/2 full Plug the Never distil to dryness!! heating mental into the Variac FIRE HAZARD!
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What do you do if you see a fire in your rbf? A Immediately tell your TA and have him/her A. Immediately tell your TA and have him/her deal with it. B. Yell “FIRE” and evacuate the lab! C. Quickly switch setups with your neighbor and blame it on him/her. D Calmly cover the flask with a watch glass or D. Calmly cover the flask with a watch glass or other glassware. E Pour the distilled ester into the rbf to put out E. Pour the distilled ester into the rbf to put out the fire. F. Run in circles, scream and shout. Purification by Distillation 1 drop per second is a good rate. Pure material has constant b.p. (minor fluctuations of ~1-3 o C are ok). Do NOT discard any of your fractions. Constant b.p. temperature is better indication
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CHE327lecture7 - Announcements Submit the trimyristin...

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